can I convert 8x56R to 7.62x54R?

[stevekl]

I know, most people do it the other way around. But I need innexpensive 7.62x54R brass, and graf's is sold out.

However, they do have 8x56R cases, and I have heard of people converting 7.62x54 to 8x56R, so can it be done the other way around?

[Bob Krack]

I know, most people do it the other way around. But I need innexpensive 7.62x54R brass, and graf's is sold out.
However, they do have 8x56R cases, and I have heard of people converting 7.62x54 to 8x56R, so can it be done the other way around?
Steve,
I'm not sure I can answer your question but here's a place to look.

http://stevespages.com/jpg/cd8x56r.jpg
http://stevespages.com/jpg/cd762x54rrussian.jpg

http://stevespages.com/page8d.htm for several others....

Vic

[jonk]

Yes, you can. Should be no issue. I turned some 7.62X54 into 8X56 (well more or less, they were short) when Grafs didn't have the proper stuff in yet a few years back. When I got the proper stuff I resized it back to original 7.62X54R no issue.

[Andy_P]

It can be done, but it's a fair bit of work. You're likely going to run into problems when you try to convert 8x56R into 7.62x54R. The base will be too large for your dies and chamber, and the rim will be too thick so the bolt won't close. You can of course turn down the base and rim and trim to length.

When you go the other way (7.62x54R to 8x56R), the problems are different - it's too loose and short, but fireforming and subsequent neck sizing takes care of that.

8x56R

Case Base Diameter .491
Case Rim Diameter .554
Case Rim Thickness .060
Case Length 2.20


7.62x54R

Case Base Diameter .484
Case Rim Diameter .564
Case Rim Thickness .055
Case Length 2.11

[jonk]

Most mosin chambers I've encountered aren't going to balk at a few thousandths an inch difference.