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Posted: 10/13/2004 6:59:04 PM EST
Here is a link to a thread talking about FH's and MB's for the above calibers...for a great price!

Thread

Bigant
Link Posted: 10/14/2004 3:54:44 AM EST
You know, I have a problem feeling comfortable with a 5/8" threads on a .50 cal bore. .50 cal is 4/8", that leaves 1/16" of muzzle all the way around, that's .0625".... Do the threads cut into that, or is 5/8" the diameter of the bottom of the threads?

Maybe I'm missing something, but it just doesn't seem prudent
Link Posted: 10/14/2004 5:34:49 AM EST
[Last Edit: 10/14/2004 5:43:08 AM EST by Bigant]

Originally Posted By Griz:
You know, I have a problem feeling comfortable with a 5/8" threads on a .50 cal bore. .50 cal is 4/8", that leaves 1/16" of muzzle all the way around, that's .0625".... Do the threads cut into that, or is 5/8" the diameter of the bottom of the threads?

Maybe I'm missing something, but it just doesn't seem prudent




I'm not sure how the thread stuff works, but I emailed AA to see what their response would be, but if I'm not mistaken the .458Socom can use the 5/8, so why not the beowulf? But then again the barrel might have more meat around it than the wulf.

I read the thread about the socom and LW wanted them to use a bigger threading....so maybe someone with experiance with this could chime in..

Bigant
Link Posted: 10/14/2004 6:11:57 AM EST
Link Posted: 10/14/2004 3:06:40 PM EST
[Last Edit: 10/14/2004 3:42:11 PM EST by AnArKey]
Hey guys, I'm the guy advertising the FHs and brakes.

I can make them any thread you want! We just need a concensus on what to use. I myself read a few threads on the debate, and thought the conclusion was 5/8x28 thread was marginally ok.

I have a feeling this may start a new standard, seeing as how these will be the first threaded barrel attachments for the SOCOM and Beowulf. Let's make sure we pick a good one.

Since apparently no one has threaded their barrels yet, and none of the current 5/8x28 attachments will clear a .45+ bullet anyway, we really are going from scratch. Cut a bigger hole in the attachment, and less off the barrel. I need to know the OD of the Beowulf and SOCOM barrels at the muzzle.

For an initial group buy, I would be willing to offer barrel threading services with the FH and/or MB for an additional $60+shipping. That entice anyone?
Link Posted: 10/14/2004 4:19:43 PM EST
Here's the latest design for the big bore ARs.
1.5" diameter, tapering to 1" OD at the muzzle
3" long
Thread is undecided as of yet.
http://www.derekdevises.com/pictures/50_brake2.jpg

This is a serious purpose built brake to really cut down on the recoil of these big bore ARs. The Alexander Arms brake really isn't a serious brake, it's a serious compromise. Can't have real effective braking unless you have multiple baffles that let the bullet through and not much around it. The big open tube of the AA brake that allows for over the barrel installation, also means it doesn't cut recoil half as well as a purpose built brake, like the above brake.
Link Posted: 10/14/2004 5:52:18 PM EST

Originally Posted By AnArKey:
I have a feeling this may start a new standard, seeing as how these will be the first threaded barrel attachments for the SOCOM and Beowulf. Let's make sure we pick a good one.

Since apparently no one has threaded their barrels yet, and none of the current 5/8x28 attachments will clear a .45+ bullet anyway, we really are going from scratch. Cut a bigger hole in the attachment,



Um, actually I have a 458 SOCOM, threaded, and wearing an A2 type flash suppressor. Custom made by Kurts Custom.

I've seen at least one guy with a muzzle device on a Beowulf.

Let's not get carried away on who is first to do what.......mmkay?
Link Posted: 10/14/2004 6:28:12 PM EST
[Last Edit: 10/14/2004 6:34:04 PM EST by AnArKey]
Was the Beowulf in question using the "slip over" AA brake? You didn't specify if it was threaded or not. If so, I'd love to know what thread.

OK, grant ya that on the birdcage FHs.

Aren't they using 5/8 thread,? The SOCOM standards have a .93" OD barrel right? I'm guessing the Beowulf has something similar? Why cut like ~85% of the steel from around the bore, to accomidate the 5/8 thread, when you could use a 7/8" thread that only takes ~35% of the steel off?

7/8 thread, optimum for the .93 barreled big bore ARs, with a custom brake to go with that thread.

I meant to say I don't think there is some standard thread for barrel attachments above 5/8x24, unless some of you know otherwise. I've looked quite a bit.
Link Posted: 10/14/2004 6:58:42 PM EST

Originally Posted By AnArKey:
Was the Beowulf in question using the "slip over" AA brake? You didn't specify if it was threaded or not. If so, I'd love to know what thread.

OK, grant ya that on the birdcage FHs.

Aren't they using 5/8 thread,? The SOCOM standards have a .93" OD barrel right? I'm guessing the Beowulf has something similar? Why cut like ~85% of the steel from around the bore, to accomidate the 5/8 thread, when you could use a 7/8" thread that only takes ~35% of the steel off?

7/8 thread, optimum for the .93 barreled big bore ARs, with a custom brake to go with that thread.

I meant to say I don't think there is some standard thread for barrel attachments above 5/8x24, unless some of you know otherwise. I've looked quite a bit.



I'm very interested! I'll get you the measurements as soon as I can or someone else will.....also I like the design that you have posted here...I'll see if I can get some interested, since I have sold some Wulf Uppers so I'll check with my customers. How many do you need to do a run?

Bigant
Link Posted: 10/14/2004 8:06:36 PM EST

Originally Posted By AnArKey:
I have a feeling this may start a new standard, seeing as how these will be the first threaded barrel attachments for the SOCOM and Beowulf. Let's make sure we pick a good one.



Tromix and Teppo Jutsu have been offering a variety of threaded attachments for the .458 SOCOM for years, including flash hiders, muzzle brakes and suppressors. Add to that the fact that Tromix has done it for the .50AE and 440 CorBon as well.


Since apparently no one has threaded their barrels yet, and none of the current 5/8x28 attachments will clear a .45+ bullet anyway, we really are going from scratch. Cut a bigger hole in the attachment, and less off the barrel. I need to know the OD of the Beowulf and SOCOM barrels at the muzzle.


Barrels for the latest 458 SOCOM GP are FACTORY threaded at 5/8 x 24 TPI. Note the thread is not the 28 but the 24. This is a firearms industry standard for suppressors, as well as muzzle brakes. When properly done it can be successfully used on calibers up to .500 caliber. Several folks make muzzle devices in this thread. Regarding successfull use of this size thread, VAIS is considered a well respected brake maker, and their #12 is .458 specific with 5/8x32 thread ... if they are OK with it, who am I to argue? Same with the Gentry Quiet Brake (.458 with 5/8x28) and KDF (.458 with 5/8 x 24). Furthermore, most brake companies make their brakes with a small centerhole and leave it to the competent gunsmith/machinist to open it up to the appropriate clearance for the chosen caliber. To afford the customer the largest number of choices of muzzle devices, this choice of thread was the logical one. Heck, even the M-60 flash hider uses this thread.

To illustrate, we approached both DPMS and Smith Enterprises for making custom flash hiders for the .458 SOCOM. Both agreed and will now offer these (DPMS with an M-60 style and Smith with their Vortex, which is patented, BTW) Neither of them raised an eyebrow at the choice of the 5/8 x 24 thread.

Also to consider, for the 1911 pistol in .45 ACP (.451), the industry standard threads are .575" x 40, .581" x 40 and .685" x 40. Makes 5/8 (0.625) on a .458 seem not so strange afterall.

Will I am by no means a conformist and do not promote "going with the crowd", in this case I would suggest using the industry accepted standard and going with 5/8x24. It would allow folks currently using a muzzle device an easier means of switching to your product if they so desired (provided they use this thread). Some of the folks using it are Vais, Gentry, OPS Inc, KDF, Shrewd, etc.

I wish you the best of luck, and am glad to see someone else is offering large bore flash hiders. I would be happy to put one on one of our test mules that goes out for law enforcment demos and let you know how it holds up. Welcome to the party!

Marty ter Weeme
President/Founder, Teppo Jutsu LLC
Developer of the .458 SOCOM
Link Posted: 10/14/2004 10:28:26 PM EST
MartytW, thanks so much for offering that input. Clears up a lot. Looks like I'll use 5/8x24.

There really a demand for a FH on the big bores? I'd only be thinking about cutting recoil down as much as possible on those. My thinking was FH and MB for .30 weapons, and only a MB for the SOCOM and Beowulfs. Of course if you think I should make big FHs too......?
Link Posted: 10/15/2004 2:52:01 AM EST

Originally Posted By AnArKey:
MartytW, thanks so much for offering that input. Clears up a lot. Looks like I'll use 5/8x24.

There really a demand for a FH on the big bores? I'd only be thinking about cutting recoil down as much as possible on those. My thinking was FH and MB for .30 weapons, and only a MB for the SOCOM and Beowulfs. Of course if you think I should make big FHs too......?



More than happy to help a newcomer, considering I was one at one point myself, and still am nothing more than a neophyte.

Regarding demand for FH on the bigbores, yes there is, the SBR versions put off huge muzzle flash and even the 16" depending on the choice of powder (H110 is notorious for roasting hot dogs down range)

Recoil really is not that bad, granted I am 6'6" and 220#, but both my 12ga and 308 seem worse and I dread shooting the 7mm Win Mag ... it is more of a shove, and as stated in the linked thread at the start of this one, due to the operating pressure of these big bores, MB don't work as well as expected. Suppressing these calibers is a real challenge due to the low pressure and big hole, the gas is not as eager to be redirected and shed it's energy.

I would look at two designs, a FH and a MB, that can be adapted to all calibers. Some designs like the Vortex are patented, so tread lightly. Others are "common place" so pricing is essential. For the FH, I would stay with the 5 prong you showed, but be aware of what was posted by someone else. The Vortex is made of 8620 and then heat treated to very high Rc to prevent "blooming" of the tines. With the lower pressure of the big calibers it should not be as big of a problem, but I would be nervous with the 30 cal version on a FAL. For the MB, perhaps a merging of two designs. The baffles work well but for the big bores the multi hole versions seem to work. Perhaps one that has two "chambers", the first one with the multi holes, the second one a baffled one. Kinda like the OPS but with holes instead of a large opening in the chamber closest to the barrel. Does this make sense?

Marty
Link Posted: 10/15/2004 4:30:32 AM EST
Can someone explain to a neophyte how these threads are measured?

The large boar brake looks nice, am toying with trying it on my 45-70 hand cannon if the numbers add up (will check the treading that the hand cannon manufacturer used on a different barrel this weekend.

That manufacturer used a single chamber multi-hole brake on it, kind-of spiralish. (Will edit after I measure it).

A quick question to MartytW, notice that the 500 Phantom used a JP brake. How did it compare to spiral and more traditional multi chamber designs?
Link Posted: 10/15/2004 5:59:39 AM EST

Originally Posted By mousehunter:
Can someone explain to a neophyte how these threads are measured?

The large boar brake looks nice, am toying with trying it on my 45-70 hand cannon if the numbers add up (will check the treading that the hand cannon manufacturer used on a different barrel this weekend.

That manufacturer used a single chamber multi-hole brake on it, kind-of spiralish. (Will edit after I measure it).

A quick question to MartytW, notice that the 500 Phantom used a JP brake. How did it compare to spiral and more traditional multi chamber designs?



Thread measurement is done with calipers and thread gauges. Measure the OD of the thread for the size, measure the thread pitch with the thread gauge. Actual thread dimensions can be found in Mech Eng hand books. 5/8 x 24 UNEF Class 3A for instance has max OD of 0.625", min OD of 0.6169". Max Minor diameter (the through of the thread) is 0.5655".

On the Phantom, again, the muzzle pressure is low. The sponsor for that project supplied that brake, so that is what we installed. We did not have a chance to test it against other brakes, as the JP has some rather esoteric thread .... From what Joe has told me, the brake does not add much in terms of recoil reduction - that low pressure large bore challenge ....
Link Posted: 10/15/2004 6:32:38 AM EST
[Last Edit: 10/15/2004 6:34:50 AM EST by Griz]

Originally Posted By MartytW:
5/8 x 24 UNEF Class 3A for instance has max OD of 0.625", min OD of 0.6169". Max Minor diameter (the through of the thread) is 0.5655".



On a .50 bore, that will leave .03275" (worst case) of steel between the bottom of the thread and the bore, that's the thickness of a credit card. I'm sure it will be OK once the brake is screwed on, but I sure wouldn't let end users install them, I could see someone cranking down on it and wringing the end of the barrel off

(edit: I wonder if the rifling cuts into that .03275"... I don't know if a .50 bore is measured land to land or groove to groove)
Link Posted: 10/15/2004 6:33:11 AM EST
Thanks for the response. Understand that trying to defy the laws of physics can be a bit of a problem sometimes ;).

Will still keep looking for hope, but understand that I probably should just keep the hand cannon in the safe, and invest in other progects.
Link Posted: 10/15/2004 10:22:12 AM EST

Originally Posted By Griz:
I could see someone cranking down on it and wringing the end of the barrel off



On the .458, that leaves approx. 50 ft-lbs of torque before that happens
Link Posted: 10/15/2004 10:42:52 AM EST
[Last Edit: 10/15/2004 10:43:35 AM EST by Griz]

Originally Posted By MartytW:

Originally Posted By Griz:
I could see someone cranking down on it and wringing the end of the barrel off



On the .458, that leaves approx. 50 ft-lbs of torque before that happens



Roger that, the .458 has more than twice the metal left compared to a .50 bore with 5/8" threads. I have a .50 Beowulf and would love to add a threaded muzzle device, but I am having a hard time convincing myself that .03275" wall thickness (or less if the rifling cut into that) is kosher.
Link Posted: 10/15/2004 11:45:42 AM EST
[Last Edit: 10/15/2004 11:52:25 AM EST by AnArKey]
Now you guys are feeling my predicament.

The standard is 5/8x24, BUT it's really, really less than ideal. It's sounding like as little as 20-30ft/lbs of torque could schear off the threading on a 5/8 thread Beowulf. I know if I had a unthreaded Beowulf and was looking for a MB or FH, I'd certainly not want to have to cut the threads down to within .03275" of the bore.

Then again, the SOCOMs are already shipping with 5/8x24 thread.

What to do.......

Maybe a 5/8x24 specifically for the SOCOMs, with the bullet clearance made just for the SOCOMs. Not gonna sell these too often. Maybe Teppo Jutsu LLC would be interested in buying some and offering them with their new threaded rifles? This proposal, since it's centered entirely around the SOCOM, I'd be more than willing to take any/all suggestions from you Marty.

For the Beowulfs, I'm really thinking the best solution is to do it right, just for the Beowulfs. 5/8 would make me nervous on my weapon, and I wouldn't blame anyone else for the same. Remember, MBs work by PULLING on the barrel, another possibility is the thing flying off from a shot. I wouldn't feel comfortable populating the world with Beowulfs that could potentially launch a MB. So I'm back to a custom Beowulf MB and/or FH, with custom 7/8 thread, and threading services offered as well.

Marty, you said the JP brake offered very little recoil reduction? This was the original tank like brake? And it was properly clearanced for the bullet (not overly so)? If that is so, then you are right about a MB not being of much use. If the muzzle gas energy isn't but 20-30% of the bullet impulse energy, there really isn't much to be done for recoil at the muzzle. I'd just make the FHs.
Link Posted: 10/15/2004 12:53:47 PM EST

Originally Posted By AnArKey:
Marty, you said the JP brake offered very little recoil reduction? This was the original tank like brake? And it was properly clearanced for the bullet (not overly so)? If that is so, then you are right about a MB not being of much use. If the muzzle gas energy isn't but 20-30% of the bullet impulse energy, there really isn't much to be done for recoil at the muzzle. I'd just make the FHs.



Original JP tank like brake, installed by JP himself, so you know the clearance and timign was right ... it did VERY little to reduce recoil ... muzzle pressure is around 4-5Kpsi compared to the 10K psi+ for rifles like the 308 ....
Link Posted: 10/15/2004 3:15:54 PM EST
Well I think you may have spared all of us the waste. A FH is the only thing worth doing in that case.
Link Posted: 10/15/2004 3:32:54 PM EST
Link Posted: 10/15/2004 3:44:30 PM EST
I think a compensator would still work, to keep the muzzle down for fast follow up shots.
Link Posted: 10/15/2004 3:50:21 PM EST
[Last Edit: 10/15/2004 3:51:32 PM EST by Wave]
Link Posted: 10/15/2004 4:15:16 PM EST
[Last Edit: 10/15/2004 4:37:55 PM EST by AnArKey]
Some think they are the same thing, but are a little different actually, at least as far as I have read,

Some people may think a compensator is a type of muzzle brake or vise versa, but I keep them seperate in my mind.

Muzzle brake: Recoil reducing devise. Works by trapping muzzle gasses to pull on the barrel, counteracting DIRECTLY recoil forces of the projectile. As discussed, effectiveness of this design requires the muzzle gasses to have a high amount of inherent energy, preferably as close to the energy of the projectiles motion as possible. Works good on high power rifle cartridges. Not so good on others where muzzle gas energy is much lower at the muzzle. Most eject gasses directly to each side.

Compensator: Muzzle flip counteraction. Uses muzzle gasses to push DOWN on muzzle, counteracting any muzzle rise inherent when backward forces of projectile meet your shoulder, and tend to lift the end of the muzzle. Barrell porting is basically compensating a barrel. A round about way of doing it, as you are still getting pushed back nearly as much, but have the added force of the muzzle being pushed down. Works well for pistols and lower pressure cartridges, as you need far less muzzle gas to keep the muzzle down than to try and counteract rearward recoil directly. As gasses are vented upwards, they can be blinding in low light situations. One solution is to use offset ports so the gasses don't escape directly in line with your line of sight.

Here's a potential Beowulf Compensator. 3" total length, 1" diameter, adds 2" to barrel.

http://www.derekdevises.com/pictures/compensator1.jpg

Link Posted: 10/15/2004 6:42:54 PM EST

Originally Posted By Wave:
Sounds like a MB for the Beowulfs are a lost cause.



No, no, no!! The baffled design like the JP appear to be not as effective. But the Shrewd when bored to .458 with the chamber bored to 0.600 to make for a small expansion chamber and "lip" at the opening, does appear to have some effect. It is just not as pronounced as with the high power rifle rounds. It is not a lost cause, but not the Holy Grail either. And due to the burning characteristics of the short fat rounds, muzzle flash can be ugly. Go the CMMG website, look up the videos of the 458 SOCOM SBR in F/A .. you'll see what I mean

Marty
Link Posted: 10/16/2004 6:11:44 AM EST
Very nice modeling work and some interesting concepts. I assume that you have analysed how the gas flow in your units will effect the back pressure in the Beowulf and the result on the long term fatigue life of the bolt assembly. (Need to run 12K durability).

Also in your design work please remember that a large proportion of the effect you are trying to achieve is associated with the precursor supersonic shock not just the combustion gas flow. baffles are not a bad answer but they are not essential in this type of flow work.

Beware comps on rifle barrels where the precursor is dominant as the barrel can move off line before the bullet exits (lots of testing first please).

Bill Alexander
Link Posted: 10/16/2004 9:58:39 AM EST
[Last Edit: 10/16/2004 10:40:19 AM EST by AnArKey]
MartytW, you mention a expansion chamber, but there are vent holes too right? I'll assume so as I was able to find a picture of a Shrewd muzzle brake on a 223, and it's a bunch of holes.

Here's a couple designs of that type. I made them the same OD as the barrel, and 3" long. I like the vents better than the holes, looks better.
http://www.derekdevises.com/pictures/chamber_brake_vents.jpg
http://www.derekdevises.com/pictures/chamber_brake_holes.jpg

The compensator was a thought, but like mentioned, it has some drawbacks. The flash is concentrated right in front of your eyes, and it can pull the barrel down before the bullet exits, killing accuracy. Since MartytW is asserting that a shrewd type brake, just built larger to be more optimum, would work pretty good, I think that's probably the best idea at this point.
Link Posted: 10/16/2004 10:16:55 AM EST

Originally Posted By Trestles:
Very nice modeling work and some interesting concepts. I assume that you have analysed how the gas flow in your units will effect the back pressure in the Beowulf and the result on the long term fatigue life of the bolt assembly. (Need to run 12K durability).

Also in your design work please remember that a large proportion of the effect you are trying to achieve is associated with the precursor supersonic shock not just the combustion gas flow. baffles are not a bad answer but they are not essential in this type of flow work.

Beware comps on rifle barrels where the precursor is dominant as the barrel can move off line before the bullet exits (lots of testing first please).

Bill Alexander



Mr. Alexander

Its nice to see you post here! Since you have dropped by can you tell us if you can thread the barrel on the beowulf? If so what thread do you recommend we use? Just a FYI their is interest in other types of MB's and FH's.

Bigant
Link Posted: 10/16/2004 10:44:09 AM EST
I second that question Mr Alexander. Do you plan to start offering thread on your barrels? If so, what is it? If you are planning on doing this, I'll use whatever thread you are going to use.
Link Posted: 10/16/2004 11:18:03 AM EST
It is of course possible to thread the barrel of the Beowulf but one must always exercise a little caution as the barrel wall at the muzzle is not too thick (0.775" dia). Be aware that the dimension quoted in most thread specs is the outside dimension hence the minor dimension is the one that must be considered. The steel employed in the manufacture of the Beowulf barrels is a Krupp material from Lothar Walther. This is a very good barrel material but does not machine well.

With the sunset of the AWB, Beowulf muzzles will gain threads, in this case 49/64-20 but this will not be for some time. The non standard thread is not ideal, but it has been tested to ensure that no problems occur such as the ovality that is sometimes seen in any bore when thin wall sections are created. (It also will not fracture with long term use). Muzzle brakes will be made to match this set up.

The current Beowulf muzzle brake uses a low angle divergent chamber to take advantage of the large volumes of gas without modifing the back pressure curve of the gun. The benefit of the design is that it also mixes a lot of air with the gas to initiate the flash and then diffuses this flash through the ports. In the design of a flash hider the port size must be increased to be truly efficient, hence the frequent use of slots.

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