Were these sons of Nippon armed with 6.5s or 7.7s

Bore Size in Jap Military Rifle


43
51 shares, 43 points

Q: I intend reloading for a 7.7mm Jap rifle for use in military rifle competition. One reference lists the bore diameter as .303″; groove diameter .315″; groove depth .006″. I question these figures. Can you tell me what the proper bore and groove dimensions as well as groove depth is for the Japanese Model 99 Arisaka rifle in 7.7x58mm rifle? What diameter bullet gives the best accuracy in these rifles?

Bob Wilson

 

A: It is possible that some Jap rifle barrels may have those dimensions, but I have found that groove diameter is more likely to be near .312″. Reloading Manuals recommend use of .311″ to .312″ diameter bullets. A friend of mine who is a keen gunsmith- experimenter tells me he has found that .308″ bullets will give the finest accuracy in the 7.7mm Jap rifle. Use of a larger diameter bullet may well result in unnecessarily high pressures.


Like it? Share with your friends!

43
51 shares, 43 points

What's Your Reaction?

super super
16
super
fail fail
10
fail
fun fun
8
fun
bad bad
6
bad
hate hate
4
hate
lol lol
2
lol
love love
20
love
omg omg
16
omg
Nick Harvey

Nick Harvey is one of the world's most experienced and knowledgeable gun writers, a true legend of the business. He has been writing about firearms and hunting for more than 65 years, has published many books and uncounted articles, and has travelled the world to hunt and shoot. His reloading manuals are highly sought after, and his knowledge of the subject is unmatched. He has been Sporting Shooter's Gun Editor for longer than anyone can remember. Nick lives in rural NSW, Australia.

0 Comments

Send this to a friend