by Wapiti » 26 Sep 2026, 7:17 am
I have struck what madang is talking about too, and it's quite a pain.
I get this when measuring rifling to bolt face dimensions to get a consistent number too, using a dedicated comparator tool, as well as the simple tool above that Dye posted up a pic of. I even get it with a OAL gauge set.
Some soft projectiles are just bastards (yes, big name copper jacketed ones), it's so easy to get the long tapered tips to stop in the measuring gauge consistently each time. Especially with the super-accurate dial calipers available now. They pick up this inconsistency every time.
And when dropping a projectile into the chamber and having it stop against the rifling to measure it with the tool... to get the number in the first place...
it's so easy to push a bullet in differently each time. I pick that up using a dial caliper.
This does not make any sense, but when I was using a Chinese electronic caliper, I could NEVER get a consistent number.
Buying a Mitutoyo one made in Japan solved that.
Being numbers nut I much rather use an analogue dial gauge.
When seating, you cannot get a measurement consistency quite often as well, bullet grip (neck tension) is a factor. This changes with older cases as they get harder in the necks.
This is more compounded though, if you have a sharp-edged seating stem that "bites" into the long, soft copper ogives of the bullet designs demanded by visual looks and "long range" long-tipped shapes people use.
The seating stem bites into the bullet differently every time, with the inconsistent neck tensions of each case. No matter how much people screw around with annealing, a waste of time because that in itself gives different hardness numbers between cases. Forget that.
Try looking at the inner of the seating stem. Does the bullet sit in it supported over a few mm, or does it bite into the bullet and actually swage it a little as it seats in a tight case neck? The bullet tip is the first thing to compress, and then spring back differently each time.
I think it was that incredibly experienced LR shooter and reloader, Erik Cortina, who says, YES this is a pain, but you can only get an average number. pretty sure he's often said it's impossible to be 100% consistent with this each time, you can only get an average number and work with what you have. He reconned that this makes no difference, or at least one that is uncontrollable 100% consistently.
"The only way to avoid criticism is to do nothing, say nothing, and be nothing."
Aristotle.
Regards G,
AKA Dr. Doolittle