donut

[moosemoose]

I was seating bullets the other day and I noticed some resistance during the operation. This resistance seemed to vary from case to case. I realized that it was due to the donut forming at the base of the neck. I have been a full length resizer for some time and of course never ran into this problem before.

I understand that I can ream out the neck to remove the donut,I assume I would ream the neck after resizing but what size would the reamer need to be? Resized outside neck diameter - neck wall thickness x 2?

Better yet how do I avoid this problem?

 

[BoydAllen]

The degree to which the diameter of the body is changed by sizing, and the amount of shoulder bump both play important parts in donut creation. Are your necks turned? If they are, and you did not extend your cut onto the shoulder, this can also contribute to the problem. If you do not turn necks, be aware that case walls are tapered from base to case mouth, and that this should be taken into consideration when making measurements. What caliber, what die, how much shoulder bump, what sort of chamber?

 

[moosemoose]

Thanks for the response...

I'm loading for my son's hunting rifle a Remington .243, I don't turn case necks, I'm using a wilson seater die with a .270 bushing. I use a body die occasionaly, and full length resize when the case doesn't fit in the wilson case gauge.

 

[BoydAllen]

Do you have a way to measure shoulder bump when you use the body die? If you do not, you can square up a deprimed .38 case and use it, turned over the neck with its mouth on the shoulder. If you have a dial caliper, you should be all set. .001 shorter than a tight case should be about right.

 

[Gman]

Could you please explain how to use a .38 case as a gauge to check shoulder bump?

 

[Winchester69]

I use a body die occasionally, and full length re-size when the case doesn't fit in the Wilson case gauge.

Full length size when the case doesn't chamber in the rifle. Then only size enough to both bump the shoulder minimally and tighten the body sufficiently.

The Redding Competition Shellholder set makes the operation simple and repeatable.

If the brass flow is still sufficient to cause donut formation, the simplest cure is reaming. Reaming is performed to caliber dimension. Depending on the brand of your trimmer, the mfr. may provide the necessary tool.

 

[BoydAllen]

Place the mouth of the pistol so that it rests on the shoulder of the rifle case, like a cap over the neck), and measure from pistol case head to rifle case head, both having had their primers removed prior to measurement) with your dial caliper. Adjust your die till the sizes case measures .001 less than the unsized one.

 

[rayjay]

The cheapest thing to do is buy some new brass

 

[Hammer47]

Seat your bullets longer, they should not protrude into the case. If you cannot seat longer, use another bullet or have the rifle re throated for the bullet of choice.