Are my bullets oversized?

[Dolomite_supafly]

I have a recently built 7.62x39 bolt gun. I built it because I like the idea of being able to shoot factory ammo as well as my reloads. I also chose the caliber because I am very recoil sensitive because of a helicopter crash in Afghanistan a few years back. Shortly after the accident I sold most of my heavy kickers and went to 223 or rimfires.

I have decided to try casting for the x39 now. But before buying molds I had a friend send me a bunch of cast bullets and they are .311"-.312". I bought a sizer and it sized them to .307". I chucked it into my lathe and opened it up using 1000, then 2000 grit sandpaper. During the process I would size bullets to check. Well through some screw up the bullets are now sizing at .310".

The rifles bore is .3000"x.3085".

The cast bullets will be gas checked. Max velocity for any of them is going to be around 1,800 FPS.

I have been reloading for quite a while using jacketed as well as bought cast bullets. I have been casting for about 6 months. I cast 9mm, 45 and slugs for my 12 gauge. I enjoy shooting and casting has allowed me to be able afford to do the amount of shooting I do.

So is a cast lead bullet that is .310" too large for a .3085" bore?

Thanks
Dolomite

[pdawg_shooter]

Nope, should work fine. Start low and work up.

[Dolomite_supafly]

Ok, thanks.

I was worried I might have pressure issues.

Dolomite

[Ben]

The pressure problems that would occur with a jacketed .310 bullet going down a .308 barrel just are not there with a cast bullet. I've shot " tons " of .310 " cast bullets down .308 barrels. Enjoy ! !

[largom]

I shoot .312 Dia. unsized in my 30 cal. if they will chamber. Opened up the throat on a 308 to accept this Dia. and it shoots great with 2000 fps boolits lubed with Felix.

Larry

[Westwindmike]

Welcome to CastBoolits, Dolomite.

(from another TGO person)

[DeanWinchester]

Welcome to CastBoolits, Dolomite.

(from another TGO person)

...and another TGO person.

[Echo]

Welcome, Dolomite, and thank you for your service.

[MBTcustom]

I would dare to say that .310 is perfect for a G.D of .3085. My custom 358win I built has a G.D. of .3582 and it loves .360 diameter boolits. @ 1800FPS, use a GC and lube with 45/45/10. No gooey lubes needed at those pressures. Enjoy! I would like to have a bolt gun in that caliber someday.

[popper]

Curious about the effect on accuracy with high BHN (>22) over-sized CBs. Anybody have any experience with this?

[felix]

Depends on the gun. Harder things size straighter, coming out any kind of sizing die, which in your question is the gun barrel itself. The trick to any sizing, hard or soft, depends on how the item is initialized into the die. Obviously, the center line must not be taken for granted by either gun (die) or item. ... felix

[1Shirt]

Believe in going with what shoots most accurately, and for most 308 bbls, in my experiance, either .310 or .311 will probably shoot best. Excepting to that for me has been my K-31 that wants .309 and nothing larger.
1Shirt!

[stubshaft]

Believe in going with what shoots most accurately, and for most 308 bbls, in my experiance, either .310 or .311 will probably shoot best. Excepting to that for me has been my K-31 that wants .309 and nothing larger.
1Shirt!

I have had 2 barrels that liked .309 boolits.

That's the beauty of cast boolits. There are no absolutes.

[Larry Gibson]

Curious about the effect on accuracy with high BHN (>22) over-sized CBs. Anybody have any experience with this?

If the load is worked up it is quite ok. The bullet will be sized to barrel dimensions in the 1st bearing length of travel into the barrel. This happens very early in the time/pressure curve. Once the bullet is sized to the barrel in that 1st bearing length of travel it then is like any other bullet that fits the barrell with regards to pressure going down the rest of the barrel.

My "go to" sizing for all my .30 cal rifles is (if the loaded round will chamber) is .311 if the bullet drops from the mould at least .3105.

Larry Gibson

[JDFuchs]

Taming recoil is one of the resins I love reloading and bullet casting. When I bought my 45-70 I was so eager to shoot it I garbed some factory ammo and the kick was so bad I almost sold the rifle. After I ran some lighter loads though her I love that rifle. The most common Load I use for 45-70 is with Trail Boss. That powder Will safely tam just about any big rifle round. I also have some loads using the Lee 311-93-1R for the 30-30 that feel like shooting a 22lr.

And for the most part all my 30cal rounds are sized to .312