Schmidt Rubin chamber variations ?

[1Hawkeye]

Has anyone noticed a difference between schmidt rubin 96/11 and k 31 chambers? Iv'e got both but my handloads will not fit in the 96/11 but fit fine in the k31. All measurements of the rounds are under max dimensions, the dies are adjusted correctly and a chamber cast of the 96/11 shows nothing abnormal. I'm stumped and its making me nuts because the 96/11 is a real accurate piece when I could get the rounds to fit or using factory ammo. I also had a m1911 with a hammerli barrel but it had the same problem from the first round so I sold it off thinking it was a very undersized chamber. The bolt will not close the last say 10 or 15 thousandths of an inch which is preventing the charging handle from going the last 1/2" to an 1" which keeps the locking lugs from rotating to the locked position. The interior of the action and the bolt are spotlessly clean and very lightly oiled. Anybody out there run across this before?

[beemer]

I have loaded for the K31 but not the older rifles. From what I understand there is a bit of difference in the chambers. The military ammo will fire in both but the K31 chamber is larger in diameter at the shoulder. Dies are made for the K31 chamber, they will not size the case enough to use in older rifles, On the other hand dies for 1911 chambers oversize for the K31. Check your dies.

[Stewbaby]

Yes, K31’s have wider chambers. If you bought dies specific to K31, your rounds will be too large for the older rifles. Buy the generic RCBS or Lee 7.5x55. The Redding are for K31. I think Hornady has both.

The K31 specific keeps one from overworking the brass too much but it’s not a major benefit. Probably not worth it to the casual shooter given you can’t use those loads in the older ones. I do have both styles of dies and segregate my brass by K31 and the older Schmidt Rubin though just to be ‘that guy’.

Parashooter over on the Swiss board has this demonstration example in this post:

https://www.tapatalk.com/groups/theswissriflesdotcommessageboard/reloading-7-5x55-and-many-questions-about-sizing-t-t16294.html

[Czech_too]

While I no longer have the 96/11, I did find that I could not use the rounds loaded for the K31 in it. Redding dies were used.

[1Hawkeye]

I'm using a new set of RCBS dies.

[Stewbaby]

Do your RCBS sized case dimensions match the .455 as shown below are are they larger?


https://uploads.tapatalk-cdn.com/20201126/2b7d6e4f9f5381e09b7814b94e2aba2d.jpg

[Stewbaby]

PS: how does the fired case compare to the resized case?

[Whole Bunches]

1Hawkeye,

Don’t forget, I need a mailing address for the Swiss Airforce collar patch that matches your K31 soldier tag.

Bruce

PS and all the above chamber info is why I keep all my Swiss’s brass separate for each rifle.

[swheeler]

My Lee FL dies size the brass back like the RCBS do in the picture so I bought the collet sizer works great. Since you are using RCBS FL dies you should be sizing the shoulder area down enough, maybe screw the die in and try to bump the shoulder back a couple .001"

[1Hawkeye]

Fired case shoulder measurements are

K31 .4745" on 2 cases

96/11 .458" on 2 cases

I've tried the bumping the die trick from the bottom of the die just contacting the top of the shell holder to 2 complete turns of the die checking a case every 1/8th of a turn with no luck. Looks like RCBS dies are cut for the K31 chamber.

[Pressman]

I use RCBS dies and the cases must be full length resized or they will not rechamber in the K-31. I never measured the cases to study the issue, just know I cannot neck size with the dies I have.

In my conversations with Pierre St. Marie of Swiss Products he said the 96/11 is the most accurate of all the rifles in their testing.

[Stewbaby]

Yea, sounds like those RCBS dies are off some if the cam over didn’t work. Maybe try some Lee.