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-   -   Bolt Carrier Group Discussion (http://www.firearmstalk.com/forums/f20/bolt-carrier-group-discussion-96374/)

Shade 09-01-2013 04:17 PM

Bolt Carrier Group Discussion
 
I have a Bushmaster AR-15, I have it in the A2 configuration, part
sentimentality and part it fits me well like in that configuration, that or a few
Gunny’s beat me into submission. Mostly, I shoot service rifle matches with
it as well as some coyote control; and it is one of my SHTF rifles, should that
need arise. I have been wearing out gas rings between 3,000 and 4,000
rounds, and that seems more frequent than it should be. Any thoughts on
that would be appreciated. I was thinking of an upgrade to a new bolt
carrier group (BCG). Reliability and longevity are my key aspects that I
want in a replacement/upgrade. Several that have come to the top of the
list are:

http://www.bravocompanyusa.com/BCM-Bolt-Carrier-Group-MPI-Auto-M16-p/bcm%20bolt%20carrier%20group%20auto%20mp.htm

http://www.brownells.com/rifle-parts/bolt-parts/bolt-carrier-parts/bolt-carriers/jpbc-2a-full-mass-bolt-carrier-sku452000130-45574-102057.aspx

http://www.aimsurplus.com/product.aspx?item=XDADBCG10016&name=AR15%2fM16+.22 3%2f5.56+Bolt+Carrier+Group&groupid=723

I am not married to any of the options above, they are just what I have
found researching the internet and those that had good reviews. Price is
always a consideration, but it is not a primary. Reliability and longevity are
primary. Price is flexible as long as the value is there.

All ideas and comments are welcome.

sweeper22 09-01-2013 04:32 PM

1) I love BCM's BCG. They're a little spendy, but rock solid. A year ago they were easy enough to land for like $150. Most of my personal guns have them.

2) You can also get a pretty great M16 BCG from PSA for $100-150. It's probably right near BCM quality, and this is where you're likely to get the most bang for your buck. PSA's stuff is constantly offered at blowout prices, it's just a matter of waiting a handful of days until a product/package that suits you gets listed on the cheap. Then pounce!

3) The only premium finish BCGs I like are cerakoted M16s. These can be found for $160-230. In my experience they cycle smoothly and are easy to clean. My preference are those produced by STS Arms. I think NiB is probably perfectly great and all, but I dislike both the blingy look and the often squeaky cycling sound. Personal preference.

There are others that are good. I also have a DD, which is fine. But the above three options are what I tend to count on and where I think you'll get the most value.

sweeper22 09-01-2013 04:54 PM

BUY THIS.

Don't hesitate. Don't look back. You win.

End of story.

JonM 09-01-2013 06:14 PM

bcm bcg are the best ones out there bar none.

but i dont think the bcg is the issue. bushmasters are normally way over gassed and this leads to greater wear on the internals. only fix for that is a different barrel.

Quentin 09-01-2013 07:39 PM

I also like the standard BCM unit. Good price for a great BCG. Sweeper's link to the PSA BCG plus 5 PMAGs is amazing, too. As Jon said a new BCG probably won't extend ring life much. 3,000-4,000 isn't horrible for ring life considering how cheap they are. Let us know which way you go and how it works out!

ETA:

By A2, does that include the A2 rifle stock? If carbine, you might try an H buffer or even H2.

Shade 09-01-2013 10:53 PM

Quote:

Originally Posted by sweeper22 (Post 1354001)
1) I love BCM's BCG. They're a little spendy, but rock solid. A year ago they were easy enough to land for like $150. Most of my personal guns have them.

2) You can also get a pretty great M16 BCG from PSA for $100-150. It's probably right near BCM quality, and this is where you're likely to get the most bang for your buck. PSA's stuff is constantly offered at blowout prices, it's just a matter of waiting a handful of days until a product/package that suits you gets listed on the cheap. Then pounce!

3) The only premium finish BCGs I like are cerakoted M16s. These can be found for $160-230. In my experience they cycle smoothly and are easy to clean. My preference are those produced by STS Arms. I think NiB is probably perfectly great and all, but I dislike both the blingy look and the often squeaky cycling sound. Personal preference.

There are others that are good. I also have a DD, which is fine. But the above three options are what I tend to count on and where I think you'll get the most value.

Great information! Thanks.

Quote:

Originally Posted by JonM (Post 1354109)
but i dont think the bcg is the issue. bushmasters are normally way over gassed and this leads to greater wear on the internals. only fix for that is a different barrel.

Had not hear this before. Is it that the port is drilled too large in the barrel?
What size should it be?

Quote:

Originally Posted by Quentin (Post 1354186)
I also like the standard BCM unit. Good price for a great BCG. Sweeper's link to the PSA BCG plus 5 PMAGs is amazing, too. As Jon said a new BCG probably won't extend ring life much. 3,000-4,000 isn't horrible for ring life considering how cheap they are. Let us know which way you go and how it works out!

ETA:

By A2, does that include the A2 rifle stock? If carbine, you might try an H buffer or even H2.

Full solid A2 stock, personal choice not to fond of the adjustable, and the
A2 fits me well.

But my younger son shoots a carbine AR, also a Bushmaster, tell me about
the H and H2 buffers.

Shade 09-01-2013 11:06 PM

1 Attachment(s)
My son and his carbine from today at the range. He had a friend sleep over
last night they "camped out" in the deer camp trailer, and after breakfast we
headed to the ISRA range in Bonfield, IL.

JonM 09-02-2013 02:43 AM

Quote:

Originally Posted by Shade (Post 1354398)
Had not hear this before. Is it that the port is drilled too large in the barrel?
What size should it be?


yup. depends on barrel length and ammunition that the barrel maker expects to be run through it or the end assembler requests.

i believe colt uses .063 for a carbine length 16"

makers like dpms, bushmaster, s&w market their guns and dont like to have returns so they tend to over size so they work with all civvy shelf ammo from 52grain to 75grain.

only drawback as you have discovered is its a little hard on the gas rings and rear portion of the bolt and gas key. most of these types of guns never see a round count in the thousands.

gas rings are cheap and 3000 is a typical count on overgassed guns to replace the rings. 3000 is also the typical point at which full auto m4 need to be changed. shorter gas tubes hotter gasses higher pressures more ring wear.

being over gassed isnt really bad since it tends to be more reliable if the buffer weight is selected for it. thats why a lot of makers do it. just need to keep an eye on the rings

Quentin 09-02-2013 02:15 PM

Quote:

Originally Posted by Shade (Post 1354398)
... my younger son shoots a carbine AR, also a Bushmaster, tell me about the H and H2 buffers.

Normally the H2 functions well with 16" and carbine gas, especially an overgassed BM or DPMS. But definitely hang on to the standard buffer which may be needed for weaker Tula. If you have to drop to an H (because of short stroking) you can swap a tungsten weight for a steel one in the H2 and standard and end up with two H buffers.

There's a current thread going now with more info.

Quentin 09-02-2013 02:20 PM

Also a fresh action spring (or heavier aftermarket spring) might soften the cycling of the A2 a bit.


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