Sizing question

[JanZ]

I'm casting and shooting a lot of 45 stuff for my Ruger Old Army as I have the Kurst conversion cylinder I'm loading ACP.

I slugged the barrel and it's a solid .451 and standard jacketed stuff shoots fine as well as Berrys plated I've also been sizing the cast stuff at .451 and it shoots fine but I think I may need to go to .452 for better accuracy.

Am I all wet here or on the right track, the lead I cast with is wheel weight/linotype/range lead 1/3 ea and is pretty hard.

[fredj338]

Go bigger, rarely hurts anything w/ led bullets & most often accuracy is mproved as well as leading reduced. A bullet 0.001" min larger than groove dia works best. Measure the cyl throats as well, some Rugers have small throats & may need to be opend up for best reuslt.s My RBH in 45colt had 0.4505" throats & while accuracy was ok, I got leading in the first 2" of bbl. I opened them to 0.4515" & the leading virtually gone & accuracy is almost twice as good.

[noylj]

I never size my cast bullets--not since I tried as-cast (using a sizing die 0.001" larger than the average as-cast diameter) and sized back in the late Pleistocene (about 1978).
You can only know what works best in your guns if you try as-cast and sized. Likewise, you can try a Lee sizing vs Lubri-sizer (if you have a Lubri-Sizer). Then, tumble lube vs. pan lube vs. Lubri-sized lubrication.
If you are not getting any leading with your current "undersized" bullets, I see little to be gained (other than trying some as-cast).
People need to think about what they are doing, but they need to experiment to find what works for them.

[realfisher]

good info to know

[Calamity Jake]

Check the cylinder throats for size, if larger than groove then size to throat dia. I think you will see better accuracy.