Black Powder experience please !--458WM BP loads

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obiwannabe

New member
458 Win Mag and Goex FFg. I know folks have done this before and I've searched and read some threads, and read this page and that page to get some clue before I started, but I'd like a sanity check on the loads I've put together from someone with more experience than me.

I filled one of my Hornady cases with Goex FFg all the way to the top through a 24" drop tube and measured 96.02gr by weight. The interior of the case measures 2.280" from the web to the mouth. So every 0.1" of case holds 4.2gr of Goex FFg. The bullet is a Missouri 405gr RNFP which has a seating depth of 0.605" measured from the base to the top of the crimp groove. If I subtract the seating depth from 2.28" and multiply by 4.2gr I get 70.35gr to the base of the bullet (uncompressed). If I want 0.150" of compression (not including my 0.030" card) I add 1.5x4.2gr or another 6.3gr for a total of 76.65gr.

I melted off the factory smokeless lube and tumbled with LLA. These bullets may be a bit hard at BHN 18 but they're all I could find locally.

So I have ten 458WM cases stuffed with 76.65gr by weight of Goex FFg under a 405gr cast boolit with a 0.030" card. Primer is a Federal 210.

Does anyone see a problem or have a suggestion before I start smoking these boogers? FWIW, the weapon is a Savage 110 with a Shaw aftermarket barrel cut down to 21".
 
My BP experience does not include cartridges, but your load sounds reasonable, if a little on the warm side, to me.

It's far more sane than some of the things I've done, or seen done, with muzzleloaders.... ;)
 
Finally shot through these loads this afternoon. Super fun, easy shooting and it turned my mild mannered Clark Kent bolt rifle into an super sulfer-belching smoke wagon. :eek:

Kinda like making mud pies. Great fun and an ENORMOUS mess! Holy blackened barrel, Batman!

Only got 1230fps out of them though. I was hoping for closer to 1450. And accuracy was...meh. At 25yds it put them all in the same hole but between 25 and 100yds something went terribly wonky. Couldn't get them on paper. It's possible that they made a little 2" group somewhere in the constellation of holes in the target board off the paper but I couldn't find them.

Gonna try stuffing a little more powder into the case with a little more compression. Or maybe back the charge off and try a duplex load with a pinch of 4759. And find a fresh target board next time to see if I can figure out what's going on down range.
 
458 BP

I shoot 45/70 original Trapdoor . I use both BP and Smokeless. I found out by trial and error that hard cast bullets work well w/ smokeless but not with BP . With BP you need a soft almost pure lead bullet. BP doesn't have the initial pressure to swage the hard bullets in to the grooves. With smokeless I use Moyers 405 GC and for BP I use Chey 405 BP bullets.
 
I would make sure bullets are lubed with SPG or any good BP lube and use grease cookies, otherwise subsequent shots will string or spread.
 
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