I have a Lyman universal case trimmer, for the first time I was attempting to trim some 9mm cases and noticed I can't trim the cases because the collet won't go into the case for enough to make contact with the cutting head, the shaft appears to be about a sixteenth inch to short, the cutting length adjustments are set for as short as possible. Are there any adjustments that I don't know about or a possible fix.

Freddy, I had a Lyman trimmer many years ago but I don't recall the appearnce of much of it. I'm thinking you may be able to put some washers on the shank of the cutting head to space it out a bit. Might work okay, might not.

Interesting trying to trim cases that headspace on the case mouth and actually shorten on firing.

Swifty has a good point, are you sure you need (or want) to trim them? I "might know" someone who ruined some auto pistol cases by trimming them.

What you say is true, but they'll lengthen again when resized. I know you know that.

I honestly can't recall ever having trimmed a .40 S&W or a .45 ACP case, but IF I saw "considerable" length variation in sized cases AND I was concerned with getting the very most accuracy possible out of a pistol, I might consider trimming them in order to uniform the headspacing. Not that I can shoot a pistol well enough to see the difference it would make...just sayin.

I'd be interested in hearing SotG's story on this. There's always insights to be gained when someone shares a snafu story.

I went out and measured brand new 380, 9mm and 45 ACP. All the new cases were 10 thou under max sammi length. Once fired of those same cases were 2-3 thou shorter than new, and on resize they grew 3-4 thou on average. So if everything’s linear which I know it isn’t then it would take 10 cycles to possibly stretch to max. In my case I do a rotation. Fired cases go in an empty tub, next batch loaded gets pulled from a previously filled tub, then when fired go into the other till all 3 of my full tubs have been cycled. This way it is really hard to grow a case to max as I generally lose some and the ones that have been fired up to 10 times are about to the point where they split on sizing or have obvious flaws that make them trash.

RR, it's not very dramatic story. I had made it a practice to trim my revolver brass to minimum to aid in uniform roll crimps. On my first venture into auto loading I did the same thing, but for some forgotten reason I took a bit more off from a group of WW 10mm. Fired cases showed very flat primers with moderate loads which I could only assume was due to high pressure which made no sense to me, but I ditched that batch as a precaution. Looking back thirty years I am sure the flat primers were from too much headspace and pressures were normal.

The only thing I can remember breaking on that Delta is an extractor, not sure if the short cases contributed to it or not. I have read the threads where guys claim to have fire .40 S&W in their 10mm Glocks, it amazes me.

Now I never even check the length of auto cases, taper crimps make it pretty pointless and, as Swifty said, it takes a lot of firing and reloading for them to grow, I've usually lost the before it can happen.

Thanks for your responses, I am new to the 9mm in fact this the first semiautomatic pistol that I have ever owned, did notice that the cases actually got shorter after fireing, after loading and fireing them three times they are actually a thousand of an inch shorter, again thanks for the input.