I just purchased a .58 caliber sidelock, one of those Hawken carbine sorts from Cabela's from a few years back. Any thoughts on good loads for it, best conicals... really any real-world advice at all. Thanks for reading and sharing.
Pickings are skinny for pre-made 58 caliber conicals, since both Hornady (Great Plains Bullet) and TC (Mini and Maxi Hunter) quit selling 58 calibers. A good source for premades is Track of the Wolf. They have TC Maxis from a mold along with an assortment of minies. All those minies are not the best idea for hot loads due to thin skirts, which distort and kill accuracy with charges above about 60 grains. One exception is the LEE 575-472-M with the thicker skirt and great big meplat for good hunting performance, but you're in casting land. I've had very good accuracy with that one using 80 grains of 3f or 90 grains of 2f. Another great one from LEE is the REAL.
With both the TC Maxi and the REAL, you're likely to get the best accuracy if you'll add a lubed felt wad (also called bore button) between the powder and the base of the bullet. I have the same gun as you (along with several other 58 cals), but mine has the 28" barrel rather than the carbine barrel. It's real fond of 80 grains of 3f or 100 grains of 2f under both the REAL and the Maxi, but always with that felt wad. The recoil starts rattling your teeth when you move beyond 80 grains or so, but thankfully you don't need any more powder to turn those 58 caliber conicals into game stompers.
I'm also real fond of round balls (.570 Hornady with a .018 lubed patch) over 100 grains of 2f or 90 grains of 3f for hunting and cheap shooting. I've always had through and through penetration with the balls as well as the conicals, and the balls are sure a lot more comfortable to shoot. Best of all with the balls, if you drop down to 30-40 grains of 3f, it's a dandy head musher for snowshoe hare and lots of off-season practice.
Dunno about your carbine barrel, but I sighted mine in dead on at 75 yards with the round balls and 100 grains of 2f. That puts it a little over 1" high at 50 yards and around 5-6" low at 100. Kinda loopy, but these are just not long range guns. No change of sights, that 30 grain charge of 3f puts the round ball dead on at 25 yards. With that same sight setting any of those conical loads I listed aren't much over an inch high at 50, around 2" low at 75 yards and 10" low at 100.
My favorite hunting caliber up here. You know you uncorked something when you pop the cap, but you see pretty satisfying results when lead cuts hair, too.
Scroll down to the bottom of this page for both lubed and dry. I cut my own from Durafelt using a 5/8" (.625") arch punch for my 62 caliber smoothbore, but the little oversize doesn't seem to matter in the 58 caliber. I'm using this stuff for lube, but almost any grease or paste type lube like Bore Butter will work, too.
BTW- Here is where my arch punch set came from and they sell singles, and here is my source for Durofelt.
I've been a big fan of the.58 for years now. I have three... one in a Green Mountain round ball barrel, one 32 " bbl. in a custom made fast twist (1-28) for the conicals and one of the last produced Thompson Center barrels in 58, (1 to 48"). Love them all, all do different things. You might check out Peter Niess Ballisti-Cast, Inc. 701-857-6366 for some custom made bullet molds. I had these folks make me a 550 grain mold similar to the old TC Maxi-ball design and have enjoyed good success over 130 grains 2F Goex and a tophat musket cap. This is a religious experience shooting that load. I recall the first time I touched off that artillery. I expected a stout load so I leaned in well. The recoil lifted my front foot off the ground 6 inches and I have cracked a seasoned TC Hawken stock shooting that load. But what a rush! I fear no chipmonk when afield with this rifle.
My accuracy has dramatically improved by swaging and lubing the conical bullets I shoot through the sizing press. It is an extra step to the process but is the single most important accuracy enhancement I have found for my equipment used and load shot. The performance of this load is simply devastating on carbon based life forms.