Determining safe powder loads?

[R1GT]

A good place to start is the old-time rule of thumb, one grain of powder per caliber. That would be considered a light load now, and you could work your way up judiciously. I don’t know what your maximum charge would be. A lot might depend on the thickness of your barrel wall. Your barrel likely measures either 15/16” or 1” across the flats. I would be more conservative with the lighter barrel. In your smoothbore, assuming it really is .58 caliber, a .562” patched round ball would be a good choice. This ball size (and the mould to cast it) is readily available.

Your .58 caliber smooth bore is essentially a 24 gauge shotgun, and I think 2-1/4 drams of FFg (approximately 62 grains), with an equal volume of shot, with two card wads over the powder and one over the shot, would be a good starting shot load.

24 gauge was probably the most common bore size in 19th century smoothbored trade guns, although actual bore diameter was more commonly around .600”. A lot of the fellows here shoot trade guns, and could advise you regarding their loads.

Be safe, and have fun with your gun!

Notchy Bob

I originally started at 60gr of 2f and went up to 70gr before starting this post. Previous owner was doing 60/60 2f to #4 shot. So I started there at 60 with a RB.

I’ve got a mold for .575 so I’ve been running that with an .010 patch but I feel like I’m not getting adequate lubrication. I think I’ll try out a smaller mold and a .018-.020 patch.

After reading all the comments in this post I went out to my range today and set the gun up in a sled and remote fired it with a long string in increments from 70gr 2f all the way up to 100gr 2f. Smooth sailing.

I really just wanted to get up to 100gr in the sled so I’d feel good about 80gr in hand. Once I’d done that I loaded up some 80gr loads and had some fun on steel.

After that I filled up a few milk jugs with water and let the girls have a go at them with the 80gr charges.

They really don’t get the blackpowder allure but that definitely flipped a switch inside of them. They both had a very special kind of smile after that. Fun times.

 

[SDSmlf]

After reading all the comments in this post I went out to my range today and set the gun up in a sled and remote fired it with a long string in increments from 70gr 2f all the way up to 100gr 2f. Smooth sailing.

Watch the heavy loads in a sled. Just repaired a stock for someone shooting heavier (less than OEM ‘instruction booklet’ max and not outrageous) loads using a sled. Little bit of a crescent shaped stock and the toe was broken after a shooting session, plus there was a crack through the lock mortise.

 

[R1GT]

Watch the heavy loads in a sled. Just repaired a stock for someone shooting heavier (less than OEM ‘instruction booklet’ max and not outrageous) loads using a sled. Little bit of a crescent shaped stock and the toe was broken after a shooting session, plus there was a crack through the lock mortise.

This sled has hydraulic dampers on it so it’s not locked completely in place and has quite a bit of recoil absorption.

 

[SDSmlf]

This sled has hydraulic dampers on it so it’s not locked completely in place and has quite a bit of recoil absorption.

Those hydraulic sleds do work well at absorbing recoil, although the gentleman that broke his stock was using a Caldwell Hydrosled. I believe it was stock design (drop) and curved butt stock typical of many traditional muzzleloaders, used with heavier loads, though I sure some sleds are more forgiving and easier on stocks than others.

 

[tenngun]

You have a real tight load. You have to strain to get it down. Maybe sixty or eighty pounds of force to dive it home.
Powder goes off and weakest area will fail first.
What do you think that will be? 3/16 of steel or the tight ball?
Guns have held up through God awful loads
Old guns were on forge welded barrels. These were art not science
Color of the metal was judged by eye and experience and the iron was of questionable quality. Guns needed proofing.
Today not so much, even cheap Indian guns stand up to outrageous charges without issue.
Your shoulder will protest long before your barrel does
Your gun could easily take an accidental double charge
You say you’re shooting a .575 in a .58 and patched. Try that ball bare with a wad just on top. You may well be surprised by your accuracy

 

[flatcreek]

Your shoulder will protest long before your barrel does

Good comment, my shoulder protest at about 75gr in my 50 cal.

 

[R1GT]

Those hydraulic sleds do work well at absorbing recoil, although the gentleman that broke his stock was using a Caldwell Hydrosled. I believe it was stock design (drop) and curved butt stock typical of many traditional muzzleloaders, used with heavier loads, though I sure some sleds are more forgiving and easier on stocks than others.

You have a real tight load. You have to strain to get it down. Maybe sixty or eighty pounds of force to dive it home.
Powder goes off and weakest area will fail first.
What do you think that will be? 3/16 of steel or the tight ball?
Guns have held up through God awful loads
Old guns were on forge welded barrels. These were art not science
Color of the metal was judged by eye and experience and the iron was of questionable quality. Guns needed proofing.
Today not so much, even cheap Indian guns stand up to outrageous charges without issue.
Your shoulder will protest long before your barrel does
Your gun could easily take an accidental double charge
You say you’re shooting a .575 in a .58 and patched. Try that ball bare with a wad just on top. You may well be surprised by your accuracy

You know that’s a really good series of points. Short of stuffing a steel ball bearing down the barrel I doubt my standard RB has the ability to hold its form while a barrel is peeling apart.

And funny enough my first intro to BP was as a teenager, and I found myself a double charge on day 1. My friends dad was a huge muzzleloader hunter so naturally my buddy had a 50 hawken we drove around with at their ranch. My friend was teasing shooting a large 100gr charge so we stopped and fired a few into a tree stump.

Being kids and not paying close enough attention he accidentally loaded a double load of powder on the last go. And yes I’m 100% sure it was a double load, fairly obvious to my shoulder. The pure concussive force even knocked the side mirror off his suv from nearly 4 feet away.

I’ve always figured with modem metallurgy that these guns are likely quite strong. But I’d rather ask questions than make assumptions that could win me a Darwin Award.

 

[longcruise]

Lead shot

https://www.sagesoutdoors.com/reloading-components/

 

[OldRust]

My closest shop is 100 miles away and doesn’t have much anything if you can even catch them open. I’m out in the middle of nowhere in the Texas desert, so I’m really looking for an online vendor.

Online vendors: Ballistic Products https://www.ballisticproducts.com/BAM-4-Antimony-Lead-Shot-6-110-275mm-22/productinfo/UB06/
Roto metals https://www.rotometals.com/eagle-magnum-lead-shot-25-lbs-bag/

Thanks,
O.R.