I purchased a LEE 356-125-2R mold and cast up several hundred bullets. I selected this mold because it was roughly the same shape as the 115 grain round nose jacketed Winchester rounds I have been shooting with much success. Not having reloading data for this mold, I used loads from similar 125 grain lead bullets listed in a couple of reloading manuals (Lyman, RCBS, etc.). I seated the LEE bullets to the same Over All Length as the factory Winchester rounds, but they wouldn't chamber. So I started reducing the OAL and shooting them, then taking the ones that didn't chamber and reducing the OAL until they did. I also started taking the barrel out of the gun and making sure they fit. I started out with 1.155" for an OAL and ended up with 1.072" OAL with the cast bullets. Then I noticed that maybe I wasn't getting the mold clamped tight as I cast these bullets and some of them may have been fat. Although when I look at them after sizing them I can't tell. Also should I reduce the powder amount as I reduce the OAL? I am at 4.1 grains of W-231 over a Winchester small rifle primer in Winchester cases.