Thread: 223 over resized brass?

Was it a Redding shellholder to match the die? I have seen this once before but in the opposite direction - a FL die from one manufacturer combined with a shellholder from a different manufacturer resulted in cases that wouldn't chamber in any rifle. It didn't matter what was tried in die adjustment, the die was down as far as it would go and any further winding down just meant the press handle didn't go up as far or 'cam over center'. Replacing the shell holder with a different one and adjusting the die meant that the case shoulder was bumped back that little bit more. The cases were milsurp, once fired and I suspect out of a belt fed weapon as they were too long to be chambered in a 7.62 bolt action sporting rifle. I subsequently tried the cases in a matched set of Hornady full length die and shellholder, that worked fine but in keeping with other's reports about the Hornady die the cases were very straight but the force on the press in resizing and then breaking the case out of the die was huge and did not give me any confidence at all! Ended up going back to the original die and a matching brand shellholder, and on measuring there was a noticeable and measurable difference in height between the base of the shellholder where the case sits and the top that the die contacts (the taper in the shellholder to clear the rim of the case and case head was noticeably longer on one shellholder as well).

There's a good chance that something like this has occurred, except that somewhere there is an equivalent smidge of metal missing to the amount of difference you have measured between the two cases (your dummy/once fired and the recently obtained batch). To verify if this is the case, find a shim washer that slips over the .223 case of the right thickness and resize a case, measure it, then take the shim off and reset the die up and remeasure. That will tell you if the issue is the dimensional error (the combo of shellholder and die is missing that amount of material) but it won't tell you which end is missing the material.

In normal operation of a die and shellholder, when setting up for the resizing operation you would set up long and resize down to the point the resized case is just firm in the rifles chamber (unless you are reloading to fit into any rifle in which case you would set for SAMMI maximum case size dimension but 99% of reloaders aren't in this situation). That would usually avoid this situation.

The guy just missed the step of checking the first resized brass pieces dimensions before doing the whole batch.

Originally Posted by Tentman

My pick on this is that if loaded in their current state they won't even go bang, but if they do, then a case head separation is a dead certainty!

And how did they get like this?

Greetings @Tentman,
I'm not familiar with the nut thingy but I went out to the shed and a.223 case in my .330 chamber looks about the same. Yes your cases have been grossly oversized by around 0.020" or 0.5mm. Mixing up the competition shell holders is not to blame as this will make the cases longer rather than shorter. I would check your fired and unsized cases with the primer out to be sure. You also may want to measure one of your sized cases before you load it just to be sure. How this happened is a worry. It may be a dud (or ground) die or shell holder. Firing very light loads can set the shoulder back as can firing them in some semi auto rifles but 0.5mm is a lot. Firing protrusion is generally around 1.5mm or so and the rounds would probably fire but whether they would separate on the next firing is anybody's guess. I would just recycle them and buy some new cases. It is just not worth bothering with anything that is substandard.
Regards Grandpamac.
PS. The possibility of small base dies occurs to me. These size the body more than standard dies but don't know if they set the shoulder back. My guess would be substandard or butchered dies, shell holder or both.

I did that once with a .223. Screwed the die down too far. Used them and no head separation or dramas.
I checked them using the same tool as Tentman and they were a few though under spec.

If you want salvage the brass you can fire form it by seating the projectile out so it jams in the lands using a low starting range load. This holds the case against the bolt face and allows the case to stretch back out from the front to rear rather than all the stretch coming from the section just in front of the web. A tangent ogive bullet is better.
Small base dies are no different in length to a standard FL die and like any FL die need to be set up correctly to give the desired shoulder bump.
Not understanding die set up and headspace would be the most common mistake reloaders make in the beginning. The generic advice you get from reloading manuals doesn't help.
I would bin it though, I dont buy second hand brass, its often a more expensive option.

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

push a .243/6mm sizing button through neck and then do partial length resize to create a false shoulder perhaps???

Originally Posted by Micky Duck

push a .243/6mm sizing button through neck and then do partial length resize to create a false shoulder perhaps???

Yup that's exactly how I'll tackle it unless old mate prefers it back.

Originally Posted by sneeze

If you want salvage the brass you can fire form it by seating the projectile out so it jams in the lands using a low starting range load. This holds the case against the bolt face and allows the case to stretch back out from the front to rear rather than all the stretch coming from the section just in front of the web. A tangent ogive bullet is better.
Small base dies are no different in length to a standard FL die and like any FL die need to be set up correctly to give the desired shoulder bump.
Not understanding die set up and headspace would be the most common mistake reloaders make in the beginning. The generic advice you get from reloading manuals doesn't help.
I would bin it though, I dont buy second hand brass, its often a more expensive option.

What is the difference between small base and full length?
The Small Base Sizer Die sizes the case from the shoulder to the head of the case a couple of thousandths smaller than a Full Length Sizer Die. In certain calibers it also sets the shoulder of the case back a thousandth or two more than the Full Length Sizer Die.

Originally Posted by TeRei

What is the difference between small base and full length?
The Small Base Sizer Die sizes the case from the shoulder to the head of the case a couple of thousandths smaller than a Full Length Sizer Die. In certain calibers it also sets the shoulder of the case back a thousandth or two more than the Full Length Sizer Die.

Yes its in the name "small base". I said "they are no different in length". How it bumps the shoulder will depend solely on how you set it up, the same as a Full length die. In the situation here a small base die was put forward as a possible cause of the .020 set back which in itself will not be.