Resizing 7.5x55

burns k31

burns k31

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So I decided to finally start reloading some 7.5x55. Have a bunch of PPU once fired brass, from my own rifle. Got in a Lee die set with a full length resizing die. Resized 5 cases, with the die set to meet the shellholder plus a half turn. Trimmed the cases to spec.

Now the good part, they won't chamber in my rifle. I would love some input on this. Do I need to buy a different set of dies? I was thinking of shaving some material off the bottom of the die or top of the shellholder so that the case can be pressed in further to size the shoulder properly. Thoughts?
 
So, full length sizing is going to squish the body back down in diameter - that results in the shoulder getting pushed forward. You can verify this by starting with fired case that does chamber, then start FL sizing with .030 or more clearance between die bottom and shell holder - work the die down half turn or so at a time and sooner or later the casing will no longer chamber. If you are thinking that the Lee FL dies are not pushing the shoulder back far enough, you can check by inserting feeler gauge into shell holder under casing - often there is up to .010 or more clearance there , so, in effect, you get to push case a further .010" into die without changing anything. An alternative - how is your overall case length once sized? Maybe the case is hitting its recess in the chamber at the mouth, rather than at the shoulder?
 
Lee dies are made to the 1911 chamber spec. which is actually tighter than the K31 chamber. I never had any trouble when I had mine getting cases to chamber.
Do you have a bullet in the case? Remember the K31 throat is ridiculously short.
 
I load the Swiss without having the dies. I just neck size (with a 32ACP die).

If the brass was shot in your rifle, you can neck size, too. Just adjust the FL die so it misses the shell holder by a tenth of an inch.

Try that and see if the bolt closes.
 
I have the lee dies and have had no issues. At first the the resized brass with a projectile seated would not chamber and I thought it was the brass but all I needed to do was seat the projectile further since it had a different profile than a gp11 projectile.
 
Potashminer said:
So, full length sizing is going to squish the body back down in diameter - that results in the shoulder getting pushed forward. You can verify this by starting with fired case that does chamber, then start FL sizing with .030 or more clearance between die bottom and shell holder - work the die down half turn or so at a time and sooner or later the casing will no longer chamber. If you are thinking that the Lee FL dies are not pushing the shoulder back far enough, you can check by inserting feeler gauge into shell holder under casing - often there is up to .010 or more clearance there , so, in effect, you get to push case a further .010" into die without changing anything. An alternative - how is your overall case length once sized? Maybe the case is hitting its recess in the chamber at the mouth, rather than at the shoulder?
Click to expand...
Something to try. Thanks.
It's not a case length issue, they were trimmed after sizing.
 
kawicrash said:
Lee dies are made to the 1911 chamber spec. which is actually tighter than the K31 chamber. I never had any trouble when I had mine getting cases to chamber.
Do you have a bullet in the case? Remember the K31 throat is ridiculously short.
Click to expand...

This is with empty cases.
 
2 Questions:
1) which bullet are you using?
2) What is the cartridge overall length?.

Use a black marker on the bullet to see if it is contacting the rifling.
 
I have a Lee 7.5x55 sizing die that is the opposite of the OP's problem. When I F/L resize, there is no firing pin to primer contact, not even the slightest dimple (K31) - btw, surplus GP11 fires perfectly with a nice deep and well centered primer crater.
I had to dismantle 100 cartridges that I had loaded, expand the necks with a .375 H&H expander and adjust the die stroke to give me a false shoulder for fire-forming. Now I use a Lee Collet die which works very well.
 
diopter said:
2 Questions:
1) which bullet are you using?
2) What is the cartridge overall length?.

Use a black marker on the bullet to see if it is contacting the rifling.
Click to expand...

These are resized and trimmed cases, with no bullet, that won't chamber. I realize I didn't make that clear in the original post.
 
Dump the Lee dies, had the same problem reloading for my K31 using the Lee dies. Bought a Redding die set.......issue solved. (I love my lee dies btw, that's all I use on other calibres, just not for the k31)
 
Read this blast from the past, especially post #2 from parashooter.

http://theswissriflesdotcommessageboard.yuku.com/reply/28112/Lee-dies-in-75x55mm#reply-28112

I had the problem in 6.5x58P on my RCBS Rockchucker with CH4D dies, but the dies work fine on Hornady LNL Classic. Go figure.

Try to screw in the dies a bit more and see if you can still crank it over the top. Try castor oil for case lube.
If still a problem, try annealing the cases , castor oil and resize with the dies in as far as you can screw against the shellholder.

I only use castor oil as case lube.
 
Last edited:
diopter said:
Read this blast from the past, especially post #2 from parashooter.

http://theswissriflesdotcommessageboard.yuku.com/reply/28112/Lee-dies-in-75x55mm#reply-28112

I had the problem in 6.5x58P on my RCBS Rockchucker with CH4D dies, but the dies work fine on Hornady LNL Classic. Go figure.

Try to screw in the dies a bit more and see if you can still crank it over the top. Try castor oil for case lube.
If still a problem, try annealing the cases , castor oil and resize with the dies in as far as you can screw against the shellholder.

I only use castor oil as case lube.
Click to expand...

Excellent information in that thread. Thank you.
 
Had some time the other day to have another go at it. I started over from square one. Reset the die in the press, made sure the cases were well lubed, ran them into the die slowly. I applied extra force to the press at the top of the stroke (handle all the way down, brass all the way up in the die). Had to do it standing. Held the case in the die for a couple seconds too.

Fired cases that had not been resized chambered easily. I checked all 50 cases after my first failed attempt at resizing, none would chamber. Case length was within spec, therefore resizing was the issue, not trimming. Checked all 50 cases for fit after second resizing described above, all chamber easily now.

The extra force was needed to push the shoulder of the case down to its proper position. Looking at a fired case next to a case I had failed to resize, I could see the slight difference in the shoulder angle. This is possibly due to the expander plug in the resizing die.

In summary: more/ better lube and more force required to properly size 7.5x55 using Lee full length sizing dies.

Easy solution to a rather frustrating problem lol. Thanks for everyone's input.
 
Ganderite said:
If the brass is a bit thick in the neck, the expander button can pull the brass neck out of shape. Solution is to lube the button/inside of neck a bit.
Click to expand...

I did do that. Both during the first resizing attempt that failed, and the second time that succeeded. Therefore I do not think that was the problem.
 
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