Signs of excessive pressure

[njc110381]

Hey guys. I've got myself a load to work to with the new AH. I need to make sure I know what I'm looking for regarding pressure. I've taken the load given to me, reduced it by 10% and fired it. The primer looks strange? it's really flat (you know they're kind of domed so you get a gap around the edge when they're seated? Well that's not there). There are no marks on the base of the case from the ejector cut out in the bolt face and the primer still has a good sharp edged dent in it. I think this is ok but just want to check!

 

Your advice would really be appreciated!

[njc110381]

Right, I started off at 9.8grns of Lil-Gun under a 25grn V-Max and it was giving me flat primers. I backed off to 9grns and they still look the same! I've compared it to the primers in some fired .22H cases and they look nowhere near as flat (although they were using Lil-Gun which is very low pressured in the .22H). I'm miles under the suggested load, should I back off more?

 

Suggested load was 10.8grns

[Cornishman]

This is a low pressure cartridge and things can quickly get out of hand in such a small case. I suggest caution. When I first bought my 17AH I tested several makes of brass. They vary considerably from one manufacturer to another and I guess that means the internal dimensions, and pressures, vary as well.

 

I've only ever used Vhit N120 and find 12.2g is perfect with a 20g Vmax and Remington brass - not so hot it beats up the cases but fast, flat and super-accurate.

 

Cornishman.

[Vermincinerator]

Your primers are backing out of their pockets, this not usually a sign of high pressure but shows that your primer pockets might not be as tight as they could be.

I had the same happen when fireforming both my 22-250AI and 257 AI in brand new brass but once formed and the pockets uniformed it stopped.

 

TB.