AR Pistol in 7.62x39

[lar45]

Hi Everybody, I ordered a new toy to keep me occupied during the great quarantine of 2020. It's an AR in 7.62x39. It should be coming in tomorrow.
https://p1.gunbroker.com/pics/860371000/860371617/pix217005890.jpg

I checked my 30 cal molds and all I have is the 311041 in plain base and gaschecked, the RD TLC311 165 RF, original and improved, I have an NOE 30XCB and the 190gn Fat 30 also.

I've been reading though a bunch of the old posts. and it seems like guys are shooting various 150s. Has anybody tried the Ranch Dog 165 in the little Rooskie?
I could get a new mold to go with it if needed. I'll have to do a chamber cast when I get it and see what size it might prefer.
I'm open to any thoughts.

[cupajoe]

Probably all molds you have will work if powder coated to get the diameter up to spec. As far as what to push it with I don't have a clue what will work with that gas setup, probably the same powder the 300 BO guys use. I am having good luck in the Ruger American Ranch with the RD offering for that Rooski round but I don't know if it will feed in an AR. It feeds in a mini 30 but damages the meplat a bit in the process. The RCBS 130 SP would probably shine if you don't mind a pointy one. I believe Corky is using that one in the Hammer albeit with a much longer gas system.

[rockrat]

I would think the 30xcb would work well. Ya gonna have a bit of muzzle flash there!!!

[fcvan]

I built an AR Pistol for 300 BO with a 10" barrel. Subsonic loads are cool using the Lee 309-230 5R, for Supers I have a Lee C309-150 RF, and an NOE C309-150 3R. The 300 BO is a fun shooter and I did not experience too much muzzle flash. My 7.5" 223/5.56 on the other hand is is so loud it is obnoxious . . . but I like it! I have the 223/5.56 downloaded using a cast boolit that normally gives my 16" carbines 2250 FPS, and I think the 7.5" only getting about 2000 FPS.

Your 7.62X39 should be a real fine distraction. I went on an AR building kick a few years ago which cost me double what most people are charged. It could be that if I build 1, the first one goes to SWMBO, and she really likes her AR 15 in 9mm using Colt stick mags. Sure, I could get the Glock mag adapter but then I would probably have to get my SIL a Glock to go with his 9mm AR.

I look forward to hearing range reports from your new acquisition.

[lar45]

They sent me the wrong Caliber!
It's a 223 Wylde, not 7.62x39.
I couldn't see the caliber marking on the barrel because it was covered by the barrel shroud.

[cupajoe]

Dangit, keeping it or sending it back?

[lar45]

Sending it back. Unless they want to send me another one at a huge discount, lol. I don't know if the wife would go for that...

[jdfoxinc]

Just received my 7.62x39 pistol upper from delta team tactical.

[PositiveCaster]

What bore diameter? Some makers chamber 0.311” barrels, some use 0.308”. It matters of course...


.

[lar45]

When it finally gets here I'll slug the bore, do a chamber cast and let you know.
I'm still waiting on them to send me a return shipping label.
I emailed and suggested that they just sell me a 7.62x39 upper and then they wouldn't have to pay shipping back and forth and should be alot less paperwork... They said that they had to have this one back, so maybe they shipped out the wrong serial number and need it back to make their books straight?
I've got some excellent looking 150gn RD powder coated boolits sitting here just waiting to know how deep to seat them.

[cupajoe]

So Glenn, what company made that pistolla and how long is the barrel ? That ought to be a hoot to shoot!!

[lar45]

Federal Arms in Fort Smith AR. The barrel is 7.5".
I picked up one of the Tromix linear comps to help with the muzzle blast.
https://tromix.com/wp-content/uploads/2018/06/Lin-Comp-7.jpg
The inside and end comes out so you can clean it. Should help with shooting cast in it.
I put one on my 450 Bushmaster and really like it.

[Cosmic_Charlie]

If you can find a subsonic cast load that cycles reliably you will have a really fun steel clanger.

[cupajoe]

Really looking forward to a range report, and maybe seeing one (video) also. The comp is threaded 5/8-24 ? Looks like it may be easier on the ears compared to "regular" comps I have used on rifles.

[PositiveCaster]

Linear comps, especially the longer ones, do reduce concussion from short barrels and do deflect some of the sound away from the shooter. The one the OP has is a nice concept since comps do load up with lead and powder fouling, taking it apart for cleaning is a great idea. The downside is that it weighs about four times what an A2 flash hider weighs ( 8 oz vs ~2 oz). That may or may not matter to many, just a point to consider.



.

[lar45]

Well, I finally have it.
http://www.lsstuff.com/pics/ar-pistol/762p-01.jpg
This time it showed up in the correct caliber. The castle nut for the buffer tube was loose, the muzzle device was barely tight. At least the handgaurd was alligned with the upper so the rails were at the same angle. On the first one it was off by more than a little bit.

I got it sighted in and started testing the different factory ammo for accuracy, nothing was spectacular, then I noticed that the quick detatch base had come loose from the scope mount. So I locktited that back together and got it rezeroed.
I kept having problems with misfires with Tulammo. It looked like light primer strikes. If I loaded the same round and tried it again, then it would fire.
http://www.lsstuff.com/pics/ar-pistol/primer-01.jpg

I tried some Win FMJs and they all fired without a hitch.
Cupajoe found a longer firing pin, so I ordered a couple of those along with a Wolff extra power hammer spring. Hopefully that will help.

I have some different cast loaded to try next.

[rtyler8140]

Could just be the angle, but it looks like that primer in the Tulammo is set pretty deep. I've had some issues with Tulammo before. I've found Wolf to be a little better as far as cheap ammo goes.

[popper]

How much does the tromex help? Another one doesn't have the baffles.

[rockrat]

Firing pin should correct things. Had to modify mine on one of my x39 uppers to work with steel cased ammo

[lar45]

The Tromix linear comp works great on the 450 Bushmaster, I can hunt with it without hearing protection and don't notice it.
I didn't shoot the 7.62x39 pistol with the stock muzzle brake, so I can't give a direct comparison. It's not bad to shoot with earplugs in, but I don't think I want to try it without.

[popper]

I have a 10" BO pistol, use 170PB PC (my RD version) @ 14-1500 fps. Not so much looking for noise reduction but heard linear comps will redirect recoil without the 'side' blast of a brake. I also use 145gr GC @ >2k in the pistol and it is a bit hard to handle. Heard also the nite flash is less. One I was looking at had no insets, just a solid 'cone' compensator. Also (not too worried about BATF) length over max allowed.
For a kinda frugal guy, is it worth the $?

[Burnt Fingers]

https://www.blackriflearms.com/AR-15-762x39-Enhanced-Firing-Pin_p_9.html

Highly recommended!

[lar45]

The Tromix is just over $100 and a high quality piece.
I looked pretty long and hard at this one.
https://www.kawvalleyprecision.com/KVP-Magnum-Linear-Compensator-p/kvp-mag-325.htm
https://cdn3.volusion.com/thomg.adnuo/v/vspfiles/photos/KVP-MAG-325-2T.jpg

[WinchesterM1]

I just shot this out of my Ruger ranch in 7.62x39 with the NOE 165 RD with a deep hp260286

[lar45]

I'd be very happy with that :)
I have a cabinet full of powder, but no Varget.
Did you measure the velocity of your load?

[charlie b]

I just shot this out of my Ruger ranch in 7.62x39 with the NOE 165 RD with a deep hp260286

Was that at 100yd?

I had not heard of those comps. Looks like a great application. Now I wish my .308 had a threaded muzzle :)

[Dapaki]

Thats a small group for the x39! NICE!

I am casting the CTL312-160-2R for my x39 from BCA, it does have a 16" barrel though. I too had a few steel cased light strikes and thought I would have to do the same with the firing pin and spring but BCA told me to just put 200 rounds through it first (Yes Sir!) and sure enough, it just needed to be broken in.

I have shot Golden Bear and Tula through it with pretty good results. 2" at 25 yards off hand is just fine for my use! I cannot beat the accuracy of boolits with J-words no matter who makes them, it may be just my gun but I read plenty of people having the same results. I do PC my boolits though, no GC's, no need.

IMR 4198 seems to give me the best results but 2400 may be a little more thrifty and it may work better in the short barrel. Here is a link to C.E. Harris Practical Dope: http://castboolits.gunloads.com/showthread.php?13453-Practical-Dope-on-the-7-62X39&p=151614&viewfull=1#post151614

[lar45]

I may have found the problem with the light primer strikes. The hammer spring was put in backwards. That probably explains why the trigger pin was walking out.
There is lots of slop between the upper and lower, so I layed in some thin strips of Aluminum tape. I'll shoot it tomorrow and see if that improves the accuracy. If it does, I'll probably have the top of the lower ceracoated very carefully to get rid of the slop.

[cupajoe]

Glad you are getting things sorted out. Looking forward to some good news.

[popper]

300BO with 170 PB (RD style) PCd over 8.5gr A2400. 10" 1:8 AR pistol, 10 shot 1 sec/shot mag dump - 50 yds. ~ 1400 fps. Fun.
260501

[Tracy]

I have a 10" BO pistol, use 170PB PC (my RD version) @ 14-1500 fps. Not so much looking for noise reduction but heard linear comps will redirect recoil without the 'side' blast of a brake. I also use 145gr GC @ >2k in the pistol and it is a bit hard to handle. Heard also the nite flash is less. One I was looking at had no insets, just a solid 'cone' compensator. Also (not too worried about BATF) length over max allowed.
For a kinda frugal guy, is it worth the $?
Max allowed? State law?

[WinchesterM1]

My load was going around 1800fps and yes that was 100 yards

[cupajoe]

That is a very nice load in that Ruger bolt, plain base, gas checked? I have that mold I bought from Michael, I will have to give it a try.

[lar45]

Well, I did a chamber cast last night and the barrel is .301"x.306" !!
I don't know if I should send the whole thing back, or just get a new barrel at this point.

[popper]

Ordered the KAW Thursday, got it today, nice looking.
IIRC, 26" length limit for pistol, batf.

[lar45]

I picked up a new barrel yesterday at the LGS . Just did a chamber cast and it is .301x.307 what gives? The throats on both are .312

[popper]

KVP comp (magnum 308) does reduce sound a noticeable amount from the pistol. Not that I'd go without muffs, but some. Cleaned it today after ~ 50 rnds cast. Dumped in US with kerosine - no fire. Washed the lead particles out OK, not all the powder residue. Have to keep the threads clean as it comes off to clean the barrel - don't want patches stuck in it. Shooting 357mag level cast, not much recoil. No diff. for full power loads. Tromix looks neat but wonder if the threaded insert will stick.
Barrel hadn't been cleaned for ~500 rnds, so blasted some speckles out.
260848

[Lloyd Smale]

give the rcbs 130 spitzer gas check a try. I use it in the BO and its very accurate. I don't know for sure but id guess it would go fat enough out of the mold for a 762x39. I KNOW it would with pc on it. Ive pushed that bullet to 1900 out of blackouts and get 2moa or better at a 100 yards out of my scoped 16 inch gun and my American and at least that out of my two ar pistols at 50 with red dots on them.

[lar45]

Thanks Lloyd , I don't have that mold, but may have to get one.
Fed Arms emailed me back about the undersized barrel and said they are looking into facilitating a new barrel. It's been a few days since I've heard from them, so I hope they're still working on getting a proper barrel.

[lar45]

I've done chamber cast on 2 different barrels and it appears that they are using standard .308" barrels with a 7.62x39 chamber. The throats are around .312", but the groove is .306-.307". So with that big of a squeeze, do I still size to the throats, or try for .001-.002" over groove?

[cupajoe]

I think I would try some at .311. Maybe that RD 165 bullet just to see if it will shoot. Even some .308 jacketed would be worth a try just to see if the barrel will shoot.

[popper]

So a x39 chamber and 308.300 bore - sounds normal to me, fill the throat. If throat was smaller, factory x39 might not fit.

[cupajoe]

If these are the "new specs" for 7.62x39, Ruger had it right in the early mini 30's and then dropped the ball with the newer rifles as they are .300 bore and .310 groove. Waiting to hear from Glenn with an update.

[lar45]

Hi Popper, the measurements are .306" groove x .301" bore.
Does .306" still sound normal? I think that FedArms is using out of spec parts picked out of somones trash bin and is trying to pass them off as something worth having.

[lar45]

I put the new barrel on, got the scope zeroed and shot a couple of groups with the TulAmmo 124 and 154 sp. The 124 on the left shows some promise. I picked up some 150 Sierras , I'll see if I can get them to behave, then switch to cast.

261064

[lar45]

I went to the LGS and found some 150 Sierra RN to try in the new barrel. I loaded 5 rounds each at 24.8, 25.0, 25.2, 25.4 and found some time to shoot them this afternoon.
The COAL was 2.200", powder CFE-BLK, primer WLR, case PMC
24.8, 1948fps SD 35.94 group 1.9"
25.0, 1946fps SD 28.54 group 1.75"
25.2, 1993fps SD 30.11 group 2.0"
25.4, 2007fps SD 11.87 group 1.575"
I'm pretty happy with 1.575" :) , this was my first attempt with this bullet, I'm betting that I could get it down some more. Probably the first thing that needs to happen is a trigger job. I've taken both the hammer and trigger sear surfaces to the buffer wheel until I got a bright shine, but the hammer still has horizontal machine marks that will need to be stoned out as the trigger pull is still kind of jerky and not smooth at all.

http://www.lsstuff.com/pics/ar-pistol/150sierra-01.jpg
For velocity comparison Tul 124gn 2186fps, Tul 154gn 1940fps from the 10.5" barrel

It looks like all of the groups have a trend of going from the bottom left to the top right diagonally. I'm shooting from V-bags front and rear from a seated bench. Any thoughts on how to sort out the diagonal stringing?

[Lloyd Smale]

nothing wrong with an ar pistol that will shoot 1.5 inch at a 100 yards.

[popper]

Not the best but near 300/308. Shallow grooves but with jacketed they did OK. Cast might need harder alloy to hold properly. Yea, probably poor barrel quality. With all the mistakes they made, I wouldn't depend on them. Even I can bolt one together decently, doesn't really take a gunsmith.

[Lloyd Smale]

my 16 in 300 bo with a scope will do 2 inch or maybe even slightly better with the rcbs 130 spitz gas check cast out of 18bhn and powder coated. Two loads I use are 16 grains of aa9 and 20 grains of 110. Velocity is right around 1800-2000 fps depending on barrel lenght. now my 8.5 with the same loads will do about double that with a 3x burris prism sight. The 7 inch gun with a red dot? Well lets just say I don't intend to find out. Anymore 4 inch with a red dot on a moa gun is about it for this guy. That ones for blasting beer cans. nice thing about a 130 cast is it shoots a lot closer to poa when you switch to 110-130 grain jacketed stuff for hunting.

[lar45]

I have put alot of rounds through this little AR Pistol in the last couple of months and haven't really found anything that was spectacular.
http://www.lsstuff.com/pics/ar-pistol/762p-01.jpg
I found a partial box of Barnes TAC-X 123gn sitting on the shelf that I tried in the AK a few years ago and decided to give them a try. I didn't have many left, so I just loaded 3 at each powder level to see if they would shoot at all. I was pleasantly surprised to see tiny sub 1" groups. I know they are only 3 shot groups, but they look pretty consistent. I ordered a couple more boxes of the Barnes X's so I can give them a proper test.
http://www.lsstuff.com/pics/ar-pistol/123x-01.jpg