I'm waiting on a barrel for a build and was wondering if someone could run some numbers through Quickload to give me an idea of what I should be using in load development for this rifle. It's going to be a .257 Roberts AI and I will be using H4350 and 75gr V-Max bullets (24" barrel). I'm hoping to be able to get around 3500fps but there isn't a lot of load data out there that I can find. Thanks in advance.
Quickload question
- Thread starter KDX
- Start date
unstableryan
CGN Ultra frequent flyer
- Location
- Beautiful Okanagan Valley
Says:
3476 fps with 52gr H4350 at 47645 psi at 96.4% case full
3547 fps with 53gr H4350 at 50716 psi at 98.2% case full
3619 fps with 54gr H4350 at 54003 psi at 100.1% case full
75gr v-max, .257 AI OAL of cartridge 2.775", bullet seated 0.323"
3476 fps with 52gr H4350 at 47645 psi at 96.4% case full
3547 fps with 53gr H4350 at 50716 psi at 98.2% case full
3619 fps with 54gr H4350 at 54003 psi at 100.1% case full
75gr v-max, .257 AI OAL of cartridge 2.775", bullet seated 0.323"
unstableryan
CGN Ultra frequent flyer
- Location
- Beautiful Okanagan Valley
That should vaporize some critters eh?
btw, shows max pressure at 51488 PSI, but if you are working with an AI cartridge, you probably know not to follow my information without double/triple checking.
btw, shows max pressure at 51488 PSI, but if you are working with an AI cartridge, you probably know not to follow my information without double/triple checking.
SAAMI pressure is 54,000 psi for regular cases and 58,000 psi for (+P) cases.
With any AI cartridge, you just start with the max load for the parent cartridge. The increased case capacity gives you the 10% reduction the starting loads would with the parent case.
You'll get higher velocities with that bullet weight if you go to a quicker burning powder.
With any AI cartridge, you just start with the max load for the parent cartridge. The increased case capacity gives you the 10% reduction the starting loads would with the parent case.
You'll get higher velocities with that bullet weight if you go to a quicker burning powder.
None of those are too fast. But, I think IMR-4064 would be a good choice, or H414 if a ball powder is preferred. It has a similar burn rate to H4350, but you can stuff more of it in the case. Not sure that you will hit pressure with H4350 without compressing the snot out of it.
I finally did some reloading with the fire formed cases and went up to 55gr of H4350 without compressing it. I made a dummy cartridge and the OAL is 2.894" with the 75gr V-Max. I started @ 51gr and worked my way up in 1gr increments. Not sure when I will be able to get out and test them though. They are +P cases and I'm using magnum primers (all I have on hand) BTW.
