7.62x39 upper same as 5.56?

[Dolt]

Gemmuns: I want to build an A4 upper in 7.62x39. Are the 5.56 upper receivers interchangeable with 7.62x39?

[bug]

Yes, everything is the same except the bolt. You'll need a 762 bolt but carrier is the same.

[Litt'le Lee]

you can use 10-15-20 rd. 223 mags for 6 or so rounds-no change on stock springs-I built 2-1 with collsp. stock and one with A1 stock-both 16 " barrels-very accurate with hand loads and horn bullets

[Dolt]

Bushmaster does not seem to sell stripped a4 uppers anymore. Any suggestion who to by the upper receiver from?

[gwp]

Bushmaster does not seem to sell stripped a4 uppers anymore. Any suggestion who to by the upper receiver from?

After a quick search this is what I found.

Brownell’s has Bushmaster stripped uppers:

http://www.brownells.com/rifle-parts...458-51869.aspx

This is the lowest priced complete 7.62x39 upper I could find, using coupon code SG762X39MID it is $400. The code is good till the end of the month.

http://www.slickguns.com/product/16-762x39-upper-38995

http://www.shop.ar15hardware.com/pro...&categoryId=58

44mag.com has 7.62x39 magazines for the AR:

http://www.44mag.com/category/7_62_x_39_ar_15_magazine

[da gimp]

Rock River makes exc. quality uppers, lowers & complete rifles.... John Holligen of WhiteOak Precision, arguably the best service rifle in the USA uses nothing but RR uppers .............. or did anyway.. I haven't talked to him in quite some time.

[Dolt]

The one from Brownells looks like a great deal. So since I am going to barrel it for 7.62x39 does it matter if it has the M4 ramp cuts?

[gwp]

The one from Brownells looks like a great deal. So since I am going to barrel it for 7.62x39 does it matter if it has the M4 ramp cuts?

It is best not to mix M4 receiver cut with rifle cut barrel extensions. Most of the current receivers have the M4 cuts and most of the current barrel extensions have the M4 cuts. In an older barrel with the rifle barrel extension, the feed ramps can be matched by careful filing or grinding if the rifle is not feeding correctly.

[Dolt]

Thanks to everybody for their help. As usual, the research done on this site helps a great deal in making my decisions. I purchased the upper from slickguns, and it includes the bolt carrier and bolt. Total with mailing is $422.00, which I think is a great deal. I purchased a EOtech on special from Cabelas, and with my purchase points I ended up paying $269.00 for it. I will see how the whole package goes together and let everyone know. Thanks again guys and gals.

[SpearheadOrd]

I have 2, a Colt HBAR Match Target lower w/ a Colt factory 7.62x39 factory upper and a 11.5" n AR Pistol. Both shoot great. Colt originally used a different weight buffer ( from the 5.56) for the rifle. Colt should be able to tell you the weight. I am using the new ASC and Promag "30" round caliber specific mags w/o any issues. Nice thing is the factory Colt barrels are .308 so reloading bullet selection is not limited. Hopefully your barrrel muzzle threading is 5.56 standard. Colt barrels have a 36 thread pitch on 7.62x39 and 9mm barrels so had to get a specific thread adapter to let me install Troy Claymore muzzle breaks.