Velocity is written on the target at the bottom, around 11520fps. Pressure would be much harder to arrive at.
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Average velocity was 1159fps from the three shots at 1153, 1172 and 1152. Had been loading the same bullet in a 458 Lott over 18.5gn for 1250 so used that as a starting point which gave me about 1130fps and worked through to the 20 gn load which improved accuracy and narrowed the velocity spread. 20.5 gr started to open things up again.
Thanks for the details V G, Sorry I missed the velocity number on the pic. It seems more mild than wild, but I'd love to see some measured pressure figures for that big ol MH case with all the loads out there. I'm pretty sure the real numbers (pressures) would be reassuring for some and sobering for others.
All I can say about the pressure is that I neck size by having a 1/4 brass ring under the Lee FLS dia so that it leaves most of the case untouched except for the top end of the neck which is visible in this pic. I have a worn extractor that needs building up as it fails to touch the case rim, but the fired cases fall out by raising the muzzle.
http://i667.photobucket.com/albums/v...pse60d3305.jpg
Your results speak for themselves. Congrats on your excellent stock work too. Very impressive work.
As per below is an extract from an old gun digest treasury demonstrating the approach for turning up brass for the 577/450:
Attachment 103485
I have it as the original pdf scan however couldn't work how to add it so saved this jpg picture, however the forum software keeps re-sizing it down too small. I think that if you look at this link it will link to a fullsized, more legible picture:
http://tinypic.com/r/144d6yb/8
I tried several powder's last weekend, but this pic is the result of 25gr of 4759 held with a dacron tuft.
When I pulled the trigger the hammer fell and that was the only sound. I poped out the case and had to use the cleaning rod to get this out.
http://i807.photobucket.com/albums/y...ps77505a00.jpg
The force of the primer blew the wad of Dacron forward which vastly increased the volume, dropped the flame temp and prevented ignition. As mentioned on the other thread a filler should be used, not a wad. I suggest a size of around 1 - 1 1/2 gr will work. Key is to fill the airspace between the powder and the base of the bullet.
A reading of my post #4 in http://castboolits.gunloads.com/show...use-of-fillers will explain the proper use of a Dacron filler. That is the best filler to use BTW for your application.
Larry Gibson
I'll use 3-4 square's this weekend.
Do you have a link to the post you mentioned above?
Went out again and what a differance!
I have both real kapok and the artificial stuff, and it take's a lot more of the real stuff to get to the same 1 1/2gr weight of filler.
Tried 2 grain's of both dacron and kapok and didn't like the look's of the fired case's with all the soot, so instead tried 2 square's of toilet paper inserted one at a time and have had success!!
15 grain's of 700X is looking like the winner. Tried it today at 400 yard's and it was almost hitting where I was aiming.
Sounds interesting. Do you know what sort of velocity with the 700X loads?
It looks like a fairly fast powder (like our AS50N or Hodgdon International) so did you decide to use it without a filler or with?
Don't know the velocity, but I used 2 "square's" of toilet paper inserted one at a time and pushed down for my case filler.
I read about using backer rod as filler so tried it and it does work. I used 24 grains of 4759 and the x-ring 500 grain .470". I am going to try the 400 grain bullet next. Want to load up some using Black MZ. The stuff works great in everything else!