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Been playing with the new toy :shakeshout: ..............any comments, constructive or otherwise, about these cases with regard to pressure signs would be welcome. Extraction was free and easy.
The primers have flattened and cratered progressively, but no mushrooming apparent. The cratering is just visible at 23.0 grains, so it's I think it's partly due to a sloppy firing pin. These are the top end of a sequence starting at 23 grains.

Loaded to a COL of 2.260", these bullets are shoved well down into the powder...............................re-throating for 75 grain A-max's is definitely on the agenda. Then 1000yds, here I come.............

MV's (average of 5 shots) were: 25.0 gn 2932 fps
25.5 gn 3003 fps
26.0 gn 3020 fps

H/man

25.5 is about as far as I would want to go, of the three you post.

The 73gr berger will not be supersonic at 1K with that mv, and tbh it is a 600 yard bullet really.

What twist is the barrel? I do think a longer throat would be a seriously good idea, too.

It's a 1:8 twist barrel, 29" long from receiver abutment to muzzle. I wouldn't seriously consider the Bergers for 1000 yds either.
With a G1 BC of 0.343, they're a bit lardy...........but then at £20/100, they were cheap.........


H/man

80 amax if you can then - best 80gr bullet for BC....

Hauptman wrote:Been playing with the new toy :shakeshout: ..............any comments, constructive or otherwise, about these cases with regard to pressure signs would be welcome. Extraction was free and easy.
The primers have flattened and cratered progressively, but no mushrooming apparent. The cratering is just visible at 23.0 grains, so it's I think it's partly due to a sloppy firing pin. These are the top end of a sequence starting at 23 grains.

Loaded to a COL of 2.260", these bullets are shoved well down into the powder...............................re-throating for 75 grain A-max's is definitely on the agenda. Then 1000yds, here I come.............

MV's (average of 5 shots) were: 25.0 gn 2932 fps
25.5 gn 3003 fps
26.0 gn 3020 fps

H/man

Your 'cratering' is purely a sign of firing pin clearance. (your primers still show a radius on the edge therefore not 'flattened')
Primer condition does not necessarily indicate pressure problems.
To really check you need to measure case head expansion.

j0e_bl0ggs wrote: Your 'cratering' is purely a sign of firing pin clearance. (your primers still show a radius on the edge therefore not 'flattened')
Primer condition does not necessarily indicate pressure problems.
To really check you need to measure case head expansion.

See the sticky "Checking for signs of pressure" at the top of this forum.

http://www.full-bore.co.uk/viewtopic.php?f=11&t=8480