Sizing CBs for a revolver, reference on cylinder or bore

[JBMauser]

I figured I would ask first and slug second. I am just now going to load for 45LC with a proper LC bullet. up to this point I have been stuffing them with 45acp bullets (I had the mold) and crimping on the ogee. Now I am going to set up for the LC and I figured I would size them so they feed easily into the cylinder and allow them to swage themselves as they pass through the forcing cone. I have a lyman .451 and .452 sizer and I was planning on opening up the .451 (don't know why I would ever want to go that small on any .45) on my Saeco's I have .452 and .457 so I don't have anything that is just right for spec 45LC. I have seen LC referenced as .454 and .456. I will figure this out but I figured I would ask first. JB

[felix]

I have two Hammerlii colt 45 replicas, and both are 456 on the nose. ... felix

[Larry Gibson]

I figured I would ask first and slug second. I am just now going to load for 45LC with a proper LC bullet. up to this point I have been stuffing them with 45acp bullets (I had the mold) and crimping on the ogee. Now I am going to set up for the LC and I figured I would size them so they feed easily into the cylinder and allow them to swage themselves as they pass through the forcing cone. I have a lyman .451 and .452 sizer and I was planning on opening up the .451 (don't know why I would ever want to go that small on any .45) on my Saeco's I have .452 and .457 so I don't have anything that is just right for spec 45LC. I have seen LC referenced as .454 and .456. I will figure this out but I figured I would ask first. JB

It is my experience through testing numerous revolvers of several different cartridges that regardless of bore size best accuracy comes when the cast bullet is right at cylinder throat diameter. My usual test is that the cast bullet should require a gentle push through the tightest throat of the cylinder.

With my Uberti SSA (artillery model, throats run .454 - .455") in .45 Colt I size 452424s and Lee 452-200 RNFPs at .454". They give much better accuracy than when sized .451/452". Just a side note on the revolver; it is the very one Dwayne Thomas did an article on in G&A in '91 or '92. Not that that makes it special in any way, just interesting.

I also am finding with Lee tumble bullets in .41 and .32 that if larger than the cylinder throats velocity with the same loads will be about 75 - 50 fps less than with bullets sized to the throats. As cast both bullets are .002-.003" over throat diameter. This make sense as it takes energy to size them down and that energy must come from the powder burning which means less to propel the bullet.

The same thing occurs when using equal loads in fire formed cases vs FL sized cases in rifles. As it takes energy to expand the cases there is less energy then available for pushing the bullet. Also probably why ES and SD is almost always less with fire formed case vs Fl sized with the same load.

Just some of my observations.

Larry Gibson