Don't rule out H335 for the Big Bores either. Check Hornady and Barnes for the .458 Win Mag and .45-70 with the heavies. I've found nothing better in those two. And I'm not alone in that discovery -- when you need more room for powder. As well, I've found temp stability to be awesome... one of the best for .458 caliber. It might be a different story for the small bores, I acknowledge, having never used it in anything but .358 and .458 bores.
And, in the Big Bores there's little cleaning to do anyway as you'll rarely fire enough to dirty the barrels. The exception is all copper fouling.
Bob
www.bigbores.ca
