Question on Best practice when changing brass

[Bassnbow]

I have been loading for a fairly new 280 AI with 26" barrel. Been using Nosler brass and am close to deciding on a load for 143 HH. I'm also working loads for 152 Cutting Edge Maximus and 168 Bergers. My 143 Hammer Hunter load is with 53.5g H4350 and I'm getting about 3060 with it.

I have been on a "notify me" list for months and was finally able to score Petterson brass for it. My question is: Obviously I'm not starting from scratch with my loads, but where do I start? I know with the Nosler brass, with each firing (currently on 3 times fired) it seemed to show signs of pressure with same load when reloaded the next time. I know from watching posts here that the brass was still getting fire formed to my chamber and would likely continue building more pressure until fully formed. Do I use same load in new brass and just back it down a certain amount to start (if so how much)? Really don't want to just burn up components in our current crisis.

Also, again not wanting to burn up expensive and hart to get components, should I just waste powder and only shoot extra bullets I have on hand(that the gun does not like) to fire form the brass? Any idea how many firings the Petterson brass will take to fire form, is it softer or harder than the nosler?

Thanks for any help, excited to finally get the high quality brass, but don't want to start all over! Thanks Pat

 

[blacktail 8541]

I just recently switched from Nosler to Peterson brass also in my 280AI. I had been running H4831 / 61.5 in the Nosler with Barnes 145 LRX @ 3050 fps and will drop 3 grains and work up in .5 grain increments. I will run them over a chrono till I Reach the same velocity as my prior load as long as no pressure signs show up. If accuracy is good I may stop there or I may continue to fine tune. I have a lot of components on hand.

When changing any component, Drop down and work up.

 

[Bassnbow]

Thank you, wasn't sure how much to drop down. I also tried the same Barnes which was showing promise, but haven't found anymore in 4-5 months