Switching brass, can't reach previous velocity

[goathunter]

Has anyone not been able to reach a previous max velocity when switching brass? What I mean is I used to shoot nosler 180 book RL17 load at 64 gr, and got around 3000fps with WIN brass and a 24.3" barrel. I cut my barrel to 20" and got ~ 2850 with the same exact components. Now switched to ADG brass, and and can only reach ~ 2800 before pressure signs and probably 2780fps where I'd comfortably stop. This is with less powder since ADG has less volume, but I expected to reach ~ 2850 with less powder.

 

[Pickettpuncher]

What signs are you seeing

 

[Wapiti1]

Less powder will always equate to lower velocity at the same pressure because the produced gas volume is lower. Powder weight directly correlates to final volume of gas. Since your case volume is smaller, you hit max pressure faster at the burn rate of that powder.

I would try to a slightly slower powder to get back to where you were.

Jeremy

 

[SDHNTR]

Not surprising, ADG pressures up before other brass in my experience. Petersen even more so.

1. If it’s accurate I wouldn’t worry about losing 70fps

2. Change powders if you must.

 

[goathunter]

What signs are you seeing

Heavy bolt lift and a big ejector mark.

 

[goathunter]

Less powder will always equate to lower velocity at the same pressure because the produced gas volume is lower. Powder weight directly correlates to final volume of gas. Since your case volume is smaller, you hit max pressure faster at the burn rate of that powder.

I would try to a slightly slower powder to get back to where you were.

Jeremy

How much slower would you recommend - any suggestions? I couldn't get reach advertised speed out of RL22 with WIN brass but maybe different with ADG? Or I have a little RL19 and IMR4831

 

[Wapiti1]

How much slower would you recommend - any suggestions? I couldn't get reach advertised speed out of RL22 with WIN brass but maybe different with ADG? Or I have a little RL19 and IMR4831

I would try RL19 first and then IMR4831. Ramshot Hunter could be another to try.

Was your previous brass not available, or problematic? Selling the ADG and getting more of the original may be the best option if you find you'll just be spending money on different powder. Sounds like you had a good load combo.

Jeremy

 

[goathunter]

I would try RL19 first and then IMR4831. Ramshot Hunter could be another to try.

Was your previous brass not available, or problematic? Selling the ADG and getting more of the original may be the best option if you find you'll just be spending money on different powder. Sounds like you had a good load combo.

Jeremy

New gun, just looking to start fresh. The win brass is good stuff though

 

[The Guide]

New gun, just looking to start fresh. The win brass is good stuff though

What is the cartridge? You mentioned new gun, so are you comparing 2 different barrels and chambers?

Jay

 

[SDHNTR]

New gun, just looking to start fresh. The win brass is good stuff though

Wait, new gun? That changes everything. You can’t expect same speed out of a totally different barrel!

 

[goathunter]

No, all data posted in first post was from this one single gun, a 300 WSM. I had a previous 300 WSM and that is simply where the WIN brass came from. But I got a new rifle and new ADG brass, that's all I meant. I began with some known book loads using previous components as a baseline, that worked well in my previous rifle though

 

[wind gypsy]

Agreeing with what has been said. More capacity = More velocity at the same pressure. The "X brass gets the same velocity with less powder [full stop]" comments have always been odd. Yes, it gets more velocity with the same powder charge because it builds more pressure. The bigger case could go faster if loaded to the same pressures.

I'm surprised you're hitting pressure at those velocities with RL17. If there is a powder that will push a 180 faster in a 300WSM than RL17 it cant be by much so I wouldn't go chasing velocity with different powders.

What is your new rifle and how many rounds are on the barrel?