Help with .300 Weatherby Mag load data


Well-Known Member
Jun 18, 2019
As part of a transaction I did to get a bunch of ammo boxes, I also got several bags of miscellaneous .308 caliber bullets. I have load data for most, but two I'm particularly interested in giving a try I have no usable data: Barnes 168gr TSX BT and Barnes 175gr LRX. You can indeed find load data on Barnes' web site, but not for any powders I have on hand.

I'm wondering if anyone here has some experience and charge weights they would like to share for either (preferably both) bullets using RL-25 in a .300 Weatherby Mag? I also have some IMR 4381, but that may be a bit too fast burning for the Weatherby.
I use H4831 behind a 180gr nosler accubond start at 78 and work up .
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Thanks, JKB57! That was exactly what I needed. Looking at similar bullets from Hornady, it did look like I could start there, but I had no practical experience to base that on. I also don't have the 20+ years of experience you all have to feel confident enough to let that explosion go off next to my head without some confirmation.

From the Hornady comparison, it looks like I'll start approaching a max load around 83gr. Has that also been your experience?
Yes I own 2 Mark V 300's both 26" barrels USA made both will shoot 81.0 gr H4831 but 82.0 start seeing a little pressure and groups start to open up
Thanks! My 300 is a Japanese made Mark V in stainless.

I'll start at 78gr and work my way up, paying special attention as I get closer to 81gr and beyond.

Just Country, I did a Google search first for loads and found lots of chatter around H4350, which is in Barnes' book, but also not what I have on hand. I then searched here and found similar chatter, but it also included RL-22, which I don't have, either. Hence my appeal to the collective wisdom on this board.

For the next guy seeking this information, here is a starting point.

Barnes 168gr TTSX
H4831 78gr to 81.5/82gr

These are not officially published values, so your mileage may vary.
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