Going to start loading for a .450 marlin. Looking for suggestions on the best powder to start with. This is from scatch and I will Hafta purchase new powders.

I can not advise you on powder as I do not own a 450, however, if I were starting to load for it I would buy a large amount of brass cases. It has been discontinued by freedom group and brass my not be readily available down the road.

I´m reloading the .450Marlin with Norma N200 behind 300grs, 350grs and 400grs bullets. Since over 10 years.
N130 should be also a good choise, but I didn´t test it.


Martin

I shoot a 450M and load 400g Speer bullets with RL-7

and

Speer 300g with IMR-4198


Both are excellent rounds in both mine and my son's 450M

T

I shoot a lot of 450M. Great results with BLR and Marlin GG using IMR4198 and Wolf LR primers.

300 TSX, 300 H-day HP, 325 H-Day Flex Tip, and 405 gr Rem. All shoot 3 shot MOA or under with that powder.

One not often used or thought of is Ramshot's Exterminator powder. If you seat the bullets out long, this powder provides excellent velocities for the heavier bullets by giving you more room and no compressed loads.
The other guys' advice about IMR(not H)-4198 and RL-7 are right on for lighter bullets.

I reload for 450M levers, a couple of custom 450M bolts (a pre-64 Win 70 and Ruger M77 II) and a H&R single shot. I use H4198 and cast, jacketed and solids from 300gr-465gr 1750fps-2400fps.

Carnyman:

I have a BLR 450 Marlin and it is one of my favorite guns. I tried several different powders all over the chronograph and the very best, most consistent powder I found with 400 grain bullets was Accurate 2230. It is superb in the 450 Marlin with conventional bullets. However, when I tried it with homogenous bullets like the Woodleigh Hydros which are much longer, I got too much powder compression so I switched to Accurate 1680 and it worked perfectly. You might give the Barnes Busters a try with 2230. They are fantastic bullets.