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.
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.
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
diplomacy is being able to say, "nice doggie" until you find a big rock.....
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
BP | Bronze Point | IMR | Improved Military Rifle | PTD | Pointed |
BR | Bench Rest | M | Magnum | RN | Round Nose |
BT | Boat Tail | PL | Power-Lokt | SP | Soft Point |
C | Compressed Charge | PR | Primer | SPCL | Soft Point "Core-Lokt" |
HP | Hollow Point | PSPCL | Pointed Soft Point "Core Lokt" | C.O.L. | Cartridge Overall Length |
PSP | Pointed Soft Point | Spz | Spitzer Point | SBT | Spitzer Boat Tail |
LRN | Lead Round Nose | LWC | Lead Wad Cutter | LSWC | Lead Semi Wad Cutter |
GC | Gas Check |