I’m also thinking about doing this it would be more economical route than the 6.8
But
I would like to know what are the pros and cons to the 7.62 x39?
I believe I can I still use the regualar 223 or 556 lower?
what would be some good 30 round mags for it?
and are there any decent flash suppressor options for 1/2 x36?
Is there anything else I’m missing concerning this round?
A regular M-4/AR-15 lower will work with a 7.62 upper as far as I’ve seen… but buy spare extracter(s) as I’ve found out as of yesterday… after waiting on some where to freeze over and got my 7.62x39 barrel, BCG. shot about 100-120 rnds and the extracter broke of the tip. and good training for malfuntion drills… fail to feed, fail to extract, and fail to fire. 
and mag malfuntions:rolleyes:
Who makes a 7.62 x 39 upper for the Ar-15?
I have heard of the 5.45 x 39 but not the above, just wondering.
The only place I’ve seen was Model 1 Sales. I was considering building one (since I have 5k+ rounds of '39 for the AKs), but magazine availability/reliability and price led me to stick with 5.56.
At one point before the 1994 ban Colt used to make complete 7.62x39 AR’s. The lower was even marked with cal.7.62x39. However, there are NO good magazines over 10 rounds for these rifles. The franken mags have feeding issues and are not recommended. I would not get a 7.62x39 rifle with a 5.56 standard AR lower used a base.
I have the colt 7.62x39, I have the 5 mags for it, and about 1000 rounds sitting at home. it was the first AR I ever bought.
I do have the converted franken mag’s and they really seem to feed better than the other 7.62x39 mags.
I’ve seen that Bushmaster has the 7.62x39 round mags, and curious to know how well those functions.
My colt is marked with the 7.62 on the barrel and the upper. I will say, it does have more kick than the 5.56, and not too bad of a round.
I’ve tried to sell it over the years but can’t seem to get what I want for it. Overall the frankenmags are the best ones that I feel are the best ones for that round. the others seemed to jam up quite a bit. hope that helps.
DPMS (mags will be your hang up hard to find good ones)
I’ve got a self-assembled 7.62x39 upper using a 16" MGI carbine barrel. The only problem was finding a 1/2x36 muzzle device was a little difficult, I ended up using an RRA 1/2x36 9mm A1 flash suppressor. I use it with 30rd C Products magazines, never had an issue with them. Here’s a video of my dad shooting the upper on my M16.