Gauging a dial caliper for reloading (9mm)

[Doubs]

Originally Posted by JONABI

Thank you for the answer. Well I understand your arguments. But, since I'm only starting the reloading process I think it's good idea to start square.

Forgive me for being a bit confused but I don't understand what you're trying to say. A normal dial caliper as sold by places such as Midway, Graf's etc. will be accurate enough for your reloading needs.

I shoot competition centerfire rifle benchrest and few people in this world are more anal about precision than benchrest shooters.

If you reload to an overall length, you'll discover that the difference in your cartridges will be + or - more than you might think. That's due to a number of factors. I load my cartridges for an ogive-to-lands setting that is zero + or - .001". I turn the outside neck to a consistent thickness and load for .005" neck tension. Case length is trimmed, flash holes reamed to remove flashing and primer pockets uniformed. Others take it much farther than I do.

Reloading 9mm or .30 Luger does NOT require that level of precision... especially if you're shooting them in a Luger. Between manufacturers, cases can have thicker or thinner walls and vary in length. Bullets of the same weight and general design from different makers will have different ogive lengths.

I don't want to make it seem that reloading 9mm is difficult because it isn't but if you expect to keep all your measurements within .001", you won't. There are simply too many variables.

[JONABI]

I've lost my first reply( took too long, I was logged out).
Now I've zeroed my caliper: good. Measured a 9mm cartridge first reading mm=29,15 converted in inches= 1.1476 rounded to 1.148 compared to vernier combined with dial measurment= 1.145. Difference of at least .003 inche. That's why I want to calibrate my caliper because I won't be sure of any measurment until I can gauge it. I understand that I will face many variables while reloading. But at least I should know for sure what's the real reading before I start reloading to expect some kind of accuracy.