Reloading 7.62x39 with 303

[po18guy]

Soviet Bloc and Chinese weapons have shown wide variances in groove diameter. It's not all that popular to actually do, but slugging the bore is the only way of ensuring that a given bullet is compatible with the rifle's bore. If you have an SKS or AK with a large bore, then .312 bullets may just be the thing. But, just as they can run on the large side, they can also run tight - and that is much more likely to result in big trouble.

 

[ditchtiger]

I bought several thousand 54r slugs. 150gr tracers. Found data in "Load Books" Been shooting them in my Yugo with the gas block turned off so I don't lose reloadable brass.

 

[osprey]

Just out of curiosity I measured the diameter of the 123 gold dots I have been loading in 7.62x39 and the recently loaded 125 sierras that are sold as 303 cal. bullets. The gold dots are advertised at .310 and actually measure .31075" ish. The sierras are advertised as .311 and actually measure .31125" ish. That is why they both seat with very similar force with cases sized using the .310 expander button.

 

[Anonymous 510]

I've been loading 7.62x39 with .308 bullets Hornady 150 gr. Fmjs I had a decent amount around from some of the 300 blackout lower loads and some 30-06 loads and I use the same bullet for a .308 load... Tested them in sks with no issue but was using bl-c2 I just done up a different load with cfe blk and the same bullet s gotta go test em In the sks and ak..this weekend

 

[DLS]

Soviet Bloc and Chinese weapons have shown wide variances in groove diameter. ...

This!

Most 7.62 x 39 rifles have bores ranging from .310 to as large as .314! The only way to know for sure is to slug the barrel.

To increase accuracy and to recognize the reality of better component availability, Ruger started putting .308 barrels on the Mini-30, which is why there are two sizes of expanders in a die set.

The chamber spec on this cartridge is such that using the larger bullet won't cause serious pressure issues, but is harder on the brass and rifle due to higher energy absorbed in the extraction/ ejection cycle. This assumption is that you are using mil-spec factory rounds.

If you are hand loading you can run afoul of pressure, so you should really ensure you know you rifle's bore size and load accordingly.