7mm Mag cases, some won't feed

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bamaboy473

Inactive
Hello to the forum from a first-poster, but I've been casually re-loading about 40 years; everything from 9mm to 45-70. My 7mm Mag has me at a loss.

Twice-used brass, RCBS dies, Lee presses, Winchester LRM primers, between 67.0 and 69.5g of 7298, behind Hornady139 BTSP.

After firing, cases are cleaned, they are lubed, full-length sized, de-primed, pockets cleaned, necks trimmed and ready for primers.

Placing each case into the rifle is where I'm finding the problem I'm having of some cases not wanting to load; the bolt won't close, and there is bright scuffing on parts of the faces of the un-loadable brass.

After full-length sizing, then length trimming, there doesn't seem like anything else I can do. Do I toss the brass, or have I missed a step?

Sorry for the long-winded post, but don't want you guys to have to ask for obvious information.
 
Welcome to the forum.

Sometimes the belted cases can get too fat just ahead of the belt and are not fully returned to diameter by a standard resizing die because of the chamfer at the leading edge of the narrowing portion of the die. The chamfer is necessary to prevent gouging the brass during resizing. Larry Willis designed a collet-type sizer to resize the portion of the case the standard die misses. It's the third item down on this page. Not inexpensive, but it addresses the problem. Read the description and I expect you will recognize the issue you are seeing in it. Then you just have to decide if you are shooting the gun enough for the die to save you enough brass to be worth it.
 
thanks, Nick, so it isn't something that is unusual (just expensive to fix). Looks like new brass is a lot less expensive for shooting less than 40 rounds/year.

Will sticking to lower-power loads reduce the amount of bulge, or is this just the nature of belted cartridges, regardless of loads? These loads are for paper, not meat.
 
I shoot 7mm Rem mag and use RCBS dies....never had any issues you mentioned but I have read about others having them. Perhaps you can contact RCBS (800) 533-5000 and tell them of the issue...they may ask you to send in your sizing die and a few fired cases and then may well send you a new sizer die that will address the issue. I think that the $119.99 Belted Magnum Collet Resizing Die is far too expensive.
 
bamaboy473 said:
thanks, Nick, so it isn't something that is unusual (just expensive to fix). Looks like new brass is a lot less expensive for shooting less than 40 rounds/year.

Will sticking to lower-power loads reduce the amount of bulge, or is this just the nature of belted cartridges, regardless of loads? These loads are for paper, not meat.
Click to expand...
If you are punching holes in paper only, I'd lower the power. I reload for the 7mmSTW, which is a 8mm Remington mag necked down to 7mm. So it's a bit faster than a 7mm Remington mag. I experienced the same problem, case swelling above the belt. Rather then buy the special collet die, I load at velocities down around the .280 Remington, 2800-2900 fps. Brass seems to last longer, still very accurate, and much nicer on my shoulder.

To this day, I still don't know why I bought a rifle chambered in 7mmSTW. But I guess I've done dumber things.
 
Decades before the Willis collet die was used to size that ridge a few thousandths in front of the case belt down, a standard full length sizing die was cut off behind its chamber shoulder and just in front of the die belt clearance. After first full length sizing the fired belted case setting its shoulder back a couple thousandths, this "body" die was used to size the fired case body all the way back to the case belt.

That prevented occasional chambering problems and let the case headspace on its shoulder. Accuracy was best and often equaled that new belted cases produced in chambers made to let new cases headspace on their shoulders.
 
bamaboy473 said:
Hello to the forum from a first-poster, but I've been casually re-loading about 40 years; everything from 9mm to 45-70. My 7mm Mag has me at a loss.

Twice-used brass, RCBS dies, Lee presses, Winchester LRM primers, between 67.0 and 69.5g of 7298, behind Hornady139 BTSP.

After firing, cases are cleaned, they are lubed, full-length sized, de-primed, pockets cleaned, necks trimmed and ready for primers.

Placing each case into the rifle is where I'm finding the problem I'm having of some cases not wanting to load; the bolt won't close, and there is bright scuffing on parts of the faces of the un-loadable brass.

After full-length sizing, then length trimming, there doesn't seem like anything else I can do. Do I toss the brass, or have I missed a step?

Sorry for the long-winded post, but don't want you guys to have to ask for obvious information.
Click to expand...
The "scuffing" is the only part that seems odd.

Are you using correct shellholder?
A certain family member of mine has shell holders from 4 manufacturers and seems to regularly look at the wrong chart for the wrong box. With the scuffing exception, he quite often has the problem you describe.
 
The cases in question, are they twice fired in the same rifle chamber you find them too tight? Or, were these cases EVER fired in another rifle?
 
Can you determine whether the problem is a bulge above the belt, or the shoulder datum to case head dimension being too long after sizing?
 
I would take one of the problem cases and go over it with a magic-marker pen until all the brass is covered; then try to chamber the case, remove it carefully, and inspect for shiny wear-marks. That will confirm the location of the problem, before you spend the money on expensive solutions to an unknown problem. If you hadn't mentioned that you have trimmed your cases, I would have suspected that; make sure you're not missing any.
 
BBarn said:
Can you determine whether the problem is a bulge above the belt, or the shoulder datum to case head dimension being too long after sizing?
Click to expand...
This can happen if the shellholder stops more than a few thousandths short of touching the fired case head.

Do you have the means of measuring case head to shoulder? This dimension should be a couple thousandths less after full length sizing a fired case; a before and after measurement.
 
Interesting.
I neck size only (ok, collet size :rolleyes:), and have none of these issues.
My rifle tends to like towards max charges of RL26 with 150gr and heavier bullets.
For 120-145 RL22 gets the nod. Again towards max loads. Just where the accuracy node tends to be.

I usually get about 6-9 reloads before the primer pockets start getting loose.
 
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