N560 temperature stability in tikka 22-250

[cq0302]

Shooting my tikka 22-250 with 38gr n560 and Berger 85.5s with nosler brass yesterday and saw pretty extreme pressure (blew two primers out) in what I thought was a fairly moderate load. When developed it was 40f seeing ~3050fps and I thought about 1.5-2gr off pressure signs, the load shot phenomenal out to 1000 so I thought I had it dialed. Yesterday it was 70f and when I zeroed it was ambient temp rounds they were ~3150fps. After sitting out with some sun on the box for about 30 minutes I went to the long range and they were 2950+ and blew two primers with VERY heavy bolt lift on other so I stopped shooting them. Anyone else with similar experience ?

 

[cbuck516]

If you are going to lean hard on pressure, Nosler brass is not the way to go. You will only get a couple firing out of it before your primer pockets are wrecked. Ask me how I know

N560 does have a reputation for not being as temp stable as some other powders such as N565 or N555. However, I have had success using N560 for hunting loads where I do development at 70-85F and hunt at 0-32F. If you plan on using it in hot conditions (over 85F) I would reduce load a bit, but I would give that same recommendation for any powder to be honest.

 

[cq0302]

Yeah for sure, nosler brass sucks

 

[cq0302]

If you are going to lean hard on pressure, Nosler brass is not the way to go. You will only get a couple firing out of it before your primer pockets are wrecked. Ask me how I know

N560 does have a reputation for not being as temp stable as some other powders such as N565 or N555. However, I have had success using N560 for hunting loads where I do development at 70-85F and hunt at 0-32F. If you plan on using it in hot conditions (over 85F) I would reduce load a bit, but I would give that same recommendation for any powder to be honest.

The n560 shoots well. I did a temp sensitivity test with freezer, room temp, and then 120f and found about 120fps spread at roughly 100degree differential temp. I believe I over charged some of the other loads