I finally got out to shoot this weekend with the 458. It was a good day in the hills. Without waxing poetic; I'll get right to it.
Weather: Classic spring weather in the coast range. 51° F, 92% humidity, pretty constant drizzle and heavy overcast. No wind. The elevation was 1190' where I was shooting.
I wasn't shooting for score, just for initial load development.
The bullets that I was shooting were all dropped from Saeco molds. 350 grn gas checked, 405 plain based and 465 grn gas checked. All bullets were sized to .459" except the 405 grain. The 405 grn were sized to .451" and paper patched, then sized to .459". The powders were AA5744 and H4895. All strings were five shots over the chronograph.
This is the first trip out where I was actually shooting loads over the chronograph.
The 350 and 465 grn loads were a bit of a disappointment...not horrible but, not stellar.
The 405 grn, paper patched loads were just what the doctor ordered though. One in particular exceeded my expectations.
405 grn soft lead.
Sized to .451"
Two wraps of 100% cotton drafting velum.
Waterproofed with Sno-seal. (bees wax boot grease)
Sized to .459"
Loaded into new, slightly flared Hornady cases.
72.0 grains of H4895, CCI large magnum rifle primers.
Medium crimp with Lee factory crimp die.
Heres the shot data:
Max velocity: 2,248 fps.
Min velocity: 2,237 fps.
Ave. velocity: 2,243 fps.
Extreme spread: 11 fps.
Standard Deviation: 5 fps.
No barrel leading and no unburnt powder. No pressure signs. Easy recoil. Very easy cleanup. I only used 7 patches, three of which had Butch's bore shine on them.
The gas checked 350 grn bullets and the gas checked 465 grn bullets were OK. I wouldn't shoot a bunch of the 465 grainer's because of the added recoil, plus you don't gain that much if anything over the 405 grn bullets.
The 350 grn bullets were running about 2,200 fps with pretty erratic velocities and minor bore leading. The 465's were running about 1,465 fps and were pretty consistent, but not as consistent as the paper patched 405's.
I have a ton more data from the shoot if anyone is interested.
Oh, and the best loading for the paper patched bullets is almost a 100% case full... I'd have to figure it out, but it is about 92% as an estimate. I am all jazzed up over this load. Now to work on group size!