Do I have a max spec die/min spec chamber?

[Patrick L]

I have farted around with a 7.7mm Japanese Arisaka off and on for the past 20 years or so. I obtained a set of Lee dies several years ago. I have several sets of Lee dies in other calibers and find them to be of good quality. I also own RCBS, Lyman, Hornady, and Redding dies, so I am not biased. I think everyone makes good stuff. With the 7.7 it was a no brainer, since Lee priced these right along with their other calibers (therefore relatively cheap) while most other companies considered it a specialty (and therefore $$$.) This is just a fun gun for me.

Anyhow, I notice something peculiar when loading this caliber. Even with the sizing die set low enough for a hard bump against the shellholder, the case neck shows the sizing to stop a good 1/32nd or so shy of the neck/shoulder junction. Its enough that I can feel the bolt "crush" slightly as it closes on a new empty FL sized case. I think I have in effect a de facto neck sizing die. Its not so hard I can't chamber a round, and I have shot these reloads for years.

BTW, Norma factory ammo chambered easily and smoothly.

I think I probably have a die that is at the top of the specs, and possibly a chamber that is at the minimum. Do you all agree?

Even though its not a huge problem, I would like to set things right. I was thinking of grinding a bit off of the bottom of the die, just until the sizing line meets the neck/shoulder, and the bolt closes with no resistance. I could always back the die off if I decide I want to do the partial FL size (I think thats what they call it if you do this deliberately) but I would like the option of truly full length sizing.

Opinions please?

[1hole]

"Even though its not a huge problem, I would like to set things right. I was thinking of grinding a bit off of the bottom of the die, just until the sizing line meets the neck/shoulder, and the bolt closes with no resistance. "

That's exactly what I would do if it were mine. Only I would limit the grinding to enough to allow a sized case to chamber just right, no point in going further. The shoulders will get blown out to fit and no more die mod will be needed.

Doubt the "real" problem is the die, more likely it's the chamber, so a minimum adjustment seems in order. Most factory ammo for surplus rifles tends to run on the small side for just that reason. The rush of war production didn't allow the Japs much time for trivia, if it could fire factory ammo the first time, it would have been good enough for what they wanted!

[Patrick L]

Well, that seemed to do it. I took probably less than a 32nd off the bottom of the sizer die, there is now no "shoulder" where the sizing of the neck stops short of the case shoulder. Bolt now closes easily on a sized case.

It remains to fire these cases and THEN resize them and see what happens.

[nicholst55]

I suggested something similar on another forum a day or two ago and everybody thought I was insane! I've had to do this with a couple of dies in the past, and none of them were Lee dies. As long as you do it properly and remember what you've done so as not to set the case shoulder back too far, there's absolutely no harm in this that I can see.

[45 2.1]

If the bolt closes easily, I would suspect that your cases will stretch some and thin the web of the case setting your cases up for a case separation upon firing after a few reloads. You should be interested in not setting the shoulder of the case back. Jap rifles vary a lot in chamber specs. Fireform the brass initially to the chamber useing a starting load with spray furniture wax on the loaded case to prevent the web from stretching. Clean the chamber afterward and set your sizer so the the shoulder of the case isn't set back while allowing for smooth chambering. Whether the full length of the neck is sized is immaterial.