7.7 Jap Reloading


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myhandle87
January 18, 2009, 12:05 PM
Anyone have any experience making 7.7*58mm ammo for the Arisaka 99?

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Norsecat
January 18, 2009, 12:54 PM
Reloading 7.7J is the same as any other rifle case.
If you are asking about making the from another, there is no other case that can be formed in to 7.7 safely.

MMCSRET
January 18, 2009, 01:12 PM
I have a sporterized type 39 from the late 50's. Really nice job with what today would be a $600.00 walnut stock with nicely done checkering, butt plate, grip cap, and ebony forend cap. I paid $80.00 for it about 10 years ago. I tried making cases from US military 30-06 brass and fireforming, was I surprised!!!! The chamber is 7.7X58 and tight, full power loads show exactly the same fired dimensions as a Remington 700 30-06. It is the original barrel and maybe was set back and the chamber recut, I don't know, but a fine shooter. I made up a batch of cases using FA 58 Match brass and Hornady 150 gr. spire points over surplus 4895. Fine rifle.

fguffey
January 18, 2009, 02:08 PM
Myhandle87, yes I have, someone near Ft. Worth, TX ask the same question on another forum, he got the same answers, more opinions than answers, I contacted him outside the forum and offered to help him, I formed 60 cases and sent him 54, I kept 6 in case there was a question.

I used LC 68 Match unfired for 20, I used 20 Remington unfired (new cases) and 20 Winchester once fired cases.

I set the beginning of the shoulder on the LC cases at 1. 867, datum at 1.931 and told him he would be able to load, primer, powder and bullet, then chamber and fire.

I set the beginning of the shoulder on the Remington cases at 1.872, datum at 1.936 and told him he would be able to load, primer, powder and bullet then chamber with slight resistance.

I set the beginning of the shoulder on the Winchester cases at 1.877, datum at 1.941 and told him the cases would not chamber and would require full length sizing, that is the shoulder would have to be moved back at least .005 thousands. I did not say the shoulder would require 'bumbing' because bumping sounds too much like an accident, and to 'bump' requires a cam-over press.

I met him at the Market Hall Gun Show while visiting Don Wooldridge, by this time he had fired each case at least 5 times, The LC chambered, the Remington chambered with slight resistance and he had to size the the Winchesters as instructed. I told him I could have gotten all 54 cases alike if I had fired cases or started with the chamber.

I do not have a 7.7 forming die, I used an 8X57 by adjusting the gap between the shell holder and bottom of the die with a feeler gage.

The datum is not a line, it is a circle, a hole, a round hole, the datum for the 30/06 and 7.7 is the same, 3/8, .375, I measured the datum, the distance from the circle round hole of .375 with home made tools. I told Dale the LC were .005 under a go-gage, the Remington were go-gages and the Winchester were no-go gages.

Final sizing was accomplished with a set of C&H dies from El Monte, California.



When forming cases I prefer military because of the absence of a caliber specific head stamp.



F. Guffey

MMCSRET
January 18, 2009, 02:18 PM
I have dislexic fingers; I meant to say "Type 99".

MMCSRET
January 18, 2009, 02:21 PM
To form my cases, I used Lee 7.7 jap dies. Ran '06 case in all the way, trimmed back using the Lee case trim tools, chamfered and loaded.

fguffey
January 18, 2009, 02:27 PM
MMCrest, the shoulder on the 30/06 is forward of the 7.7 by .076, I would suspect the 7.7 chambered was reamed with a 30/06 reamer, with a litter effort and corrections made by neck and throat reamers the chamber would be called a 7.7/06, then there is the 7.65/06 (from 7.65X53 BM) and my favorite the 8/06 (from 8X57 Mauser), some of this came about for improvment, most was about the availability of ammo or the cost.

F. Guffey

fguffey
January 18, 2009, 02:42 PM
MMCSRET, sorry about that, knowing 60 case formed from 30/06 cases would required 12.44 inches of trimming I used a hack saw and file first then finished with the standard trimmer, 100 cases would require 24 inches of trimming.

F. Guffey

Kernel
January 18, 2009, 03:27 PM
A couple of links to Surplusrifle.com articles on forming cases, reloading, and simple mods for the Type 99. Cases can readily be made from .30-06 brass.

Part 1: http://www.surplusrifle.com/shooting2006/srtype99/index.asp

Part 2: http://www.surplusrifle.com/reviews2006/srtype99part2/index.asp

MMCSRET
January 18, 2009, 03:45 PM
My 7.7 easily chambers new Norma ammunition. I bought one box when I got the rifle, fired 3 rounds then decided it was tooooo expensive and formed my own. I also have an 8MM-06 and have a 7.65X53 in a '91 Argentine. My 7.7 ammo, I load in 7.7 dies, full length sizing each time, shoulder set back is almost none existent, the chamber is that close.

Sport45
January 18, 2009, 10:49 PM
To form my cases, I used Lee 7.7 jap dies. Ran '06 case in all the way, trimmed back using the Lee case trim tools, chamfered and loaded.

I do the same thing. I usually anneal the shoulders before running the '06 through the 7.7jap die since that does work the brass quite a bit. I use a Lee trimmer chucked in a drill to trim and chamfer after forming. While they're still spinning I run fine steel wool down the side to shine them up.

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