Newbie; rcbs mic question

[mroels]

So I'm just getting into reloading. Finished reading a lot. Got the Lee hand press cheap to see if this was something I'd get into...although I haven't been this exited about anything shooting related I a while. I really wanna see every step so I figured the hand press would be perfect. For now I don't want to experiment too much, just want to learn about a whole new aspect to shooting. I'm really just looking to recreate the factory .223 ammo I'm shooting pmc-55gr and BHA 69gr, and I'm not even really talking about performance just safety and reliability. I'm shooting RRA AR-15 platforms with Wylde Chambers. Once a I have a couple hundred of rounds under my belt I'll start playing with velocities & accuracy etc. For now just middle of the road loads, of course I'll try some different loads to inspect the effect on casings and rifle, but am not planning to go near maximum loads yet.


I've been using the rcbs mic gauge to figure out how far back to set the neck when FL sizing. Factory pmc and BHA are reading -3 unfired, 0.003" under ANSI minimum. Fired I'm getting a reading between +1 +2. So my understanding is that the headspace in my rifle is probably around +0.004" above the ANSI minimum, considering brass shrinking back down a little again, well within the limits. I also understand that factory ammo is sized under the minimum for reliable loading. What I'm wondering is what should I push the shoulder to? In my quest to just replicate factory cases Im setting back to the -3 reading. However as I was adjusting the die I got a few cases right at the 0 reading, or right at the ANSI min, would these be ok or am I gonna have feeding issues? It's only 3 cases so I don't care about tossing them but just curious. I understand that the closer i set to the chambers actual headspace the more accurate the reloads should be but at what point will autoloaders stop feeding nicely? Or is that really more an OAL issue?

Also as I was adjusting the dies I went a bit too far and ended up with a couple of cases around -0.005" under ANSI minimum. Again I'm happy toss a few cases for safety as part of the learning curve but I do want to learn something from it. I understand that a case going from -0.005" expanding to +0.002" is going stress the brass a lot and shorted life of casings. But how far under min can you set the shoulders before absolutely having to toss them?

Hope I made sense and at least show a little understanding of what's going on.


Thanks for all info!

[mroels]

Anyone? C'mon Calguns, I know you got answers for me!!

[afrancke]

Bump to 0.000 and that's plenty for the fired cases that show +0.001 or +0.002. You don't want to replicate factory ammo dimensions, after all, when you can size for your chamber instead!

Let's assume you are loading for an AR. Feeding success for these is both an OAL and a headspace issue, but you'll see OAL problems as soon as you load rounds into a magazine; things appreciably over 2.26 aren't going to fit. You'll only see headspace problems when you close your bolt on a round, and it's hard to say that you'd actually "see" such a thing since I don't think there isn't any positive sign of full bolt closure and lug lockup on an AR. Somebody can correct me on that point - for example, if it's possible to know by pressing on the forward assist whether things are actually all the way locked up.

I don't have any advice about oversized brass. Given this is .223, and they are only worth pennies, I would just keep them in a box of tester brass for calibrating your annealing process one day, etc.

[gau17]

get the reading from 10 fired cases. Get an average and bump +.002.

Toss the ones you bumped too much. Not worth having a case head separation.

[30Cal]

Too short by 0.005" isn't all that bad. Just don't make a habit of it. I'd shoot them and then toss em.

[mroels]

Thanks for the info guys!!

[mroels]

Quick follow up question... After tumbling I mic'ed a bunch of cases at -0.005 to -0.01, this is before fl sizing. This was factory ammo fired from the same rifle discussed in the op where most are coming in at +0.002. Does this indicate anything? The brass looked fine, no stress marks or anything. It's possible I grabbed someone else's brass by accident but I'm careful to sweep before I shoot so I know what I'm picking up is mine, plus it was still pmc brass. About 10% of the cases measured like this and I tossed them.

[thomashoward]

Just shoot them. You probably won't get as many loadings as others. I only toss them when they are too damaged to reload.
Size then measure. Read up on neck sizing. That's all I ever do.

[afrancke]

After tumbling I mic'ed a bunch of cases at -0.005 to -0.01, this is before fl sizing. This was factory ammo fired from the same rifle discussed in the op where most are coming in at +0.002. Does this indicate anything?

I've noticed the same thing - not all brass seems to expand to chamber size consistently (or perhaps it springs back more afterwards). If you are trying for consistency, you might just keep these separated out and reload them last/make a "questionable brass" pile.

[mroels]

I've noticed the same thing - not all brass seems to expand to chamber size consistently (or perhaps it springs back more afterwards). If you are trying for consistency, you might just keep these separated out and reload them last/make a "questionable brass" pile.

I like that idea, as long as they're safe to shoot. Just plinking rounds they will become then.


What would be the absolute low limit though?

[gau17]

I've noticed the same thing - not all brass seems to expand to chamber size consistently (or perhaps it springs back more afterwards). If you are trying for consistency, you might just keep these separated out and reload them last/make a "questionable brass" pile.

This is probably due to the large chamber of the riffle. The shoulder has not grown to the max length of the chamber. If you want to do it correctly, do not bump the shoulder until the brass can no longer be chambered. From there you bump the shoulder back .001-.002. Going forward you should end up with consistent shoulders because they will no longer have room to grow.

Does that make sense?

[30Cal]

I like that idea, as long as they're safe to shoot. Just plinking rounds they will become then.


What would be the absolute low limit though?

Shoot them alongside what you consider to be the "better" brass. It'll be just as accurate. All that does is create extra piles of brass to keep track of.


The case mic is used to set the die. Once that is done, there's no point in measuring anymore. Lube your brass well, and start sizing.

[mroels]

The case mic is used to set the die. Once that is done, there's no point in measuring anymore. Lube your brass well, and start sizing.

I'm just being an overly curious newbie, but yeah I understand that the mic is for setting the die. But right now I just can't help but measure everything and figure out what it means. Hopefully I'll get over that sooner than later, because I'm moving really really really slow right now.

This is probably due to the large chamber of the riffle. The shoulder has not grown to the max length of the chamber. If you want to do it correctly, do not bump the shoulder until the brass can no longer be chambered. From there you bump the shoulder back .001-.002. Going forward you should end up with consistent shoulders because they will no longer have room to grow.

Does that make sense?

Makes sense indeed, thanks for the help

[afrancke]

This is probably due to the large chamber of the riffle. The shoulder has not grown to the max length of the chamber. If you want to do it correctly, do not bump the shoulder until the brass can no longer be chambered. From there you bump the shoulder back .001-.002. Going forward you should end up with consistent shoulders because they will no longer have room to grow.

Does that make sense?

Great idea! Presumably they'll get there after a second firing, but we'll see after I have a chance to try this. I am worried that I won't know for sure whether my AR is fully in battery - is there a sure-fire way to check (other than to find out that it isn't after I touch a round off)?

[afrancke]

Shoot them alongside what you consider to be the "better" brass. It'll be just as accurate. All that does is create extra piles of brass to keep track of.

I wouldn't have suggested making distinct, sorted piles of the "other" brass - just a single undifferentiated pile. Case volume should matter for precision rounds ultimately, but for blasting, I agree it really won't. No, I haven't personally tested how much it matters - I don't shoot well enough.

I do find it useful to have "bad brass" for experiments when calibrating the dwell time for my annealer or checking out the trimmer setup, and so on. This is where keeping a separate small pile (undifferentiated, as I said) seems like a good use, but of course to each his own.