M14 Forum

Rojkoh · January 26th, 2012, 02:03 AM

Quote:

Originally Posted by Blademaker

Been thinking of building an AR for a while now, and debating on 5.56mm vs 7.62x39 for a chambering.

I've got a lot of experience with 5.56mm and am not really a big fan of it. On the plus side it's almost no recoil and is accurate at practical distances and there's plenty of surplus ammo out there and it's what the AR was designed for.

If you look at my "pictures", you'll see me testing the M249 in 1980. All the years I've been around firearms, I've battled with the fact that .223 is nothing more then a cartridge that was meant to replace the .30 Carbine. It's a 300 yard round and that's it. I took some suits out to the range, with the 249, a BAR, a 1919A4 and a NM M14. They couldn't even see dirt strikes past 300 yards when I had them put a laser range finder on things I was shooting at. Not one of the .30 cal weapons had any problem staying up with the range out to 700 I think it was. I simply dialed in the iron sights and away we went.
I consider the .223 the biggest POC the military has ever adapted, including all the "new" magic rounds for distance. I KNOW someone that got accuracy out of an AR out to 600... I won't discuss what it took. None of us can do it with what we have on hand.

7.62x39, a harder hitting, more penetration, I've got tones of ammo already. Not sure how accurate it would be in an AR platform, or even how reliable it would be.

1) AK and SKS actions are inherently inaccurate. We know the AK can take a beating... but accuracy? No.

2) Mini in 7.62 by 39? No... I know Bill Ruger's attitude about the mini, I won't have one (and I did at one time).

3) Suggest either an AR or bolt action for accuracy and in fact if you're going that route, I'd seriously suggest looking at surplus .303 rifles. You'd be shocked at what you can do with them and reloading.

I'm leaning toward 5.56mm just for simplicity and to add yet another caliber to load for.

.223 is about the only rifle round I'd load on a progressive press... it's ball accuracy so why not? For match rifles (chuckle), has be be single stage.

Also not sure which would be a good manufacture now days.

*IF* you have a stash fo either Soviet block and primarily ChiCom ammo, go to Brownells.com and get yourself a case/head extractor... you'll need it. Once people found out I could fix rifles, I say more ammo problems then I want to know about with 7.62 X 39, especially the ChiCom ammo. Case separations are not uncommon and why I wouldn't use one to save my life unless it was either Finish or US made ammo.

Any and all thoughts and suggestions welcome.

BTW, I did a search but came up empty.

Hope this helps, PS in 1980 we actually ended up with an AK74... wasn't impressed with it either.

Thanks.

Anytime

Rojkoh · January 26th, 2012, 02:10 AM

Quote:

Originally Posted by Blademaker

Thanks, I'm defiantly leaning towards 5.56, but will look into 300 black out, never heard of it before.

Now to figure out what lower to use.

Not really sure what you were talking about, but if you're discussing a decent and fine .30 rifle to snipe with, try a Remington heavy barrel in either .308 or .300 Win Mag. I've shot an M40 in .300 Win mag... I was impressed with it. Sadly they couldn't deploy anything larger then .308 at the time.

If this isn't what you were discussing... sorry to intrude.

Rojkoh · January 26th, 2012, 02:15 AM

Quote:

Originally Posted by Albud3

Believe it or not, the 7.62X39 in an AR platform is decently accurate because of the barrel: tighter tolerances. A friend's AR in 7.62 shot approx. 2.5 - 3.5 moa with mil-surp ammo and around 2 - 2.75 with US ammo. However, the mags are not reliable; all he tried jammed at least once per mag! Plus, they're hard to find and expensive. That's why he sold them.

There is (was?) a manufacturer that sold a modified AR lower that uses AK magazines, but I haven't a clue who it is...maybe someone here knows? I believe it's the same company that sells the modular (can switch between 5.56 and 7.62) lower?

If you took an AR with a decent heavy barrel in 7.62 X 39, you could well develop good accuracy with it. But to clearly define it, it would require handloaded ammo and not on a progressive press. Powder throwers throw by volume, not weight. This is a big issue for accuracy as is using good brass (US commercial or Lapua), Federal 210M match primers and I'd start with the Sierra 155 PALMA MKs. I have some in the shop for ammo testing and the 155s should be fine, but I would check with the rifle and barrel vendors about stepping up to the 175's... I don't know since I mainly work on .223 ARs/M16s. I do my accuracy loading on a Forster Co Ax press. I also use their trimmers etc. I do this mainly because it's what I learned so many years ago from the team shooters I knew and "educated" me. Chuckle. But hey, I'm still above the ground! LOLOL.

For barrels, I still like the Krieger barrels. I have 2 medium grade NM barrels waiting to go for ammo testing and they're better then all the USGI NM barrels I've had over the years.

Blademaker · January 26th, 2012, 08:53 AM

Thanks for the info. I've about decided to go with the 5.56, though I'm still thinking about the 300 black out. Got to do a little more reading on it.

I use a progressive turret press, but hand throw and weight all my charges, never could get accurate weights with a dispenser.

Mindfield · January 26th, 2012, 09:04 AM

The issue w/ the 5.56 round is predominately an issue of 2 factors

1. Ammo:M855 is a penetration round designed to punch armor then flesh, so its prone to the ice pick effect on soft targets

2. Carbine Length barrel: They kill velocity of the 5.56, it falls below the minimum it needs to perform properly @ less than 100yds

The solution is a full size barrel 20". If you MUST compromise no less that 17.2" and to run non M855/SS109 ammo, like the heavier 72gr SMK loads as long as you have the proper twist in the barrel to handle them

IE the biggest complaints about 5.56 performing has come from the Army w/ their M4s, and not the Marine Corp w/ their 20" A4s

perazziboy · January 26th, 2012, 09:39 AM

Take a look at Noveske upper and lowers for your build. I used these products and they are outstanding both fit and finish.