7.7 jap

[RyanJames170]

Anyone here shoot/load cast for a 7.7 Jap in a type 99. I ask as it’s Medford rifling, and chrome lined. 2 things I’ve never worked with before and I was curious what people found worked.

[beagle]

Messed with one for a while with fair results. I used modified .30/06 brass which is suppose to be a no no and I used .308" bullets. First off, get some 7.7 Jap brass and eliminate the brass hassle. Then, get a bullet that will fit. They make good plinkers. Normally, rough as a cob but they shoot pretty well and you can bring home the venison with one if you tweak it a little. They're strong as all get out. Now, the 6.5. I ain't going there./beagle

[JM7.7x58]

I have two. They slug .3165” and .3160”. I size too .318”.

The chambers are quite oversized. I get a fair amount of bulge just above the case head. I would discourage the use of commercial 7.7x58mm brass. I’ve used Norma and the brass that Hornady uses for their factory 7.7 loads, it’s just too thin. What I do recommend is forming your brass with heavy walled military 30-06 brass, it bulges out in a gentle curve. I’m much less concerned about a case head separation with the heavier military brass.

I have used a few different molds. Most are 8mm molds that I size the bullets down to .318”. They all shot fine. A Lyman 323470, a plain base Lee 324-175-1R, and an NOE 323365.

I now have an NOE 316-155 PB/GC combo mold. It drops at .3175” and I powder coat it wich adds a bit of size.

Both of my rifles struggle to reliably feed round nosed bullets. They cycle the best with the pointed NOE 323365.

I use bullseye, Herco, and 2400 in most of my loads. Any load that will work in a .303 British in safe in the 7.7x58mm.

JM