I am in the midst of processing a batch of about 300 pieces of once fired Federal (FC head stamp) brass. After full length sizing and de-capping the brass, I tumbled them to remove lubricant and checked over-all length as part of my pre-load inspection. I found that about 25% of the cases measured less than the trim to length (1.750) listed in my manuals. Many of the cases were as short as 1.740, and a handfull exceeded 1.755. All of the cases were checked with a Dillon head space gauge and did pass.

Two questions. First, has anyone run into this with FC cases or with any other cases for that matter? Second, with my loads, which are mid-point mild loads, will the short cases cause pressure issues?

Thanks for your comments and help.

Frank

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sona si latine loqueris .

I don't see how that will effect pressure. You'll have a little less contact area between the bullet and the case, but you still have plenty. The case volume behind the bullet will be the same (assuming you seat to the same OAL), so the pressure should be the same.

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"I also cook."

+1 agree 100%. Just think, you will get more reloads before trimming out of those cases!

"First, has anyone run into this with FC cases?"
Yes, much of the FC brass I've measured is as short as 1.740. I haven't seen this with other manufacturers brass.

Thanks very much for the replies and advice. I will re-start the production line.

Frank

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sona si latine loqueris .

The Federal .223-Rem brass that I have processed, and I've done a bunch, have always been short even after resizing. Sort of a bonus.

you sure it was "trim to" and not "maximum"? The cartridge drawings will often show maximum length, whereas trim to is usually specified somewhere else.

Short is'nt really bad, its just not ideal.

In the world of rifles, consistency is the key. And changing one aspect of a load at a time. Sized brass that is inconsistent in length needs trimmed, even if it is just .005 to make it all the same.

Brass length is a happy medium between where the chamber ends, and too much bullet jump. But, they all HAVE to be the SAME LENGTH. Or your groups suffer.

I agree that brass length is important when you are going for ideal accuracy. In the case of the AR and clones, the point is to be under maximun case length so that the rounds will feed properly from the magazine. When I load Lake City, Remington, Winchester, or PMC the cases "grow" to something between trim to and maximum case length. I typically trim them to a uniform length as a matter of process. In this case I was surprised to find sized cases that were below the trim to length, hence the question. Since I am loading these primarily for plinking, I will accept the shorter cases.

Thanks again for your input.

Frank

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sona si latine loqueris .

As said by the OP, this is for an AR and plinking. If accuracy was really that huge of an issue, the undersized brass would be set aside and one would only use brass of the exact same length that was not under the trim to length.

This not being the case, load them up, shoot it up, and have fun.

The bullet seat depth dictates case volume, and as long as they are all the same, excessive pressure (original concern) will not be an issue.

Different brass length WILL affect the amount of crimp your die does, but I don't generally crimp .223/5.56, or most any, rifle brass. In the few rifles I have shot my .223 handloads in, crimpless hasn't mattered.

.223/5.56 brass does seem to stretch faster than most other rifles I shoot, so brass that starts off a hair shorter than trim-to length would be a bonus in my book. One or two more reloadings before it needs trimming; a good thing as trimming and chamfering is so tedious!