switching from nosler 260 brass to lapua, idea on charge wgt difference?

[6brshooter]

When i got my tikka t3 sporter all the 260 brass i could find was nosler. It has been good brass, 10-11 firings and still has tight pockets. The problem is some are getting a donut .005-.006" below bearing surface and some are at the bearing surface. My old load is nosler brass br2, 44.5 h4350 with a 142 .020" off. Gets me 2830 fps, 17 es, and 8.xx sd in a 24" barrel. As tight as components are i hate to start completely over. Figure i would load up some 3 shot tests in .3 gr increments starting at 43.0 or 43.5 sound about right or should i start at 2 grs lower? Thanks for any insight.

 

[shoot4fun]

Curious as to why you would be getting donuts?
Usually only happens when you are forming from other caliber brass, neck turning for tight neck or using smaller caliber (say 243) and necking up to 260. I don't remember ever having donuts using factory brass stamped for caliber of rifle.

 

[Gray]

With Lapua Brass I would start at 42 grains and work to 44 MAX. Most rifles find a node between 42-43 grains with a 140 grain bullet, at least most that I've shot/seen. I did have a rifle that shot 44 gr but had a slightly harder bolt lift.

 

[EOD350]

I use Nosler brass now, and have used Lapua in the past. Nosler is close to Lapua in thickness, but I did start at 40.0 and worked up (we all know that drill). I ended up with the same charge weight for both, but that is my gun. I have shot thru the Nosler now 6 times so it is hard to beat.

 

[Beluebow]

When i got my tikka t3 sporter all the 260 brass i could find was nosler. It has been good brass, 10-11 firings and still has tight pockets. The problem is some are getting a donut .005-.006" below bearing surface and some are at the bearing surface. My old load is nosler brass br2, 44.5 h4350 with a 142 .020" off. Gets me 2830 fps, 17 es, and 8.xx sd in a 24" barrel. As tight as components are i hate to start completely over. Figure i would load up some 3 shot tests in .3 gr increments starting at 43.0 or 43.5 sound about right or should i start at 2 grs lower? Thanks for any insight.

I run almost the same charge weight as you.H4350 44.3 142SMK .005 off.with es of 10-11 get about 10 reloads on the brass before the primer pockets go south.