I believe the whole upper receiver, including the handguard section is one piece, so a polymer lower section would be very difficult to do unless you made the whole upper out of polymer.  In that case, you might as well get an XM8 or a Hesse.  

The heat issue would probably be the same as Knights or Daniel Defense type systems.  You would have to use rail covers.  How many mag dumps are you doing all at once and how much heat are you experiencing?  Rail covers and Nomex gloves for extreme mag dumps.  It works for me!

I wouldn't think it an impossibility, since it comes down to the eliminating the lower section of the HG & employing a bolt on lower HG replacement. Even bolt on rail sections would be possible, just like the SIR. The only issues, relative to LMT, are the will to do it, and any patent issues related to ARMS' proprietary design.

Of course, there's also the issue of product uniqueness/identity, and I suppose a too-close similarity to the SIR could generate problematic business issues in terms of relations for them??? But, that's just a wild guess on my part.

I think the reason they have not incorporated it into the design may be that Crane hasn't noted any dissatisfaction over the metal rails currently in use on the RIS/RAS systems, otherwise they would have noted it on the SOPMOD II requests.  

Another reason for the one piece rather than a slide out bottom section would be to sustain rigidity through the whole rail.  A lower section could conceivably loosen and cause problems if a person were to put too much torque on the lower half.  Overengineering a system that they have probably tested extensively and performed well enough to pass on for SOPMOD submission would be unnecessary at this point.  tehy may go back in the future and do it, but at this point I assume it works and works rather well.

Bolt on rails are prone to be lost by your everyday soldier and sportsman.  It is inevitable.  Personally, I have never liked that aspect of the SIR.  Although with the width of the original SIR, it was necessary.

The fact is, there is no perfect system.  You have to give something up to get something else.  ARMS gave up a top rail that is on the same plane to balance the extra weight of the SIR over the whole rifle, thus making it seem much lighter.  They added more bulk or 'real estate" in order to achieve the superior cooling abilities.  

The URX gave up ease of dissasembly in order to make the URX as solid as possible without making it a monolithic upper.  The RAS systems all give up superior cooling abilities (although they are far superior to stock ahndguards and similar railed systems of similar design) in order to lessen the footprint of the system.  

The MRP gave up ease of replacing just the upper or just the rail system in order to have a same plane rail and be the most rigid system available from stem to stern.  

The daniel Defense system seems to give up the same things the FF RAS series give up.  However, it has superior ergonomic shape.  It might also give up a slight bit of sturdiness for the lighter weight.

There is no perfect system.  Each has strengths at the cost of weaknesses.  The only way for anyone to choose is to see what they need more and pick the system that offers it.  Crane will be doing that soon.  

Yes, well, if Crane can ever get around to making the final decision, what w/ the current hold up. I suspect the appeal & re-evaluation will result in a several-months delay of the final decision. I've anticipated the results for some time, but this is typical of the slow development process model the gov't follows, so I shouldn't be surprised. Just annoyed.

Of course, I agree re: MRP design protocols. Doesn't make any sense to fix what isn't broken, & compromise is always factor in the design equation at some level. Still, I like the potential this design offers, particularly the easy-swap bbl. (& that Troy front sight, too).

I hope the delay isn't too long.  I am itching to buy a suppressor and I want to wait for the SOPMOD decision before i make a decision.  If they haven't made a decision by late spring, I might just choose something already available.  I agree, the Troy sight looks promising.  So does their suppressor.  Troy looks like they may have some pretty good stuff coming out.  I wait eagerly for their release.

Well, if the winning suppresor's maker is located in Kali, then consider it [i]unobtanium[/i], as Kalifornya DOJ prohibits C3 mfg's from selling their wares to civilians anywhere in the country, which would seem to be a violation of interstate commerce to me...but that's a different topic.

I have been planning on the KAC unit, but higher priorities keep it on the burner for now. From what I understand, the Troy suppressor was designed by former Seeburger/OPS asociates. The mounting method is a virtual copy of the OPS, though the FS is a std bird cage instead of the 2-/4-port brake OPS uses.

Yeah, the OPS suppressor would seem to be the obvious choice at this time, but one never knows.  Maybe Troy out OPSed OPS or someone wlse did.  There is only one real contender from Kali and it is OPS.  However, there are some very good makers of cans out there.  We'll see.  If the winner is OPS, I'll get the Troy or whatever Knights might unveil.  Or maybe I'll hope OPS moves out of Kalifornistan.  I wish I could have them all.  God willing, one day I hope to be able to afford them all.

I bet on either OPS or Shurefire:)
Jack

Well...Ops anyway.

Im a little confused, I know of California class 02/07 manf of suppresors that have a do sell out of state to civillians.

What supprssor manufacturer in Kali that sells to civilians out of state?

So West,

A question about using the LMT on a RR M16.  DO they have 16 bolts?     I really like the idea of converting over to the 6.8 from 5.56.

Yes, either a standard M16 or AR15 Bolt Carrier/Bolt can be used

Good word has it that the LMT design is at the top for the SOPMODII contract.  GAO delay is over also so things should be mocing nicely, at least as nicely as a Govt. can.  As for the polymer lower, I think it is unnecesary for this application.  Good idea but with the use of foregrips somewhat makes them obsolete.  Folks who hate foregrips would be in the minority compared to the problems a removeable polymer handguard could cause for the military.  Loosing little parts constantly and having to replace them.  This happening on a huge scale would be a headache for sure.  IMO that is one of the main reasons the KAC and now LMT designed forends are so desireable for the Military.  Less parts!  Like said above, rail covers and gloves work fine.

I still want to see how LMT gets around the requirment to mount the M203...


KAC had to come up with URXII to do that (URX would not)

Well, since LMT also makes the M203 (or a variant of it), maybe it's compatible after all. Or, if not, maybe they are offering a retro mounting interface for a free float mounting option on the MRP. Hope the results get published sooner, rather than later.

There is a requirment in SOPMODII to take the original M203.

Now I just dont see how the MRP will do that with an adaptor bracket or with out...

Correct me if I'm wrong but isn't LMT one of the largest M203 manufacturers in the US?  If so I'm sure they have some cool way to attach a M203 to the MRP.[:D]

Yojimbo,

Dont get me wrong I am not trying to wish them ill, but how can you affix the barrel yolk when there is no opening in the lower rail?

If you do make an adaptor it will not mount at the 6 - close to the boreline as was spec'd.

Before the blowhards come out:
I have seen M203's mounted in many different forms, and many different weapons - IMHO the worst mounting system has to be Diemaco's current crop - it hangs so low it cannot be shot in all positions...







-Kevin

I believe you will see the MRP used for the future SPR rifle. It is very special in many ways. Especially the change of cal. feature  for Spec ops who canm use that feature for special missions, enemy ammo. SPR's do not get used like M4's and high volume of fire is not normaly used in a sniper rifle unless your in a world of shit. The MRP is not designed for high volume of fire as any barrel totaly surounded by metal in close proximity of the 900 degree barrel in full auto is nothing you can hold very long even with panels that eventually get too hot to hold.
I think the MRP is about as good a sniper set up as you can get, and if the barrel change feature holds up after prolonged gov't testing, that it will be the SPR winner for years to come.
Good Shootin, Jack

Forward grip answers this.  Has answered this[;)]

As far as mounting the 203 question I am not sure but it was either Wes or Chen who stated they (LMT) had something coming up for it but it was awhile ago when I saw it though so take that for what it's worth.  I agree with you Kevin in that I don't see how they can do it without it hanging lower than desireable.  Without the standard M203 bracket could the unit be fitted to the rails and ride at the aproximate distance from the bbl.?

Everyone hear that?  [size=3][b]ARMS is buying LMT!!![/b][size=3]

Just kidding, having a little fun w/ you Jack.

Good Shooting,
/S2

This could be just rumor and conjuecture that has been floating around, but I could have sworn I heard that LMT has a second unit that is separate from the MRP project that was submitted for the SOPMOD II instead of/as an alternative to the MRP and has not yet been unveiled to the public and the MRPm was only released because it had been DQ'ed from the project.  Like I said, I could have just heard rumors, but I swear I did hear this somewhere.

This MRP upper looks just like a copy of the Leitner-Wise uppers.  I think the Leitner-Wise upper came out months before the MRP uppers.

 Other than that without having the time or a decent scope to shoot it with it looks and feels great!

Maybe LW got theirs from LMT?

I understood LMT does stuff for LW

I don't mean to underestimate Karl Lewis /LMT at all
- Knightone your point could be very valid.

Do tell? If someone knows the skinny on this story, I hoped they'd chime in. I'd like to know what they've submitted. More thant that, however, I'd like to know the final results of the trials. Waiting sucks.

My version of the ideal upper would combine the features of various platforms. It'd be an LMT-style upper w/ the following features:

a) Synthetic lower HG (from the SIR)
b) Swappable bbl. & gas tube (MRP)
c) LMT bolt carrier w/ [b]gas piston[/b].

Basically, an AR-18 action combined w/ a modern rail mount system. It would be sweet. But, unfortunately, it's not in the specs.

I have been priviledged to be briefed on the SIR's, hence I know some things not generally realized/known in the market place.                                    There are a lot of things that seem not to be realized by some regarding the SIR's. The lower hand guard is very capable of a lot of things besides a hand grip or mounting something to it via a dovetail rail. If you don't need a selective rail outside, they can be selectively stored inside at the bottom of the hand guard. Same storage for the swivel. A clever easy to get at and clean/replace heat shield provision is at the bottom sides of the hand guard and allows their yet unvield heat shield to slide in via the two little narrow tracks. No rivets etc. and it is trapped so it can only come out from the rear after removal from the upper rail. The other neat thing is the lower is set up for push buttons that can trigger any light or laser up top. The button/s are placed thru the top row of holes that have the flat area under the hole. Talk about well thought out and not having to have wires/cables all over the place, and out of direct reach of heat. They have other hand guard abilities for intergrated special devices in their other hand guard designs that slide right on just like the standard current ones.
Very Good Shootin, Jack

ARMS & LMT should put their collective knowledge together & turn out a SCAR-AR upper. Wadd'ya say, Jack?

[size=6][b]Oh God, please...[/b][size=6]

or ARMS and KAC for that matter...

[booze]

Yeah I think it would rock.
Imagine a URXII lower with recessed thumb levers for dismounting the lower or M203

Hell, I'd be 100% happy with the SIR if they'd reinforce the inside of the lower handguard (where the lower rail screws in) with a metal insert.

I love the SIR, but I recognize it's shortcomings.

-Cap'n

BTW, I thought Karl Lewis and Dick Swan were pretty good pals? I coulda swore one mentioned the other a while back?

could be that one swore at the other a while back [:P]
MM

They may have already done someting on the SCAR,, but I havn't seen any evidence of it. Maybe those three companies have been having closed door meetings on the SCAR together too?
Jack

You are correct in this assumption.  It is LMT.

Would not surprise me at all...
It is their collective best intrests that a AR derivative SCAR beat out a HK plastic gun SCAR / XM-8
And IMHO the Army as a whole

There are some outstanding minds with those guys (ARMS, KAC, and LMT - done alphabetically as not to get anyones knickers in a knot)

God I hope this is so.  I hope any possible rivalries between the companies do not interfre with good business.  A joint project between these major players would probably yield something pretty fantastic.

Ditto that.

I just got the opportunity to check out the A2 length MRP with the 18" stainless barrel recently.

It was on display so i didn't get to shoot it, but from handling it, the MRP is a very streamlined compact package. I really liked the quick change bbl. assemblies.

I do see rail covers being need needed for Auto fire. Other than that it was just a bit heavy(just the upper). Other than that I Really like it.