Japanese Militaria at Castle-Thunder.com

[chucksniper]

will excess headspace hurt accuracy? I had primers back out. I they backed out alot with full length sized brass, not on new norma loads.

[DEFUC]

backed out primers sounds like excess pressure possibly,maybe too light of a load? or way too heavy? ld lean toward too light tho if theres no other pressure signs. As for excess HS effecting accuracy it can.what does your fired brass mic to?

[chucksniper]

[Smokey]

I almost always back FL sizing dies out for surplus rifles. Normally the headspace is a little generous in the rifle, and the die brings the case right down to minimum. Set the die so the shoulder is not affected and you should be fine. You will have to reconsider the cases you've sized, they're probably candidates for head separations eventually.

[chucksniper]

[Garandshtr]

I'm not familiar with Norma brass (too pricey!). If the primers of those didn't back out, but did on other case types, I would get my calipers out. It does sound like an excess headspace issue, and perhaps the Norma cases don't grip the chamber walls as others do. See how the fired cases compare with each other, and the dimensions specified in a reloading manual.
Does your bolt serial match the rifle? If mismatched, you could easily have a problem. If they don't match, I would suggest you have the rifle inspected by a reputable gunsmith with the proper gauges.
Both of the Arisaka actions are among the toughest actions ever built, so I don't think you are in real danger, but given the stories of how ship board war trophies were made safe for a sea voyage, mismatched bolts are too common!

have fun!
Mark
_________________
Still trying to learn what I can, mainly about the Type 99 and Type 38. I have more curiosity than time, and more time than money.

[chucksniper]

[Garandshtr]

I still suggest you check your bolt and receiver serial numbers.

Mark
_________________
Still trying to learn what I can, mainly about the Type 99 and Type 38. I have more curiosity than time, and more time than money.

[DEFUC]

the norma Ammo is usually undersized to start with, so the case expands to match the chamber,where as home worked up properly FL sized brass is a snugger fit ,I expect the norma is using the pressure to expand the case to meet the chamber dimensions,while the FL stuff is pushing back against the primer.Purely a guess tho on my part,as I dont know exactly what you have going on or what loading your using.Backed out primers is a pressure sign, but why you have pressure can be a lot of things,its not high enough to cause concern,but does need further study to see whats causing it,some mic work and possibly a chamber casting SHOULD solve the matter.How does your brass work once its fireformed to the gun, just neck size and reused? measuring your fired brass versus your new FL brass should tell you quite a bit, other wise, running some cerro-safe in and measuring the exact chamber dimensions would be an idea also.

[chucksniper]

[DEFUC]

lots of matching arisaka out there,tho some did get messed up like you say and a lot more have since by careless owners.but theres lots of them that match completely and correctly around