Dial calipers off = long 223 cases

Lock them in your bench trimmer and trim. As long as you're using a conventional trimmer, you should be fine, since nothing will be go that far down in the case.

After trimming, just chamfer and deburr with the case upside down, that way no shavings get in the flash hole. At least that's what I've done.

devils4ever said:

It was off by 0.015" or so. ARGH.

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You should be able to adjust the dial back to zero when the jaws are closed. There should be a lock on the dial. Nifty feature that allows you to make comparative measurements on things by zeroing the dial at any jaw position..

As long as you are not using a trim system such as the Lee system, trimming should be fine. The ls trimmer measures through the flash hole which is not possible with a primer in place.

Another watch out, if you use a L E Wilson trimmer, use caution inserting and removing the cases from the case holder. When tapping the case into the holder, you might hit the primer by mistake.

You can decap the primers out very carefully. I've done this for over 200 rounds and all went bang when used. You have to be very gentle while doing it though.

This - You can decap the primers out very carefully. Then reinstall them after trimming.

One reason I like a case gauge, like a standard, it never loses zero.

I still use my original Lee trimmer with an electric drill. It trims to about 1.75". Afterward I spin the chamfer tool a couple of times before taking it loose from the shellholder. Simple and easy.

Sorry, just got the gist of your message - primers already installed. If it were me, I'd sacrifice the primers.

Also, if 'zero" isn't in the correct place at the top of the dial you can take the caliper apart, rotate the gear teeth and get it back to position. Possibly the gears have slipped a tooth? Takes a tiny screwdriver.

Know that a dial caliper can jump a tooth, that usually is .020", depending on the dial layout (0.100 or 0.200/rev) a small tool comes with many calipers to set it.
It's a small/thin (0.015") thing that most never know what it's for.
If you don't have the tool a straightened paper clip can be used.

show that caliper some love, clean and lube the rack
if you have the old padded type case, look under the padding for this tool

I'm tempted to just seeing if they'll chamber in my rifles. The longest is about 1.765".

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The odds are in your favor that there will not be a problem. Are you feeling lucky?

One more time, primers are set off by impact, not by slow pressure. Sudden pressure ie: impact by a firing pin sets off the primer.

You will be fine using your trimmer.

Maybe I missed something here. Why all the talk about removing primers? Just trim the cases and move on. I don't see a problem.
You said they are bolt guns. I'm betting they chamber and shoot just fine as they are.

Carbine85, the Lyman Universal trimmer needs the primer pocket empty.

If your rifle is amenable to a chamber test, I would go that route.

I would measure each one with a good caliper to find the longest half dozen cases. Then I'd test those cases. If they pass, then I'd load those cases with no crimp and try again. If those pass, I'd load and shoot the rest without worry.

If this works, you get a bonus. You can now put off trimming even longer, lol. Write that length down and subtract a little for your new must-trim length.

For all you know, your rifle might be able to handle cases that are 1.785!

I wonder, if your chamber is cut right, and you let your brass grow, can your chamber start acting like an X die to limit the maximum length? Oh, of course not, duh... when sizing, the brass lengthens.

Your concern of whether or not they'll chamber isn't really relative as to why we must maintain SAAMI trim lengths.

When a bottle neck case exceeds the SAAMI max head to mouth length, it will very often chamber without any noticeable difference. The reason for trimming brass is because the mouth can get pinched / restricted in the throat during firing. This prevents the mouth from expanding adequately, which creates a pinching effect of the projectile and prevents it from freely leaving the case mouth, that's when pressures can go unpredictably and dangerously high, and why we trim our brass.

Chamber fit, which is what you are referring to is controlled by the resizing die by how far the shoulder is bumped and sized case body diameter. Also, if a bullet is seated to long, in other words, when completed cartridge over all length is to long, the projectile will engage the lands, thus preventing proper chamber fit of a cartridge, this as well can drive pressures up.

GS

rg1 said:

Also, if 'zero" isn't in the correct place at the top of the dial you can take the caliper apart, rotate the gear teeth and get it back to position. Possibly the gears have slipped a tooth? Takes a tiny screwdriver.

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This .015 error probably occurred when apiece of "dirt" in the gears made the dial "skip".
A thin piece of brass inserted properly between the gears will "skip'" the gears to your advantage. Mitutoyo once furnished a similar brass tool with their calipers.
It's a good habit to check the zero on dial calipers before each use.

It sounds like a good reason to get a WFT to trim your brass. It indexes off the case shoulder

Or a Lee Trimmer set up, I know I like mine better than my Lyman trimmer.

As far as the calipers, get a digital one, they are only 10 bucks at Harbor Freight, ya I know, you need batteries for them, want cheap batteries, buy a couple of those LED pointers/kitty toys, the cheap ones, they use the same batteries. Throw the pointer away and use the cheap batteries, cheaper than buying batteries from Menards or Walgreens or even WalMart.

Look for a small chip or piece of trash in the gear rack of the calipers. We run into that a lot here in the shop. It doesn't take much. Usually just blow them out and reset the zero with a small paperclip as described above.

Careful how and where you blow, I've blown the lens off calibers already.

Yes you can! A can of air will work or you may need to get a magnifier and look up close to the end of the rack, it won't be very big if it's there. I've got Mitutoyo calipers 20 yrs old that still work fine. They not Starret but close.

I use calipers many times a day at work and have made the habit of checking zero every time i pick them up, even if i have just set them down a minute ago. Same with mics. The standards are right there next to the mics in my box, why not use them?