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Thread: Oh No I bought a RRA.....Did I fix it right?

  1. #31
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    Raider97, thanks a lot for the info bro.


    Matt

  2. #32
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    Quote Originally Posted by Rider79 View Post
    The difference in diameters on the RE is because the milspec is made from better material, with raised threads forged in. The commercial extension has the threads cut into the RE, that's why commercial extensions are a thicker diameter. The threads are the same and they will fit your lower. I have a RRA lower that I initially built with a commercial RE I had laying around, I've since replaced it with a milspec RE.
    The only maker that uses forged RE that I've been able to find is Colt. Every other maker has stated they extrude, and has acted like forging an RE is just crazy talk.

  3. #33
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    Quote Originally Posted by rob_s View Post
    The only maker that uses forged RE that I've been able to find is Colt. Every other maker has stated they extrude, and has acted like forging an RE is just crazy talk.
    What about BCM? Maybe forging isn't the right word, but I think I remember from one of your posts that the difference in diameters is because the milspec are made with the threads, the commercial is just a tube with the threads cut in.
    "It makes no difference what men think of war, said the judge. War endures. As well ask men what they think of stone. War was always here. Before man was, war waited for him. The ultimate trade awaiting its ultimate practitioner."

  4. #34
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    As I understand it (and ignoring questions of material for a moment)...

    The original Colt REs (and current production) were/are forged. However nothing is forged into it's final state, even lowers, and everything gets some machining at the end to get it to it's final shape (the exception is net-shape forging, which I don't think the RE is due to cost, although they might be which would explain the high cost of a Colt RE). Forging is used to get the raw material to the general shape, and it aligns the material at the microscopic level which adds strength. You can take two blocks of identical aluminum and machine one lower from the block and forge the other into the rough shape and then do the final shape via machining and the forged part will be stronger (this is why, incidentally, billet lowers are thicker/fatter, they need to be to make up for the reduced strength, IMHO billet lowers cut to the identical dimensions of a forged lower are a really bad idea and should be avoided)

    If the Colt RE is a net-shape forging, it would actually make a lot of sense. This would explain why the threads stand taller than the tube. Or at least explain how that shape was originally achieved, if not the why they chose to do it that way.

    Either way, all of the other receiver extensions, Bravo included, whether commercial or milspec diameter, and regardless of material used, are extruded AFAIK. When I asked LMT abut theirs I got the "of course they are extruded, only an idiot would forge them" kind of response. This means that all of these tubes are effectively the same, it's just a matter of how much material they cut off of the extrusion and what material they make them of. There is no reason someone couldn't make a commercial RE out of the "better" material or a milspec RE out of the "lesser" material.

    One of these days I'll round up a whole collection of RE and try to do a photographic explanation of the differences, but it's pretty far down on my list of things to do as I don't think there's actually much interest in the subject, and I've come to believe that the stock and RE are two of the least worrisome parts of the gun.

  5. #35
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    Quote Originally Posted by Matt2124 View Post
    Well depending on whats is available I have bought Monarch 55grain .556 from academy, and have bout 2 cases of .556 m193. The cases are waiting for a Magpul Dynamics Class in October so I guess I ought to run a few mags of those to make sure its going to feed/fire. When reading about receiver extentions on the AR Technical Discussion Knowledge Based Threads I believe that I read that the milspec has a different thread then the commerical ones, if that is true will a milspec fit on my commerical receiver?

    Matt

    I doubt that the Monarch is true 556.

    The thread pattern on commercial and mil-spec RE's is the same.



    C4
    Last edited by C4IGrant; 09-11-09 at 09:32.

  6. #36
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    Quote Originally Posted by Matt2124 View Post
    Alright guys for those following this thread I appreciate all the input thus far in this thread, and the information been relayed to me. So I got my chance to take it to the range today. My plan was not to work on drills/technique ect...but I did make sure I used my fundementals cause no round is wasted right. I loaded up 99 rounds of ammo, I planed to shoot 100 rounds but mis loaded one of my mags. Out of the 99 rounds I fired 98 rounds, I had one Fail to Feed problem. Immediate action and I was back in the fight. The main concern I have is not so much at first but the last 40 rounds I fired were out of 3 different mags and the bolt did not lock back when the last round was fired on all three mags. In my limited wisdom I think that using the extra power spring has caused a bit of short stroking and this may be the reason for the fail to feed and the failure to lock back upon firing the final round. I had no problems with performance minus what has been explained and all in all without the fail to feed and fail to lock back x3 the new bcg/buffer/and spring ran fine. But I guess to say that is to accept that that it may/will happen when I need my rifle so that in and of its self is not acceptable. I know that rifles are machines and mechanical instruments and will all fail...but until it reaches failure I need it to run as close to 100% as it can. Especialy under favorable conditions. I think being new to the AR paltform, 3 years owning and shooting, has possibly caused some "rookie" mistakes in trying to tinker with it and make it better thus leading to the range problems I had today.

    Questions and my options:
    1) I'm thinking of keeping the extra power spring to use as a back up only with my origional bcg and car buffer and purchasing a standard spring to use with the new bcg and buffer. The good, bad and ungly of this? (questions/comments/gripes concerns)
    The spring you bought (red model) is too long IMHO. This is why I only sell the blue one. Your spring is most likely the issue. Load one round into a mag and fire the round. Did the BCG lock to the rear?

    2) Also while speaking of the old bcg while browsing the BCM website I found the BCM Sopmod bolt upgrade/rebuild kit, the BCM extractor spring upgrade, and the BCM extractor spring upgrade kit (set of 3). It was mentioned earlier in this thread that buying a bolt upgrade kit would be a good option. So which one is it? I'd assume the Sopmod upgrade/rebuild kit but then again I'm just assuming.
    The extractor spring upgrade kit (3 pack) is the best value.

    3) Could the extra power spring be causing the fail to feed and fail to lock back due to short stroking? I should add that I was using 3 usgi mags with Magpul ranger floor plates and it was the first time I have shot them since adding the floor plates but have not had issues with them in the past. Am I correct in diagnosing the problem or is there potential for other factors to cause this?


    Thanks again guys,
    Matt

    Most likely. If you are running standard GI mags, the springs in them can be weak (even as new) and might not be pushing the follower up fast enough to lock the bcg to the rear (doubt it though).


    C4

  7. #37
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    Quote Originally Posted by Matt2124 View Post
    BTW, I trying to apply these suggestions and not waste any more money.

    1) Stake the gas key:
    As of the current I have two BCG's the Anvil Arms and RRA. While the Anvil is properly staked compared to the pics of staking posted on M4C the RRA which has been staked in the past is not quite up to snuff. The staking does not quite carry over from the gas key material to the screws and I'm working on finding someone to stake it for me.
    That should be fine.

    2) Add a BCM bolt upgrade kit
    As stated in my last post....which one? The Sopmod upgrade/rebuild or just the upgrade kit?
    Bolt upgrade kit (3 pack).

    3) Buy a spare bolt
    I currently have 2 complete BCG's that both function right now. I know the movotation behind my op is to gain some check marks on the list and upgrade my rifle. So I plan on implementing #2 above on the RRA bolt, and saving for another quality bolt if not complete BCG.....maybe BCM or LMT who knows.
    Don't worry about buying another bolt.

    4) Add an H buffer for a middy gas system and an H2 or H3 buffer for a carbine gas system
    I think it has been determined that I have a carbine gas system so I've got the ST-T2 buffer which seemed to function well today at the range so I think I'll hang on to it.
    That buffer should run just as long as you do not use that spring.

    5) Check the chamber to make sure it is 556 NATO
    Not too sure how to check the chamber minus reading the markings.....any ideas?
    Send it to someone that has a chamber checking device.

    6) Remove the RE and installed a mil-spec one and then staked the castle nut.
    As soon as I can verify that if I buy a mil-spec RE it will work (threads are the same) I'll be doing this and maybe if I get lucky I'll find a smith who can install and stake the RE and castle nut. But who will also be able to check my chamber and properly stake my gas key.


    I now have a plan

    Matt
    They are the same so there are no issues here.



    C4

  8. #38
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    Grant, Thanks a whole bunch for all the advice and too all the others with the wiscom and knowledge and thought put into this thread.


    Matt

  9. #39
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    Swap the X-power buffer spring for a standard one.
    Also what kind of mags are you using?

  10. #40
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    This is what I did to my RRA

    I'm not sure I can really call it a Rock River anymore.

    Some pieces have been falling off my DDM4 and they have found their way to my RRA.

    The stock handguards have been replaced by a DD 10" lite rail and lo pro gas block.

    The commercial tube and stock fell off so it got a Vltor Milspec tube and the MOE stock off my DDM4.

    A DD QD receiver endplate found it's way on properly staked.

    The DD VFG found a home on the RR.

    The safety had already been swapped out for an ambi.

    The std M4 profile barrel from the DDM4 found it's way there too so now it's light 1/7 twist with chrome bore and M4 feed ramps.

    The BCG has been swapped out for a DD one FA/milspec.

    A pair of troy buis have found their way there too.

    It's having an identity crisis and doesn't know what to call itself anymore.

    I was able to sell the parts from the RRA and I ended up with very little out of pocket using parts off my DDM4 to improve the RRA.


    Shad
    ------
    I knew where I was when I wrote this..
    I don't know where I am now.

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