6.8 spc or .300 ham'r?

[MISportsman]

Keep in mind that a lot of US manufactured ammo is a bit watered down to SAAMI pressures where 7.62x39 gets a lot of performance gains running between SAAMI and CIP pressures, a lot of European/Combloc ammo can be found running higher pressures. So understand that when reloading a lot of US data will be neutered to what the 7.62x39 can actually achieve when loading under the guidelines of CIP pressures.

Max SAAMI pressure = 45,010psi
Max CIP pressure = 51,490psi

So the CIP chambers and testing of the 7.62x39 yield 12.5% greater pressure allowance than the SAAMI chamber pressures.

For reloading if you want to hunt with it, CFE BLK and 123gr Hornady SST's are a great pairing. CFE BLK really opened up the potential of the 7.62x39, everyone who reloads for the round says the same.

You maybe surprised the accuracy you can find with some steel cased ammo as well with a good platform to shoot from.

Is there anywhere I can find reloading data to cip specs? And yes some steel case ammo can be fairly accurate. My sks loves wolf black box stuff.

 

[MISportsman]

If you do end up doing a 7.62x39 just a few pointers, if you want to consider in the build.

1. I would stick with carbine gas, if you desire to run steel case, to help with the dirtier nature.
2. Run a heavier buffer H2 (H3 if it will run will be better) this will increase dwell time allowing for pressure to subside a few more milliseconds to ease wear on locking lugs.
3. C-Products magazines work great, I really only use the 5 rounders for hunting and 20 rounders for range. I've heard to stay away from the 30 rounders but that the 28 rounders will work.
4. A big part of getting the 7.62x39 running right is having a good wide feed ramp in the barrel extension, early on in the life (we are talking 15 years ago) of 7.62x39 barrel manufacturers were using standard 556 feed ramps and were having major issues. Barrel manufacturers today probably have all realized this and don't do that anymore, but it's always good to double check with the barrel maker to make sure they accounted for a 7.62x39 feedramp in the extension.

It is one of my favorite AR chamberings, it really is one of the perfect cartridges for starting young kids out with hunting, mild mannered and great performance with handloads.

What barrel did you use in your build? About all I can find is the bca, which seem to be decent. I fully agree that x39 is a great cartridge to start kids with. We got my daughter a cz 527 in x39 for Christmas last year, great little gun!

 

[BreechFace]

I don't have a source for CIP spec reloading. As always work up loads, most SAAMI loads for 7.62x39 max out at 2,400fps with a 123gr, but I feel comfortable working up to 2,500fps+ with CFE BLK and 123gr SST's out of a 16" AR barrel (which is more than adequate for my needs, I just work up above 2,500 watching pressure signs and find an accuracy node and call it a day. There are some that have got their 123gr SST's to above 2,600fps out of a 16" barrel without issue. I think @someguy2800 is one of them as well as @CarJunkieLS1, maybe they'll comment on their experiences.

I think a few members here have developed loads for their rifles that achieve 2,600+fps with the 123gr SST's.

 

[BreechFace]

I have a Rainier Arms barrel, but looking at their website it seems they don't sell x39 barrels anymore, which is a shame as it's been a great barrel.

I would look at Faxon, Ballistic Advantage if you don't mind spending $150-200, but it looks like a lot are out of stock.

I don't have any experience with Bear Creek Arsenal but a lot on this website do and seem to have good luck with them.

 

[MISportsman]

I have a Rainier Arms barrel, but looking at their website it seems they don't sell x39 barrels anymore, which is a shame as it's been a great barrel.

I would look at Faxon, Ballistic Advantage if you don't mind spending $150-200, but it looks like a lot are out of stock.

I don't have any experience with Bear Creek Arsenal but a lot on this website do and seem to have good luck with them.

Who makes a good bcg?

 

[BreechFace]

Who makes a good bcg?

I'm currently running an Aim Surplus 9310 BCG that has been reliable and no problems. I have a Lewis Machine and Tool bolt (made from AreMet) as a backup that I bought long ago when they still made them and they are considered the toughest bolt out there, but I have not had to use it because my Aim Surplus bolts have been fine. My brothers have bolts from PSA, Hardened Arms and another that I can't remember and haven't had any issues.

Looks like Aim Surplus is OOS https://aimsurplus.com/aim-ar-m16-7-62x39-nib-9310-mpi-bdg-bolt-carrier-group/

 

[MISportsman]

I'm currently running an Aim Surplus 9310 BCG that has been reliable and no problems. I have a Lewis Machine and Tool bolt as a backup that I bought long ago when they still made them and they are considered the toughest bolt out there, but I have not had to use it because my Aim Surplus bolts have been fine. My brothers have bolts from PSA, Hardened Arms and another that I can't remember and haven't had any issues.

Looks like Aim Surplus is OOS https://aimsurplus.com/aim-ar-m16-7-62x39-nib-9310-mpi-bdg-bolt-carrier-group/

Thank you, I will look very closely into this before I make a final decision.

 

[MISportsman]

Has anyone heard of KAK barrels? Are they any good?

 

[someguy2800]

yes they make excellent stuff

 

[someguy2800]

check and see if Green Mountain has any listed

 

[MISportsman]

Will do, thanks

 

[MISportsman]

I have decided to build a 6.8 this time, but I'm sure there will be another build in the future lol. If I could find all of the components and a source for ammo, I'd love to build a 9x39! It seems to have awesome possibilities!

 

[mshootnit]

I have decided to build a 6.8 this time, but I'm sure there will be another build in the future lol. If I could find all of the components and a source for ammo, I'd love to build a 9x39! It seems to have awesome possibilities!

I think you have made a very good choice. I like my 6.8 and consider it to be a perfect little round for the regular frame AR. Its shape results in very slick feeding and plays well with the geometry of the AR mags/lower. I have had two, the first was an Armalite factory midlength upper, the second I built with a Bison Armory 18" stainless lightweight barrel, and Midwest Industries suppressor ready 10.5" handguard. I ordered the barrel with a headspaced standard bolt and Young manufacturing chrome carrier. I have had this upper on a couple lowers but right now it has a Spikes Spartan lower with a POF drop in straight trigger. Both my 6.8's were spec II with 1:11 twist. They shoot very well. the Bison (shaw) barrel really likes the Hornady 110 Vmax Black ammo. I have been using m16 carriers, H buffer and regular spring. I like the Kaw valley Heavy buffer. There are polished springs too.
I dont reload for this one, but if I start, I will be 123 gr. SST at a little over 2500 fps out of that 18" barrel.

 

[Steve in Allentown]

I have decided to build a 6.8 this time . . .

Sorry if this has already been covered but I highly recommend AR Performance barrels and bolts for the 6.8 or Blackstone Arms for a fully assembled upper.

 

[mshootnit]

I think you have made a very good choice. I like my 6.8 and consider it to be a perfect little round for the regular frame AR. Its shape results in very slick feeding and plays well with the geometry of the AR mags/lower. I have had two, the first was an Armalite factory midlength upper, the second I built with a Bison Armory 18" stainless lightweight barrel, and Midwest Industries suppressor ready 10.5" handguard. I ordered the barrel with a headspaced standard bolt and Young manufacturing chrome carrier. I have had this upper on a couple lowers but right now it has a Spikes Spartan lower with a POF drop in straight trigger. Both my 6.8's were spec II with 1:11 twist. They shoot very well. the Bison (shaw) barrel really likes the Hornady 110 Vmax Black ammo. I have been using m16 carriers, H buffer and regular spring. I like the Kaw valley Heavy buffer. There are polished springs too.
I dont reload for this one, but if I start, I will be 123 gr. SST at a little over 2500 fps out of that 18" barrel.

They really are just a spiffed up 7.62X39 performance wise, maybe a little hotter, and more accurate, bu fun to build, and shoot nonetheless

 

[mshootnit]

Sorry if this has already been covered but I highly recommend AR Performance barrels and bolts for the 6.8 or Blackstone Arms for a fully assembled upper.

I think AR performance is the best, I just have not called them to pull the trigger yet.

 

[Txhillbilly]

I think AR performance is the best, I just have not called them to pull the trigger yet.

Harrison sure has his fans, but I'm not one of them. I've tried 3 different ARP barrel's, and they were all utility grade at best. I've tried his 223, 6.5x6.8, and 6.8 SPC II barrel's and none of them would shoot consistent groups.

If you want a good 6.8 barrel, I'd suggest buying one from White Oak Armory. They will embarrass anything that Harrison sells!

 

[MISportsman]

I think you have made a very good choice. I like my 6.8 and consider it to be a perfect little round for the regular frame AR. Its shape results in very slick feeding and plays well with the geometry of the AR mags/lower. I have had two, the first was an Armalite factory midlength upper, the second I built with a Bison Armory 18" stainless lightweight barrel, and Midwest Industries suppressor ready 10.5" handguard. I ordered the barrel with a headspaced standard bolt and Young manufacturing chrome carrier. I have had this upper on a couple lowers but right now it has a Spikes Spartan lower with a POF drop in straight trigger. Both my 6.8's were spec II with 1:11 twist. They shoot very well. the Bison (shaw) barrel really likes the Hornady 110 Vmax Black ammo. I have been using m16 carriers, H buffer and regular spring. I like the Kaw valley Heavy buffer. There are polished springs too.
I dont reload for this one, but if I start, I will be 123 gr. SST at a little over 2500 fps out of that 18" barrel.

I was very closely looking at the bison 18"no barrel, but I think when they come back in stock I'm going to order a Wilson combat 16" ranger barrel. It's extremely light and has excellent reviews. I think it would make for a great lightweight quick handling rifle!

 

[uuolf]

Given equal weight bullets and barrel lengths the 6.8 keeps up with the ham'r... The 6.8 gets my vote for higher sectional density in the 110gr and 130gr pills IMHO... I laddered a load that sends a 125gr (.400 bc) pill downrange at 2650 over a chrony.. from an 18" barrel... That, and a 90gr gold dot are my go to rounds for this rifle.

 

[FL-NC]

Unless you are a reloader, I would go with blackout. If you are set on the other 2, I would pick 6.8.

 

[robin banks]

what do you get for velocity out of the ham’r? I’ve always scratched my head at the cartridge because all the velocity data I see is slower then my X39 by a good bit and barely faster than my blackout.

I say the velocity for the ham'r is exaggerated. with CFE black powder you can easily get 2600 FPS with 125 gr bullet in the 7.62x39. they are trying to sell expensive rifle and ammo by massaging the stats for the ham'r

 

[robin banks]

This is based off what I have heard from the grendel guys: but the x39 bolt in an ar has thin walls. I'd be kind of leery trying to hot rod that round in that gun. You might start shearing lugs off.
Or not.

he can get the RRA mutant AR which has a bigger bolt not hogged out

 

[someguy2800]

I say the velocity for the ham'r is exaggerated. with CFE black powder you can easily get 2600 FPS with 125 gr bullet in the 7.62x39. they are trying to sell expensive rifle and ammo by massaging the stats for the ham'r

i would tend to agree with you. I have personally shot 125’s at 2605 fps from my 16” 7.62x39. I get the benefits of using ubiquitous 223 brass and mags, but I think they are trying to make it into something it’s not.

Now with that said, I actually have a 10” 300 ham’r barrel on order for my contender pistol. I don’t buy into the BS of it being a 30/30 equivalent, but I think it will be a good metallic silhouette round in a pistol.

 

[robin banks]

i would tend to agree with you. I have personally shot 125’s at 2605 fps from my 16” 7.62x39. I get the benefits of using ubiquitous 223 brass and mags, but I think they are trying to make it into something it’s not.

Now with that said, I actually have a 10” 300 ham’r barrel on order for my contender pistol. I don’t buy into the BS of it being a 30/30 equivalent, but I think it will be a good metallic silhouette round in a pistol.

yes that is a good platform for the ham'r and a good use for it plus you will not be blasting that ammo with a semi auto

 

[greyling22]

Now with that said, I actually have a 10” 300 ham’r barrel on order for my contender pistol. I don’t buy into the BS of it being a 30/30 equivalent, but I think it will be a good metallic silhouette round in a pistol.

I've got a 7mm tcu barrel if you're interested. .