Colt FSB Markings > AR-15 / M-16 Retro Forum

Posted: 4/7/2010 12:39:14 PM EDT

I just noticed that the FSB that came with that last kit has a mark I can't find reference to as Colt. Anyone seen this mark on a Colt FSB before:

If not I need to find out why.

Posted: 4/7/2010 1:25:41 PM EDT

[#1]

I've seen "B" in a diamond on Colts before. I don't know what the significance is except a guess; the letter indicates a certain casting house that was used.

Posted: 4/7/2010 1:30:19 PM EDT

[#2]

Thanks, Since it came with the kit and matches perfectly with the rest of the parts I have no reason to suspect it's not a Colt part ... but it's odd - I have seen the unmarked, the Bell with the C and the "F" but I don't think I've seen this one before. I can't find any reference to it over at RBR.

Posted: 4/7/2010 3:18:45 PM EDT

[#3]

From Ekie's "Colt's USGI M16 series variation guide edition IV" :

Mid to late M16A2 barrel has a raised Bfi marking inside a diamond, can be found on left or right side:

Sounds like it may be a A2 FSB. Does it have a round or square front sight post?

Posted: 4/7/2010 5:32:24 PM EDT

[#4]

My SP-1 carbine has a Bfi/diamond marked FSB. Definitely A1 barrel/sights.

Posted: 4/7/2010 6:48:19 PM EDT

[#5]

kilo905 - If you are willing, what are the first two digits of your SP 1 serial number and how many digits are there?

For example 15XXXX. I'm just curious to see what the date for that FSB is.

Posted: 4/7/2010 7:13:36 PM EDT

[#6]

Thanks, hk45shooter - I looked over at RBR but forgot to check Ekie's guide.

It has the round post - it's off of one of the M16A1 kits - supposedly from the mid to late 70s.

Posted: 4/7/2010 7:44:43 PM EDT

[#7]

For what its worth, I've seen these B marked FSB recently on M4's.

Posted: 4/7/2010 7:50:57 PM EDT

[#8]

Odd isn't it? This is a .625" - the other M16A1 kit had an unmarked FSB.

I'm assuming that it's the marking of a contractor for Colt? Or what?

Posted: 4/7/2010 7:58:30 PM EDT

[#9]

There is a current marking that is <B>1 and looks similar to the one you showed. I have it on a Tac Sol upper and a FSB I got from DEZ arms; both .750. Delton may use them, too. It is in the front, right side of the FSB.

Posted: 4/7/2010 8:10:47 PM EDT

[#10]

Quoted:
There is a current marking that is <B>1 and looks similar to the one you showed. I have it on a Tac Sol upper and a FSB I got from DEZ arms; both .750. Delton may use them, too. It is in the front, right side of the FSB.

That marking is similar to the one that Dodger has. Both my Model 1 and my ArmaLite upper have them.

Posted: 4/7/2010 8:16:31 PM EDT

[#11]

The first one to the rear of the FSB is Colt. The second one I have no idea, but it seems a lot of current companies use it. They are definitely different, but similar enough that if I saw them at different times I would probably confuse them or think they were the same thing.

Posted: 4/16/2010 10:36:07 AM EDT

[#12]

Quoted:

Quoted:
There is a current marking that is <B>1 and looks similar to the one you showed. I have it on a Tac Sol upper and a FSB I got from DEZ arms; both .750. Delton may use them, too. It is in the front, right side of the FSB.

That marking is similar to the one that Dodger has. Both my Model 1 and my ArmaLite upper have them.

http://i212.photobucket.com/albums/cc145/dieselpowrguy85/AR-15/100_3939.jpg

This is the one I was referring to, sorry, got them confused.

Posted: 4/16/2010 12:45:26 PM EDT

[#13]

The FSB is likely from a forging made by Bourdon Forge.

Harlan
NoDak Spud LLC

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