7.62x39 bootlits?

[moyneur]

A little confused over what size boolit to use for my CZ 725 7.62X39, one manual (Sierra) references 308 & others reference 310, does it really matter which one I should use?

And what does C.O.A.L. stand for?

[stubshaft]

Slog the bore first to determine what your bore size is. Cartridge Overall Length.

[moyneur]

Forgive my ignorance...what's "slug the bore".....

[Horace]

"slug the bore" Horace

[Mk42gunner]

I'm using .313" for my Mini-Mauser. One thing you have to remember, most current loading manuals are referring to metal patched bullets, not cast.

Robert

[jcwit]

I shoot gas checked lead sized to .310 in my Norinco SKS. I've never sluged my bore but I have no issues shooting .310 sized bullets.

[Duckdog]

Slug the bore, but a couple of thousands over really shouldn't matter. I do not have a 7.62x39 that is less than .310, including a newer Rossi, so .308 seems a bit small to me. Being a couple of thousands under would cause an issue with accuracy and leading.

[Nobade]

I've got one of those CZ rifles. It works best with boolits .313 - .314 or so.

I normally use the Lee C-312-155-2R, and 17gr. WC680 powder with Cream 'O' Wheat filler. No gascheck, as cast, tumble lubed. 1700 fps and near MOA accuracy. Before I started using the filler the best it would do was about 6 MOA.

Also shoots under MOA with the NOE 247gr. Whisper boolit and enough AA#9 to get to 1000 fps. No filler needed.

[725]

Slug the bore refers to pushing a soft lead "slug" or round ball through the barrel and then using the resulting chunk as a way to measure the exact bore and rifling measurements. That's where you start when you decide on what "size" boolit to use.

[Bullet Caster]

I agree with 725 and several others that suggested that you slug your bore. You want to use pure soft lead to slug the bore. Most sinker weights that you use to fish with would be the right softness to slug the bore. If you have access to black powder boolits, slugs, or round balls you can use one of those to slug the bore. Do a search on the threads here on how to slug the bore of a rifle. You'll need a micrometer to measure the grooves (not the lands) to determine your bore size.

Thanks to a member here, I have a Lee .312 155 grain -2R mould that I intend on using for my AK-47. Haven't gotten the dies for 7.62x39 yet so I won't be able to reload for it yet. I have a total of 4 Lee moulds--one for .452 255 grain RNFP for my Colt clone that drops boolits at .452 so I don't have to size them before shooting. I have another for my 9mm that drops .356 and I don't size for that one either. I think most Lee moulds drop (depending on alloy) exactly what they're supposed to (at least that's what I've found so far).

After determining your bore size, then you can make a decision on what mould to buy and what sizer you'll need. Hope this helps. BC