Jacketed bullet sizing question

[Muddydogs]

I have a 7.62x54R and a 7.7x58 Jap that both slug out at .315 barrel diameter. I loaded some .311 FMJBT bullets and while I could get a 5 inch group out of the X54 there was nothing measurable from the X58. Right now Hornady is not selling there .312 bullets so there not an option to try. I was thinking about getting a Lee .314 push through bullet sizing die and sizing down some 32 special .321 bullets or a .322 bullet to .314 and giving them a try. Has anyone done this? Good or bad idea?

 

[Edarnold]

Your problem is in the bullets you tried: a flat-base bullet will slug-up to fill the grooves of an oversize barrel when fired with a full power load. Because of the base shape, boat-tail base bullets cannot expand on firing and depend on a proper fit to the barrel for best accuracy. I'd suggest trying some .311 or .312 flat base bullets before you go to the trouble of swaging bullets to fit. Loading a .315 or .316 bullet is also going to give you some interesting problems with expanding the sized case necks, you would have to get a custom made expanding button for your dies.

 

[Muddydogs]

Good point Edarnold. I will try some regular base bullets in them. The X54 seems to be on the verge of shooting ok with the .311 BT bullets so the others might bring it around. Not sure about the X58 as cleaning it last night the 30 cal bore brush almost drops right through the barrel, I ended up using my 35 cal bore brush on it. I was thinking about shooting cast through these rifles but the over sized bore creates all kinds of problems with expanders dies and throats. After measuring some once fired case neck diameters I found I won't be able to go much over .312 for the X54. For the X58 the inside case neck on once fired brass measured .316.

 

[918v]

Have you considered casting?

 

[243winxb]

Reduce diameter of Jacketed bullets

Corbin has said. sizing down more than .005" may result in a loose lead core. The lead does not spring back. after sizing, as much as the jacket. But many have sized down .008" like you want to do with good results. Its worth a try. I have never done it. From Corbin-

When you draw down an existing bullet to smaller size, you can only reduce it about .005 inches before the spring-back defeats you by attempting to go the other direction (larger) when pressure is released. This releases the grip on the core and lets the core fail to spin with the jacket when rifling is engaged, resulting in poor stabilization and poor accuracy. Swaging, which works by expanding the diameter, tightens the grip of core and jacket. Drawing down makes the jacket loose if it exceeds the elasticity of the jacket (.005-inches is a good approximation for most jackets).

http://www.corbins.com/answers.htm The lands are about .004" high, this should compress the jacket into the lead core on firing. Just how i see it.

 

[41 Mag]

If you can hustle up the Sept. copy of The American Rifleman, there is a write up of doing exactly what your referring to. Don't know if the calibers are the same but the article is.