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Mongo
Reply with quote  #1 
I'd like your input (good and bad) on this idea I have for removing donuts on .223 brass, fired in a tight neck chamber, so they are already turned and of course have donuts now...

I have an extra Wilson case trimmer, and I see where MSC Industrial has reamers available in .0005" increments. My thought was to make a new crank handle, carefully measure the fired ID of the cases with a small hole Gage and micrometer, select a reamer (mount it into the new crank handle I will make) and then run it thru while trying not to scuff the side walls of the fired brass.

The cases would be held in the Wilson case holder.

I realize that K&M has the carbide tipped mandrel/cutter as an alternative approach, and I also know that you should be able to "push" the donuts to the outside and neck turn them off. It seems that the Wilson/reamer method I'm thinking of may be easier, and it gives me something else to build..

Am I barking up the wrong tree ? Aside from the extra work, do you think there will be run-out issues ?

Let me know what you think.
tightneck
Reply with quote  #2 
The Wilson trimmer with Mic attachment is my favorite trimmer bar none, for it's ease of adjustment and consistent case lengths. I don't think however it is precise enough for neck reaming. The case holders and the "bed" in which they lay would have to have near zero runout in relation to the reamer, and this tool cannot provide that kind of accuracy. I haven't used K&M's donut cutter so I can't comment on this, but pushing the donut out and re-turning the outside will do it.
anyrange
Reply with quote  #3 
I could not get a reamer to work and ended up doing it this way in the following articles:
15 MOA inside case neck taper
My Donut Machine
Latest method using the K&M fluted mandrels
NCVarhtr
Reply with quote  #4 
Mongo, I shoot a couple of short neck cases and I have found that I need to cut the donut out of the cases on a fairly regular basis.....After talking with some BR shooters and trying a couple of different things I have found that the K & M neck turning tool with the carbide inside neck cutter does a great job. You can use it to turn the necks and cut the donut out at the same time. K & M also makes the exact size mandrel to expand the neck so the pilot mandrel will fit perfectly. Its very easy to adjust and can be adjusted in very small increments. I use an electric (Battery operated) screwdriver to hold the case while I cut the donut out and while my case is in the case holder, I chamfer the inside and outside of the necks also. I think you'll like it....Hope this helps..
AlNyhus
Reply with quote  #5 
Quote:
I have an extra Wilson case trimmer, and I see where MSC Industrial has reamers available in .0005" increments. My thought was to make a new crank handle, carefully measure the fired ID of the cases with a small hole Gage and micrometer, select a reamer (mount it into the new crank handle I will make) and then run it thru while trying not to scuff the side walls of the fired brass.


Wilson makes an inside neck reaming tool that fits in their case trimmer in place of the crank handle. Back when I had some donut issues, I used this exact setup to remove donuts in fired cases. You do need to be careful not to contact the inside of the neck when doing this. Wilson has made up several special sized reamers for me in .0005 increments and Sinclair stocks the standards sizes and some undersize ones as well. Be aware that their 'standard' neck reamer is .002-.003 over bullet diameter. Measuring the i.d. of a fired case with a pin guage will give you a good idea where you need to be with the reamer dimension. In most cases, I use a reamer .002 under what a fired neck i.d. measures.

FWIW, a great way to virtually eliminate donuts is to push the shoulder on virgin cases back .025-.030 (by facing off a like amount on a shellholder), neck turn down and blend into the the new neck/shoulder junction, then seat the bullets hard into the lands and blow the shoulder foward on the first firing.

Hope this helps. -Al

Wilson neck reamer
Mongo
Reply with quote  #6 
Thanks to everyone for the advice.

I tried pushing them to the outside and turning the little buggers off. My method was to use the original neck turner (Hart version, which was not moved from the original neck turning operation). I used the Hart supplied button (mandrel) for pushing the donut back out.

While turning them there seemed to be quite a bit of material removed from the shoulder area, while the neck portion seemed untouched, as you would expect. Everything seemed fine, went out and fired them off... worked OK..

But, I looked at the cases after shooting, it seems the donuts are back. I am guessing that the issue was the expander not pushing them out completely. I'm thinking I should have used the K&M version... any ideas on what I did wrong ?

I will be sending Ken an order for his fluted carbide mandrels. Might as well try 'em, I have most of his other tools....
Clark
Reply with quote  #7 
I looked at anyrange's links a few days ago and could not stop thinking about it.
Late last night I made some hardware.

.223 necks sized with a .246" bushing FL "S" die will typically accept a .221" or .222" pin gauge into the neck, but not past the donut.

I turned down a piece of round .25" water hardening tool steel to .243" on one end and .224" on the other.
I beveled and sharpened the .224" end.
I hardened the metal with Propane and then water.
I put the .243 end in a collet .243 bullet puller die.
I put the die in a press.
I put a .223 case in the die and stroked the tool in and out for 15 seconds, while turning the brass.
I resized the brass.
The neck now accepts .221" and .222" pin gauges past the donut.

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