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Old September 20, 2012, 03:02 AM   #45
FrankenMauser
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Join Date: August 25, 2008
Location: 1B ID
Posts: 6,794
A minor accuracy and velocity update; since it may be all I can manage before the Elk hunt.

I got another chance to shoot some of the 275 grain bullets across a chronograph last Saturday. I was quite surprised at the result. The velocities are as much as 150 fps faster than I had estimated.

Whether it's due to decreased bore friction, from the zinc in the brass; or due to using slightly under-sized projectiles (by 0.0005"); I don't know. But, they are running faster than expected.


Back in post 17, I had estimated 47.5 grains H4198 to be pushing these bullets at 2,225 fps. However, Saturday's testing showed that load to be averaging 2,363 fps.
From there, the velocities consistently increased.


I was having a bad day and couldn't really hold things together. So, I only managed to print a 4-shot group of about 3" @ 80 yards (I didn't bother measuring).
However, my father was 'on his game', and managed to hold on to a 1-3/4" 4-shot group, at the same distance.

So, these bullets appear to be perfectly capable of "hunting accuracy" at a minimum; and further load development may even tighten things up.


I say "may" because I wasn't able to finish testing everything I had loaded. I had barely gotten started with the .40 S&W bullets.
My experimental "One Ounce Suppository" cast bullet loads managed to shift the scope in its rings, and I didn't have the tools to fix it. So, the .444 had to be put away for the day, without finishing what I had started with either set of tests.
--The one ounce suppository being a 428 gr bore-rider bullet, whose load increments got it to 1,855 fps in a 6.3 lb rifle, before recoil took revenge on the scope. (I can't say that the shooter was really enjoying the recoil, either, though....)


If all else fails before then... I may just do some more testing during the Elk hunt.
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Last edited by FrankenMauser; September 20, 2012 at 03:13 AM.
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