7mm Remington Magnum dies

[sfdoc2000]

I have been loading for over 50 years but have come up against a new problem. I have two 7mm Rem Mag rifles, one a custom 700 long action with a Bartlein barrel, the other, a factory Browning A-bolt. When I try to use cases that have been fired in the Rem 700 rifle (even with full length resizing in either RCBS or Forster dies), I cannot close the bolt on the Browning rifle. I know that belted magnums headspace on the belt, but here's the problem. The base to shoulder length of the fired cases checking with a Hornady headspace comparator. the rounds fired from the 700 even with full length resizing have too much base to shoulder length to allow the bolt to close on the Browning. In other words, the base to shoulder length is about 0.020 longer on the fired cases from the 700 than a new factory case (Norma brass). The only way I can reload for the Browning is to keep cases separate from the cases fired in the 700. It bothers me that the shoulder is not bumped back to SAAMI specs using either RCBS or Forster dies.
Maybe the gunsmith who chambered the Bartlein barrel made the shoulder depth about 0.020 deeper than a SAAMI spec chamber, I don't know since the headspace gauges for a 7mm Rem Mag only headspace for the belt, not the shoulder, so I can't actually measure the true chamber depth. I don't like the thought of rechambering the rifle. but maybe that may need to be done.
Does anyone know any other full length resizing dies that actually bump the shoulder back to SAAMI spec? I hate to try to buy multiple dies only to find they do the same as my RCBS or Forster dies. The other problem I also see here is the significant working of the brass to bump the shoulder back that far. Thoughts???
Doc Z

 

[MagnumManiac]

Hate to burst your bubble, but no die made will bump the shoulder back .020". The chamber dimension for shoulder position are not held to tight tolerances, this because the case head spaces on the belt, so the shoulder doesn't come in to play until after the case is formed to the chamber. This can take 3 firings with neck sizing only.
Belted mags vary in base to shoulder length. 300WM can be .026" longer than a new case, 338WM is often only .010" and the .264WM is around .015".
I have 4 factory rifles in 300WM, they all have their own batches of brass, dies and seaters. I also have 3 F-Class barrels, luckily for me, they were all reamed to be within .001" of each other and brass is interchangeable between them, but I do keep brass seperate because they use different loads in each.
I have 2 264WM, the brass cannot be switched between the 2 rifles.
I have found it very rare that brass fired in 1 rifle will fit in another.
You may want to measure the portion of the case just above the belt, but above the web.
Unfortunately your wish of swapping brass between rifles is not going to pan out...sorry.

Cheers.

 

[TXTrained]

I have been loading for over 50 years but have come up against a new problem. I have two 7mm Rem Mag rifles, one a custom 700 long action with a Bartlein barrel, the other, a factory Browning A-bolt. When I try to use cases that have been fired in the Rem 700 rifle (even with full length resizing in either RCBS or Forster dies), I cannot close the bolt on the Browning rifle. I know that belted magnums headspace on the belt, but here's the problem. The base to shoulder length of the fired cases checking with a Hornady headspace comparator. the rounds fired from the 700 even with full length resizing have too much base to shoulder length to allow the bolt to close on the Browning. In other words, the base to shoulder length is about 0.020 longer on the fired cases from the 700 than a new factory case (Norma brass). The only way I can reload for the Browning is to keep cases separate from the cases fired in the 700. It bothers me that the shoulder is not bumped back to SAAMI specs using either RCBS or Forster dies.
Maybe the gunsmith who chambered the Bartlein barrel made the shoulder depth about 0.020 deeper than a SAAMI spec chamber, I don't know since the headspace gauges for a 7mm Rem Mag only headspace for the belt, not the shoulder, so I can't actually measure the true chamber depth. I don't like the thought of rechambering the rifle. but maybe that may need to be done.
Does anyone know any other full length resizing dies that actually bump the shoulder back to SAAMI spec? I hate to try to buy multiple dies only to find they do the same as my RCBS or Forster dies. The other problem I also see here is the significant working of the brass to bump the shoulder back that far. Thoughts???
Doc Z

My friend that is just a common problem..I shoot a Winchester 70 Super Grade 7mm Rem Mag..., A Remington 700 7mm Rem. Magnum and a Browning White Gold Medallion 7mm Rem Magnum and the 1st two require me to reload their fired brass..My Browning shoots anything I throw in it just finne.

 

[sfdoc2000]

Hate to burst your bubble, but no die made will bump the shoulder back .020". The chamber dimension for shoulder position are not held to tight tolerances, this because the case head spaces on the belt, so the shoulder doesn't come in to play until after the case is formed to the chamber. This can take 3 firings with neck sizing only.
Belted mags vary in base to shoulder length. 300WM can be .026" longer than a new case, 338WM is often only .010" and the .264WM is around .015".
I have 4 factory rifles in 300WM, they all have their own batches of brass, dies and seaters. I also have 3 F-Class barrels, luckily for me, they were all reamed to be within .001" of each other and brass is interchangeable between them, but I do keep brass seperate because they use different loads in each.
I have 2 264WM, the brass cannot be switched between the 2 rifles.
I have found it very rare that brass fired in 1 rifle will fit in another.
You may want to measure the portion of the case just above the belt, but above the web.
Unfortunately your wish of swapping brass between rifles is not going to pan out...sorry.

Cheers.

That's what I was thinking but hoped not to hear. I was worried that .020 bump back might work the brass too much. Too bad for the belted magnums. Will just accept the fact that belted brass must be allocated to one weapon only. Maybe a good idea for other non belted cartridges as well. Thanks for input.

 

[LaHunter]

That's what I was thinking but hoped not to hear. I was worried that .020 bump back might work the brass too much. Too bad for the belted magnums. Will just accept the fact that belted brass must be allocated to one weapon only. Maybe a good idea for other non belted cartridges as well. Thanks for input.

The belt has nothing to do with it. How do you know for certain that it is the base to shoulder that is preventing the bolt to close. It could be the web just ahead of the belt or it could be the cases are too long and need trimming. Alex Wheeler has a method of measuring the headspace of your chamber. You can do a search and look it up. I would recommend getting that measurement established for each rifle.

When reloading for precision, it is wise to keep each rifle's brass separate.

 

[entoptics]

Two important things that have been danced around in the replies, but not fully addressed...

1) Forget about SAAMI base to shoulder. Forget about virgin brass base to shoulder. The only measurements that matter here are the base to shoulder measurement for 1X-2X fired brass from each rifle.

2) DO NOT size the brass more than enough to bump the shoulder ~0.002" ± 0.001". You will get incipient head separation after 2-3 firings at most, and full on case separations by 3rd or 4th firing if you size them more than a couple thousandths.

In summary, unless you get lucky, there's usually enough difference between chambers, that sharing brass and loads is difficult. I loaded for two identical Savage Long Range Hunters in 300WM, and they had 0.008" difference between base to shoulder, and 0.010" difference in base to ogive. Had I chosen to attempt to share brass between them, and bumped 0.002" back on the shorter of the two, the brass would have been 0.010" BTS for the longer rifle, and would have probably separated after a few firings in the longer chamber.

Usually, the only time you can get away with sharing is on virgin brass. After that first firing, it's time to keep stuff separate.

 

[sfdoc2000]

Thanks for all the input, guys. Yes 0.020 of case expansion bothered me. Will not try to use cases on different rifles.