On my 325wsm I need to trim the cases after every firing but my other rifles I only need to trim about every third firing. I’m getting no induction of over pressure is it just the wsm cases or is the load to hot. All of the cases are on there 4th reload.

That can't be right. Even with hot loads, it will take several before the case grows from min length to max length. You only need to trim them when they approach the max.

I do not know the answer, but some experts have said these may help. Try a different lube. Lube the inside of the case neck. Control shoulder bump when FL sizing. Neck size only.

That what I thought but after each firing I need to trim. Do you think I over working the brass when I resize. Thanks for the help.

Are they nickel cases by chance? I have a bunch of factory Win ammo w/nickel cases for my 7mm RM that had to be trimmed after the initial firing and trimmed after the second. Using brass cases I have not had to trim in two firings.

If you have just the wrong combination of circumstances you can find yourself inadvertantly stretching the necks on each firing. This might happen if you have a somewhat long chamber or somewhat short die (as measured to the datum line of the shoulder). Under these circumstances, you could set the shoulder back significantly during FL resizing, then the drag of the expander button through a tight and possibly unlubricated neck could stretch the neck forward enough to make the OAL of the case exceed the maximum case length. This will tend to pull the shoulder forward, but if the mismatch between the die and the chamber is enough, the case will still chamber without resitance.

Try this: Set your resizing die so that it barely touches (or not quite touches) the shoulder of the fired case. Lubricate the insides of the case necks to assure minimal expander button drag as it is withdrawn. See if this makes a difference in your OAL case length.

An over pressure load would cause the brass to flow more. Hard bolt lift would be a sign. Having seen this problem on other forum, with different cartridges, no one had the answer. The trim length always gets longer after FL sizing a fired case. How much it grows may have to do with chamber size & how much the dies work the brass. Maybe taking measurement of fired & sized brass will give a clue as to what is happening. SAAMI Measurments

I"d go to a PLF (partial full length) resizing and see if that helped.

I just picked up a neck resizing die will see if it helps. don’t think it is the loads Im not running them to hot 65 grn RL17 with a 200grn nos prt running about 2934 avg over my chronograph. Thanks for the help

I read somewhere that this was a problem with the newer short magnums, and so it has been in my personal experience. I know it is a problem with the old 300 H&H and to some extent with the .375 H&H but to a lesser degree...I have seen this with belted cases over the years.

You can cut back on the load as these newbies operate at very high pressure by comparison, and they are loaded to impress folks. Loading down solves the problem or you can simply keep trimming them, either works equally well. If you loaded a .270 or 06 to those factory pressures you would have the same problem.

I love my 300 H&H, I make it cook but I feel its a fair price to pay for such a great old caliber.

Ok thanks I had a feeling it was a shot mag thing