Thread: 223 over resized brass?

Gidday Folks

I have recieved some Sako 223 brass, once fired, resized and cleaned.

However I just happened to measure it with a comparator (not the proper headspace one, just a bullet type) and as far as I can tell the shoulder is about 20 thou to far back (compared with my other brass measured by the same method). We don't know how this occurred, he thought he sized it "normally".

So I either need to borrow a proper case guage (down here in Southland, I tried the local gunshops but no one has one) to determine if I do in fact have a problem, or find a way of fixing it - fireforming or false shouldering it maybe?

Remove firing pin.
Take an empty case and check it chambers.
Add layers of "tape" to the case head till you feel resistance.
It's then just a matter measuring the tape thickness.

Originally Posted by Oldbloke

Remove firing pin.
Take an empty case and check it chambers.
Add layers of "tape" to the case head till you feel resistance.
It's then just a matter measuring the tape thickness.

Yes I thought of that too. My own sized cases will take 2-3 layers of 0.001 aluminum tape to "no go", old mates cases, well I gave up at 5 layers and the bolt was still dropping.

Originally Posted by Tentman

Yes I thought of that too. My own sized cases will take 2-3 layers of 0.001 aluminum tape to "no go", old mates cases, well I gave up at 5 layers and the bolt was still dropping.

Another way is using your "comparator" just measure a tight or correctly sized one and the loose one.

As mentioned earlier if they are like say,, about 0.015 - .020" load up some "light" loads to fire form them.

Originally Posted by Oldbloke

Another way is using your "comparator" just measure a tight or correctly sized one and the loose one.

As mentioned earlier if they are like say,, about 0.015 - .020" load up some "light" loads to fire form them.

From experience with the .308, .303 etc if the load is too light the case will not fire form and could wind up shorter than it started. The load should be no lighter than a start load. When a cartridge fires the blow from the firing pin and the primer ignition shunts the case up the front of the chamber, slightly shortening it in the process. If pressure is not high enough it just stays there. If the pressure is higher the front of the case grips the chamber and stays there and the rear of the case is forced back to the bolt face stretching it just in front of the case head. To low pressure will be easy to spot as the primer will be backed out of the case. If you want to fire form try a couple of loads to make sure you have enough pressure.
GPM.

Originally Posted by grandpamac

From experience with the .308, .303 etc if the load is too light the case will not fire form and could wind up shorter than it started. The load should be no lighter than a start load. When a cartridge fires the blow from the firing pin and the primer ignition shunts the case up the front of the chamber, slightly shortening it in the process. If pressure is not high enough it just stays there. If the pressure is higher the front of the case grips the chamber and stays there and the rear of the case is forced back to the bolt face stretching it just in front of the case head. To low pressure will be easy to spot as the primer will be backed out of the case. If you want to fire form try a couple of loads to make sure you have enough pressure.
GPM.

@grandfamac
I reckon your right.
But can be done this way. Key seems to be controlled feed system.

I would think some shotty powder and a cadt bullet would do the job tho.

https://youtu.be/WYbAFrloGVA?si=Z8sITNg4HKsk2Cvs

Remove firing pin.
Take an empty case and check it chambers.
Add layers of "tape" to the case head till you feel resistance.
It's then just a matter measuring the tape thickness.

Watch from 7 minutes

https://youtu.be/htvk1UYOXm8?si=nrQznPE8CaVkA0en

Sounds like a job for a cheap cheerful bullet, a start load and some plinking to run the shoulders forwards. Or find some other brass for the cost and hassle...

Greetings,
This does surprise me a little as the two .223 rifles I have here currently are close to minimum. I can't see how you can measure headspace, even for comparative purposes, with a projectile. If the headspace is actually anywhere near 0.020" this is grossly excessive which would point to a problem with the rifle, die or both. Perhaps you could tell us how you actually measured it.
Regards Grandpamac.

Originally Posted by grandpamac

Greetings,
This does surprise me a little as the two .223 rifles I have here currently are close to minimum. I can't see how you can measure headspace, even for comparative purposes, with a projectile. If the headspace is actually anywhere near 0.020" this is grossly excessive which would point to a problem with the rifle, die or both. Perhaps you could tell us how you actually measured it.
Regards Grandpamac.

Using a .33 comparator, this goes down over the neck and sits on the shoulder, it can't give the actual head clearance as it isn't at the shoulders mid point, but does give a means of comparing case to case.

Originally Posted by Tentman

Gidday Folks

I have recieved some Sako 223 brass, once fired, resized and cleaned.

However I just happened to measure it with a comparator (not the proper headspace one, just a bullet type) and as far as I can tell the shoulder is about 20 thou to far back (compared with my other brass measured by the same method). We don't know how this occurred, he thought he sized it "normally".

So I either need to borrow a proper case guage (down here in Southland, I tried the local gunshops but no one has one) to determine if I do in fact have a problem, or find a way of fixing it - fireforming or false shouldering it maybe?

I have just come across a similar problem with new brass. I bought two lots (different batches) and with one lot (loaded from new) I have around 1 in 5 misfire. I am putting this down to excessive head space? Haven't come up with a solution yet.

Probably the most likely answer is oversized brass as old mate probably wound the die in as per die instructions of - touch shell holder plus a 1/4 turn (or whatever) and didn't measure resizing at the start of the batch.

Originally Posted by Roarless20

Probably the most likely answer is oversized brass as old mate probably wound the die in as per die instructions of - touch shell holder plus a 1/4 turn (or whatever) and didn't measure resizing at the start of the batch.

I have discussed it with him (and he does a lot of reloading but in a different city to me so we cant actually compare set-ups etc) but we are both puzzled. I wondered if he'd gotten a set of competition type case holders mixed up but he doesn't have them . . .

What does it measure once fired out of your rifle?

Maybe send them back for a refund?
Or if loading a long projectiles seat them jammed to lands and reduce load slightly to fire form while still shooting a usable load?