.257 weatherby load

[hardpan]

All,
I shoot a .257 weatherby mag and bought a box of accubonds (110gr). Problem is that the book does not have load data for 110 gr bullets. I will be loading weatherby brass, fired once and then completely sized, prepped, and neck turned. I also am using federal primers and IMR 4831.

Anyone out there have a load worked up already? I do not own a chronograph (yet), so all information is welcomed.
thanks,
Hardpan.

 

[300winnie]

Hardpan,

If you are stuck on using IMR 4831 the Nosler #4 manual lists the following maximum charges for the following bullet weights:

100 grain bullet (Partition/ballistic tip) - 68 grains
115 grain bullet (Partition) - 64 grains
120 grain bullet (Partition) - 64 grains

Based on that, I would be conservative and start load development at 64 grains and work up in 1 grain increments until you find a load that starts to look promising, or you start to see excessive velocities (which I would start paying really close attention at 3,450 and monitor it from there). Factory velocities for the 115 grain bullets are 3,400 fps, 117 grain bullets are 3,402 and the 110 grain AccuBond is rated at 3,460.

If you are not dead set on IMR 4831, I have had really good success in my .257 Roy with IMR 7828 and RL-25.

 

[hardpan]

Hey,
I can use imr 7828 as well. So, a load there would be great. Also, you mentioned to watch the velocity... Why?
thanks,
Hardpan.

 

[Guest]

I believe the reason he said you should watch the velocity is because you are extrapolating a load for an 'unknown' combination from data of known pressures for known combinations of similar components. If you were to load all the way up to 68gr, and find velocities of, say, 3900fps (clearly an exagerration, but you get my point), you'd be way over pressure, and thus dangerous to your welfare.

In any case, you would also be extrapolating for the 7828 data, as there is none yet available in 110gr loads. Generally speaking, 5gr of bullet weight is not enough to make a difference, according to a powder manufacturer's tech support (and this was for a 243 load, so the comparison applies), so you could use 115 data and approach with due caution, watching velocity. You would likely end up under pressure a tad, but with a good load that is accurate, giving up 50fps or so would be worth the trade of keeping your fingers!

You can also try the following data for the 110:

http://nosler.com/index.php?p=15&b=25%20Cal&s=207

 

[300winnie]

Dubyam hit it right on the head. Given proven powders in a cartridge (which IMR 4831 and IMR 7828 are) a person then has to kind of extrapolate between knowns and unknowns and experiment a little bit. Better to start of on the low side of things (within reason) and work up. Velocity is a really good indicator of pressure if you are working with components proven to work in a certain cartridge...in fact, I use it as my number one pressure test if nothing shows up before hand. If I get to 3,550 - 3,600 in my rifle with 110 grain bullets, even with no other signs, I know I am entering deep water.

Hope this helps

 

[hardpan]

Guys,
I really appreciate this. I find that loading accurately is not very hard, but getting to the right load is a trick. The knowledge shared on velocities is practical, and helps with safety.

Again, thanks!
Hardpan'