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View Full Version : BCG 'BOTTOMING OUT?!?!'


supersonic
11-07-2009, 8:48 AM
See if any of you guys can figure this out, because I'm friggin' flabbergasted. I finished building a retro 'Pre-Vietnam Prototype' XM-16E1 with an NDS-32 carry handle 'trigger' charging handle upper receiver. I used an A1 stock with a rifle-length extension & same-same on the buffer. As far as I know (unless I'm missing something obvious!), all the parts I used appear to be correct. Here's the problem: when I pull the BCG back to chamber the first round, it BOTTOMS OUT about 1.5 inches short of clearing the ejection port. And, of course, the buffer is slamming against the rear inside surface of the receiver extension. WhatTF??????:confused:

Trendkill
11-07-2009, 9:10 AM
See if any of you guys can figure this out, because I'm friggin' flabbergasted. I finished building a retro 'Pre-Vietnam Prototype' XM-16E1 with an NDS-32 carry handle 'trigger' charging handle upper receiver. I used an A1 stock with a rifle-length extension & same-same on the buffer. As far as I know (unless I'm missing something obvious!), all the parts I used appear to be correct. Here's the problem: when I pull the BCG back to chamber the first round, it BOTTOMS OUT about 1.5 inches short of clearing the ejection port. And, of course, the buffer is slamming against the rear inside surface of the receiver extension. WhatTF??????:confused:

Good thing you didnt just go ahead and test fire that thing...

I dont know too much about the older stuff....but it sounds like either the receiver ext is too short or the buffer is too long.

supersonic
11-07-2009, 9:14 AM
Good thing you didnt just go ahead and test fire that thing...

THAT, my friend, is why function-checking EVERYTHING is always so important, especially when building your own firearm from scratch.:cool:

Well, would an "A1" tube (which fits the A1 stock) be shorter than an A2 rifle tube? And then, if the answer is "YES," that must mean that there is a specific buffer that is "A! compatible???"

Trendkill
11-07-2009, 9:19 AM
THAT, my friend, is why function-checking EVERYTHING is always so important, especially when building your own firearm from scratch.:cool:

Well, would an "A1" tube (which fits the A1 stock) be shorter than an A2 rifle tube? And then, if the answer is "YES," that must mean that there is a specific buffer that is "A! compatible???"

Not sure....but something doesnt add up. I think it may be a buffer issue.

shark92651
11-07-2009, 9:23 AM
Did you cut down the buttstock screw? Since the A1 stock does not use the spacer you need to take a hacksaw to the screw and take off 3/4"

Trendkill
11-07-2009, 9:24 AM
From what I've seen...the a1 / a2 buffer's and tubes are the same...maybe something is just way out of spec....or mis-marked somehow.

supersonic
11-07-2009, 9:24 AM
I'm going to pull the stock right now. Someone over on ARF.COM mentioned that the stock screw could be an A2, which is like 1.5" longer than the A1 type. This would mean that the screw is blocking the buffer from moving any further. Who Knew??? We'll see.

supersonic
11-07-2009, 9:55 AM
Did you cut down the buttstock screw? Since the A1 stock does not use the spacer you need to take a hacksaw to the screw and take off 3/4"

It appears you are correct. The screw is definitely preventing full rearward travel of the buffer. Whew! I thought it was something right in front of me that I should have absolutely known! But this is my first ever A1 experience, so one little 'chink' is not bad, considering the rest of the rifle appears flawless. Thanks, guys, for the lightning-fast responses. Cheers.
-Scott

Trendkill
11-07-2009, 9:56 AM
It appears you are correct. The screw is definitely preventing full rearward travel of the buffer. Whew! I thought it was something right in front of me that I should have absolutely known! But this is my first ever A1 experience, so one little 'chink' is not bad, considering the rest of the rifle appears flawless. Thanks, guys, for the lightning-fast responses. Cheers.
-Scott

Cool.....cut that thing down and shoot that bad boy.

Josh3239
11-07-2009, 3:42 PM
http://pkfirearms.com/product_images/0000/1193/item_1145.jpg

Trendkill
11-07-2009, 4:44 PM
http://pkfirearms.com/product_images/0000/1193/item_1145.jpg

The blue pill...or the red pill....???Hmmmm

gemini1
11-07-2009, 5:29 PM
Blue pill! A1 is shorter and dont need a spacer so shorter screw is needed.

goober
11-07-2009, 5:43 PM
http://pkfirearms.com/product_images/0000/1193/item_1145.jpg

thats what i was gonna say :D

paladin4415
11-07-2009, 6:27 PM
And the pics of this new rifle are where?

jasonnorcal
11-07-2009, 6:28 PM
Where's the pics :shrug:?

supersonic
11-17-2009, 5:45 AM
OKAY! OKAY! Here it be. This is an XM16-E1 Clone with an ULTRA-rare Armalite prototype upper receiver with the Gen. 1 Charging Handle (inside of the A2-style carry handle). There were only a few of these uppers ever made (<20, IIRC - this one's an NDS replica). Enjoy Ladies!

http://i205.photobucket.com/albums/bb181/giftedgiver/DSCN0026.jpg
http://i205.photobucket.com/albums/bb181/giftedgiver/DSCN0028.jpg
http://i205.photobucket.com/albums/bb181/giftedgiver/DSCN0029.jpg
http://i205.photobucket.com/albums/bb181/giftedgiver/DSCN0030.jpg
http://i205.photobucket.com/albums/bb181/giftedgiver/DSCN0031.jpg

jaq
11-17-2009, 6:18 AM
THAT is supercool! Thanx for sharing :)

badtrout
11-17-2009, 6:30 AM
THAT is supercool! Thanx for sharing :)
x3
That charging handle is very cool!

goober
11-17-2009, 6:51 AM
nice.
w/ NDS making those retro uppers there are probably more replicas now than there ever were originals :chris:

run8
11-17-2009, 7:29 AM
Yuppers, I learned that just recently about the buffer screw, I kept thinking why won't this darn screw (the A2) go into the buffer tube, then it clicked, ah there was a reason I bought the A1 screws, lol.

run8
11-17-2009, 7:32 AM
Very nice photos, I'm doing the same thing, though I think my lower isn't the right one, darn I knew I put the wrong one together, see what I get for not studying my books.

I just need to get my barrel anodized to match, it's from a Colt upper and is black.