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Posted: 7/21/2003 8:11:21 AM EDT
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I was cleaning my colt AR-15 (PREBAN) last night and noticed that the carrier key was loose on the bolt carrier. I tried to tighten it, but the screws are still locked in place and will not turn. Anyone have this happen to them? What is hte fix since the screws are still locked in. |
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Waldo is very serous about the bolt being on thier way out. If you try to re-torque the allen head screws to 40 inch LBS, there going to snap, which leaves you trying to dig the broken bolts out of the carrier. Age and heat are all that it takes to stretch a bolt, since yours are loose, and still staked in (thread stretch), REPLACE THEM. |
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Hey give yourself an attaboy for finding it before it failed. [BD] That's why they tell you to check them from time to time. Anyway, it happens once in a while, especially if you actually happen to shoot your rifle. BTW, this is one time you want to get the proper grade bolt from a repuatable supplier (order a spare pair) |
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I always check these screws on my new carbine b/c I didn't have the tools to stake them when I built it and just locktited the bolts intot he carrier key. I will get it staked. I was surprised that my colt was the one that got loose. Of course, I have been shooting it since I bought it in the early 1990's. |
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The forward carrier key screw on my factory (less than 500rnds) bushy was about a full turn loose. Do I need to take the key off and clean between it and the carrier and reinstall? If so, how do I restake the screws? I haven't found any specifics on the procedure of restaking. Thanks in advance, Mean in Green ontheline |
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I would remove the key and install two NEW bolts, then stake. Don't waste your time with Loctite; the heat kills it. Torque with these bolts is critical. If you are not pretty skilled in that area I advise you find someone to final tighten them for you that has a torque wrench. Too tight, they break; too loose they back out & / or break. Stake them in place by laying the carrier on a rag on a very hard, stable surface such as a concrete floor or an anvil. Use a center punch and large hammer. The idea is to displace a little metal from the key into the bolt so it won't turn. You need to slightly deform the outside of the bolt to know you went far enough. Repeat twice more on each bolt, spaced equally around the bolt head. Why do these loosen, everyone asks? They were not torqued properly at installation and are often poorly staked; sometimes poor material is involved. What keeps a bolt in place is STRETCH. The bolt is tightened until it stretches a bit, say .002 to .004". The tension keeps it from working loose. Steel quality of the bolt is very important too. Crap fasteners = crap results. This area has teremendous thermal cycling and the bolts are tiny which is why the stretch is so critical. A good socket head bolt (allen head) is a about 160,000 psi yield, same as a grade 8. Check often; stock spares and needed tools to fix. |
| The reason for the stakes is retain the screws if they come loose or break. Loc Tite melts at high temperatures, bolt carriers get hot. You can make a staking tool from a busted 1/16" pin punch (grind tip to shape) or use a standard center punch. Staking instructions are in the TM -23&P. |
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