doughnut question

[bow shot]

I was expanding brass last night, preparing to turn necks. Almost all of the cases "felt" the same, as the mandrel made its complete insertion and withdrawl in/out of each case: Just a gentle drag in, and then drag out.

However, I expereinced a sort of soft "stop" on several cases as the mandrel made the deeper portion of its insertion. Applying a tad more force to the press' lever would overcome that. There was also significantly more drag after reaching past that "bump" or stop.

The question is:
1) Is this the dreaded "doughnut"?

The background of these cases is doubtful, since I bought them used as "1x fired". I no longer have faith in my fellow man to tell the truth when he sells me something, so I'm not shocked, disappointed, etc., if these have been abused after one manner or antother.

I say that for this reason: Frankly I don't positively know the history of these. I was just told that they were 1x fired and FL sized thereafter. I annealed them as soon as they came to me.

 

[Larryh128]

It could be but it also could be a lot of other things like powder residue or tumbling media. You should be able to see it with a pencil light.

 

[dkhunt14]

It could be where the neck shoulder junction is or close too. It would be harder to push out there. Either way if you ran them over a mandrel and pushed the neck out you will be able to turn it off. You will need to turn to the neck shoulder junction. Matt

 

[fdshuster]

A quick and easy check for donuts is to take a fired, but not sized case & drop a bullet into the neck. If it falls all the way in to the case, no donut. If it stops with the base at the neck/shoulder junction, yup, a donut.

Your choice then what you want to do about it.

 

[P1ZombieKiller]

A quick and easy check for donuts is to take a fired, but not sized case & drop a bullet into the neck. If it falls all the way in to the case, no donut. If it stops with the base at the neck/shoulder junction, yup, a donut.

Your choice then what you want to do about it.

Only if this is a tighter necked chamber. If this is a .243 caliber and you have a bigger chamber, and thus the fired brass expands out to an ID of .274+ the bullet will slide right over that donut.

IMHO, anytime you start with a new gun, you should start with new brass. The ONLY time I don't is if it is a SAMMI spec hunting gun where 1.0 - 2.0 MOA is acceptable.

 

[bow shot]

hmmm.... never thought of the powder residue Idea.

I do notice that it dos not go away after the mandrel passes in/out. I can nut 'em though the expansion proces over and ove, and the "bonk" remains.

I'll put a light on it tonight (gotta borrow one from work...)

 

[bigedp51]

hmmm.... never thought of the powder residue Idea.

You must have led a sheltered life...........

 

[fdshuster]

The bullet will slide right over that donut". Strange ! My factory chambers in 222 Rem. 223 Rem. and 308 that are not tight, fitted or no-turn, have the same results with the bullet drop test as my tight fitted (requiring outside neck turning) and tight no-turn necks. The bullet hangs up on the donut, and the donut is there as verified with my Hawkeye.

I can't explain it, just know that it does.

 

[P1ZombieKiller]

The bullet will slide right over that donut". Strange ! My factory chambers in 222 Rem. 223 Rem. and 308 that are not tight, fitted or no-turn, have the same results with the bullet drop test as my tight fitted (requiring outside neck turning) and tight no-turn necks. The bullet hangs up on the donut, and the donut is there as verified with my Hawkeye.

I can't explain it, just know that it does.

Well... then this will make the 3rd time that I was ever wrong. Wife #1, wife #2, and donut #1......

 

[Jay Christopherson]

One thing I've seen that can cause the change in feel that you mention is buildup of brass residue on the mandrel, right past the initial taper. Looks like a brass ring around the mandrel. Usually happens when I don't lube the necks well enough before expanding.

 

[jcampbellsmith]

Run a Wilson internal reamer into a couple of cases (before they have been resized) and see what comes out. I suspect you will get brass flakes and then be able to see a shiny ring at the neck/shoulder junction.

If your cases are resized by now, run a couple through and expander mandrel.

Regards

JCS

 

[Nomad47]

Well... then this will make the 3rd time that I was ever wrong. Wife #1, wife #2, and donut #1......

Wrong again!! You were wrong twice before your last statement. Wife #1 was a "practice" wife.

 

[bow shot]

thanks for the advice folks.

Unfortunately, these have all been resized, so I'm unable to do some of the suggested experiments

ok… so I cross-sectioned one of the cases, and it looks fine. these have been tumbled, and there was not discernible build up of… stuff. What the tumbling left behind in the cases is more similar to anodization or bluing in thickness than it would be to a poor polish job.

Alos, the mandrels (both the expander and the turner) are spankin' clean, and I use just a tiny bit of RCBS lube 2.

Something I should mention here… these ail absolutely not fit past the "bump" spot on the turning mandrel, but that may be because I'm using a sinclair expander, and the turning tool is 100% K&M. As I understand it, the dimensioning between the Sinclair and K&M mandrels is not "equal".

I'll buy a K&M expander set up (or a sinclair turning mandrel) and report the findings… If someone has one on hand (K+M expander and 6.5 expander mandrel) they want to sell to me...

 

[bow shot]

bigedp51: LOL!!!!!

 

[amlevin]

Donuts don't intimidate me anymore. I just use a pilot/reamer on my RCBS Trimmer. Cuts any donut out as I trim, chamfer, and deburr, all at the same time.

 

[searcher]

I'm sure folks occasionally sell brass they think was only fired one time....

 

[bow shot]

yup... not necesarily of evil intent...