Guys I have been reluctant to ask you guys this but I need to hear your inputs.
I have been reloading for a good long bit but I considered myself starting over especially since I found this site. You don't know how much I appreciate all of you and Len for having a great place to learn.
Rifle. 6 creedmoor MPA BA PMR PRO
H4350
CCI 41
ALPHA BRASS.
Hornady 110 A-TIPS
STARTED out 41.0 gr and worked my way up to find pressure. Ladder test.
I always make 3 of each load. Increasing by .3 grains Don't ask I just do instead of 1. Just feel more comfortable.
41.7 is considered max by my Manuel
Well 41.7 has come and gone with zero pressure indicators to note. I again today loaded up 2 more increases to find that pressure but nope.
Now I feel like I am not sure to continue just to know where max is. Hmm.
Hesitant to say what load is as not sure Len would be happy with me if I posted it.
Oh, My last load was a freaking Hammer too
I think manual max is as high as you should go. You are already making a pretty big assumption when you extrapolate the manual pressures to your rifle, since your rifle differs from the test barrel. Pressure signs don't start appearing at SAAMI max pressures (<65000 psi for most high rpessure cartridges). Pressure signs, like flattened primers, sticky extraction, ejector marks, case head separations, may not appear below 80,000 psi or 85000 psi. Velocity would be a good indicator if you were using the test barrel, but you aren't. And while your modern bolt rifle may be strong enough to operate at 80,000 all day long, brass may not be.
Engineers have set the upper pressure limits to ensure safety taking into account factors of which we are likely unaware. It's not wise to exceed them. For most of us, with no access to pressure measurement, that means staying at or below manual max loads. I know reloaders have pushed pressure boundaries since the dawn of reloading, mostly without negative consequence. But it's not rational, just to gain a little velocity.
All bullets drop, some more than others, and you can't remove drop from external ballistics consideration. A little more or less drop is easily compensated by knowing how your rifle/load shoots. For hunters, a little less downrange energy is easily compensated by limiting the range at which you shoot. There's no need to break cartridge pressure limits.
My cousin had a nice classic wood Mark V 300 Weatherby from the 60s. His stock kept cracking at the tang; happened 3 times. Many years after he died and after my father died, I found in my Dad's stuff a can of 4350 with a note affixed to it in my cousins handwriting, addressed to Dad. It gave my cousin's favorite load, which I found to be 13% more powder than manual max. I think he "worked up" a load that showed no pressure signs under his conditions, but that did dramatically exceed cartridge pressure limits. I speculate whether that may have caused or contributed to his split stock issues. For what its worth, Weatherby on inspection refused to pay for his stock replacements. And Dad, due to his natural caution and common sense, never sought to use that load in his Weatherby. His rifle is mine now, and it's as solid as the day it was first put into his hands.
There may be many who disagree with all this. That's fine. It only reflects my thoughts on the matter, which aren't necessarily the last word.
