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Posted: 9/4/2013 6:55:32 PM EDT
| I am just starting on a precision AR build. Does the type of BCG affect accuracy? |
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If I remember correctly some of the outfits selling stuff for match guns sell barrel and bolt as a combo . Not sure if they headspace them , fit them or just select ones out of the stack that fit correctly ..
I don't really know but the design of the AR bolt with the all around lugs seems like a big deal for accuracy |
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The Armalite bolt design is better for accuracy if nothing else.
I would suspect it increases bolt life also. I have personally seen a varmint rifle go from 1.5 MOA to .75 MOA with the Armalite mod applied to the weapon's bolt. All setups would not see that much of a change never the less it was an eye opener. BCG = Bolt Carrier Group So presuming the OP knows his nomenclature he asked about the carrier and bolt. |
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Quoted: He asked BCG, not bolt. And matched bolt means matched to the barrel. And it may affect accuracy, but minimally. Biggest factors are barrel, trigger, and user. Free floating barrel, having solid optics and sights, and ammunition. |
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Quoted:
The Armalite bolt design is better for accuracy if nothing else. I would suspect it increases bolt life also. I have personally seen a varmint rifle go from 1.5 MOA to .75 MOA with the Armalite mod applied to the weapon's bolt. All setups would not see that much of a change never the less it was an eye opener. BCG = Bolt Carrier Group So presuming the OP knows his nomenclature he asked about the carrier and bolt. What is special about the Armalite bolt design vice other brands of AR pattern BCGs? |
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A while back I tested that theory of different carrier groups and accuracy
and I got different results in groups. I had 4 brand new bolt carrier groups that headspaced good with a new upper and used the same ammo for the test. The first bolt carrier group gave me an average of about 1 .1 inch group at 100 yards, the second bolt carrier group gave me .75 of an inch, the third bolt carrier group was around .75 of an inch and the last bolt carrier group gave me a .300 group. This test was done with the gun bagged and clamped down on a bench. So in my case yes it did make a difference, maybe not a big difference to some but big enough for me if I wanted a extremely accurate gun at longer ranges. I did the same test later with three 9mm bolts and upper and got different results again. |
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Quoted:
He asked BCG, not bolt. And matched bolt means matched to the barrel. And it may affect accuracy, but minimally. Biggest factors are barrel, trigger, and user. Free floating barrel, having solid optics and sights, and ammunition. Trigger and user do not effect mechanical accuracy. Bolt does. |
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Quoted:
A while back I tested that theory of different carrier groups and accuracy and I got different results in groups. I had 4 brand new bolt carrier groups that headspaced good with a new upper and used the same ammo for the test. The first bolt carrier group gave me an average of about 1 .1 inch group at 100 yards, the second bolt carrier group gave me .75 of an inch, the third bolt carrier group was around .75 of an inch and the last bolt carrier group gave me a .300 group. This test was done with the gun bagged and clamped down on a bench. So in my case yes it did make a difference, maybe not a big difference to some but big enough for me if I wanted a extremely accurate gun at longer ranges. I did the same test later with three 9mm bolts and upper and got different results again. 1.1" Vs 0.3" is a big difference. |
| I don't think it does. I have been assembling and shooting ARs for a dozen plus years and have have switched bolts/BCGs around countless times and never noticed a change in accuracy with my precision builds. I don't see how the bolt would have any effect on accuracy as all it does is hold the round in the chamber; the chamber and barrel (bore and crown) are really are that matter. Steve from ADCO has weighed in on this subject before and he said the same thing, and he builds these things for a living. When companies sell "matched bolts" it just means they were headspaced with the barrel, it doesn't mean they are machined to match the barrel extension or anything like that. Get a good barrel and free float it, a good trigger to help the shooter and there you go. |
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I don’t know about swapping around regular bolts, but I have seen the Armalite mod work personally.
We shot a 24” barrel rifle and got 1.5 MOA, machined the bolt, went back to the range and shot .75 MOA. I have no doubt the results will vary between weapons. I was a military armorer in the 70’s and have been assembling and shooting ARs since then. |
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