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Posted: 3/13/2013 7:04:38 PM EDT
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I assembled a lower recently using an A2 stock. I have no previous experience working with these as my only other builds have involved collapsible stocks. At any rate I have a noticeable amount of wobble between the stock and the lower. It seems as if the stock isn't being tightened enough by the screw but it is bottomed out and I'm afraid that I will strip the extension if I try to tighten it any more. I have taken it apart and put it back together a couple of times with the same result. I have never noticed any wobble in other rifles with A2 stocks that I have handled/shot (admittedly only 4 or 5). I am wondering if I have done something wrong during assembly or if this is a "known issue" that sometimes occurs with fixed stocks. I bought the stock as a kit from PSA which included the reciever extension, spacer (for the end of the extension), buffer & spring, and the stock. Any advice or suggested fixes would be appreciated. |
| There's a recess in the receiver below the tube, and a matching key of material on the stock that goes in there for anti-rotation. A snug fit is desired here, and can be achieved by building up the key on the stock with JB Weld or epoxy, and then grinding to fit. Make sure you put the A2 stock spacer bushing in there before putting the stock on the tube as well. |
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Quoted: There's a recess in the receiver below the tube, and a matching key of material on the stock that goes in there for anti-rotation. A snug fit is desired here, and can be achieved by building up the key on the stock with JB Weld or epoxy, and then grinding to fit. Make sure you put the A2 stock spacer bushing in there before putting the stock on the tube as well. The spacer is on the receiver extension. I will probably try the JB/Epoxy fix that you suggested though. Is it just that some stocks are out of spec in this area? Thanks for the replies. |
| A milspec A2 stock will have a small o-ring around the small projection on the forward face of the stock. The o-ring fills the gap between the stock and the recess in the lower receiver. Aftermarket stocks are usually missing the o-ring. Try finding one to fit and see if that removes the slop. |
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If the rattle you determine to be in the spacer area (I've had this problem), use a zip tie or similar dimension piece of plastic cut to 3/4" to wedge in there. Fix ya right up...
Otherwise, check at the receiver where the anti rotation nub fits in as others have mentioned. I've never had to fill that spot, but I imagine electrical tape may work best as it will flex, and you can build it in layers. |
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Quoted:
A milspec A2 stock will have a small o-ring around the small projection on the forward face of the stock. The o-ring fills the gap between the stock and the recess in the lower receiver. Aftermarket stocks are usually missing the o-ring. Try finding one to fit and see if that removes the slop. never saw one, do you have a pic? my Colt didn't come with one and the stock fits perfectly. also I cant find said o-ring in any TM I have |
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Quoted: A milspec A2 stock will have a small o-ring around the small projection on the forward face of the stock. The o-ring fills the gap between the stock and the recess in the lower receiver. Aftermarket stocks are usually missing the o-ring. Try finding one to fit and see if that removes the slop. thats incorrect |
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Quoted: A milspec A2 stock will have a small o-ring around the small projection on the forward face of the stock. The o-ring fills the gap between the stock and the recess in the lower receiver. Aftermarket stocks are usually missing the o-ring. Try finding one to fit and see if that removes the slop. Like others I have not heard of this before but it seems like a simple fix that makes sense given the problem at hand. I may give it a try as it is low cost and easily "undone." Quoted: Is your extension screwed in all the way and torqued to spec? I don't know the target torque value for a receiver extension so maybe not. I did use a pretty substantial multi-wrench and was fairly aggressive in tightening it. What is the target torque value here? Quoted: If the rattle you determine to be in the spacer area (I've had this problem), use a zip tie or similar dimension piece of plastic cut to 3/4" to wedge in there. Fix ya right up... Otherwise, check at the receiver where the anti rotation nub fits in as others have mentioned. I've never had to fill that spot, but I imagine electrical tape may work best as it will flex, and you can build it in layers. I will look into it a little more to see if I can determine exactly where the wobble is coming from. Electrical tape as a shim seems to be an even easier fix than the o-ring as I have some on hand at the house... Quoted: Electrical tape works like a champ. I had to do the same thing with my Magpul UBR, attaches similarly to a standard stock if you havn't installed one. Thanks. I assume that you mean in the area where the anti-rotational nub is like the post above? Thanks everyone for your replies. I will have another go at it this weekend and post what worked here...  |
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Quoted: How much thread locker is on the screw?... try removing some of it and see if the screw goes in easier... my stock from PSA was the same way, wouldnt tighten down all the way, i removed some of the tread locker from the threads and now it snugs up just fine. Well I would feel like a dope if that was the issue... I'll check that too. Thanks. |
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Quoted:
Quoted:
A milspec A2 stock will have a small o-ring around the small projection on the forward face of the stock. The o-ring fills the gap between the stock and the recess in the lower receiver. Aftermarket stocks are usually missing the o-ring. Try finding one to fit and see if that removes the slop. never saw one, do you have a pic? my Colt didn't come with one and the stock fits perfectly. also I cant find said o-ring in any TM I have 
It's easy to miss, but it's there. All of my Colt stocks had this ring; most of the non-Colt stocks I have owned or handled did not. Perhaps instead of saying "milspec A2 stock", I should have said "Colt A2 stock" (who wrote the milspec?  ).
A minor, non-critical, non-NSN component of an assembly would not necessarily be mentioned in the TM. Those who have been around this forum a long time may remember that the o-ring was mentioned several times in old threads, but I had no success finding a reference when searching the archives (ETA: Mods/Admin, the search function will not work for terms as short as "A2"; can we get that fixed?!). Note: the stock pictured is not an A2 stock; it is a Colt "CS" stock. I used it to demonstrate the o-ring; I no longer own any A2 stocks. ETA: OP, the poster above me probably nailed the problem. |
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There is some (not much) rotational play in rifle buttstocks until they are tightened enough.
The dab of Nyloc on the screw is there to keep it tight. It is easy to tighten with the right screw driver tip, hollow ground and sized to fit the screw. Tapered tips tend to be difficult. There was always two things arms room inspectors were guaranteed to check for. Loose stocks and cocked hammers. |
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