I am new to reloading so bear with me if this is a dumb question. I got a bunch of Lake City brass from a friend that was already sized, trimmed, etc. Just to be sure I took measurements of the brass and everything was within SAAMI specs. I took some of the reloaded rounds out to the range and fired them, didn't have anything abnormal happen.

This brings me to my actual question - does .223 need to be resized every time? I just measurements of the brass again and although some measurements are slightly larger, they are all still within SAAMI spec. I have a Hornady Custom Grade resizing/decapping die which is a full-length resizing die, but is a FL resize necessary every time? Should I bother purchasing a die that decaps only and doesn't resize?

Thanks!

Yes, you need to do some kind of resizing every time.

If you’re shooting a single bolt-action rifle, you can probably neck-size. Otherwise, full-length size every time.

Time for another dumb question - if I'm using a caliper to measure the case specs and it's the same or barely off, what exactly am I resizing?

Minimally, the neck. Unless you are using a gauge you can't measure to see of the shoulder needs a bump either. If you are only using it in a Bolt action rifle, you can just neck size, otherwise you need to FL resize for a SA.

Decades ago I bought a bucket of spent military brass and it did not chamber properly in my AR, it stuck. Was told to use a small base die for resizing to ensure military brass you may have in your pile chambers ok. Same thing for .308.

THIS! ^^

I learned the hard way....I have a bunch of loaded 223 that will not chamber in my ARs....luckily I have a Mini-14 that eats it like fat kid eating cake...

I'm not convinced that small-base dies are needed. I don't use them, and I've never had a problem through any of my rifles.

I *am* convinced that you absolutely MUST use a case gauge. Because if you're not pushing the shoulder back far enough, the rounds won't chamber properly. Ask me how I know.

Do you know? I'm pretty sure you still have all of your fingers...

Well, I am missing a piece of a finger . . . but that wasn't firearms-related.

I used to spend a fair amount of time slamming the buffer tube of my AR pistol into the ground, trying to get live rounds out of the chamber . . . until I figured out the case gauge secret.

If you have a good set of dies you do not even need a case gauge you simply follow the instructions that came with your die set to ensure that indeed you are full sizing your brass. You can even do a plunk test to make sure.

Sorry, I’m not buying that for rifle loads. There are too many variables. Yes, you might get it right, but you might not as well.

My early reloads (pre-case gauge) worked just fine in the one AR that I owned at the time. I thought I had it all figured out, I loaded a few thousand rounds. Then I bought another AR, and bam, they started getting jammed in the chamber. I bitched at the business I bought it from, I thought the gun was bad. I finally bought a case gauge, and it became clear that my reloads were the problem. Once I fixed my brass, everything fed fine, and they have worked like a charm in every .223 I’ve had since.

Agree, always use a case gage, at least in the early stages of a run. I perform spot checks for successive runs to make sure something did not get out of whack.

My Colt LE6920 eats just about any rounds but the wife's 223 Wilde chamber has tight tolerances, those shoulders need the max bump back or they stick.
Yep, case guage for the win.
I personally also anneal the cases after about 5 loadings. I've only had 3 neck-split cases in the 5 years I've had the same 3,000 brass pieces and I believe in annealing!

Probably a good idea, seems like an easy step, do once and it's good for a few uses.

That's really not an ideal way to set up dies except as a "worst case" where the round has to fit any barrel ever made for that cartridge. It usually works the case more than necessary, and often results in excess headspace (which in turn results in false pressure signs like flattened primers) but you wouldn't know without measuring. I have seen some combinations of dies and barrels result in as much as .020" shoulder bump (which is .020" headspace when fired), and ~.010"-.012" is pretty common. It's not about die quality, it's about tolerances. Tolerances stack up in mass produced dies, mass produced barrels, and widely varying case hardness which changes every time a case is fired. The die has to size enough to bump the shoulder back in a hard springy case to fit most barrels out there, even those with tight chambers. But then the same die used with a soft piece of brass bumps the shoulder farther, and maybe the rifle chamber is on the looser side; pretty soon you've got significant headspace and the die setup instructions don't address that.

You don't need a case gauge or small base dies for most rifles (including most AR barrels), if you learn to measure shoulder bump instead of just following the die setup instructions. It's very simple, and only requires a digital caliper and an attachment with a hole that contacts approximately halfway up the case shoulder. You can also use a piece of sized brass; 9mm, 38 Spl, and 357 Mag work well for a lot of different rifle cartridges but something a little smaller is better for 223. It's the same method as base to ogive measurements on bullets, just a different size hole.

Zero the caliper on brass fired in YOUR rifle (not range pickup from someone else's rifle). It's best to punch out the primer first. I like to keep that case in the reloading die box for reference after that. (The case in this pic is a 308, but the same principle can be used on any bottleneck case, including pistol ammo like 357 Sig.)


Size the brass in your die, and measure again. Adjust the die lock ring as necessary; .001"-.002" bump is great for bolt actions and single shots, and .002"-.004' is good for ARs and other semi-autos. The reading shows that the shoulder of this case was pushed back .0025", which is great for my 308 AR and will result in a good fit to the chamber with minimum brass working. In case it's not clear - that .0025" measurement is the functional headspace between that round and the chamber.
You can buy special shell holders to accomplish the same thing, but once you figure out how easy this is you won't need those.



The adapter is simply a clean round hole that's sized to contact the middle of the shoulder. The precise size doesn't really matter, because it's a relative measurement between unsized and sized.



Here's another example showing the same measurement with a piece of 357 Magnum brass to contact the shoulder. The cartridge being measured is a 6.5 Creedmoor.