Seating depth affect pressure

[Highvoltage1]

My buddy is going through the same thing. Just shot his new 7wsm this weekend, all loads under max by a few grains and had ejector marks. His barrel is a carbon 6. The odd thing was the 162 eldx and 165 Gamechanger hit pressure way before the 175 elites. The first 2 were around 2800-2850 while the elites was 2900-2925. 26” barrel. We felt like his loads would be pushing 3000, but like others have stated, all barrels are different.

 

[RuggedYogi]

My CA Ridgeline in 300 WSM also gets ejector marks no matter what load.

 

[Gear-Reviewer]

I have nasty ejector marks on a christensen ridge line 28 Nosler I’m messing with and should be nowhere near pressure that’s basically destroying brass aka bending the rim between the 2 ejectors. Primers look fine. Not hard bolt lift or extraction. Even found a group that basically shoots 1 hole that should be a moderate/slightly decently pressure load. Does this with 3 diff types of brass. Done messing with it now…

 

[SDHNTR]

I have nasty ejector marks on a christensen ridge line 28 Nosler I’m messing with and should be nowhere near pressure that’s basically destroying brass aka bending the rim between the 2 ejectors. Primers look fine. Not hard bolt lift or extraction. Even found a group that basically shoots 1 hole that should be a moderate/slightly decently pressure load. Does this with 3 diff types of brass. Done messing with it now…

Peterson is thick. Pressures up quickly in my experience. You’ll usually get the same speed with a grain or two less powder. Did you work up and use a chrono? does the bolt close easy? Are you bumping shoulders back?

 

[Gear-Reviewer]

Peterson is thick. Pressures up quickly in my experience. You’ll usually get the same speed with a grain or two less powder. Did you work up and use a chrono? does the bolt close easy? Are you bumping shoulders back?

Yeah I know it’s thick. It made these marks bad even during the first firing breaking in the barrel/fire forming with a mild load of 7828 and 180 Bergers… Bolt closes fine. I don’t understand how there’s not other obvious pressure signs and these are so bad.

 

[LoneStar]

I was just starting to work up a load for a new 300WSM and am seeing some pressure signs. I am using 168g TTSX and RL-17. Book states 61.2-68.0, but I stopped at 63.0 with a sticky bolt. I only fired 14 rounds before stopping. The primers still have rounded edges, but I do see one or two with a small rim around firing pin mark. No ejector marks, but there is slight scraping on some rounds. My chrono was out of commission so am unsure of velocities.

I plan on checking case length, since I had 2 rounds that would not let me close the bolt. I will also check seating depth again to be certain I am not on the lands. Any other suggestions? Once I get another chrono I plan on working up a load at the bottom end of the recommendation. I did get some very tight grouping at 62.0g just not sure about velocities.

Thanks for the discussion above, it really helps with my thought process.

 

[longrange13]

I am working on loads for my Christensen Ridgline in 6.5 PRC and have been getting pressure signs on multiple different powders before reaching book max. I am shooting Berger 156’s and seating them to 2.950 coal. I am using Lapua brass and 210M primers and have tried Retumbo, H1000 and N570. All are producing cratered primers at mid to max book loads. Could seating depth play a part in that?

As you get really close to the rifling it can raise pressure a bit. If you seat your bullets a lot deeper it will also raise pressure. More than likely your rifle has a tighter chamber causing pressure to come on faster. This isn’t necessarily a bad thing. Usually it means you can get book max velocities with a few less grains of powder which is a win win. Christensen rifles commonly have this issue. Not sure if they stretch their reamers out too long before retiring them or what.

 

[ZipsNLbs]

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