I'm looking for some reloading data for a 300 weatherby mag. I will be using a 180 gr. bullet. I want to use reloader 22 powder. Just really looking for a starting point but if you have a great load with reloader 22 it might help as well. Thanks in advance

Norma
http://www.norma.cc/en/Ammunit...00-Weatherby-Magnum/

MRP and rl22 is very similar both made by Bofors.

Even though the 300 Wby Magnum was introduced in 1944, there seems to be a lot of discrepancy between loading manuals as of late for maximum loads.

In the latest Nosler manual, when using RL 22 with 180 grain bullets they list a maximum load of 80 grains.

In the latest Barnes manual, when using RL 22 with 180 grain bullets they list a maximum load of 84.5 grains.

Big difference, to be sure.

Hornady and Sierra agree more closely to Nosler, listing maxium loads of 80.5 and 80.7 respectively.

My own personal testing has lead to a favorite load of 82.5 grains of RL 22 behind the Nosler 180 grain Partition.

This is in Weatherby cases, if you use Remington cases you will have to drop the charge a grain or two as they have less powder capacity.

Warning, do not start with any of these max loads or mine, start low and work up.

I ended up loading 168gr TTSX's in my 300Wby with 78gr of IMR4831 for 3267fps velocity. With the 180gr TSX, I ended up loading 82gr of RL22 for a muzzle velocity of 3060fps. The Barnes data starts at 79gr of RL22 and max at 84.5gr with the 180gr TSX. I loaded some up to 84gr of RL22 but my velocity peaked at just over 3100fps and groups started opening up. When I tried several different powders with the 168gr Barnes, it was obvious that the rifle liked IMR4831 better than any of the others including RL22. I may go back and test IMR4831 with the 180gr TSX's I have left.

I ended up at 84 gr RL22 shooting the 168TTSX in my 300 roy and it loves the bullet and load. Like noted above this is in WBY brass and if you go to Nosler brass back off and work up and doubt you get to 84.

Some of the loads listed here are a bit scary to me, though they may be perfectly safe in THOSE rifles.

I use 82 grains of the original 4831 sold by Bruce Hodgdon. That load is 2 full grains OVER listed max for that powder as shown in many of the older manuals, where the book max was usually about 80 grains behind 180 grain bullets. And Bruce's powder was at least a grain or two SLOWER than most of the modern manufactured H-4831 (powder gets weaker as it ages). Additionally, modern H-4831 is about 4 grains slower than modern IMR 4831.

My recommendation is to look up book max in several books, average them out, and start a full 10% below that. Obviously, given an 80 grain average max, that would be a starting load of 72 grains...8 grains less than our hypothetical calculated average listed maximum.

Then work up CAREFULLY. As soon as you get ANY signs of high pressures, drop the load 2 full grains from there and use that as your regular MAXIMUM for YOUR rifle.

The animals will never know the difference, but your rifle, brass, and wife will have reason to thank you.

I've had great luck with Weatherby cases, Federal large magnum rifle primers and H-1000 under a 180 grain bullet.

Depending on the bullet, I've went as high as 90 grains with Sierras but come down a few grains to 88 or 87 grains for Partitions.

quote:

Originally posted by kacole:
I'm looking for some reloading data for a 300 weatherby mag. I will be using a 180 gr. bullet. I want to use reloader 22 powder. Just really looking for a starting point but if you have a great load with reloader 22 it might help as well. Thanks in advance

Someone else's great load might not be so great in your rifle. In other words, you'll have to come up with your own pet load.

For a starting load, go to any reloading book and use the starting load listed for bullets of jacketed lead core or copper construction. Better yet, if possible use the reloading manual put out by the manufacturer of the bullet you wish to use.