I recently had to change the seating depth on one of my 7mm08's in order for the cartridge to fit in the magazine. Because of scheduling conflicts between some construction at the range I belong to & my work, I am not going to be able to test until next week. I am running out of time before a hunting trip I have scheduled, so I wanted to get some opinions on how much this would affect pressure. I don't want to load up a bunch of them & then a few days before my trip find out that I need to back off the powder charge because it is blowing the primers.
Here are the specifics:
7mm80
Winchester brass & large rifle primers
Nosler 140gr Ballistic Tips
IMR 4895 powder 40.5gr.
2699fps from 26" barrel.
Change in seating depth - .059" deeper ( shorter overall length).
The maximum charge in the Nosler manual is listed as 41gr.

That change should lead to a decrease in pressure typically, so if it shot without pressure signs seated closer to the lands, then you should be OK. All that said remember the 'every rifle is an individual' thing, and I have seen crazier things than seating farther from the lands cause a pressure increase, but I have never had it show those signs in my rigs.

Good Luck --Don

I can say with 99.9% certainty that you will see no change in pressure unless you were already operating with pressure signs.

I would be more concerened about your accuracy. If you are changing a lot, this could affect accuracy & POI. You are going to have to shoot them sometime.

I would expect that your right fredj338. I will need to check the zero before my trip & after I get there. I just really didn't want to load 50 or 100 rounds & then have to pull them all & work up another load. I would really enjoy working up another load but I just don't have the time. I was not showing signs of pressure with the longer seating depth, so it is my understanding that I should not see any pressure signs from seating the bullet deeper?

If push come to shove you would be better off using the ammo you zeroed in with even if that means using your rifle as a single shot. The first shot is the one that counts and you'll find that you will take greater care in placing it. A second shot isn't impossible to get but you probably won't need it.

A number of my Mausers are single shots. One 6.5X55 in particular has accounted for a number of mulies. An old hunting buddy of mine used nothing but Ruger # 1s from .243 to .458 and a lot in between. He did as good as anyone I know.

Talk about a confidence builder- - -. roger

I doubt unless you`re at the ragged edge that you`ll notice a thing.
The reason pressures rise in your cartridge when seating the bullet deeper is from the reduction in case volume. The little you mention (0.059") likely won`t cause a difference that will show out side of the normal deviation of pressure in your load.

I finally got a chance to test the rounds in question. The deeper seating depth appeared to make no difference. I did not have time to set up the chrony, so I don't know if there was a difference in velocity. They grouped well with each hole touching at 100yd.