I personally wouldn't. Those pellets are much hotter than BP, and I would only use them in modern muzzleloaders.
I was shocked when my nephew bought them for his CPA to go deer hunting, and we ran them across my Oehler chronograph. Way faster than any BP loads could ever make.

 

NO!! Please don't.

 

There is a warning on pellets in a sidelock on the package. No. 11 is not hot enough to ignite them reliably and the twist on the barrel is too slow for sabot loads.

 

What AZ said. Pellets wont reliably ignite with less than a 209 or magnum rifle primer. Don't try it unless you want to figure out how to get un-burnt pellets back out of your barrel. Stick with triple-7 powder or pyrodex.

 

Those pellets are called/labeled “black powder substitutes”. Read the label. It should tell what grain equivilant they are. They are not “hotter” if they are a black powder sub. As far as PowerBelts go, they have their downsides. In some barrels they will actually migrate down the barrel towards the muzzle because of being a loose fit. Muzzle loaders are not SAAMI spec’s for diameter. They are all over the map for size. You should be shooting a patched round ball with your gun or a TC maxi ball correctly sized for your TC rifle. If it’s another brand, not TC, you’ll have to play around with different ball diameters and/or patch thicknesses. You’re very likely to find that your #11 cap will not ignite the pellets you are using. Try putting a couple in the barrel without a bullet and hold the gun muzzle up. See if firing a cap ignites the pellets before you jam a bullet on top of them.

 

Yes, of course, all of that is correct. Has been so long since I used a side lock, that I didn't think about the percussion cap not being able to ignite the pellets. Now that I think about it, I believe that I used to use Thompson Maxi Hunter bullets in it. Looked for them this morning but I must have disposed of them when I sold my Renegade.

Thanks.

 

I've got one of the Thompson's maxiball molds from back in that day. If you need a few, shoot me a PM.

 

The pellets will most likely not ignite off a #11. We used to put a kernel or two under the nipple just to ensure the loose powder would ignite. Powder for powder, it should be the same stuff. We used Pyrodex in ours for decades.
The barrel twist is most likely 1:28". You will be lucky to get it to stabilize anything other than a ball. There were some 100% lead bullets that would stabilize, but most of those won't either.

 

Never mind, I have found that someone has broken off the bottom of that front tangle screw in the stock, thus a new screw can not follow the correct path into the wood. Am going to probably have to try to drill that broken screw out, fill the hole with wood putty and then redrill the hole at the proper angle, I hope !!!

 

Question, would it be advisable to reassemble this gun with only the rear tang screw installed and try to shoot/use it in that condition ?

Thanks.

 

Get a left hand drill bit and the broken screw may just screw out. If not drill it out and glue in a dowel of the proper size and then drill a small pilot hole for the replacement screw. I would call the tang a tight fit but it needs both screws. I picked up and killed a buck last year with an early TC Hawken 45 cal with real bp and a maxi ball. I also just picked up a Lyman receiver sight set for the old sidelocks. They are fun to shoot.