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Posted: 5/20/2010 4:39:23 PM EDT
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I was told by other AR owners that I should always have a spare BCG on hand. If I purchase 1 is this a "drop in" install ? Won't I have to check headspace? Are AR rifles that interchangeable? I Currently own a Bushmaster MOE M4 and a Colt HBAR, would the BCG be interchangeable between these 2?
Thanks |
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NEW bolt!!! Always replace a broken bolt with a NEW one... never a used one. I doesn't hurt to check head space ether. Better safe than sorry. What he said. This will be a long thread. Try. No, keep the same bolt with it's upper until it fails or is replaced. Checking head space is never a bad idea. I'm sure those that think AR parts don't wear and or magically will always fit, will chime in. 458 |
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I see a common theme in the responses so far and that is a spare BOLT should be OK. Your question was about a BCG (the whole group). I don't know enought to give you a difinitive answer but It appears that if you swap the BOLT and the bolt only, you should be OK. Then again, it would be nice if someone actually read your post before responding (not just the title).
Good question as I wonder the same thing. |
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"I was told by other AR owners that I should always have a spare BCG on hand."
Good advice. Bolt lugs break on the best of bolt brands. Bolts break in half at the cam pin hole. Cam pins break. Firing pins break. Gas rings malfunction. These breaks always occur when you're at the range. So beside a BCG, an extra bolt or two is handy along with an extra cam pin and firing pin. "If I purchase 1 is this a "drop in" install ?" Bolts, carriers, cam pins, firing pins, gas rings, gas keys and firing pin retainers are all standard and 100% interchangable. They are made to exacting specifications to very tight tolerances. "Won't I have to check headspace?" If you think you have to. The BCGs are mass produced to such tight tolerance and tight quality control that headspacing at assembly is compltely un-neccessary. "Are AR rifles that interchangeable?" That is the beauty of the AR platform, you can literally built one from parts bought from any of the multitude of suppliers. They, aside from some tolerance stacking in non-critical parts, are totally interchangable. "I Currently own a Bushmaster MOE M4 and a Colt HBAR, would the BCG be interchangeable between these 2?" As long as your Colt doesn't have a fixed sear block, a BCG would be interchangable between the two. Currently DPMS and Bushmaster use BCGs made by Toolcraft (TC). Other manufacturers buy their BCGs from suppliers like LMT, CMT and Advanced Ordnance Corp. At the factory they grab a BCG at random and drop them in at assembly, the rifles are then test fired and then packed in shipping cartons. They would random batch test the headspacing on a sample from a rack of assembled rifles as part of their QC. You'd be surpised to find out that Bravo Company buys their BCMs from a USGI suppler. |
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I see a common theme in the responses so far and that is a spare BOLT should be OK. Your question was about a BCG (the whole group). I don't know enought to give you a difinitive answer but It appears that if you swap the BOLT and the bolt only, you should be OK. Then again, it would be nice if someone actually read your post before responding (not just the title). Good question as I wonder the same thing. The carrier isn't that big a deal. It would be easier to just swap carriers in the event that the gas key worked loose. This wont effect Head pace. Originally Posted By altopwescap
If you think you have to. The BCGs are mass produced to such tight tolerance and tight quality control that headspacing at assembly is compltely un-neccessary. A head space gauge isn't expensive or hard to do. I think checking this when changing bolts has more to do with inspecting the condition of your worn chamber and barrel extension than if the bolt is to spec. |
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"I have built 7 carbines and rifles over the past 3 years and checked the headspace on all of them just for good measure
and self assurance." Jusbo47 Hi Jusbo47, I'm curious, out of the seven carbines that you built how may of them had headspace issues? Just how would go about correcting out of spec headspacing? Drop in another standard bolt? Do you know anyone that had a headspace issue? How did they tune it in? Talk to any armorer, you'll find that out of spec headspacing is pretty much a non issue. |
| Thanks for the Info, Although I have owned my Colt since the early 90's I really didn't know how modular and yet intricate the AR rifle is. It's nice to find a site just as this full of knowledgeable firearm enthusiasts as this one has. Now who makes a good "spare" BCG? Many Thanks. |
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Now who makes a good "spare" BCG? Try this, it's very popular around here. BCM Bolt Carrier Group MPI Auto - Bravo Company link If you want to spend more money get a Colt M16 auto BCG, auto bolt carriers are perfectly legal and a few high end AR brands are including them with their production configuration, Colt, BCM, Daniel Defense, and Noveske are some of these manufacturers. |
| Thanks for the link, I hate to keep beating this subject to death but the BCG on my Colt HBAR looks different than the ones I have seen on sites and on my Bushmaster. The one on my Colt has the bottom of it milled away I think because the Colt has a sear block pinned in the rifle. I am guessing that I would have to buy one that fits a rifle with a sear block? The one on my Bushmaster looks identical to the ones I see pictured on BC's site. |
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Thanks for the link, I hate to keep beating this subject to death but the BCG on my Colt HBAR looks different than the ones I have seen on sites and on my Bushmaster. The one on my Colt has the bottom of it milled away I think because the Colt has a sear block pinned in the rifle. I am guessing that I would have to buy one that fits a rifle with a sear block? The one on my Bushmaster looks identical to the ones I see pictured on BC's site. Got one of those bastard Colt's. The block can be removed by ADCO, CLE and others I'm sure. Try the BM carrier. It should work It should not prevent your choice on carriers. Mine has a FA carrier and functions as designed. Damned large pin POS 458 |
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