NEA in 7.62x39 - The Guinea Pig thread :)
- Thread starter id64
- Start date
Those things were embedded in to the freaking ice! 
Had a chance to clean them up today
Had a chance to clean them up today Man there's alot of x39 brass on this range floor. You've been busy id64
Another 300 rounds of Czech ammo this time. No problems with the new bolt.
I've run maybe 100 rounds of Dominion FMJ through an NEA 7.62 upper, no issues so far other than a few light primer strikes, but I just put in an extra power hammer spring to see if that fixes it. The Dominion primers sit a little bit low to me.
What I did to eliminate light primer strikes is to shave off some material from the tail of the bolt to make firing pin protrude more a little bit.
Cone_Skid_Cone
Regular
- Location
- Grande Prairie
Sorry if this question has been asked, but I figured I'd save myself 17 pages of reading.
Are 7.62x39 lowers,uppers, and barrels completely dedicated? Or would it be possible to interchange any of these with .308 parts? Having mobility between parts would be a huge bonus.
Are 7.62x39 lowers,uppers, and barrels completely dedicated? Or would it be possible to interchange any of these with .308 parts? Having mobility between parts would be a huge bonus.
308 uses an longer AR-10 action, 7.39 uses the shorter AR-15 action. So no, no real compatibility between 308 and 7.39. I think I read that the new CMMG Mutant is built off an AR-10, but I'm not sure.
The parts are somewhat interchangeable with a typical 5.56 AR-15. The barrel and bolt are different obviously, but the rest of it is pretty much the same and use a typical AR-15 lower.
I have both 5.56 and 7.39 uppers for my AR.
I built the 7.39 upper using all the same standard AR parts just with the different barrel and bolt.
Cone_Skid_Cone
Regular
- Location
- Grande Prairie
Awesome response, thats exactly what I wanted to know. I assumed .308 as its in the 7.62 class. How much did it cost to build a reliable conversion? Is it really just a bolt and barrel??
Problem is, one does not simply buy a bolt and barrel. I scoured the EE and got lucky. Bought a complete unfired upper that someone imported and changed their mind about. Then I stripped it down, raping it for just the bolt and barrel.
Up until recently, you had to pay up the arshin for a complete upper or rifle by one of the more pricier name brands like PWS. Or you had to jump the hoops to import one.
Now NEA is starting to offer uppers are rifles, as our gracious OP is testing one for us.
SFRC has the upper, like $800 ish.
Building the upper is easy, getting it to work is tricky, maintaining it can be a pain.
MY particular upper I build using a CMMG piston kit, I had to open up the gas port on the piston gas block to get it to cycle as it was tuned for 5.56.
I didn't want to deal with corrosives in my action, I also kind of wanted to simulate a proper 7.39 rifle by using a piston action.
AR mags were not designed to cycle 7.39 ammo. You can get 7.39 AR mags, but your mileage may very.
I got ASC XCR mags from questar, I had to file the front and upgrade the followers. I thing SFRCs C-P XCR mags would work better as I got a C-P 5 round mag with my upper and it works great stock, well, I did have to cut one turn off the spring for it to fit the full 5 rounds. In the end, as long as I underload the ASC mags, they run 100%.
If you use cheap surplus ammo, it's corrosive, so generally you need to know your rifle inside and out and be able to clean it thoroughly and promptly.
My piston keeps the corrosives out of the action, so I just poor boiling hot water thru' the upper barrel and piston assy'. I will also rinse any other parts that are exposed to the fouling in the boiling water. Then clean normally.
If you run normal DI, well, I would assume you got to douche your whole action with the boiling water, like even the lower and trigger. This would require you to strip it more than normal and relube everything. I'm not sure, I've never run my system DI. With my piston, I get no fouling in the lower, and after over 1000 rounds there is no sign of rust in the action.
You can get, currently, non-corrosive ammo that is still cheaper than 5.56. One is Norinco ammo that the OP was having trouble with. I plan to try it myself soon.
I've been using Polish Surplus, works well. Tried some romanian surplus the other day, was more dirty.
Up until recently, you had to pay up the arshin for a complete upper or rifle by one of the more pricier name brands like PWS. Or you had to jump the hoops to import one.
Now NEA is starting to offer uppers are rifles, as our gracious OP is testing one for us.
SFRC has the upper, like $800 ish.
Building the upper is easy, getting it to work is tricky, maintaining it can be a pain.
MY particular upper I build using a CMMG piston kit, I had to open up the gas port on the piston gas block to get it to cycle as it was tuned for 5.56.
I didn't want to deal with corrosives in my action, I also kind of wanted to simulate a proper 7.39 rifle by using a piston action.
AR mags were not designed to cycle 7.39 ammo. You can get 7.39 AR mags, but your mileage may very.
I got ASC XCR mags from questar, I had to file the front and upgrade the followers. I thing SFRCs C-P XCR mags would work better as I got a C-P 5 round mag with my upper and it works great stock, well, I did have to cut one turn off the spring for it to fit the full 5 rounds. In the end, as long as I underload the ASC mags, they run 100%.
If you use cheap surplus ammo, it's corrosive, so generally you need to know your rifle inside and out and be able to clean it thoroughly and promptly.
My piston keeps the corrosives out of the action, so I just poor boiling hot water thru' the upper barrel and piston assy'. I will also rinse any other parts that are exposed to the fouling in the boiling water. Then clean normally.
If you run normal DI, well, I would assume you got to douche your whole action with the boiling water, like even the lower and trigger. This would require you to strip it more than normal and relube everything. I'm not sure, I've never run my system DI. With my piston, I get no fouling in the lower, and after over 1000 rounds there is no sign of rust in the action.
You can get, currently, non-corrosive ammo that is still cheaper than 5.56. One is Norinco ammo that the OP was having trouble with. I plan to try it myself soon.
I've been using Polish Surplus, works well. Tried some romanian surplus the other day, was more dirty.
The other thing that I did to mine - widened feeding ramps and also make them deeper. Now it feeds well from stock XCR mags and modified (filed) ones. Also feeding now is really smooth and reliable. I really like this new NEA bolt, extractor in particular. It's fatter than the original one. I got heavy buffer installed back and now it's really smooth, evenly distributed felt recoil.
Cone_Skid_Cone
Regular
- Location
- Grande Prairie
I'm currently sitting on a stockpile of 7.62x39 Norinco from a site sponsor.. at this point I'd rather use it up than drop cash on new crates of 5.56 or .223. $800 for a complete upper sounds great, but if I can get away with buying a few pieces I'd be a happy camper. Thanks for all your help!
You widened them ? Hmmm.
SO far, I haven't noticed any issues in my system width wise. Depth wise yeah. Sometimes when the gun jams, the nose of the bullet just misses the bottom of the feed ramp. I could see wanting them deeper down the action.
After extensive testing, I've found the only time that phenomenon happens, is when the tension in the mag causes the rim of the cartridge to hang up on the bumps on the feed lips. If the rounds can pass out out the mag smoothly, they always end up right on target up the ramps.
My barrel is stainless steel, I decided that modding the ramps would be more trouble than it's worth.
