Aguila Blanca
Staff
So your question is about determining the optimum COAL, not about seating depth. Although, as you mention in this post, reducing the COAL also reduces the remaining case volume -- because it increases the seating depth.cdoc42 said:I've already fired mine and the accuracy at 7 yards off hand is acceptable. I dismantled both guns and removed the barrels. A loaded cartridge with a COL of 0.950" plunked into the barrel and compared to just a bullet plunked resulted in a calculation that the bullet was 0.04" from the leade.
Repeating the procedure with my neighbor's Sig showed the same COL placed the bullet right at the leade. This suggests to me that we can expect battery failures to occur if the bullet is seated longer than 0.950".
At 0.950" the case mouth is at the very end of the top of the lube groove, so any further seating would appear to have the bullet seated too deeply, but that's what we'll have to do if he does not obtain the same level of accuracy as I did if we want to duplicate the 0.04" jump that I have. The other concern is deeper seating and reduced powder space but I'm not concerned that 0.04" will produce a significant problem. The other option, of course, is to opine his gun simply does not "like" this bullet from an accuracy standpoint and search for an alternative.
That said, your concern about the lube groove is a non-sequitur. You are loading a revolver bullet for use in a semi-auto, and you are loading a coated bullet so (presumably) there is no lube. Even if the groove is lubed ... it's a lube groove, not a crimping groove, and the lube groove in a revolver bullet is intended to be completely within the case, not stop with the edge of the groove aligned with the case mouth.
If you need these loads to work in both guns, you can certainly load that bullet a few thousandths deeper. If you're at the maximum load already, back off the charge a couple of tenths, otherwise I wouldn't worry about it.