How to resize the rim on a 223

M

Machineguntony

New member
My 223 rounds are not sitting flush with the case gauge.

I’ve determined the problem: the rim is wider than the mouth of the case gauge, so the rim is preventing the round from sitting flush with the gauge.

When I turn a new factory round upside down, the rim will drop into the mouth of the case gauge; and these rounds sit flush in the case gauge when inserted properly.

When I buy unloaded brass, the rim will also fit into the mouth of the gauge. These rounds also fit perfectly flush when loaded. The guy says he roll sizes his brass.

Now, when I load my once fired brass, since the rim is wider than the case mouth, the rounds do not sit flush. Consequently, the rounds have a higher jam rate than new factory rounds that sit flush with the gauge.

How do I resize the brass so that the rim is resized? The rounds will be much more reliable if I can resize the rim too. Is roll sizing the only way?
 
If I understand correctly, only brass that has been fired in your gun is a problem. Is that true for both factory ammo fired in your gun and handloads from new brass fired in your gun?
 
when I load my once fired brass, since the rim is wider than the case mouth, the rounds do not sit flush. Consequently, the rounds have a higher jam rate than new factory rounds that sit flush with the gauge.
Click to expand...
(This following comment may not answer your question but it would be my suggestion for improving your rifles reliability.) Buy new or factory made reloads (Black Hills Ammo) All makers of. Measure tolerances neck to base that a specific brass is required to have. And reject those brass that don't.

The only time I've encountered some rim expansion was due to a excessive chamber pressure. i.e. Hot loads.
Frankly: I don't know of a way a home reloader can reduce the base & rim area to a smaller diameter identical to factory new.
Small Base Resizer Die won't accommodate your need.
Maybe a RCBS X die sizer may?
 
When I was loading a lot of "range brass", I found a significant number of cases with some sort of rim damage. Some cases wouldn't even fit in the shellholder for sizing. I suspect this to be from firing in full auto guns.
By doing some sacrificial "fabri-cobbling" you might be able to make a die which would reduce the rim diameter. The problem is where that brass goes when compressed.
 
"I don’t bother with cases like this. Too much trouble. I toss them in my recycle container."
Probably the most efficient solution. However, when you're processing .223 cases by the bucketful, tossing 10-15% of 10,000 cases will get expensive.
This is when "roll sizing" becomes a suitable alternative.
 
Yes, only brass that’s been fired from my guns is a problem.

So you guys think that rim expansion is caused by too much pressure?

That’s a good theory. I’ll reduce my charge and see. I do load at max. 100% of my 223 rounds fired out of my guns result in a rim that expands.

And yes, all my 223 is fried from full auto guns, including M16s and a 249 SAW. However, I don’t see why the gun type would result in rim expansion. Those guns have the same chambers as a semi auto AR.
 
"I don’t bother with cases like this. Too much trouble. I toss them in my recycle container."
Click to expand...

The last time someone tried to sell me one of those case head rollers I asked: "Are you for real?".

F. Guffey
 
Well, it's going to draw flames...
The fact of the matter is simple, but disputed CONSTANTLY.

The entire case is effected when it's fired, so just resizing the neck/shoulder doesn't do things correctly much of the time.
Recent *MATCH* chambers are an example, people 'Camming Over' presses just to beat a brass back into 'Good Enough' shape to get it fitting into the chamber is an example,
While those of us that have been using a properly sized chamber have know this for years.

There is a reason I use a case roller.
Resize the lower case bloat, roll the bloat up the case to the top where it can be sized/trimmed properly, restore the rim to SAAMI specification (more or less).
At 700 to 1,300 an hour (depending on drive speed & case size) the case roller gives a lower case that is correct each & every time.

Case rollers (and drives) aren't cheap, but unless you have a super sloppy chamber (and a remarkable amount of chambers are sloppy) this little gadget makes brass that works.
Speed gunners have know this for years, particularly hand gunners, and it's a proven way to do things, but because of cost it's shunned by most 'Close Enough' loaders.

I do large volume of military brass, I use a roller to straighten extraction rims, remove lower case bloat, and prepare the brass for shoulder/neck resize.
Fill the feeder bin, turn the machine on and let it run. Once die plates are adjusted correctly, 100% of the brass lowers comes out will fit a SAAMI specification chamber (and 100% of the oversized chambers).

100% of extractor claw pulls on the rim are pushed back into the rim where they belong,
100% have the extractor rim pushed back up into place where the 'Yank' bent them down slightly,
100% have the extractor groove straightened and burrs rolled out,
100% have the lower case bloat from unsupported auto chambers removed, rolled back up into the case walls, side walls of the case back to SAAMI specification.

All that's left is to size the shoulder for SAAMI or chamber headspace, and to resize the neck to retain the next bullet during reloading.

Remember, this set of die plates have rim protrusions, so the primer pocket is often tightened up by the compaction of the brass...

There are 'Bloat' sizers that are cheap, only size the bloated 'High' spot on the brass.
These do ZERO for extraction grooves, straightening rims or removing burrs/bulges/brass displacement on the rims or lower case. These also can't be adjusted, they are factory sized, and if it's not quite enough for your application, it's a special order, if a special order is available...
 
There is a reason I use a case roller.
Resize the lower case bloat, roll the bloat up the case to the top where it can be sized/trimmed properly, restore the rim to SAAMI specification (more or less).
At 700 to 1,300 an hour (depending on drive speed & case size) the case roller gives a lower case that is correct each & every time.
Click to expand...

The only way I can get case head bloat is with heavy loade unless we are talking about bloat above the case head. If we are not talking about case head bloat we are talking about case body bloat, I believe I got about 4 bloats in, if it is a new term I do not want to fall too far behind.

I did not have a problem with 'upset' or case head expansion; is there a difference between case head expansion and bloat.

When I bloat a case I know I hammered it with too much powder or I used a bullet that was too heavy etc.. and! I know I am working the case and working the case hardens the case and now I am wondering if someone found an exemption for work hardening the case.

F. Guffey
 
I use a Case Pro, drive and Dillon Case feeder.
As soon as the old Dillon Case feeder dies, I'm upgrading to a much larger version so I don't have to fill it as often.

As for Bloat, the case bloats just above the floor of the case, in the sidewall.
If this is the ONLY problem, then one of those round hole dies will take that out.
With most semi-auto fired brass I find much more than just bloat that needs corrected.
Ejectors deform the extraction rim leaving a 'Stamp' mark on the bottom & often a bulge in the extraction rim.
Extraction rims often get pulled backwards when the case is extracted, when your dies fit nice and tight to the machine the rim is bent back up where it belongs.
Extractors, and sometimes ejectors, punch the brass up I to the extraction groove. The forming dies have a negative (raised) ridge that restores the groove, gives a nice sharp lip for extractor to grab onto.
 
And yes, all my 223 is fried from full auto guns, including M16s and a 249 SAW. However, I don’t see why the gun type would result in rim expansion. Those guns have the same chambers as a semi auto AR.
Click to expand...

The same chambers? are you SURE???

Remember that the military only has one requirement for fired brass, that it leave the gun in the proper, expeditious manner. They don't care if it's dented, bent, swollen, dinged, striped, or polka-dotted, all that matters is fired brass extracts and ejects so as not to interfere with the following rounds.

There are NUMEROUS examples of military weapons having chambers that are "oversize" compared to commercial standards, particularly in full auto weapons. These "generous" chambers are believed to enhance function of the weapon, under adverse conditions.

IF your case rims have increased in diameter (swelled) that means the case head has done so, as well, And it means that they have done so, because there was ROOM in the gun for them to swell into.

Regular reloading practices will not fix this. Roll resizing might, but I'm afraid I don't know enough about it to give a qualified opinion. I do know the tools are NOT cheap.

Good Luck.
 
After reading all this input, I think roll sizing will be the only way to go.

The CasePro 100 it shall be.

JeepHammer, the CasePro will resize the rim? I was reading a comment in one of the videos where a disgruntled purchaser said it didn’t resize the lower part of the case.

And yes, it’s not cheap. Around $2000 for the dies, autodrive, and case roller. But it’s cheaper than buying new ammo.

I sometimes wonder if I’m really saving that much money by reloading. Lol.
 
Call for die specification changes if needed.
I find the guy that builds them to be MOST hospitable. I got custom dies for the same price as standard dies on a specific case I was processing.

Don't confuse this with punch die forming (common dies you 'punch' the brass into or through), this is brass rolled between two die plates specifically spaced apart, cut with the CORRECT profile of a BRASS case in mind.

As for the chambers, particularly AR chambers, one would have to be a fool to think the back of the case is supported, simply drop a SAAMI round in the chamber, use a light and see the last 1/2" unsupported.
Also keep in mind that ANY carbon or wear on the chamber nut means the bolt doesn't lock up exactly 90* to the bore (if the chamber nut was square to begin with...).

Unsupported bottom chamber, non square bolt face, bent cases, period.
Die plate rolling is currently the only COMMON way to straighten case heads, take the bloat out of the lower case walls, push things back in, down, up where they belong (more or less).

I find when the die plates are properly adjusted, the brass are VERY close to new production (press punched) brass and fit all SAAMI specification chambers.
 
I have some new 223 Lapua brass that has a rim that won’t fit in my Wilson Case Gauge. Can’t blame that on hot loads, since there were no loads at all. It’s just the Lapua brass.
 
Break out the micrometer and see if the Lapua brass is specification or not.
If it is, the gauge lies, if it doesn't, Lapua screwed up.

Keep in mind that a caliper usually isn't accurate enough, this usually takes a micrometer that's been checked with a standard so you KNOW the reading is accurate.
This is a sticking point with me, inaccurate measuring tools are just this side of worthless.
If you don't have standards to check your equipment, then you might as well be beating the brass with a hammer & washer...
 
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