.223 not sizing right

[ar15barrels]

Yep.
Each company makes them however they want.
The SAAMI specs are so sloppy that they can ALL claim to fall within SAAMI specs.

What you want for a GAUGE is minimum specs so that ammo that fits the minimum spec gauge SHOULD fit in ANY chamber that's in-spec, regardless of it being at one or other end of the specification range.

Also, when you get some cases that fail a gauge, try flipping the case around backwards and see if it's only the RIM that's causing the failure.
It will be really obvious when you flip the case backwards if the rim fits into the gauge or not and you can find the burrs by blackening the rim with a sharpie and them pushing it back into the gauge backwards.

[pacrat]

Yep.
Each company makes them however they want.
The SAAMI specs are so sloppy that they can ALL claim to fall within SAAMI specs.

What you want for a GAUGE is minimum specs so that ammo that fits the minimum spec gauge SHOULD fit in ANY chamber that's in-spec, regardless of it being at one or other end of the specification range.

Also, when you get some cases that fail a gauge, try flipping the case around backwards and see if it's only the RIM that's causing the failure.
It will be really obvious when you flip the case backwards if the rim fits into the gauge or not and you can find the burrs by blackening the rim with a sharpie and them pushing it back into the gauge backwards.

^^^YUP^^^

NOT ALL HOLES ARE CREATED EQUAL

[zouaveherb]

You mention your brass is "mixed headstamp" and that you bought it from someone else. That sounds a lot like range-pick-up brass to me, which means you have no way to know how many times it was fired.
<NoHeavyHitter's really good reason why you should trim your cases>

This is a good point. In addition to trimming them, you should probably anneal them all because you don't know if a particular case has been shot once or a bunch of times.

Unless the primers are crimped or staked, then it's pretty much once-fired since you have to remove the crimp/staking in order to reload those cases.

[zouaveherb]

Here is an adhesive millimeter scale that you can wrap around the die threads:

https://www.ebay.com/itm/324852152605

You will want to trim it to get rid of the numbers and all the extra blank space so it's just a 1/4" wide strip, then wrap that strip around your die's threads about 1/8" above the locknut.
Then put a pencil or sharpie mark on the locknut that you reference to the 1mm hash marks.
Now in use, you adjust 2 marks at a time to make a 0.002" die adjustment.

This. Is. An. Awesome. Idea.

[zouaveherb]

What you need is a SAAMI minimum chamber spec gauge. As others have said, if it fits this, then it will fit whatever.

What you want is a slotted SAAMI minimum chamber spec gauge.

https://sheridanengineering.com/product/223-rem-ammunition-gauge/

A slotted gauge will tell you exactly where things are binding. Run a sharpie down the side of the case and see where it's being scraped off as you rotate it in the gauge.

[MarikinaMan]

^^^YEP^^^

Not all holes are created equal.

Rifle chamber is a HOLE
Sizer Die is a HOLE

Those 2 HOLES are relevant.

Cartridge Gage is a HOLE. But until it is PROVEN to match the Chamber HOLE.

It is just another source of problems in the "TOLERANCE STACKING SOUP" that plagues all things reloading related.

There is no tolerance stacking here.

The rifle chamber is a hole, it is expected to be SAMI spec.

Die is a hole, same and adjustable.

Case gauge is hole, and is expected to be SAMI spec.

That said the gauge is the control. With a decent gauge and die, the user should be able to make SAMI spec ammo with a properly adjusted die, if he is half decent at knowing that he is doing.

If it doesnt fit the chamber, then something is wrong with the chamber. Spec reloaded ammo is same as spec factory ammo. It should fit all rifles.

Plunk tests are only for that specific firearm. I dont do plunk tests coz my ammo is for all my guns in the same caliber.

[pacrat]

There is no tolerance stacking here.

The rifle chamber is a hole, it is expected to be SAMI spec.

Die is a hole, same and adjustable.

Case gauge is hole, and is expected to be SAMI spec.

That said the gauge is the control. With a decent gauge and die, the user should be able to make SAMI spec ammo with a properly adjusted die, if he is half decent at knowing that he is doing.

If it doesnt fit the chamber, then something is wrong with the chamber. Spec reloaded ammo is same as spec factory ammo. It should fit all rifles.

Plunk tests are only for that specific firearm. I dont do plunk tests coz my ammo is for all my guns in the same caliber.

STRONGLY SUGGEST you read posts #32 and #46 by Randall. Wherein [SAAMI SPEC] is aptly explained. Because {SAAMI SPEC} IS NOT A FIXED DIM. Some, SAAMI SPEC dims. are +/- a given number. Some are only - a given number. With a listed Max. When those varying [SAAMI SPECs] conflict as Randall explained. That is cause for crap to not fit. Commonly referred to as tolerance stacking.

Your entire post is based on your own misconception of what you think, SHOULD BE............................ NOT WHAT ACTUALLY IS.

As to the bolded in your post.

That is an assumption. Based on your misconception of WHAT IS. Before even trying to determine why an issue exists.

Yes, sizer dies are HOLEs that are adjustable. But only for length. NOT DIAMETER. Even though OP is using a SB die. Cut to SAAMI spec. His cases are possibly expanded BELOW the reach of his die. In which instance the resolution of the issue requires a "ROLL SIZER" or a "PUSH THROUGH" die.

And the "underlined" in your post shows that you don't realize that Factory Ammo for rifles. Is typically sized a "LITTLE UNDER" actual SAAMI SPECs to mitigate the tolerance stacking that is always present in all things made on machines.

And a "gage" is NOT a CONTROL. It is a shortcut. To actually chamber checking.

Bottom line is that ONLY one hole matters. And it is the CHAMBER.