... if 2267 fps at 18 yards away, i was wondering what the true velocity/energy numbers would be, that fired hull on the chrono is a thing of beauty, the primer is perfect, no bolt raceway smear, no firing pin protrusion, the case fell from the chamber like they always have, and pockets remain tight, case head measurement before and after firing remains negligible ...
... i'll go back and trim all fired cases to 2.480 inch and call it good for i bet several more firings, the cases shouldn't grow much at all with that abrupt shoulder, speaking of shoulder, i'll take .459" all day long as i only size .411" length of the neck on fired brass ...
That rifle is a little 9.5 lb all up with 6 rounds on board, accurate, great functioning machine, my old 'Smith did a fine job as usual.
Sir Jerry,
Using BC for the Woodleigh 400-gr RNSN as 0.307 G1,
plug and chug in RCBS external ballistics calculator:
MV = 2315 fps and KE = 4760 ft-lbs if 18 YARD velocity was 2267 fps. HOLY COW.
Did you mean 18 feet or 6 yards ? Truly at 18 yards ?
You might have gotten one of those long-brass-pinches with brass stretch on firing (springs back if no bad-kaboom happens),
and got your pressure/velocity up even if not severe enough to cause problems.
I am especially strict on brass length since a teachable moment happened to me. I am self-taught on this one.
I once was tooling around on purpose with a cartridge very much like the .400 Whelen-Petrov
except that it had a chamber minimum length of 2.509" instead of 2.501",
and it had same neck-2 diameter (case mouth) but a neck-1 of 0.003" tighter at shoulder junction,
and it had 0.112" longer parallel-sided free-bore than the .400 Whelen-Petrov's 0.188" length.
On purpose, like a dumb adze, I was tooling around with firing brass cases that were all trimmed to 2.504" to 2.505"
A dumb adze is not the sharpest tool in the toolbox.
Let us say I successfully fired 3 loads of 400-gr .411 Woodleigh RNSN at a 100 yard target, with so-so accuracy,
then on the 4th shot velocity spiked a bit and the primer fell out of the case when the bolt was opened with no difficulty.
MV of that 4th shot was a bit over 2400 fps.
The average of all 4 shots was only 2398 fps MV, helped a lot by that 4th shot.
That 4th shot might have been a little longer in the brass than the others, like 2.505" instead of 2.504".
But maybe they were all stretch-pinching at the case mouths on firing.
Trimming all .400 Whelen-Petrov brass to 2.480" and letting it grow to no more than 2.490" is written in stone for me now.
