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Page AR-15 » AR-15 / M-16 Retro Forum
AR Sponsor: bravocompany
Posted: 9/29/2014 8:00:43 PM EDT
I was going through my parts the other night that came with some A1 kits I purchased about a year ago. So I'm looking at BCGs and this one caught
my eye because of some subtle differences. Any opinions on what it is would be greatly appreciated.

Color is parkerized  grey. Also it is non C marked







No markings on the bolt

For comparison: The top BGC is transitional non C marked
                           The center is the BCG in question
                           The bottom is a later C marked


Anyone ever seen a firing pin like this? This is what was in the BCG when I got it.


Link Posted: 9/29/2014 8:15:07 PM EDT
[#1]
they are earlish XM16E1 BCG, came out after the chrome and before they started marking them.  the enlarged hole on the side with the serrations can vary in size sometimes.
Link Posted: 9/29/2014 8:23:44 PM EDT
[#2]
Any comments on the staking and extra tool marks?
Link Posted: 9/29/2014 8:53:34 PM EDT
[#3]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Any comments on the staking and extra tool marks?
View Quote


Yes - it's been restaked. The original staking is on a longitudinal axis and 'pin marks. The side staking is the newer staking. Pretty common on early carriers. Nice BCG!
Link Posted: 9/29/2014 9:07:40 PM EDT
[#4]
My best guess is replacement BCG from one of many govt sub contractors and arsenal refurbed at least once and possibly more.  Pretty cool find as you don't see a lot of that stuff any more.  Bolt with relief on back side of lug is indicative of true milspec replacement for the era without MP stamping or such.
Link Posted: 9/29/2014 11:22:26 PM EDT
[#5]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
My best guess is replacement BCG from one of many govt sub contractors and arsenal refurbed at least once and possibly more.  Pretty cool find as you don't see a lot of that stuff any more.  Bolt with relief on back side of lug is indicative of true milspec replacement for the era without MP stamping or such.
View Quote


Dave, I believe you nailed it.
Link Posted: 9/30/2014 6:14:31 PM EDT
[#6]
Could it be a GM carrier? The horizontal machining marks & the ridges behind the firing pin retaining hole, along with the large hole on the right side for the firing pin retainer is my reasoning for thinking GM.

http://imageevent.com/willyp/firearmsalbums/uscoltarmalitem16ar15556/researchprojectsetc/hrgmproductionm16a1s?p=9&n=1&m=-1&c=4&l=0&w=4&s=0&z=9
http://imageevent.com/willyp/firearmsalbums/uscoltarmalitem16ar15556/researchprojectsetc/hrgmproductionm16a1s?p=10&n=1&m=-1&c=4&l=0&w=4&s=0&z=9
Link Posted: 9/30/2014 6:30:43 PM EDT
[#7]
The gas key is chrome lined so current production
Link Posted: 9/30/2014 6:46:35 PM EDT
[#8]
Looks pretty clean too, only a couple areas of wear. The chrome lined key with the extra staking is kind of unusual. Newer key, newer bolt?
Link Posted: 9/30/2014 8:30:51 PM EDT
[#9]
I've never seen a firing pin like this.
Link Posted: 9/30/2014 10:09:03 PM EDT
[#10]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I've never seen a firing pin like this.
View Quote


Very well could be could be a field replaced gas key but it's definatey a GM BCG. Cdemark, hk45shooter, and Hal hit it on the head.
Link Posted: 10/1/2014 12:03:11 AM EDT
[#11]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
The gas key is chrome lined so current production
View Quote


They've been chrome lining the carrier key since the beginning.  The first BCG's were all chromed, and then they settled for chome lining the bolt recess in a parked carrier, as well as chrome lining the carrier key.  The carrier key is also made from a softer steel if you look at the TDP, so that the anodized aluminum wins against it when articulating together.

Basically, any area with hot pressurized gases acting on it is supposed to be chrome lined, aside from the gas tube, which is stainless steel tubing.  Stoner would have mandated entire chome plated bolt carrier groups, but the Army wanted to cut costs, but then turned around and added abortion assist.
Link Posted: 10/1/2014 12:26:02 AM EDT
[#12]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


They've been chrome lining the carrier key since the beginning.  The first BCG's were all chromed, and then they settled for chome lining the bolt recess in a parked carrier, as well as chrome lining the carrier key.  The carrier key is also made from a softer steel if you look at the TDP, so that the anodized aluminum wins against it when articulating together.

Basically, any area with hot pressurized gases acting on it is supposed to be chrome lined, aside from the gas tube, which is stainless steel tubing.  Stoner would have mandated entire chome plated bolt carrier groups, but the Army wanted to cut costs, but then turned around and added abortion assist.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
The gas key is chrome lined so current production


They've been chrome lining the carrier key since the beginning.  The first BCG's were all chromed, and then they settled for chome lining the bolt recess in a parked carrier, as well as chrome lining the carrier key.  The carrier key is also made from a softer steel if you look at the TDP, so that the anodized aluminum wins against it when articulating together.

Basically, any area with hot pressurized gases acting on it is supposed to be chrome lined, aside from the gas tube, which is stainless steel tubing.  Stoner would have mandated entire chome plated bolt carrier groups, but the Army wanted to cut costs, but then turned around and added abortion assist.


THIS. The fact it has early staking shows that it is the original key as far as I'm concerned.
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