I have a basic Lee single-stage press that I use for my low volume reloads. I used used RCBS dies for the .45-70 and .45 Colt with no issues.
However, I picked up a set of Lee dies for .40 S&W and have been developing loads for it.
Today, I decided to whip up a batch of .40 S&W using XTP 155gr bullets in virgin Starline brass with 4.5 grains of Titegroup. Specified OAL is 1.126.
I adjusted the Lee seating/crimping die until I got the perfect length. Since I'm paranoid about over pressure with the .40, I checked every round for OAL after I loaded it. It varied wildly from round to round. Most were longer; around 1.128 to 1.131 and a couple were shorter, around 1.125 to 1.121.
I'd adjust the die to get that particular round perfect, then the next one would be off. It took forever to get 20 perfect rounds done.
What is going on? I don't recall having this issue with my RCBS die and .45 Colt, but then again I wasn't as picky. Is this common with the Lee dies? Or could it be the press itself?
I checked primer depth to make sure I wasn't running into issues there, and then made sure I was measuring on the brass itself. No idea why it would be so inconsistent in seating the bullet.