.30-30 trim stud

[mr surveyor]

According to my Hornady labeled digital caliper my Lee trim stud/trimmer cuts my .30-30 brass to 2.022 - 2.023. As long as I have the RCBS seating die set to seat to the cannalure, and the FCD collet die set to match, I suppose nothing to worry about. So far, in the short 2 years I've loaded .30-30 everything seems to be working extremely well. But, either my caliper is lying (which could be possible) or I'm seating bullets a bit deeper into the shoulder of the brass than would be ideal.

First, are there any readily available objects of known standardized lengths that could be used to verify the precision of a caliper .... similar to using check weight / calibration weight with scales?

Second, how prevalent is it for trim studs to be "out of spec"?

Third, as long as it's consistent and everything seems to work should it even be a matter of concern?


jd

[akuser47]

To verify a calibrated caliber I just use a tap measure. Obviously there is probably better ways just how I have always don it. The rule I follow is within the saami specs. .001 up or down for plinking probably no big deal. For long range shooters unacceptable. As any change in consistency can impact the out come at your target out past 300 yards big time.

[mr surveyor]

Well, I checked a few U.S. coins (based on spec's from the "mint"), and my caliper seems to fit the coin specs within a few thousandths. Also checked some of the brass on a fairly precise drafting scale (aka a finely etched "ruler") and came up with the same measurements as the caliper, again within thousandths as best as I could read the etchings.

I'm pretty sure now that the trim stud is the culprit ..... so, all of my .30-30 brass is trimmed "short" it seems. But, so far no "issues" with any loads (all jacketed 150's and 170's).


Thanks for any comments.

jd

[larryw]

Yes you can get a set of "Standards" to check calipers & mic's with.
Just google "Standards for checking micrometers" More info than you want.
Hope this helps.

[RBHarter]

There are check pins for micrometers generally in 1 inch increments.

As long as you have a load that's works I don't see a reason to mess with it.

[62chevy]

I always called them anvils and they come with the better micrometers.

I'm with the don't worry about it crowd but if you must then buy a new Case Length Gauge.

[Steve]

I had a lock stud get a spot worn where the case length gauge touched in the center. This resulted in me trimming a lot of 223 cases over .005" short, used them anyway.

I spin the case with the lock stud mounted in a drill. Found my problem was running it too fast, as well as holding the pressure on the cutter too long.

If you can see a worn spot in the center of your lock stud, that is probably the problem.

[Ranch Dog]

I'm in the don't worry about it crowd as well. As Steve mentioned it would be good to inspect the lock stud surface and for that matter, I guess the pin could wear over time. The only way you could note a difference is to establish a "Trimmer" record and make note of your trim length over a period based on your reloading.

My micrometer sets have measure standards included with them and once in awhile I will check the calipers. Really, if you check them at zero a couple of times and it returns, I would think that you are good to go.

[mr surveyor]

I really don't have any serious concern about the trim length, and the trim stud shouldn't be worn in any way as it's only trimmed a couple hundred pieces of brass. My dies are set to work with the finished trim length, and all is good. I was mainly concerned about the projectile seating farther than desired into the shoulder area of the brass .... probably not enough to stress the brass anyway. though.

Thanks, y'all, for the reassurance.


jd