I bought some new 6.5 Creedmoor brass that is as short as 1.893" and as long as 1.908". If I'm reading SAAMI spec. correctly it says 1.90" to 1.92". Some meets SAAMI but none meets "Trim To Length". The reloading manual says "Trim To Length is 1.91". I thought you shouldn't use brass shorter than the "Trim To Length" but then comes SAAMI Spec. Would you use this brass? If so, would you trim all the brass to make it the same length and what length would that be?

TIA for any help

Trim-to-length is, as the name implies, the overall length that you should trim the case to when you do trim it. You can trim it (somewhat) shorter than that if you want.

Of greater concern is the headspace length, i.e. the length from the base to the ogive location on the shoulder. The headspace length will be shorter than the trim length (headspace is also specified by SAAMI, for 6.5CM it is 1.5368 to 1.5438"). This length is set when you resize the case, controlled by how far you screw the sizing die into your press. 6.5CM headspaces on the shoulder, so variations in headspace length can cause inconsistent ignition, i.e. misfires.

Get yourself either a comparator and a caliper (more precise measurements) or a headspace gauge (cheaper, accurate enough and easier to use) and check your cases for consistent headspace. Any cases that are shorter in headspace than the SAAMI minimum, you may want to set aside and not use. For the other cases, run them through your appropriately adjusted sizing die to get them all to the same headspace length. Then load those cases and you're good to go.

Since you're using new brass, headspace shouldn't be an issue but you might want to check it anyway just for peace of mind. As long as the overall length is at or under the trim length there's no reason to worry about it either at this time.

So if my headspace is good how short can case lengths be? Since my brass is shorter than trim length should I use the SAAMI spec. of minimum case length of 1.90"? In my bag of 100 pieces of new brass 15 are shorter than 1.90"

Thanks for your help

I'd size them all, then set my trimmer to 1.895 and trim, prep and shoot it all. They're going to stretch longer when you fire them anyways.

I agree with Expert308 ^^^, be less concerned with the Cartridge OL and be more concerned with the bullet placement.
Absolutely, get a comparator such as Hornady and measure your chamber for the Ogive and take a fired case and measure the chamber headspace.
I would be less concerned with those shorter-than> 1.90" brass and measure the shoulder of that case ~ compare it a fired case.
One of those metal case gauges are a good tool as well.
Document everything and record accuracies and velocities if you can as well.

The Hornady ogive gages are your friend as is the Sheridan case gauge with the open side…Johnny’s Reloding bench is a go to source of information (sadly I think he is quitting his channel…he will be missed ).

Using a trim length shorter than the recommended one won't hurt anything. If the overall case (really, case neck) length gets to be too long, it can - depending on the chamber and the bullet - result in the case mouth being crimped into the bullet by the chamber throat and causing excessive chamber pressure. But the only risk of a short case neck, and it would have to be really short, is insufficient tension to hold the bullet in place in the case. If the neck gets to be shorter than about the diameter of the bullet (.264" in this case), I'd probably toss the case, otherwise just shoot it. The case neck will get longer with each iteration of sizing / loading / shooting. The only way it can get to be shorter than what it is now, is if you trim it way short.

To expand a little on what smschulz wrote, a comparator setup like the Hornady gives you the ability to custom set your sizing die to match the dimensions of your chamber. You use the comparator to measure a fired case, so you know the headspace length of your chamber. Then you can adjust your sizing die to minimize the amount that the shoulder gets set back when you resize your cases. I.e., you adjust the sizing die so that the resulting headspace length is only about 2-3 thousandths shorter than that of the fired case, so if your fired case measures 1.5400, adjust the sizer down just until a resized case measures about 1.5398. That generally results in a longer useful life (more reloadings) of the cases since you're not working them as hard during resizing. It MAY also have a positive effect on the accuracy of your loads. You can't do that with the (easier, cheaper) case gauge, unless you have the vision of Superman. Of course if you had that, you probably wouldn't need the gauge in the first place.

[ETA: My math was wrong on the resized case length, it should have read "if your fired case measures 1.5400, adjust the sizer down just until a resized case measures 1.5380".]

This message has been edited. Last edited by: Expert308,

Thanks to everyone who replied. The Sinclair case gauge looks pretty good. I have some made by Wilson but being able to see your case in the gauge seems like it would be better for me. The Hornady comparator looks like it would be of great use too. I have loaded rifle before and if the case was shorter than trim length it went into the trash. Never bought new brass before but figured it would need to be sized/trimmed/chamfered before loading so when it was shorter than trim length I was lost. My friend picked out a rifle/scope combination for me to try out some 1,ooo yard shooting. A total different game from pistol shooting. Thanks again for all the help.

Rifle cases stretch when they are shot. Here we are talking about just 0.007 inch on a brand new case. So I would use that case without any doubt. Now if it has 10 load cycles on it that would be a completely different story and I would drop that case in the trash. Because that is a well used case that was just trimmed too short. BTW, on used cases you need to check for "necking" a bit above the base. If you see any hint of a necked down ring formed in the case then toss it immediately into the trash.