Quickload help please

[Bang4theBuck]

I'm helping a friend redevelop his load. He had a great load on his 6.5 CM, but it was in Hornady Brass. He decide to switch to Alpha SRP brass. He backed off of his existing load, which had no pressure by a full grain, and his loads ended up being pretty hot, with signs of pressure. I'm wondering of someone can run a calculation on quickload for me. Here is what I think is needed to calculate:
6.5 CM
Case trimmed to 1.910
Case capacity to top of case 39.9 grains of IPA
140 grain berger VLD hunting
CCI 450 primer
IMR4451 (very very similar to h4350)
2.880 COAL

Wondering what the calculations say is a max load. I really just want to find the velocity that we already know the barrel likes.

 

[wildcat455]

There's an easier way to do what you are trying to do.
If you have a fired Hornady case and a fired alpha SRP case from that rifle.
Weigh both of them, and subtract the alpha SRP case weight from the Hornady.
Take the weight difference in grains and divide by 15. This will give you the grain change from one case to the next. From your post, sounds like the Hornady case is lighter, so you'll be subtracting the grain change amount from your original load

So we're clear, an example. (Made up numbers.)
Hornady case weight 130 grains
Alpha SRP case weight 160 grains.
130-160= -30 case weight difference.
-30/15 = -2 grains.
Reduce your original load in the Hornady case by 2 grains for the new case.
That'll put you close to your original velocity.

If case weights aren't that far off, you can use for every 1.5 grain of case weight is = to .1 gr of powder. Notice that is .1 as in 1/10th grain.

 

[Bang4theBuck]

Thanks Wildcat. I was mistaken on the new brass it is alpha LRP. Does this change anything about the process outlined above?

 

[wildcat455]

No, the process works the same for differing brass manufacturers.