M93 7x57 throat tolerance

[atr]

I think I understand why this Mauser 93 is so inaccurate with both boolits and J's
I measured the throat distance and it is excessive. There is almost .875" free bore when I seat a 175 gr. RN jacketed to where the ojive is touching the lands. In other words the boolits and J's are jumping this gap before they engage the lands......

I'm wonderigf if anyone else has had similiar free bore issues. I can only think that the cure would be to re-barrel. and yes I am sure of my measurements.....

thanks
atr

[Dutch4122]

One thing that may help lessen the effects of that long jump is to measure the inside of a fired case neck from that rifle. Then size your boolits to that diameter or .001" below.

Sizing like this helps to lessen the effects of the slug tilting or tipping before it enters the rifling.

My 1908 Brazilian 7x57 measured .293" when I checked the inside of a fired case neck. 45 2.1 and BRP are going to be developing a design this winter to fit these fat old 7x57's. Might be worth waiting for before you go through the trouble of a rebarrel.

Hope this helps,:grin:

[mooman76]

I have never checked the free bore space but most have an oversized bore also. That has to be a bad combo if you have both.

[atr]

Yes,,,I have both !!!

[Bret4207]

Paper patching might help. My '93's dimensions aren't that bad, but she definitely fits the term "generous". Despite that she'll plunk 160 jacketed into a 1.5-2" group for as long as I can stand to shoot if I do my part.

[atr]

Bret,,,,
at 50 yards my "group" with 175 gr Jacketed was more like 12"....and the 160gr boolits which I had at .286 diameter were tumbling....
I think the long jump due to the excessive free bore is the real culprit. neigher my Rolling Block or my M95 have this condition and they shoot the same loads(s) very accurately.

[Bret4207]

Maybe doing the partial neck size so it becomes a tight neck for part of the length of the neck to center the case in the chamber would help. Bullet/boolit run out can cause this too.

[Mk42gunner]

Sounds like time to slug both the bore and the throat.

Thinking outside the box-- It might be better to get a custom sizer and size thirty caliber boolits down? That is if the rifling is any good?

I've got a 93 that is still in the project pile.


Robert

[atr]

nope...Im going to have ER Shaw rebarrel it