So since my "inheriting" of a .308 Dillon case gauge I have noticed something peculiar. I have always used my calipers to measure the OAL on my cases after being re sized in my SB full length die. That is "cut to length" of 2.005. So last night I decided for gits and shiggles to check my re worked/trimmed cases in the Dillon case gauge. Now mind you that this was after running them through my full length die and trimming the neck down to an overall case length of exactly 2.005. So anyways, I dropped my trimmed cases into the Dillon die and noticed the neck was about .008 from the "low" SAMMI specification shelf of the neck side of the gauge. If I were to trim the case to the Dillon case gauge the OAL would be about 2.012. I used a test case to confirm this OAL finding. Now mind you that the "datum to bolt face" measurement of the case gauge is nuts on with the same said case. So should I stick with the recommended 2.005 or go with the Dillon gauge size of 2.012? My gut tells me to lean to the former 2.005 as it has never done me wrong. I also would like to add how disappointed I am with the RCBS Trim pro. It never trims the neck square. Is this a common issue with the RCBS? I am seriously considering the Giruad trimmer for my bulk loads and a Sinclair/Wilson stainless steel trimmer for my other calibers. Any input on case trimmer selection?

I'm gonna guess that your Dillon gauge it at a "middle of the road" length. Usually the trim to length is around .10 shorter than the max length.
One point, if you do have concerns, is a case that is slightly shorter certainly can't get you into trouble.

As long as your trim length is less than the listed "MAX" length you're going to be OK with the loads.....unless you're dead set on crimping....then one is well advised to hold a close tolerance on the length and IMO the dial calipers is the tool to use...

I've used several trimmers and like the Wilson....but in my particular situation I have moved to using a drill press and a holder from the Wilson tool and a cutter from Forester....much faster and easily set to hold uniform lengths.

Hmmm,I see both your points. Im still a bit concerned about the RCBS trim pro not cutting square. Took some measurements and there is about a .001 difference from one side of the neck to the other. Maybe not enough to worry about?

.001 is not enough to worry about.

quote:

Originally posted by Antelope Sniper:
.001 is not enough to worry about.

What would you consider as a "out of service" measurement? I guess what I need is what is concidered as a "no go" measurement. I'm starting to come to the realization that my biggest issue with reloading has been what the "out of specification" measurements ARE. I think that is the reason why I only accept PERFECTION when it comes to specifications, cause I don’t know what is considered excessive. Unless I have somehow overlooked it,my Lyman/Barnes/Hornady reloading manuals only tell me what is “acceptable”. So I assume that ANYTHING even remotely out of this specification is unacceptable. Man, sucks being a newbie 

quote:

What would you consider as a "out of service" measurement? I guess what I need is what is concidered as a "no go" measurement.

I'll not hazard a guess at a number as I've never seen a case trimmed out of square enough to cause concern....if you're using a piloted cutter, it almost impossible to trim out of square enough to accurately measure with even a caliper....unless you're trimming .308 caliber cases using a .257 caliber pilot or some such thing...

One could trim out of square using the Wilson tool if he isn't properly holding the case holder into the tool...

If you're trimming out of square enough to be a problem, you'll see it visually.....you won't have to measure it with anything other than your eye!

quote:

Originally posted by vapodog:

quote:

What would you consider as a "out of service" measurement? I guess what I need is what is concidered as a "no go" measurement.

I'll not hazard a guess at a number as I've never seen a case trimmed out of square enough to cause concern....if you're using a piloted cutter, it almost impossible to trim out of square enough to accurately measure with even a caliper....unless you're trimming .308 caliber cases using a .257 caliber pilot or some such thing...

One could trim out of square using the Wilson tool if he isn't properly holding the case holder into the tool...

If you're trimming out of square enough to be a problem, you'll see it visually.....you won't have to measure it with anything other than your eye!

Ahaaa. Makes sense. Thanks.

CM
Any time you see the word "Overall" in a spec, it denotes an assembly IE: Case + Bullet

On your Case Length, the normal tolerance is .020 Min to Max, with the nominal "Trim-To" length being in the middle of the 2.

quote:

Originally posted by Tailgunner:
CM
Any time you see the word "Overall" in a spec, it denotes an assembly IE: Case + Bullet

On your Case Length, the normal tolerance is .020 Min to Max, with the nominal "Trim-To" length being in the middle of the 2.

Thank you tailgunner. That is what I needed to know. I was sitting on my "think tank" (the head) reading my Lyman manual again yesterday and started finding some stuff I managed to forget. I mean, its been over a week since I read it last. Thats one thing I love about reloading, the attention to detail that makes such a big difference in the end result.

Coalminer
You might appreciate a look at SAAMI drawings for the .223 minimum chamber and maximum cartridge. They produce basically a line to line fit.
The drawing are toleranced so you can see how sloppy things get with the max chamber and the min cartridge.
PM I think I can dig them up for you.