I check cartridge base to ogive length on all loaded rounds as well. I have found enough variation in bullet lengths to warrant it since I’m not loading large quantities.

The reference point I mentioned with the Sinclair tool is the rear surface of a jig that inserts into the back of the receiver. You can probably find a demo on YouTube that will explain it better than I can.

Interesting that you mentioned concentricity. I have noticed with my dummy rounds that as I go shorter and approach the point where the rifling marks disappear, the marks are not uniform around the bullet but more to one side. I use standard Lee dies. There are probably better bullet seating products out there, I just haven’t evolved to that level yet.

It’s apparent that we use different methods although we probably arrive at similar conclusions. I will re-examine mine with the advice that has been given.

I arrived at the following maximum lengths for the two SMK bullets in question;

SMK 52 - Max cartridge length = 2.200
SMK 52 - Max cartridge base to ogive length = 1.854

SMK 69 - Max cartridge length = 2.260
SMK 69 - Max cartridge base to ogive length = 1.875

I loaded up a few yesterday with minimum charges and went to the 100 yd range.

SMK 52 - 25.0 gr W748, Rem 7-½ primer, Starline case, seated at 2.180 COL (0.020 off the lands). Cases and primers looked good after firing with easy extraction. Groups were 0.5” or less.

SMK 69 - 24.0 gr W748, Rem 7-½ primer, Starline case, seated at 2.245 COL (0.015 off the lands). Cases and primers looked good after firing with easy extraction. Groups were 0.5” or less.

I didn’t take my chronograph because it’s been acting up lately.

Back to what I was originally asking in a roundabout way - Is it reasonable to try these shortened loads using some caution? Or, would you just avoid it all together and move on to other bullets and loads that better conform to published specs?