Weird cycling issue... thoughts?

[mRad]

For reference concerning chambers. Then there are variations caused by wear, maintenance, and manufacturing tolerances as well as machining errors.

[Warp]

Factory rounds are not identical. A good hand loader can make rounds closer to identical every single time than the factory can.

I wonder why OP, as a good handloader, made rounds where some were fine and some were stuck.

Is -not- full length resizing the best way to make closer to identical rounds?

[mRad]

I wonder why OP, as a good handloader, made rounds where some were fine and some were stuck.

Is -not- full length resizing the best way to make closer to identical rounds?

No, FL sizing would not be the way to make them *most* identical.

But they can be identical and still be wrong.


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[okie]

He said his father shot some of his reloads in a different rifle at the class without the issue.

But, as we discussed, it's a bit of a stretch to assume that every round he reloaded is identical. Were they all the same once fired fired brass, from the same lot, previously fired through the same gun? And even then, if not full length resizing, who knows...it may just be that not every single round he reloaded is identical (or close enough), and the more out of spec ones happened to end up in his rifle. I mean he's talking about what 2 or 3 rounds over the course of a day that had this problem? Could be those same rounds would have done the same thing in a different rifle.

It's a guy handloading his own ammo and not resizing the cases and the rounds are getting stuck. Shoot factory ammo and magically it won't happen, promise.

I've slept a few times over the course of this thread so forgive me if I'm getting things mixed up, but this is the picture I have. The malfunction only happened in his rifle, and was consistent, and only happened when a round was allowed to cool inside the chamber was was subsequently ejected live via charging handle. His dad was using the same ammo and didn't experience the problem, and he tried it in at least one other rifle besides his dad's and couldn't replicate in that rifle either?

Sorry if I'm jumping to conclusions, but that sounds like archetypical NIB behavior to me.

[DG23]

I wonder why OP, as a good handloader, made rounds where some were fine and some were stuck.

Is -not- full length resizing the best way to make closer to identical rounds?

If you were to sit down with a can mixed brass and start sizing - checking each case as you go...

You will notice differences in your measurements and / or how they fit your gauge. How much each piece 'springs back' after coming out of the die is going to be different depending on the maker of the brass, how many times it has been fired, what chamber it was fired in and sometimes the year that brass was made (assuming same mfg).

The greatest consistency will come if the brass is all the same. Same headstamp, fired in same chamber, same number of firings, etc.

[MWAG19919]

Missed that. So it stuck in other guns, too, or it just didn't happen every single time in your rifle?

He said his father shot some of his reloads in a different rifle at the class without the issue.

But, as we discussed, it's a bit of a stretch to assume that every round he reloaded is identical. Were they all the same once fired fired brass, from the same lot, previously fired through the same gun? And even then, if not full length resizing, who knows...it may just be that not every single round he reloaded is identical (or close enough), and the more out of spec ones happened to end up in his rifle. I mean he's talking about what 2 or 3 rounds over the course of a day that had this problem? Could be those same rounds would have done the same thing in a different rifle.

It's a guy handloading his own ammo and not resizing the cases and the rounds are getting stuck. Shoot factory ammo and magically it won't happen, promise.

I've slept a few times over the course of this thread so forgive me if I'm getting things mixed up, but this is the picture I have. The malfunction only happened in his rifle, and was consistent, and only happened when a round was allowed to cool inside the chamber was was subsequently ejected live via charging handle. His dad was using the same ammo and didn't experience the problem, and he tried it in at least one other rifle besides his dad's and couldn't replicate in that rifle either?

Sorry if I'm jumping to conclusions, but that sounds like archetypical NIB behavior to me.

Ok fellas,

So the stuck live rounds (not stuck cases) only occurred in my rifle. I didn't have a means of measuring the brass on the range, so I didn't feel comfortable double checking those particular rounds in my dad's Kino (technically his is a pistol and my MK18 is an SBR).

My issue only occurred 3 times, and I don't have a tally of how many other rounds I ejected throughout the course of the day, but it was several. We did drills in separate waves and had to lock back and show clear in between drills, that's why I ejected so many live rounds. My dad had none of these issues in his BCM.

We both shot ammo produced in the same loading session. Mixed Lake City cases purchased as once fired, primer crimp swaged out. Not sure what gun(s) the brass was fired in before I bought it but Brass Bombers LLC assured me it was 1x fired brass. I did the sizing and trimming as described earlier.

I hope that clarifies.

[MWAG19919]

So I just got my Sheridan gauge in the mail today. TL;DR is that I've got some bullet pulling to do, and I have to adjust my sizing dies.

So the first photo is the handload in question, in my Lyman case gauge. It passed, so I assumed this whole time that the ammo was in spec. Not so, apparently.


Second photo, the same round in the Sheridan gauge. The case is sticking up above the "chamber maximum" step, which the instructions describe as a "NO GO" step. Clearly I've got some die adjusting ahead of me


Third photo is another of my handloads: 77 SMK using NEW LC18 brass. This brass was processed and loaded in almost the exact same fashion, except I chamfered & deburred the case mouths and chamfered/uniformed the flash hole between the "prep" and "loading" toolhead.

This round is actually slightly below the "brass minimum" step of the gauge, meaning I should probably back the sizing die off slightly. The goal is to have the headstamp at or slightly below the middle step, but above that bottom step.


Lastly, as a control, I gauged a round of Hornady Black SBR 75 gr Interlock (factory ammo that I use for HD)



SO, I've got some work ahead of me. I originally adjusted the sizing/trimming dies for my LC18 brass. I see that I should back them out a tad for that particular brass. But what's interesting to me is that the mixed LC brass run through the exact same dies actually needs to be sized more. I'm guessing it's due to the fact that it's previously fired in who knows what firearm(s).

Anyway, looks like I've found my culprit.

[georgeib]

Really glad you got to the bottom of this! I know you've got to feel better.

[MWAG19919]

Really glad you got to the bottom of this! I know you've got to feel better.

I’m glad I now have a reliable way of checking my brass, not thrilled about having to pull and re-prep 200+ rounds

As a point of clarification, I never intentionally undersized my brass. That was mentioned a couple times by others. I size in 2 different steps (both FL dies) but the end goal all along has been to have fully sized brass. My mistake was relying on a Lyman gauge that actually doesn’t mimic a chamber.

[Warp]

Solid follow up