chambering reamer for CB

[TRX]

I'm making up a chambering reamer for a .311" cartridge. I intend to shoot cast bullets only.

Looking at my reference material, it appears all the examples are for jacketed bullets.

Are there any modifications I should make to optimize for cast bullets, or does it not make a difference?

I'm mostly thinking of freebore and leade angle at the moment, but any comments are welcome.

[GabbyM]

With a specific bullet to draw from you can make the throat length to fit the bullet nose.

I'd make the chamber to match dimensions then if you need to run fat boolits just turn the case necks if need be. If you are looking to run heavy bullets from a 7.62 x 39 you would need a non standard throat for ease of fit. Personally I'd chamber that into a US thirty caliber barrel for greater bullet selection. Someone posted there 7.62 x 39mm dies would not size a case neck down small enough for .308 J bullets. But with cast you'd just use a .310 or .311 bullet and have your +.002” fit in a .308” bore with standard 7.62 x 39mm necked dies. Get a bushing die for neck size with J bullets or only shoot cast or Russian sized bullets.

Tell us more about your plan.

.308" bore will only get larger with time. Put enough rounds down it and you'll be shooting RUS or BRIT sized bullets from it.

[TRX]

I have a bunch of .311 barrels and a couple of new blanks. All but one of my rifles are .311. I even have a pistol in .311. So I'll probably stay with .311.

What I was thinking of doing was to make a reamer for something like the .300 Whisper, except to take a .311 bullet. Since it was developed as a subsonic round, it should be quite happy with a cast bullet.

The Whisper also starts with a 1.76" case that is cut off to 1.4". I was thinking about leaving the case full length, to cover up more of the grease grooves and provide better bullet retention without having to neck-size the case as much when reloading.

I'm not trying to make something "better" than the Whisper, just something interesting to make use of the excess supply of .311 bits I have on hand. I would expect the loading data and ballistics for a .311 to be almost identical to the .300.

If I bugger up the relief angles or whatever on the reamer and I just rip a big jagged hole in the end of the barrel, well, just saw it off, make another reamer, and try again... it's not like I'm experimenting on an expensive barrel.

[izzyjoe]

what cal. are you working with?

[TRX]

I'm back on the .311 project. I have some O-1 drill rod, .223 brass, and a new HSS blank for the lathe to shape to make the neck radius.

In absence of any other ideas or input, I'm going to use the .300 Whisper case up to the neck, then use the .303 British SAAMI drawing for the neck, adjusting for the extra length I can get by starting with a .223 case.

[B R Shooter]

I think it would be easy to use a 30BR as the base case, and just neck it up however much you need. The throat is the big thing, getting it to match your bullet. Neck diameter can be easy to deal with, even if you use a neck reamer too. Sizing dies with the proper bushing works great.

The BR case is easy enough to load as light or as heavy as you want with cast.

I've chambered several barrels for .310" cast, using my regular J bullet 30BR reamer. Once the chamber is done, a simple run of the right neck reamer and then the throater. You're only .001" over that size.