Questions about my M1867 Spencer Infantry rifle

[SpencerMurphy]

So I have an M1867 Spencer Infantry Rifle. It is still rimfire and I am going to convert it to centerfire but what is a good bullet to use ? I couldnt find brass but I bought some Spencer Brass off of a friend that was loaded for his modern repro. Its got smokeless powder so I have to pull out the bullets and change out the powder. My Spencer has the lane extractor so I can use the newer cartridges instead of the ones cut from .50-70 brass. Also what is a good way to pull the bullets ? I dont have a bullet puller and I dont see any with collets big enough to pull .512 diameter bullers. I have the reloading dies (RCBS) and I have a single stage Lee Classic Press. I was thinking about putting a vise grip on the bullet and then pull down on the press to draw the bullet out of the brass. I know I will most likely damage the bullets on the way out so I figure will need to buy new .512 diameter bullets. I however dont want to damage the rim of the brass or the mouth though. Anyone got any thoughts on this ? Once I get the bullets out I want to reload with FFG Goex. How many grains of powder is good for a 350gr .512 diameter bullet ? I assume I will need some overpowder cards too like I use in my .577 Snider and .45-70 BP cartridges.Thank you to all who reply.

[El Supremo]

Hello, and welcome:

Couple things, please:

Our Forum is being trolled by AI generated Threads. Seasoned members may sit back and watch.
One self-authenticating action to qualify yourself is posting clear, close-up photo's of your Spencer. If you are technically unable, like me, please seek our Moderator's guidance.

Also, most beginner questions are covered in the Spencer Oft .... "SORI" resource here. That resource saves us continuously posting long answers for questions already in SORI.
Perhaps you could review "SORI", and then ask further. Smiles.
El Supremo/Kevin Tinny