Help with Belted Magnum sizing

DocCoyote

DocCoyote

New member
Why are my cases doing this after a FL sizing pass?

Belt1.jpg


Hint: it's the rim of brass just forward of the belt.

Bel2.jpg


I'm using a standard RCBS FL sizer. Case is Weatherby in the .257 flavor. I've used RCBS, Lee, and One Shot case lube with the same effects.

Also, I'm reloading for a TC Encore and I can't get it to close with the sized brass. I'm guessing it's the rim of brass that's doing it; think so???

Any suggestions??? /ubbthreads/images/graemlins/confused1.gif
 
Hmm, if I were to guess, you have the dies screwed in too much?!?

I FL size my 7 RM with Lee dies and have never had this happen to me.

There are some very savvy reloaders here, hopefully they can solve your problem!

Tim
 
First check the web expansion just above the belt. Measure the difference of a new unfired case against the fired, unsized cases. It there is no more thana thousandths, you are setting the die too low. Back the die out to the point you are just sizing the necks and progressively lower the die 1/4 turns checking the fit in the chamber between each sizing. It should go away.
 
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Update: RagnCajn and I spoke and decided that it might be a problem with the chamber in the gun. I pointed out to him that I'm unable to close a fired case in the chamber. He said he'd never seen that before. My question is, has anyone else seen this?
 
It almost looks like the chamber is too larger and that resizing is causing the over-expanded case to flow the brass back towards the rim. I would have the chamber slugged to see what the demensions are. Then compare the slug readings to the SAAMI specs. That looks to be very dangerous but I'm not up to speed on belted cartridges.
 
I think you either have an oversize chamber, or else you over sizeing the brass or possibly a little of both. Get a cast done of the chamber ASAP then you can go from there check chamber dimensions at the belt and just above back the size die out 1/4 to 1/2 turn. That may fix the brass sizeing problem but you still need to check the chamber dimensions, BTW T-C has screwed the pooch like that before.
 
I'm having trouble getting the sized brass to feed as well as the fired brass. It almost seems to me that the chamber is too small.

Also I inspected all of the brass that I haven't tried sizing yet and all of them have a similar rim just above the belt like above. But it's only on one side. Sizing just makes that rim bigger and spreads it all the way around the case. This makes me think it's cut out of square.

Any ideas?
 
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I'm having trouble getting the sized brass to feed as well as the fired brass. It almost seems to me that the chamber is too small.

Also I inspected all of the brass that I haven't tried sizing yet and all of them have a similar rim just above the belt like above. But it's only on one side. Sizing just makes that rim bigger and spreads it all the way around the case. This makes me think it's cut out of square.

Any ideas?



Okay that sounds more like it, yes I would say the chamnber was not cut properly, maybe the reamer was screwed up and that barrel slipped thru the cracks. If you have the problem on a once fired case and it's showing a problem prior to resizing then I would tend to believe the chamber reamer was at fault.
 
What kind of brass are you shooting? The once fired brass should be exact to your chamber size. Normally they should chamber with only neck sizing or slighlt pushing the shoulder back. One thing I run into that gave me trouble on my 300Wby was insufficient lube in the neck. After sizing, then on the upward motion of the press, it was actually pulling the shoulder up as it was expanding the neck.
 
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What kind of brass are you shooting? The once fired brass should be exact to your chamber size. Normally they should chamber with only neck sizing.



Yeah, that's what I thought, that's what makes me think I have an out-of-square chamber. This brass is from fired factory Weatherby ammo.
 
I would contact the barrel maker and discuss this with them. There should be no problems in closing action on fired brass.
 
I'd also vote for a chamber that is too long. That is just the right place to look for case stretch in a belted magnum because the case headspaces on the belt. It looks like the case is stretching to fill the space between the belt and the shoulder. One way to tell would be to section a fired, unsized case and see if the brass is thinning right above the belt.

It also looks like the case is being crushed down to proper length in the die. I full-length size all of my 300 win mag cases and have the die screwed all the way down to touch the shell holder. You shouldn't get this.
 
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I would contact the barrel maker and discuss this with them. There should be no problems in closing action on fired brass.



That will be tough sincet hey are out of business. VVCG
 
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I would contact the barrel maker and discuss this with them. There should be no problems in closing action on fired brass.



That will be tough sincet hey are out of business. VVCG



This could be one reason they are out of business?

Jack
 
another thing to keep in mind is if you are using a different make of shell holder than what your die is, sometimes that could cause it to size the case too much
 


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