That sounds like a great bullet for the 45 Colt, from rifle or pistol, but one thing I'd do is wait until the rifle arrives, then slug ther bore to see what diameter your slugs need to be. Marlin 45 chambers are often on the large side, so some judicious handloading may be in your future. Some folks even decap on one die, then resize the case halfway down to extend case life in oversize chambers.

While you're waiting you can measure the chamber throats in your Vaquero, and see what size bullets they'll need. If as-cast bullets fall through the cylinder, accuracy is going to be poor. If you can press them through with finger pressure, they're about where you want them. Ruger bores tend to be very good.

Of course, I'm also a newby when dealing with home-cast boolits, perhaps some of our veteran casters can offer some more specific advice. 8)

 

still waiting for some of our veteran casters to give me some advise

alan

 

Good Evening and Regards to Newfie & Papajohn!
You haven't received much for a response - so I'm gonna jump in here.
Let me say "up front" - I do not have a Marlin in .45 Colt (yet). I do have one in .357 mag., .41 mag., 30-30, and 45-70 Government. I shoot cast bullets in all of them and the only one that was troublesome to develope a load for was the .357 mag...... :-X and she was one troublesome, cantankerous wench! How-some-ever, I digress.
The Lyman bullet you have chosen is an old and proven design that closely resembles the originals from the 1870's. Your choice of alloy is one of the mixes for "Lyman #2 alloy" and should work well in your rifle (I have used that mix for velocities up to +1,900 fps. with no leading.). Regarding sizing the bullets - Papajohn is on the right track - I would recommend waiting until you can slug the bore and go from there.
For my previously mentioned Marlins, I size as follows: .357 mag gets .358" bullets; .41 mag gets .410" bullets; 30-30 Win. gets .310" bullets; and the 45-70 gets .458" bullets. Best accuracy is "usually"attained at bore diameter or 1-2 thousandhts over.
I would slug the barrel on your Ruger and the measure the chamber mouths in the cylinder and start there. My USFA .45 Colt measured .452" for both the bore and the chamber mouths and the Ruger should be close to that.
Since the .45 Colt was originally a blackpowder cartridge, its case is a bit cavernous for most smokeless powders. Unique and WW231 have been favorites for a long time and I've used them both. However, I have recently been trying some loads with IMR's Trail Boss and it shows good promise.
I may have become a bit "long winded" but I hope this helps!
Shoot Straight and Good Luck,
Skyhunter

 

I cast the LEE 452-255RF for my 45 X 24 cowboy. It casts at .453. It shoots well at 110 yards or so. I took a turkey at 85 yards land 2 deer at close range last November. I cast from WW alloy and WW + tin. Both seem to shoot well but I have yet to sit down and test them for the better accuracy. I have also ordered a Ranch Dog 454-290TL mold in a recent group buy. It resembles the LEE 452-255RF. LEE molds are inexpensive, so try one.

Papalote