That's a pretty good group for 100 yards with green-tips.  (even counting the left flyer  )  I haven't shot green tips in a while, but I have come not to expect much when I do shoot them.  I certainly don't expect match level results.  Haha

I bet that 1-6x optic would've been fun for when there was still steel plates out beyond the berm.  That was one of the more entertaining aspects of the kokohead range.   

That's a pretty good group for 100 yards with green-tips.  (even counting the left flyer  )  I haven't shot green tips in a while, but I have come not to expect much when I do shoot them.  I certainly don't expect match level results.  Haha

I bet that 1-6x optic would've been fun for when there was still steel plates out beyond the berm.  That was one of the more entertaining aspects of the kokohead range.   

thanks.
could be a little luck helped me with that grouping
I didn't post the other 6 targets I shot that day, they weren't that great.
 

got that 2nd build done yesterday.  i think i have an addiction now.   

parts are:
Spikes tactical lower
joe bobs lower build kit, ACT/ALG combat trigger, magpul MOE carbine stock and pistol grip
PSA upper 16"with 13" KMR, PSA m16 bcg, generic ch

this time the build went about the same speed bc i bent one of the pins, the one that secures the bolt catch
so i had to bend it back
then i forgot to put in the recoil spring and i pulled back the charging handle the instant that i remembered i didnt put in the spring
so i had to backtrack and remove the buffer tube to get the bcg out, then put it all back together again
rookie mistakes, but a learning experience, so no big deal in the end

again I am satisfied with the results
now to go to the range and test it out
no optic yet, just going to use magpul pop up iron sights for now
waiting for a new optic to come out, its a 4-14x44 platform, and its going to kick *** on this AR!

Nice thread, just picked up 2 Spikes lowers to build in the future.  I also thought about building the lower and buying a complete upper but can't seem to find a 18/20" upper I want, already have a Carbine.

Nice thread, just picked up 2 Spikes lowers to build in the future.  I also thought about building the lower and buying a complete upper but can't seem to find a 18/20" upper I want, already have a Carbine.

i've been looking at parts lately, and seems to be a shortage on barreled uppers
a lot of the lower end stuff, but after that everything is pretty much sold out for now
maybe gotta wait for a while to build supply

not a new build
I just got a Radical Firearms upper in 7.62x39 and installed onto one of my existing lowers (spikes lower with all milspec parts and magpul stock)
upper came with 7.62x39 bcg
added an optic I had laying around (Primary arms 1-6x24)
also got a couple ASC 7.62x39 mags
I might test it next week

Nice!   

Looking forward to seeing how that setup shoots. 

The angle at which the mag comes out of the magwell just looks so strange since I'm used to seeing 5.56/.223 mags. 

I got to shoot a friends AR chambered in 7.62x39 this past weekend, and it shot really good.
I hope mine shoots just as well.

I ordered 2 more C products mags
there has been some reliability issues with shooting this caliber in an AR, we shall see how mine holds up.

I dremeled all my asc mags front lip. And polished the dimples in the direction of the bullet entering the chamber and smooth the top part of mag (the part between front lip and the part which holds the bullet in the mag) sorry dunno technical terms. Mine all feed 100% so far. I just used sand paper (2k grit) except the front lip which I used a dremel.

Hope the helps if you have feeding problems . If you stare at an ak mag you'll noticed the front lip is much lower than a standard 556 mag. Prob cause of the OD of the projectile.

Good luck and have fun

I got to shoot a friends AR chambered in 7.62x39 this past weekend, and it shot really good.
I hope mine shoots just as well.

I ordered 2 more C products mags
there has been some reliability issues with shooting this caliber in an AR, we shall see how mine holds up.

I am curious as to the difference in recoil compared to the 300 BLK?

Nice build.

Where are you ordering the mags from ?

I dremeled all my asc mags front lip. And polished the dimples in the direction of the bullet entering the chamber and smooth the top part of mag (the part between front lip and the part which holds the bullet in the mag) sorry dunno technical terms. Mine all feed 100% so far. I just used sand paper (2k grit) except the front lip which I used a dremel.

Hope the helps if you have feeding problems . If you stare at an ak mag you'll noticed the front lip is much lower than a standard 556 mag. Prob cause of the OD of the projectile.

Good luck and have fun

thanks, I'll keep this in mind

I am curious as to the difference in recoil compared to the 300 BLK?

It's been a while since I shot a 300blk, but the 7.62x39 AR recoil wasn't that bad at all

Nice build.

Where are you ordering the mags from ?

the 30 round ASC was from Primary arms.  was hard to find mags in stock.  some places don't ship to Hawaii.  palmetto state was sold out
and the 10 round C products was from ebay since the ones I ordered were only 10 rounds

the rifle I fired this past weekend was c products and was unmodified and fed no problem

i'll try cycling some rounds tonite and see how it does

did a little ammo chambering test last night.  the mags do look like how aaron described it above.
first I just loaded some ammo into the ASC mag and pushed it out with my thumb.  came out easy, but the last round was more difficult to push out bc it sits lower behind the front part of the mag.
besides the last round, the other rounds sit above the front part of the mag.  so thought if anything the last round might give me trouble.
next I loaded the rounds in the mag, locked the bolt back and put it on safe.  inserted the mag and chambered the rounds by pressing the bolt release and ejecting the rounds by pulling back the ch, and then did it again by pulling the charging handle back and releasing it.
all times it chambered the rounds even the last one, no problem.
next up is the range test.   

did a little ammo chambering test last night.  the mags do look like how aaron described it above.
first I just loaded some ammo into the ASC mag and pushed it out with my thumb.  came out easy, but the last round was more difficult to push out bc it sits lower behind the front part of the mag.
besides the last round, the other rounds sit above the front part of the mag.  so thought if anything the last round might give me trouble.
next I loaded the rounds in the mag, locked the bolt back and put it on safe.  inserted the mag and chambered the rounds by pressing the bolt release and ejecting the rounds by pulling back the ch, and then did it again by pulling the charging handle back and releasing it.
all times it chambered the rounds even the last one, no problem.
next up is the range test.   

Do you have an AK (7.62x39)?  Just thinking it would be great for a side-by-side comparison between the two.  I'm thinking more stuff like differences in perceived recoil impulse, muzzle movement, etc. 

Do you have an AK (7.62x39)?  Just thinking it would be great for a side-by-side comparison between the two.  I'm thinking more stuff like differences in perceived recoil impulse, muzzle movement, etc.

yes, I have an Arsenal sgl21 and wasr10 (the wasr will probably be sold soon)
I can do a little side by side comparison.  as best I can do at kokohead.

yes, I have an Arsenal sgl21 and wasr10 (the wasr will probably be sold soon)
I can do a little side by side comparison.  as best I can do at kokohead.

Awesome!  Yeah, a side-by-side comparison, even a brief one would be great! 

I often get caught up in option A or option B and usually have to try for myself since I can usually find opinions on option A and another person's opinion on option B.  But not often a direct option A vs option B comparison. 

Not to hijack the thread...

I let my friends shoot my arx39 (both of them) and my ak47 (ddi stamped version). The recoil on my girls arx39 shoots the softest. It's a mid length barrel- gas port is .099", FA bcg, 5.5 oz. buffer, tubbs buffer spring (watch YouTube on his explanation- pretty informative) the Wolff xp spring may work well too but haven't tried it. I only had a 5.1 oz buffer on my arx39 at the time. Mine is also very manageable and on par with friend 300 bo or slightly softer. I just put in an extra steel insert so now it's 5.7 oz.  girls x39. Definitely Shoots softer than my friends 300 bo and his duty colt 5.56. His 300 bo is rainier arms barrel carbine gas with .104" or .106" gas port (I forget), h buffer, FA bcg too. He was shooting supers that day and I was shooting fiocchi and American eagle x39 fmj out of mine. Of the couple hundred rounds that day only one jam but I blame ammo. Tried the fiocchi fmj x39 in my arx39. I blame ammo cause I knew a lot of the bullets were seated crooked. No joke! Oal were in spec and chambered manually before range trip so I just shot it anyway. Didn't care if it blew up cause that'll give me reason to make a new rifle  lol. - exaggeration of course.

Funny thing is I haven't shot my own ak yet cause I was having too much fun sighting in and messing with my arx39 and time ran out and had to leave. Oh well. My friend said my ak shoots nice as well. Have m472 muzzle brake and alg recoil spring. Stock g2 trigger.

Edit: my x39 has a slr synergy brake and the other has a vg6 gamma. Maybe muzzle brakes make difference too.  mine looks like a battlecomp/ griffin armament brake with front prongs and the gamma is an actual brake with squarish side ports . The ak brake is fucking loud but after much reviewing it looked to be the best (not for the people sitting on my left or right at the range tho) to keep muzzle from slinging right. I shot an ak once before with a welded thread protector looking thing. Had a metal buttplate that felt like no parking sign pole.. I was use to ctr and standard plastic m4 stocks at the time I shot that ak. The only reason I got an ak was because of my arx39 rifles lol.

OP - if you plan on keeping the x39 upper, might wanna buy an extra bolt. They are known to break with steel ammo which is why I'm only shooting brass. Plus it's cleaner and don't have to worry bout corrosive ammo. Brass works good in ak's too lol. Expensive but works.
Does corrosive ammo affect aluminum (say 6061 or 7075) like how it does steel?
Good luck with your testing and have fun!

An answer to my own question

https://www.thehighroad.org/index.php?threads/ar-15-and-corrosive-ammo.588983/

I always thought it'd be a PITA. I'm OCD so I'd take forever cleaning it.

Thanks for the info, aaronc 
That is very helpful
I think I'll get some brass ammo as well