Gauging a dial caliper for reloading (9mm)
 

I know a lot of you guys reload for the magnificent Luger. Can you give me a hint how to gauge a caliper so that I'll be certain for any measure that I make. My caliper is swiss made, 5" brand new from 30 yars ago. It has a vernier in mm and 10 th of a mm also the vernier has provision for the measure inches and tenthof inches coupled with a dial covering a hundred and thoudand of an inch. I tried to find a simple gauge block but instead they could only sale me a complete set at 1900.00$. Too much for me. Any idear ? Thanks!

If you close your caliper and zero the dial, you should be good to go.

Even if you use cases with the same headstamp and bullets from the same lot, there will be minor differences in your loads because there are differences in the components. Not all cases will be identical in length and not all bullets will have the same nose to ogive distance. The differences will be a few thousands of an inch but they will be there. You'll find the same differences in factory loaded cartridges.

You can buy a 1" precision standard for less than $20 if you want.
Search ebay or amazon.
I bought mine from Amazon, it's made by Mitutoyo/Japan.

But like Doubs said, if it "zeros" when closed- you are good to go for most work!

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

Comparing measures in 2 units-caliper
 

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.

Gauge block
 

Thanks! I'll find a gauge block somewhere else than Amazon or Ebay. I prefer to be local when it's possible. Thank you anyway!.

Your Einsteining the thing and making problems for yourself. Like a pilot on instruments..BELIEVE the gauges.

WHY are you converting anything? Your calipers read directly in inches and thousands of an inch.

The bottom picture shows your 9mm cartridge COL measurement to be exactly 1.045"

Jerry is exactly right; you're over complicating things.

I'd ditch the plastic caliper, and get a Mitutoyo, or Starrett caliper. They aren't that expensive, and are much better tools. That's just me, though.

The easy way to make and gauge 9mm Luger is to use a calibrated chamber case gauge like one of these:

https://www.midwayusa.com/product/1018249683?pid=793368

These cartridge gauges are inexpensive, and will save you more in time as you reload than any other method.

They come from a number of companies.

I 100% inspect my reloaded ammo with these gauges. Drop in the cartridge, Let it fall out and put the finished gauged cartridge in the box.

https://www.youtube.com/watch?v=hIraXq6u0VY

Here's the one I use. https://www.ebay.com/itm/Lyman-Ammo-...72.m2749.l2649

As I've explained in another thread, my loads for my 9mm Lugers are fine... in my Lugers. OTOH, my newer 9mm handguns have different chambers and will jam with the Luger loads. The bullets engage the lands too early and the bullets must be seated deeper. The same problem exists with .30 Luger loads for my Lugers and my newer .30 Luger pistols... a Benelli B80 and a Browning High Power.

What are you measuring? girth or OAL
For Girth the measuring blocks are faster and error free, you can't make a mistake

For OAL I use a micrometer a 1-2" covers almost all pistol cartridges (.380 is under 1")
E-Bay has (1,837 results for micrometer 1-2) mostly $20 -$30 but with a few about $10

I do have Vernier calipers but no dial and no plastic. I find the micrometer much easier to use for measurement, but then just set a caliper to that measured length and lock the caliper.

I have several Vernier's as I pick them up at Garage sales for $1

As a Machinist, I use dial calipers a LOT. I also reload and have a "Lyman" stainless steel caliper just for that. Calipers are perfect for reloading issues. I certainly DON'T use them for grinding a crankshaft or honing a cylinder bore when accurate readings to .0001" (a tenth of a thousandth) are required.

Of the dozens of dial calipers I've used (and it doesn't matter if Starrett or something Chinese), I often re-check my zero, as it seems as they wear, the needle will loose it's press fit on the pinion shaft and move slightly when the caliper is opened and closed quickly. In a low stress environment like reloading slowly opening and closing the jaws is more doable ;).

I also like using the case gages for checking re-loads before boxing them, however, they only check case sizing NOT COAL. Recently came across these my employer got in a box of supplies he bought from an estate;

https://www.topbrass-inc.com/collect...12832996851765

You get instant feedback regarding min/max SAMMI Specs for a caliber.

Maybe I complicate things here for you by adding this. I don't re-load for pistol, just precision high power centerfire rifle. Knowing how far the bullet "jumps" into the rifling is critical for load development. If the rifle is magazine fed, what will just fit into the mag is usually the limit unless rds are single loaded by hand.

I use this gage by Hornady to determine this dimension;

https://www.bing.com/videos/search?q...3&&FORM=VDRVRV

I have the same Hornady set but with the anvil in addition to the items you show. For Christmas my sons gave me the new Forster set that I like for measuring cases and ogive-to-lands.

https://www.midsouthshooterssupply.c...in-storage-box

For my handloading I keep both a set of digital calipers and dial calipers handy on my bench. Either will get the job done. I don't own a plastic caliper, and likely will never purchase one. Maybe I am just too "old school"!!

Thank you for the suggestion and link.

Thanks for the link!