OK, so many months after the threads heavily debating the SIR, RAS II and FIRSH systems, I am here to give a small report. I participated rather heavily in the initial discussions. So did Mark (Budam). Mark believed in the FIRSH system and very generously volunteered to loan me one for the last several months to conduct a comparison. I agreed to have the test and report done within 60 days. It has been well over 90 days. I would really, REALLY like to thank Mark for his patience and cooperation. My delinquency in posting this report has never been met with nudging or prodding. He has only ever contacted me asking if he can help. This patience and trust with me is sincerely appreciated. He really has gone above and beyond what anyone might expect. I think he did it because, among other reasons, he believes in the product and because he thought AR15.com was a good place to air the results. He has done all of us a great favor, he is a supporter of this site, and has been very helpful in participating in discussions. For these and other reasons, I think he deserves our business and could easily recommend him to someone who was looking to buy a FIRSH.

A few thank you’s are in order as well. Certainly Mark from Triple Break Products. Without him, this test wouldn’t have happened. But also to Dirk_Pitt (Sam) for donating ammo and his digital thermometer and making the below posted chart. M4Real (Matt) and Burney for letting me use their full auto lowers and bolt carriers for testing. Bradford County Sporting Clays range and the Osceola Gun Range for letting us do the tests on their grounds. Rob at Gun Gallery in Jacksonville for donating ammo and installing the FIRSH. And everyone else who helped and participated in both the testing and the initial discussions which lead to the testing.

Before getting on to the actual testing and my opinions, I need to lay my own cards on the table. I post a lot here and over the months, folks have asked me for my opinions on guns or gear. I’m always glad to share what I think. However, I am not an expert on AR’s or gear. I just like ‘em a real lot! I’m not in law enforcement, and I am not in the military. I never was. I’m a fine dining waiter and have been for some time now. I’m probably much more qualified to tell you what wine goes well with Lamb, or how it’s best not to order a fillet mignon if you like to have your beef cooked more than medium. I can tell you with some degree of authority that Napa Valley Silver Oak will be much nicer than the Alexander Valley, or that Kistler Chardonay is full of butter flavor etc. etc. (impressed?). Anyway, you get the idea.

Having said that, it is 110% true that I am utterly obsessed with AR’s and gear. It is an addiction, trying to build rifles that squeeze the absolute most potential and use possible for a given need. I am blessed enough to have never had the need to depend on my rifle with my life, or to have stepped into harms way with it in my hands. However, I fully realize that the time may come when I may. I am not deluded with apocalyptic fantasies of the end of the world as we know it. Nor do I believe 10,000 scumbags are outside my door at this very moment waiting to get me. I do however see the world in which we live, and see the value in having a weapon like an AR15, and knowing how to use it. So while I may never have had the need to have a military tough rifle, that doesn’t mean I never will. And yet, I am not a soldier, so I know that I may not need everything in a military rifle, and I also know I am not bound by the specific requirements of a military rifle. I only say all of the above to fill you in on where the below opinions are coming from.

On to the report…

The FIRSH is a good system. After having used it for a few months in limited conditions, I can say it is not as bad as I might have made it out to be before using it. I can also tell you that I don’t think it is as good as others might have claimed it to be. Real helpful huh?!

First thing is installation. The SIR (and RAS II for that matter) will drop on to any flat top AR15. If you don’t have a flat top, and aren’t going to get one, you wont even need to think about getting a SIR or RAS II. However, the SIR and RAS II do not require the removal of the front sight assembly. Contrary to what you may hear, even the “M” SIR model can be easily installed to any flat top AR without special tools or without the removal of the front sight. Both SIRs and RAS II are easy drop on additions to your AR.

While the FIRSH does not require the use of a flat top, it DOES require the removal of the front sight assembly. This means two things to me right off the bat. One, it does require at least some degree of special tools and skill to install. The other is that if you have anything on the end of your barrel like a muzzle brake or a flash suppressor, you will absolutely need to remove it before installing the FIRSH. Many post ban muzzle brakes are permanently attached to their barrels. Many preban barrels shorter than 16” have flash suppressors which are pinned and welded into place. If you have a flash suppressor or muzzle brake like this, installing the FIRSH will be quite a chore and I honestly don’t think it’s worth it. It will require having a gunsmith remove your muzzle attachment, add the FIRSH, then permanently install another muzzle device. All of this will take more money and time and I believe just going with the easy on/off SIR or RAS II is the wiser choice…

However, if you have a crowned muzzle, or your flash suppressor or muzzle brake is not permanently attached, installing the FIRSH is not all that hard. SIR/RAS II is easier, but FIRSH isn’t all that difficult.

The FIRSH Mark sent me did not come with instructions. Mark does have illustrated instructions on his www site and they were helpful. I installed the FIRSH to a postban Bushmaster flat top V-match carbine with a full front sight tower, crowned muzzle and fluted barrel. It went on without difficulty. The top rail of the FIRSH lined up perfectly with the top rail of my flat top. It added to the look of the rifle over the standard Bushmaster aluminum free float tube.

I have had this V-Match for about 3 years. The Bushmaster free float tube, like the FIRSH, is made of aluminum. After shooting the standard V-match aluminum tube for a while, it had the tendency to get hot. Here in FL, the hot sun beating down on the tube has the potential to heat the tube up all its own. The FIRSH has a lot of vents, the Bushmaster tube did not. So I liked that about the FIRSH and felt it was an improvement over what I had to begin with.

You absolutely, positively need panels of some sort to go over the unused rails. The aluminum rails are not comfortable to hold onto to begin with. Add to this the fact that they absolutely, positively WILL heat up with any amount of semi-rapid to rapid extended shooting and without rails, you better at least have gloves! This is one of a few reasons I like the SIR as much as I do. If you don’t need rails, you just take them off. On the RAS II or FIRSH, if you don’t need rails you have to cover them up with panels. I really didn’t like the rubber covers that go over the rails on the FIRSH. On the RAS II, it will take a total of 3 Knights panels to cover the bottom, left and right rails. It takes 3 of the Olympic rails to cover the just one full rail on the carbine length system. If you need rails on the bottom, left and right rails, that’s 9 little rubber rails you have. The Knights panels are nicer and better in my opinion, as far as panels go anyway. However, you cant use the Knights panels on the FIRSH. They will slide on, but they will not lock into place. I would rather have 9 little panels that stay in place than one big one sliding up and down the rail. It’s a little thing I suppose, but all those panels just bug me. The rubber panels just seem kind of cheap to me when compared to the sliding/locking panels of the RAS II. Just an observation/opinion.

Another point of contention between the FIRSH and the SIR system was the ability to mount optics to the forend rails. The SIR locks itself around the barrel nut and nearly the entire upper receiver itself. The RAS II also locks around the gas tube and a portion of the upper. The FIRSH does not lock onto the upper at all. It screws on to the threads of the upper, and then a tension screw clamps it in place. Clearly the SIR and RAS II systems provide a more stable top rail than the FIRSH. While the FIRSH is not as stable, it is debatable if the FIRSH is solid enough. While I myself have not experienced a deviation from zero while mounting an optic to the FIRSH’s upper rail, I still just don’t trust it. There is nothing locking it into place. It clamps into place, but a clamp can slip. And mounting an optic to the top of the rail seems to me like adding a lever that will make it even easier to twist the whole system and kill your zero. I would not hesitate to add an optic to the upper rail of the RAS II or SIR. I would not mount one to a FIRSH.

The next really big issue was felt heat and heat dissipation. The FIRSH (and RAS II for that matter) are aluminum systems. All the systems I am talking about attach around the outside of what is likely one of the hottest portions of the gun. Aluminum conducts heat very well. Obviously this means that the aluminum hand guards will heat up rather quickly. But how quickly, and just how hot? Could you really cook an egg on it? Or was all of the heat talk just exaggerated? Again, I think the reality falls somewhere between the two extremes.

The heat test is probably the most tangible info I have to offer. We took a digital thermometer and attached it to the outside of both systems. We then took 5 mags (150 rounds) of South African battle pack ammo (M193 equivalent ) and ripped them through both systems on full auto as fast as we could load the mags in to the rifles. Then the thermometer did its job and recorded how hot they got, how long they held on to the heat, and how quickly they cooled off. A graph of the results is provided below. The FIRSH system did not get as hot as I expected it might. I doubt you could cook an egg! It did however, definitely get too hot to hold. If you touched the metal of the system at all would have burned you. I am not exactly sure, but I believe the heat from the rails sort of melted the rubber panel a little. When I removed one of the lower panels from the rail, an indentation of the rail was left. I am not entirely sure if this was due to heat, or if this happens to all the panels because of the way they attach to the rail. All I do know is that the indentations were not there before the test, and they were after.

From the readings on the thermometer, the SIR system got hotter than I thought it would. However, at no point did it get so hot that you had to put it down. It was quite warm, but not uncomfortable to touch. Both barrels shot the same amount of ammo in the same amount of time and acquired the same amount of heat. However, the SIR took that heat and dissipated it far more evenly, never allowing too much to be transferred to the shooter. The FIRSH took the heat and held on to it, allowing the shooter to feel it. And to be honest, due to an error on our part, we took the SIR reading on a hot day in October. Outside temperature was in the 80’s. We took FIRSH readings on this day as well, but lost them. We didn’t get a chance to get another reading for the FIRSH until the end of December. Temperature on that day was in the 50’s. I don’t know if this gave the FIRSH an advantage or not on the readings, but I think that it did. I believe the cooler outside temperatures made the FIRSH cool off faster than it would have on the 80 degree day. The second time around, I had several jams on full auto with the FIRSH. I attribute this pretty much entirely on my lack of maintenance on the gun. I neglected to clean it since the first time we dumped 150 rounds through it on full auto and a few more times shooting it semi-auto after that. The first time I shot the FIRSH full auto, there were no jams at all. There were no jams on the SIR either.

All I can do now is offer what we do have and apologize for its imperfection and its delay. Finally, here are my overall impressions. The SIR offers several advantages over the FIRSH. Such as; a rock solid top rail capable of mounting optics without the worry of losing zero. Better heat dissipation and less felt heat during rapid and/or extended firing. Easier installation. Removable rails, eliminating the need for panels. Easier to maintain and clean the outside of the barrel. For these reasons (and a few others), I think the SIR is a better system. It is also 4 times the cost of the FIRSH. Having said that, these advantages may be wasted on some folks who do not necessarily want or need them. If all you want is a free float system and rails, and you are not really trying to build a tough as nails fighting rifle, the FIRSH will certainly accomplish this. And you can do it for about $130 or so (including the price of the panels). If you do want a rock solid system capable of hard use and, indeed, abuse, I don’t think the FIRSH will cut the mustard. If you want that type of system, you are going to have to pay for it, and there is nothing out there that can compete with the SIR or RAS II.

Because of this I find it hard to compare the two. I just can’t bring myself to expect the $100 FIRSH to do the same things as well as the $400 SIR (or $375 RAS II). Realistically, I think it would be foolish to do so. I honestly don’t think it was designed to. It is comparable on some levels; they both free float the barrel, they both offer rails on the hand guards, but on that’s about all. When it comes down to it, the SIR will outperform and outlast a system like the FIRSH. And you know what, for an extra $300 it darn well should! In the end, my impression of the FIRSH hasn’t changed much since the first discussions took place. Again, it isn’t as bad as I thought it would be before using it, but the concerns I did have were confirmed upon testing.

I hope I haven’t bored you all to tears, and that there is at least some usable info here for folks. I sort of get the feeling that there really isn’t any new or valuable information here, and that all of this is just rehashing what we all went through some months back. I do know Kevin (Canadian_Tactical) is doing some testing of the systems as well. I look forward to seeing his impressions. Here are some pictures for your viewing pleasure…

[img]http://www.imagestation.com/picture/sraid46/p178af2be4c984459f15aac50305a730d/fccae3ab.jpg[/img]

[img]http://www.imagestation.com/picture/sraid46/p4591efb8648ca4b812e21bf4580defe5/fccae3a8.jpg[/img]

[img]http://www.imagestation.com/picture/sraid46/p1e9005e0985c04e95c657500a945ce7f/fccae3a4.jpg[/img]

[img]http://www.imagestation.com/picture/sraid46/p8e7c75de7f686fb3ea61d9a2fc6e67c1/fccae3a5.jpg[/img]

The thermometer rigged to the SIR
[img]http://www.imagestation.com/picture/sraid46/p649b8aa92fda8d649b932b227885c9c6/fccaf71d.jpg[/img]

10 mags, 2 uppers, Dirk_Pitt and M4Real getting ready for the test
[img]http://www.imagestation.com/picture/sraid46/pda48c6a54539dee3d632545cca467359/fccaf725.jpg[/img]

See the top of the inside of this panel, I don’t know if it was the heat that caused the indents of the rails or not?
[img]http://www.imagestation.com/picture/sraid46/pc845b9e28ed9a9aa48220c85eb17873a/fccaf722.jpg[/img]

M4Real shoots the SIR system
[img]http://www.imagestation.com/picture/sraid46/pd5d58f2abe1d4a7171515017080a4e96/fccaf717.jpg[/img]

Full auto just keeps going
[img]http://www.imagestation.com/picture/sraid46/p6a672748e1e49bb9ac39cfe62d4f0780/fccaf70a.jpg[/img]

and going…
[img]http://www.imagestation.com/picture/sraid46/pb6ec0387a596ddfaccd3f832e1d79036/fccaf6fe.jpg[/img]

I am shooting the FIRSH, Dirk_Pitt is holding the thermometer, Fulda is handing me the mags, and everyone else is just along for the ride!
[img]http://www.imagestation.com/picture/sraid46/p27a44cd16dade3116923e09834e81080/fccaeeae.jpg[/img]

Feeding another mag into the FIRSH
[img]http://www.imagestation.com/picture/sraid46/pc90678184351cf764ae738dfbab64043/fccaeea5.jpg[/img]

Still going…
[img]http://www.imagestation.com/picture/sraid46/p59982e359fa03df0d7d1c3303847738e/fccaeea0.jpg[/img]

and going…
[img]http://www.imagestation.com/picture/sraid46/p79a8cb6d909f67030cd0ef33989b5fcf/fccaee9d.jpg[/img]

and going!
[img]http://www.imagestation.com/picture/sraid46/pe64495a2c7ef33c09520c49d2f1cb767/fccaee93.jpg[/img]

Now I have to go buy a SIR.[:(]

Outstanding report, my brother.  

Great report Neil. Thanks for inviting me to participate. Man that was fun running through all those mags in full auto.
-->M4Real<--

Absolute first rate report and objectivity.
Now an important technical "at work" question, how do you rate Berringer's Knight's Valley?
ColdBlue sends...

Interesting report. In a backhanded way, it's got me harder over than ever on the FIRSH.

a) Installation is not an issue for me. I can see where it might be an issue for an organization that must maintain a great many weapons, though. Even if you've got to pay someone to do it, that still puts you hundreds of dollars ahead.

b) It should never get as hot as you got it. I can't think of any likely civilian/police scenario where 150 rds would be expended as fast as they can be loaded. I'm hard pressed to think of a military scenario either. BTW, was it the temperature of the covers you measured, or the temperature of the metal rails? I'm touching the vertical grip, and maybe the covers, not the rails.

c) The FIRSH mounting provisions don't concern me at all. Has your Bushy free float tube ever moved? Mine hasn't. You haven't "levered" your front sight tower over either, right? All that's holding either one of them is the barrel nut torque (your Bushy tube *is* the barrel nut, BTW). The clamp system on the FIRSH is stronger than the barrel nut. The nut will move first, and it's not moving anywhere. If you are super-paranoid, lock it to the receiver with any one of a dozen accessory/riser rails. Then it will be just like the RAS-II, except hundreds of dollars less expensive.

d) That the KAC panels don't lock is a little annoying, but that's all. The rubber Oly panels are a little cheesy. Anyone have a better solution, or know how to mod' the KAC panels?

There's good, and then there's good enough. When the time comes, I'll save the $300 and go with the FIRSH.

I had Kurt over in the Industry section modify mine for RAS railcovers on his free floated handguard system. What has to be done is the rails need to be notched on each side to allow the clips to snap in place when you slide the covers on.

Great review on the three systems. Having the forend torqued is a valid concern on the FIRSH system. That's why I would hesistate to mount any side sling system on the side rails of the FIRSH system. Still..I believe there is a solution to the "Problem" to make it just as stable as the RASII. You stated above that the rails of the FIRSH are in line with your flatop rails. One could easily mount a modified riser to the flatop and the FIRSH, locking them both solidly togetether.
[img]http://bushmaster.com/shopping/scopes/Images/yhm-226.jpg[/img]

These are Bushmaster Mini Risers on their website. Stick something like that, or something perhaps a tad bit longer to lock them together. Notch your FIRSH rails to accept RAS panels and VIOLA! Poor mans RASII.

The SIR definitely wins in the "neato" department. For Military guys dumping a few mags quickly is entirely possible. Your SAW/M60 guy is down and no one can get to him. Some one needs to take up his slot, so everyone pitches you an extra mag. Now you are glad you have a SIR.

With a Civilian or police you won't be shooting that many rounds unless you are a stand-in for a new Rambo movie. It just won't happen. Even if you have a full auto, no one wants to burn up barrels. Those things are expensive!

I finally got to see the FIRSH up close at the Pensacola Gunshow. Looks very nice. Especially for the price.

I'll have to come up and shoot with you guys someday. I'm in Panama City, but I plan on going to one of the Lakeland shows in the summer. I heard they were really good.

Good Shooting
RED

Sheesh, all that hoopla and I neglected to post the graph showing the heat. Sorry! And I wont disagree with most of you FIRSH fans. You could probably attatch something like an ARMS #38S-ex L model rail and it would do wonders to lock the FIRSH into place and support the system. Some folks are doing the same thing to the standard RAS/RIS systems and at that point I wouldnt hesitate to mount an optic to the top rail. This still will not make the FIRSH just like a RAS II or SIR. SIR still offers better cooling, SIR and RAS II are still easier to instal/remove, SIR and RAS II still allow for easier barrel cleaning and maintenence, SIR still offers the conveinience of not needing pannels and the RAS II pannels still work much better. In addition at that point, you've spent the money on the FIRSH, pannels and ARMS rail. Your cost would be MUCH closer to the SIR or RAS II, and to me, I would just go the extra mile and pay for the other advantages of the SIR, or RAS II. But thats just me.

If saving money is more of a concern for you than building the absolute best system you can, I could easily recommend the FIRSH. But if you are a sick bastard like me who would put himself in the poor house in order to have the very best equipment on his rifle(s), and you want every last advantage you could possibly get, the SIR and RAS II are going to be HARD to beat. I really do look forward to companies trying to do so!

Just dont ask me which I like better between the RAS II and SIR. Thats a little like splitting hairs to me!!! For what its worth, I do like the SIR a little better than the RAS II, but someone with different tastes or priorities might be better suited with the RAS II. Both are at the absolute top of the field.

Here's the heat graph...
[img]http://www.imagestation.com/picture/sraid46/p24e64d1d594cb7632dcb537c46f83af6/fccaf729.jpg[/img]

Neil - excellent write up.

Neil,

Who are the Babes? [:D]

Dirk

Good job Neil.

One of the best and most informative posts that I've seen.  I have a SIR on my patrol rifle at work and I'm very happy with it.  Thanks for the work you put into this.

Posted by aa777888-2...



aa777888-2, you might want to check out [url=www.ar15.com/forums/topic.html?b=7&f=22&t=150862&w=searchPop]Darkparts Rail Covers[/url]

A couple other interesting notes worthy of mention that I was reminded of after posting this... Not completely related to the SIR/FIRSH/RAS II, but related none the less.

Someone mentioned burning out barrels. I must admit I was rather afriad of this myself. This is the same gun/barrel that was used when I shot the sub-moa groups at 300 yards one time. [url=http://www.ar15.com/forums/topic.html?b=3&f=118&t=142144&w=searchPop]Someone said I was full of crap[/url]. After that first time, I put this gun through a full auto test of sorts. So, by the time I got around to trying to shoot for groups out at 300 yards again, I had already shot this barrel full auto quite a bit on one occasion. The day I tried to shoot for groups was the same day I did the SIR test. Soooo, in addition to shooting the barrel full auto on this one occasion, we did the 150 round dump. Thats two full auto tests on the same barrel. *AFTER* two somewhat extended full auto runs on this barrel, I was able to consistently shoot sub-moa at 300 yards. I dont know how much or how frequently shooting full auto will kill a barrel, but thankfully, mine is still in fine shape.

Also related is the Vortex flash suppressor. On the first full auto testing I did, the forks of the older style Vortex flash suppressor mushroomed out. I was pretty upset. Smith Enterprises did however make good on their product, and replaced the old one with their new one. The new one was on the gun for the 150 round full auto dump of the SIR test. The thing is solid and shows no sign of mushrooming or problems of any sort. The new Vortex is a beast!

Just a couple of related things I observed while conducting the tests. I believe they were worthy of mention.

Thank you for doing the testing.

I hope my comments about the FIRSH weren't (too)over the top. I realize it is not the full mil-spec, all the bells and whistles, the military uses it, set up that some people swear by.

My point was that the top of the line systems, with their top of the line prices, may not be as cost effective as the FIRSH for a "light" or "normal" use rifle.

OLY has a system that doesn't offer some of the things that those other systems do, M-203 interface (when I get an M-203 I worry about THAT), etc. that most users may not ever benefit from. OLY's system also costs 1/4 what those other systems do.

Sorry if it seemed that I was trying to work anyone up, except for that one guy who comes up with scenarios like: "say you are underwater, deep underwater, and it starts raining ball peen hammers and anvils, that FIRSH won't stand up to that, and it could happen". [bounce]

Redleg,
Just what is involved with notching the rails?  Can you post a pic, or let us know what Kurt used to make the modification.

Thanks

There's an ad in the new Shotgun News about the FIRSH. It states that the FIRSH is currently in use by the US Special Forces. Any truth to that? I wasn't aware that it had been issued or tested since it wasn't "mil spec"

Not positive, but I thought that the Knights RAS or RIS was being used by the Special Forces.

Nice write up.  But you left out one of the rail systems I've been looking at, the Daniel Defense System.  I guess you'll have to do it all again.[:)]

aaa777888-2:

I have the FIRSH system on my patrol rifle and I have to say that I swear by it. I have used my rifle from SWAT callouts to occasionally putting deer down and it performs its job very well.
As for forarm panels, I agree that the Olympic covers are cheesy. What I did was go to AirsoftExtreme.com and bought a 3 pack of rail covers. They look just like the knights covers (as a matter of fact they are stamped with "Knights Armament" and "Vero Beach FL" on them), cost $20 for 3 full length covers (as opposed to $20 each) and they fit without modification to the FIRSH. They are so cheap and work so well I didnt feel guilty about cutting 1 of them down a few ribs to fit properly.
These things are made for Airsoft air rifles and they fit and function great on my duty rifle and I'm glad I found them.

medicmandan, man, I havent even seen a picture of the Daniel Defense system! Wes talks about it now and again, but I have looked on their wwww site and coundt find a thing! No photo's, no prices, no nothing. I wish someone, anyone, would post a picture or report about that system. I'd really like to see it. If I like it, I may just have to build ANOTHER rifle so I can check it out first hand. Maybe put a Trijicon Tripower on it whenever the heck that thing comes out.

Lancelot, couldnt say for sure, but I seriously doubt the FIRSH is seeing any use in military operation. I read somewhere that someone said Spec Ops guys were using it or something. When I dug a little further, all it meant was that some Spec Op guy had one on his personal rifle at home. Sheesh!

[url]http://www.danieldefense.com/[/url]

Thanks for the tips on the rail covers. You gotta love those airsoft guys...

I'd like to see another test done with some additional considerations to expand on what has already been shown.
Since the FIRSH is all alum with alum. dovetail rails that have to be covered to protect the hands, and the RAS2 was mentioned, but not included in the test, it is not objective to say the RAS2 is cooler if it wasn't in the test. The point being that since alum. gets very hot and needs to radiate to be cooled and panels go over it that actualy seriously retards the needed cooling, the RAS2 should not be conpaired to the SIR. The observation that marks were left on the plastic notch type rail protectors indicates how hot the alum. rails realy get, and those type covers only cover half of the rail, and all of the rail is covered by the KAC covers. That meanes one thing, the KAC rails and weapons their on get much hotter faster since rail radiation is slowed twice as much via use of KAC covers. Now compare the fact that the KAC covers also cover up most of the vent holes compaired to next to nothing covered by the notched type on the rails of the FIRSH in the test.Since both the Firsh and RAS2 have Alum. lowers, there is no reason to think the RAS2 is any better at cooling than the Firsh, in fact the RAS2 gets hotter faster than the FIRSH if you cover the rails with the KAC panels. Over heated weapons do not have as long a life as weapons kept cool, just as overheated car engines start to wear out faster, and cause more malfunctions. The 30 degree air temperture dif. has a huge affect on the cooling of any weapon comparison in any heat test.
The standard issued for years plastic M16 handguards do not get hot like alum. not even close, but if heavy alum. rails are placed touching the standard issue hand guards like under those spanel covers. The plastic eventualy gets so hot you can't hold the weapon in full auto fire, plus the melted plastic marks are much more previlent and severe under the KAC plastic panels. The tests heat graph is nice, but I would like to know where the thermometer was placed for each weapon, and as I understand it, they were from two dif. days with a 30 degree dif. in air temp, with the SIR much lower in temp. than the SIR, even tho the SIR was measured on the hottest day.
The airsoft copies of the KAC panels look nice but they are not made of the same heat resistant material and will end up melting on a real gun in full and semi auto.
Keep up the good work and I hope my observations are helpfull.
Good Shootin, Jack      

Sorry, The botom lines lines with obsevation about the SIR being cooler in the test than the SIR, should read cooler than the FIRSH.
Jack

I put the knights panels on my FIRSH and the lock in fine...you just have to "pull up" on the metal locking strip that allows you to take the panels on and off the rail. Mine are locked on tight. Hope this works for you guys.

3rdtk, thanks for adding your thoughts. I'd like to see the test done on the RAS II as well. I only just received the RAS II quite recently and was unable to include it in the actual heat testing. I may be able to do the same test on it at the end of this month, and I suppose that will include some info worth seeing, but who knows what the outside temps will be. The day we did the initial test, we just didnt know the readings for the FIRSH were lost until all of us were home. I knew the significantly cooler outside temp was going to let the FIRSH cool faster than if we got the FIRSH readings on the same mid 80 degree day we took the SIR test.

I had not thought about how guns which cool better have a longer service life. I'm glad you mention it. For those of us who are looking for hard use gear to go on guns that will be able to withstand hard use, its yet another advantage for the SIR. An important one IMO.

I agree that I can't say how the RAS II would rate in the cooling test. Which is why if you will notice, I did not mention it at all in the heat/cooling test portion of the report. Like I said, I hope to get a chance to run the same test on the RAS II at the end of the month. Maybe then I will be able to ad the RAS II to the graph and report what I notice. Even then I realize I have a rather untrained eye, and that the different outside temps wont give a true comparison.

You are the second person to ask where the thermometer was placed. The thermometer was placed in the same position on the FIRSH as it was on the SIR. You can see where the wire is on the SIR in one of the above pictures. I decided to put the thermometer on the lower portion of the outside of the handguard where the shooter would feel it.

Again folks, I do apologize for the imperfections of my testing. I do hope some useful information is still able to be extracted from these observations.

I agree with you 3rdtk about having another test and definetely wouldnt seeing one done. As for the handgaurd panels, I agree that I probably wouldnt want to put them on a full auto weapon because of the risk of meltdown. However, they feel quite sturdy and I have put many  thousands of rounds through mine already, sometimes quite quickly and havent had the first problem. Now, If I choose to just go ripping through magazine after magazine and they do show a sign of melting, well then I deserve it and wouldnt mind spending another $20 for a 3 pack.
The bottom line being that I think they are a good option for those that 1. Dont own a full auto rifle 2. are on a limited budget (I'll take $20 over $60 for rail covers any day) and 3. dont want to mess around or risk messing up the real panels just to get them to fit.
I'll keep it posted you posted if something ever happens to them, but as of now, they are still A-OK. I hope this doesnt turn into a thread similar to the FIRSH vs RAS basically that the $20 panels CANT be that good because they are so cheap. Just my .02 and I'd still recomend them.....

.223 SHooter,

Sorry I don't have a better pic, but my 9mm upper is back at Kurts having an A3 Tac Brake installed.

If you look at this pic you can see the approximate width of the clip that secures the covers. I got them on fine but had to post a question on getting them off easy...duh..[:d] That is the width that your notch will have to be. The clip is also flat endeed, so if you have a circular cut notch you either have to make it a bit wider or round the corners of the clip. I decided to round the corners.

If you look on the left side if the pic you can see the notch on the lower rail. I chose to put mine on with the clip away from the weapon so I wouldn't have to trim the panel, but Kurt cut them on both sides. Unfortunately only the 11 rib come in green.

[img]http://www.imagestation.com/picture/sraid47/p99be7b5ef3edc6dc8aae61445f3bc937/fcc71048.jpg[/img]

You could do the job yourself with a dremel if you go very slow or with the end of a file. I hesitate to dremel or file anything the WESCOG way on my weapons, so I just had Kurt do them when he made my HGs.
Hope this helps some.

Good SHooting
RED

Your apology is totally unnecessary.

The fact is you've done more than I, and 99% of us on this board, has done.

Nothing's stopping anyone on this board from getting off their A*S and running their own damn test.

I appreciate your effort and the information provided.


Chris

... Oh man! What a cool report. THIS is the AR15.com I fell in love with!

new-arguy,
Just a few questions.
When the SIR is mounted on the upper is there any play or looseness in the civilian version,does it positivly lock in place?
How does one install either the military or the civilian version?
             Thanks

I know I'm not the one you're asking the question to, but I have the SIR-C and I can answer your questions concerning it.



The SIR-C attaches to the rail of the upper receiver, and has a yoke that further attaches the SIR upper assembly to the barrel nut.

There is no play or looseness, and it's positively locked into place.



My SIR-C came with color illustrated instructions.  Basically, you remove your handguards; attach your backup sight, either a #40 or KAC 300m; attach the SIR upper assembly to your upper, blue loctiting the screws; attach the yoke under the delta ring and around the barrel nut; slide and lock the lower polymer portion on, completing installation.


Chris

I needed to take some aspirins and a nap after reading 3rdtrk's post. There was a lot to think about jammed in that post.

Keeping the weapon cool extends the barrel life, and allows for more rounds to be fired in a given time before the weapon gets overheated.

I think anything, including no handguards, cools better than the original handguards, esp. M-4 (no airflow) hanguards.

I kinda suspected the FIRSH would heat quicker. I guess I hadn't considered the RAS systems. The question I have is the FIRSH taking in radiated heat from the barrel, or since it is attached via the barrel nut acting as a heat sink, and taking HEAT that would have otherwise gone to the barrel. IE, what are the BARREL temps comparitively with the different hanguard systems.

3rdtrk, and others, I guess some have suggeested not putting panels on the top rail. You don't neeed to grab the weapon there, and heat rises, so that area should be as open as possible to allow best cooling. (i can't remember where that advise came from). I don't know what effect that would truly have on heating/cooling of that rail.

Someone asked a couple of intersting questions off list. I thought they were good questions and I think they are relevant.

I was asked if I installed the handguard cap on the FIRSH. The handguard cap is sometimes left on these free float systems to act as a bruch guard of sorts. Keeping it on will keep crap out of there, and thats a plus, but it will restrict air flow and retard cooling. Thats a minus.

Stangely enough, on the FIRSH, I did not install the handguard cap. I put the FIRSH on a V-Match carbine that never had one to begin with. However, interstingly enough, the SIR gun does have the handguard cap on.

So, the SIR stayed cooler, longer, on a day when the temp was sbout 30 degrees hotter, and with the handguard cap restricting air flow and cooling. Interesting...

One last thing for now, I do not have pannels on the top of the RAS II or FIRSH for the exact reasons Oly mentions. There were no pannels on the top of the FIRSH for the testing.

I have AIRSOFT AND KAC original pannels and I wouldn't use the Airsoft pannels on any real rifle.  (they are plastic and probably not a heat resistant variety) < these pannels will probably melt when the going gets tough.

I have also cut down KAC pannels and I didn't feel guilty at all (round the edges with a dremel and they'ld fool anyone)< this is a great way to save yourself Big $$$ on the proper sized pannels and still cover all availible Rails with ascessories mounted.

[b]b) It should never get as hot as you got it. I can't think of any likely civilian/police scenario where 150 rds would be expended as fast as they can be loaded. I'm hard pressed to think of a military scenario either. BTW, was it the temperature of the covers you measured, or the temperature of the metal rails? I'm touching the vertical grip, and maybe the covers, not the rails.[/b]

I know many people who fought in Vietnam (6 who did 2 or more tours) and all of them said that it was normal to burn through 400rounds in a firefight, so I wouldn't be too hardpressed to think of a 150+ round engagement. On the contrary I'ld be hard pressed to think of a military engagement that doesn't call for 150 rounds (most military personell will use 3 mags clearing a small house)< the idea is that the military doesn't have the same constraint or worry of civilian casualties in war as the police officer in the USA.  If the enemy is in a building- odds are everyone inside is enemy.

new_arguy, you have the M model, correct?

How easy is it to get to the barrel for cleaning (mainly I just add a light coat of CLP here for preventative maintenance) with just the polymer lower removed?

How easy is it to remove the polymer lower?

Concerning the weight on the SIR-M, how much of that weight is out in front of the barrel nut in your estimation?

Last, is there any chance I could get you to compare the diameter of handguard portion of the RAS-II with panels and the SIR-M (the part where you would grasp it if not using a vert grip)

I'm looking at rail systems and I like the RAS system better just because it is more similar to what I am used to; but I need a solid unbroken rail across the top and I'd like to be able to access the barrel for cleaning without having to make a major production out of it as well as having the barrel free-floated.

The cleaning issue seems to eliminate my first choice (FF-RAS) and the hump on RAS-II eliminates it from consideration. I am trying to decide whether SIR-M offers enough of an advantage in these areas to move to it.

I am a bit confused by a few of the statements presented by several people here.

1.  FF RAS and FIRSH make it hard to clean the barrel.

I just dont see how this is.  You just clean it from the barrel end with a long toothbrush coated in CLP.  Its a bit harder to reach the very rear of the barrel next to the reciever but you also dont have to remove anything so it takes the same time either way.  The holes in a FF RAS allow you to stick in Q tips from anywhere if you are ultra anal.  Does the FIRSH allow this also?  If it does its a non issue.  The only REAL issue with a non removable bottom is you cant mount an M203 which none of us is likely to do anyway.

2.  The heat factor vs barrel life.  

The way I see it the more the handguard acts as a heat sink the better.  If its hotter the barrel is cooler.  I can see how comfort of grip is important since you must hold on to the grip but I dont believe it has an issue with barrel life.  The FF RAS acts as a heat sink better than any other handguard because of its special barrel nut.  It will get hotter too and help preserve barrel life.

3.  RAS/RIS FIRSH no good for optics.  

The military is using the RIS/RAS system for mounting lasers right now.  Are they having issues with those losing zero?  I am not aware of any reports stating that. The lasers should lose zero exactly as much as any other aiming devise including an optic.

4.  Cost of installation.

Perhaps it will cost more for someone to have a gunsmith mount a FF RAS or FIRSH but those two PLUS installation are less expensive than either the RAS II or SIR.  Kurt swaps muzzle brakes all the time.  That means its not an at home project but the cost of getting a new KKF A3 brake installed in place of an AK or other brake AND mounting a FIRSH is still less money than doing an at home mounting of the RAS II.  The issue is one of convenience not cost.

I am getting A2TB installed on my 20" HBAR( O wait, it'll be GOv profile when kurt is done [8D]) and having Kurt install Firsh.

Cost of Firsh install by Kurt is, get ready everyone, $20. Hardly a dent in the pocket.

Thanks for this review, BTW.
Thanks to the fellow who provided the handguard also.

I hope you are true because I'm planning to get one in the future and mount an Aimpoint and top of it, in front of detachable carryhandle. Although I like ARMS #40 with Aimpoint, I want this setup (Aimpoint / ARMS #40) to be rather more-permanent-ish. My ARMS #40 will be going on top of another upper with TA31.

The Sir is very easy to get at to clean, inspect, install grenage launcher, etc., as the lower half attaches via the metal track of the upper metal frame located along the aprox. center of the barrel length.
One of the other things that ARMS did was to consider how heat radiates from something round like a gun barrel, and they took advantage of it. Not only did they figure out heat radiation, they tested several things and it was discovered that the heat on the barrel was equell all around dpo to the fact that since the bullet was spinning the friction which couses the heat also caused the heat to have motion on the outside of the barrel. Since the radiant heat had motion, the experimented to see how to best expell the heat in a faster way than other old type round tbpe shape hand guards. They actually ended up with a type of vortex design that works to rapidly expell heat via the shape of the SIR.
These are some of the several reasons that the SIR works so well compaired to all others. It's one of the many things ARMS does that others end up trying to emulate sooner or latter, usually years latter. They have had one hellava R&R team there for many years.
Keep up the good work is all that I can say.
Good Shootin, Jack

Yes, I have the M model, but I have also installed the C model on a gun. 3rdtk is, of course, completely correct about removing the lower portion of the SIR. There are two captivated type screws towards the rear of the SIR. They lock and unlock the synthetic lower half of the SIR to the aluminum upper half. In addition to these two screws, there are screws that attatch to the optional side rails. The rearward most two screws are not really threaded per-say. You give them about a half twist with something as simple as a coin, and they pop up (they do not pop-out of the system, they are locked on to the lower half so you cant lose them... very cool feature!). Once you pop these two "screws" up, loosen any of the side rail screws you may be using, they loosen with a coin as well and are also locked onto the rail so you dont loose them. Once you have these popped-up, slide the lower half forward and it comes right off. VERY simple.

In fact, taking the upper half off is almost as easy. There are 3 cross screws that hold the upper rail to your flat top, unscrew these. There are two small screws on either side of the yolk that clamps around the barrel nut. Remove these as well (these smaller screws are also attatched to the yolk and can not be lost!) and the whole upper half comes off the SIR. At this point, your complete barrel and gas tube are exposed for cleaning, maintinence, or whatever. I have to tell you all, it really couldnt be much simpler.

Real quick... I was joking with a friend of mine today at how mechanically inept I am. Folks, I dont even own a hammer. As much as it pains me to admit, I use a 2.5 lb weight for a hammer. My tool box is a little rubbermaid sqare container with a few screwdrivers, a rusty pair of pliers, a cheap wratchet set... you get the idea. All I am trying to tell you is that if I say it is easy... belive me, it is easy. A monkey could install the SIR M, a half retarded monkey could install the C.

The SIR adds some weight, but really, it doenst ad a real lot. What it does ad may be slightly towards the front. From my poijt of view, what weighs the front of my SIR gun is the Surefire M900, not the SIR.

As for the diameter of the systems, I will give you a very crude measurement I took with my cheap metal tape measure. Had to dig it out of the rubbermaid container! This is not a specific measurement, it is a total guesstimate and I am sure they are approximations. But, you will get the general idea. All measurements were taken at the rearward most part of the handguard.

Standard CAR handguards: 7 1/4" around
Colt M4 handguards: 8 1/4" around
RAS II (w/ 3 pannels): 8 1/4" around
SIR: 9" around
FIRSH (w/ pannels on bottom, left anr right) 8 1/2"

If you are looking to get a system like the RAS II or SIR, but would rather keep a more traditional look, the RAS II will barely change the look or feel of your rifle at all. When you have it on with the pannels, its very close to the same look and feel of M4 handguards. I did a comparioson between the RAS II and SIR a few weeks ago. Check it out if you like;

[url=http://www.ar15.com/forums/topic.html?b=3&f=18&t=146385]RAS II / SIR[/url]

Dev, you can clean the FIRSH like you mentioned, but cleaning and maintenence on the SIR and is sooooo much easier. After I ripped the 150 rounds through the guns on F/A, I really wanted to get in there and clean off the gas tube etc. I just couldnt really do it on the FIRSH. The SIR was a snap.

I'm 100% clueless when it comes to laser, but I am pretty sure I read that there is actually a lot of problems with the PEQ's losing zero. From what I read, I am pretty sure it was more due to the mount on the PEQ, but like I said, I know waaaaay to little about those to be trying to make comments. So I'll stop.

Miller, the worth of something is very relevant. I love Kurt, anytime I want anything done to my AR that I wont do myself, I have him do it. But he is a very busy custom gunsmith. His prices are VERY reasonable and his work is top notch. However, removing a permanent muzzle attatchment, adding the firsh, buying and installing a new muzzle attatchment, shipping to and from his shop, and the time it will be away from you are all factors I take into consideration. All of the above is going to cost someone more than $20 and will likey take minimum 6 weeks, vs. say, ordering an RAS II or SIR from Wes at MSTN, getting it in 3 days, and putting it on in 15 minutes. Like I said, value is very relative.

I'm sorry if I am being so long winded.

I measured where the hands go and the width of the SIR is the same as the RIS with the panels on.
Good shootin, Jack

I cant see how that is possible. Again, I admit I am using a regular tape measure and agree that this is hardly the most accurate way to get a measurement, but the SIR is the same diameter from the rear of the system to the front as far as I can tell. I am wrapping the tape measure all the way around the whole system. It reads just slightly less than 9" all the way around. The RAS II with three panels installed (left, right and bottom) is about 8 1/4".

Now, some of the circumference of the SIR is going to come from the raised top rail. And some of the loss in circumference on the RAS II is because the top rail is lowered and I do not have a panel on the top rail. So, even though the SIR is definitely larger all the way around as far as I can tell, this doesn't mean the lower half, (the part you are holding and would notice a difference) is going to be that much fatter.

With that in mind, I just tried to measure from one side of the lower portion to the other on the SIR, RAS II and M4 handguards.

Standard CAR handguards are roughly 3 1/2" side to side
M4 handgaurds are roughly 4" side to side
RAS II is roughly 4 1/2" side to side
SIR is roughly just under 5" side to side
FIRSH is roughly 5 1/4" (!) side to side

Having just done all of these measurement, I have to tell you how trivial I personally think this information is. I think so much of the other info posted about these systems prior to this is far more valuable and pertinent than this... YMMV.

How does the SIR system differ from a FIRSH and a swan sleeve (8")?

Your going by radious and I am going by width.  Obviously none of the handguards can be as wide as the radious of 7-8", you coudn't hold the weapon if it was that wide.
Hope this helps.
Good Shootin, Jack

banthony, I answered that question earlier in the thread back on the first page. All a FIRSH + ARMS rail will do is lock the rails into place. It wont do anything to help coolt the FIRSH, make it easier to clean, improve the pannels it uses and other things. Plus after buying the FIRSH, panels and swansleeve, your cost is much closer to a SIR or RAS II.

3rdtk, thank you, I knew there was a simple answer to that! And you are exactly right... Without wrapping the tape measure around the system and just measuring from one side to the next, the measurements are as follow (again, using my rediculously crude tape measure method... sorry!)

CAR Handgaurds; 2.2"
M4 Handguards; 2 1/4"
RAS II; 2 3/4"
SIR; 2 3/4"
FIRSH 3.2"

If handguards are getting hot does not mean the barrel is getting cool because of heat sink, it means the barrel is generating the heat that is making the handguards get hot. The heat from the barrel is transfered the the handguards via two prevelent means. One is radiant heat and the second most problimatic is the conductive heat via direct barrel contact such as a RIS/RAS devices do. Yes, heat realy screws up the lasers, big time, and I don't need to go into all the other problems it causes as those have been well covered previously.
The RIS/RAS has been in service for a few years now and the SIR has been the follow on and is also now in limited service performing as advertised to correct previous ills of other rails. There is a famous quote from a US Army Col. Chin. "THE US ARMY IS ALWAYS READY TO BUILD YESTERDAYS TECHNOLOGY TOMORROW".(Published in his volume of books for the Dept. of the Navy on machine guns) It takes years to get a system in and just as many to get it out. However the Special Operation units are not hampered to anywhere the extent the Reg. Army is, thank God, but even they can't just standardize without reams of paperwork. There is a lot of high tech equipment that must be able to do it's job on a stable versitile platform and that the SIR does better than any other I know of.
Good Shootin, Jack

EDITED FOR BREVITY.

[>:/] I say again [>:/]

[red]If handguards are getting hot does not mean the barrel is getting cool because of heat sink, it means the barrel is generating the heat that is making the handguards get hot.

the second most problimatic is the conductive heat via direct barrel contact such as a RIS/RAS devices do. [/red]

Isn't that the definition of a "heat sink"?

If each round of .223 fired generates a set amount of heat, aren't we trying to eleiminate that heat from the firing platform as quickly as possible? Or trying to limit the build up of the heat, away from the operator, and critical parts of the rifle?

If each round generates a certain anount of heat, and 2 different handguards show different temp curves when subject to the same regimen of rounds fired, and those curve show similar max. temps, and cooling cycles. Shouldn't we wonder why one system shows a faster temp increase sooner in the firing than the other?

Is it because one system has better venitlation? Or because one system has more metal than the other, meaning that more metal has to be heated, to increase the temp? Or is it that one system show a faster temp increase because it is taking heat directly from the barrel, so that the barrel is retaining less heat?

3rdtk, I understand some of your requirments for a SIR now I think, when you mention heat and lasers.

I don't have a laser, probably won't get a mil-type laser, so I hadn't considered the mounting requirements.

Most people I see with FIRSH, do it to put on vertical handrgips, or Surefire M900 type lights with a vertical handle. I think most of those are thermally isolated, not to mention heat rises, so if the handguard gets hot, and you don't ever touch it, it becomes less of an issue.(?)