just got me a Seneca came with an unfired .36 cal. barrel got on line and found me a .45 barrel in excellent condition plan to deer hunt with .45 any body got load and bullet suggestions or experience

The Seneca with its smaller diameter barrel, will not take the same max load as a .45 Hawken. Hopefully someone else will chime in a give you a max load that you can work up to.

When I hunted with my .50 and .54 caliber T/C Hawkins rifles, I shot T/C maxi-balls. If you are going to use Pyrodex pellets in the .45 barrel, you may want to consider changing the nipple to use musket caps instead of standard percussion caps, as they are hotter.

If you are new to black powder shooting, a "must have" accessory is an unloading tool that uses a CO2 cartridge to expel an unfired charge.

Doubtful that you will find a musket nipple for a Seneca. Pretty sure Seneca and Cherokee both use a smaller nipple than the 15/16 and 1 inch T/C guns. I had a 32 Cherokee and the nipple was not your standard T/C nipple.

I have an extra 45 cal barrel if your purchase doesn't work out. 60 grains of real black powder was my go-to load. I tried every load, using bp, Pyrodex, Shockey's Gold, etc and every time, 60 grains of BP was the prefered load.

The T/C manual shows 60-80gr of FFG under conicals up to 320gr. 50-90gr for round balls. 70gr should give a 250gr conical about 1450fps and 1200fpe. Only loose powder us suitable for regular sidelocks; BP, 777, or Pyrodex. I would use BP myself.

I found this manual online somewhere about a year ago, so you can probably find it too.

I use 70 grains of various powders with 45 cal tc maxi ball bullets in a TC Cherokee. Worked great on deer.

Side note: the #11 cap would sometimes give less than desirable ignition with pyrodex, etc. Never ever had the first problem with BP...ever. with the fake stuff it was always click, boom...sometimes click...boom. With BP, it's always been instant ignition.

Cleanup is also not the problem I thought it would be with BP. Credit goes to Mike Venturino for his suggestion of using Windex, vinegar formula, for cleanup between shots. That stuff is like magic!

BP, CCI #11 mags if you can get them.

Your nipple pick is your best friend. Use it every time.

Killed a deer as a lad with a CVA Kentucky 45 loaded with 60gr 3f real black under a Hornady swaged round ball. The uncle I borrowed it from has killed several bucks with the same load.

It's no powerhouse, and rarely gives an exit, but with good placement it will kill deer.

I had an identical rifle. As I remember it max was 80gr patched ball and 70gr Maxi-ball. Hawk Driver is correct about the nipples, I believe they are 12-28. Even if available I wouldn't recommend musket caps unless you have a source of RWS caps. The new CCIs are meant for re-enactors and are weaker than #11s

My Seneca .45 bought in 1982 had a 60" twist and wouldn't shoot any sort of conical, although I still tried. The recoil of 70 grains of FFFG and a Maxi-Ball split the graceful stock at the tang. I learned to limit it to patched round balls on top of 60 to 70 gr FFFG and it was wonderfully accurate.(TC replaced the stock with an even prettier piece of walnut.)

braids-
You have found an elegant rifle. Congratulations.

From your original post, it's not clear whether you are an experienced ML shooter seeking to shotcut your load development for this rifle, or a novice looking for help with your first rifle.

In either case, try to find one of the T/C instruction manuals that came with the rifle. Meanwhile, below are some loading notes scanned from two different editions of the T/C manual for the .45 Seneca. If you can't read and print these, send me a PM.
--Bob
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BullShooter is one to talk about elegant rifles! He has one that is finer than frog hair. Hope you are doing well.

thanks a lot bull shooter I been around a while since early to mid seventies I guess just never used the little stuff this is gonna be fun squirrel hunted with the .36 yesterday instantly had ignition problems figured out 25 grs of triple seven aint enough powder in the hole went to 40 no problem

I guess I was a slow learner, as I hunted deer with black powder only for probably 15 years. Only a few years ago I discovered that a smaller load of powder was way more accurate and consistent than my normal loads. I actually dropped by 30 grains in my 50 cal. TC Hawken using Hornady Great Plains bullets.