NECK REAMING ?

[Bill Norris]

There is quite a bit of good info on the net concerning neck reaming vs. neck turning for consistency of neck wall thickness and removing the dreaded donut. I am just now realizing some of this if not all of it has some merits to consider. I never thought much about how wide the donut may be or how far up the neck it would actually be spread until recently purchasing a Wilson neck reamer in order to see exactly how it would affectively clear the donut and uniform the wall thickness from inside. I like what I am seeing so far on the surface and plan to test fire a few cases to see any further results either good or not so good. My questions are for those that neck ream what is your experiences and how many firings does it take in order for the donut to re-appear sizing with bushing dies?

 

[TRSR8]

You must be unlucky, shoot 3 different necks in PPC, currently Alpha brass, no donuts.
That said, turning never reaming, IMHO, yields better result, probably resulting from support of mandrel. Micrometer tells all.
If you’re having issues, a K&M style mandrel with cutter on end, cleanly dispatches any donuts.
Are you cutting necks slightly into shoulder radius…..also helps.

 

[Bill Norris]

You must be unlucky, shoot 3 different necks in PPC, currently Alpha brass, no donuts.
That said, turning never reaming, IMHO, yields better result, probably resulting from support of mandrel. Micrometer tells all.
If you’re having issues, a K&M style mandrel with cutter on end, cleanly dispatches any donuts.
Are you cutting necks slightly into shoulder radius…..also helps.

I actually tried it on un-turned necks that had formed a donut from sizing with a bushing die. I'm using the Wilson reamer in which is used with their case trimmer and holds the case with a Wilson case holder.

 

[Mark611]

Bill, I have the Wilson set up as well but have never used it, glad you posted this!

 

[Straightshooter1]

Because of my insatiable curiosity, I also have the K&M donut cutters and just have not used them much (only experimented a little to see how they worked). They certainly got rid of the donuts, but I just haven't found that doing so is any issue for me.

I've measured donuts using pin gauges after 15 firings of my Lapua 6.5 PRC cases finding the donut was at .002 thick (or protrudes that amount). How high up the neck it was wasn't really measurable, but I'd guess it wasn't more than .025". After annealing, sizing with a FL non-bushing die and running an expander mandrel through the necks, the donut was not detectible on the inside, and that's plenty good for me. And not that it matters to me either since using boat tail bullets and don't seat them low enough to make any contact with a donut.

 

[243winxb]

OLD Huntington/RCBS neck reamers, held the neck in a die, while reaming.

Then the other Lee made a hand loading tool, that reamed while neck was held in a die. This didnt help accuracy for me. Made neck tension almost non existing, in 30-06 & 243 Win. There were no bushing dies at the time??

When forming a wildcat, where the shoulder becomes the neck, reaming would seem to be a must do. More brass is removed at 1 time, reaming, compared to outside neck turning.

Ream, then finish with neck turning?



Neck reaming would seem to need brass fl sized in a standard die, before reaming.

 

[Will Henry]

Donuts can come from two sources. In the first case, the donut is formed when the neck is turned, then fire formed, moving the ridge to the inside of the neck. In the second case, the donut is formed simply because the thicker brass in the shoulder area is intruding into the neck. Brass thickness generally tapers from the mouth to the base, becoming thicker at the base. So, in this case, the donut is built into the brass. In addition, if you neck up a piece of brass, there will be some distortion from the original neck/shoulder juncture. Fireforming with a blank load helps to eliminate this. The old Lee Target model loader did a decent job of producing a uniform, donut-free, neck. WH

 

[HPMike800]

I never inside neck reamed other than a wildcat that lengthens the neck and produces a fat spot at the old bend point. I have always cut it and forgot it. I have found a fattening at the case mouth causing neck clearance issues that are deeper than a camfer will properly deal with. I got a Wilson INR cutter for my trimmer and the results are excellent. Case mouths, old doughnuts, random fat areas cleaned up.
If you do it, get the proper bushings for your die to do the cuts in stages. It's a lot of work.

I'm getting INR cutters for my other callibers too.

F-Class Products makes a machine for this. It's like 3,000.

Mike

 

[ebb]

What TRSR8 said.

 

[Bill Norris]

I never inside neck reamed other than a wildcat that lengthens the neck and produces a fat spot at the old bend point. I have always cut it and forgot it. I have found a fattening at the case mouth causing neck clearance issues that are deeper than a camfer will properly deal with. I got a Wilson INR cutter for my trimmer and the results are excellent. Case mouths, old doughnuts, random fat areas cleaned up.
If you do it, get the proper bushings for your die to do the cuts in stages. It's a lot of work.

I'm getting INR cutters for my other callibers too.

F-Class Products makes a machine for this. It's like 3,000.

Mike

Yea, from what I see right now I will use these going forward. I can definitely feel a difference in putting a bullet in a fired case un-reamed neck vs. a fired case that I have reamed.

 

[Bill Norris]

Bill, I have the Wilson set up as well but have never used it, glad you posted this!

Very welcome.

 

[Bill Norris]

OLD Huntington/RCBS neck reamers, held the neck in a die, while reaming.

Then the other Lee made a hand loading tool, that reamed while neck was held in a die. This didnt help accuracy for me. Made neck tension almost non existing, in 30-06 & 243 Win. There were no bushing dies at the time??

When forming a wildcat, where the shoulder becomes the neck, reaming would seem to be a must do. More brass is removed at 1 time, reaming, compared to outside neck turning.

Ream, then finish with neck turning?

View attachment 1767709

Neck reaming would seem to need brass fl sized in a standard die, before reaming.

Wilson says to only ream fired un-sized cases with their reamers..

 

[SeabeeKen]

I keep my donuts to a min by bumping just enough to allow the case to chamber easy. When i was shooting 223 with its short, turned neck id ream the donuts with the wilson reamer but only when they got to the base of the bullet. I use pin gauges to find the donuts easily. Much prefer reaming to turning

 

[LCazador]

My only use for an inside neck reamer has been on brass where I didn't have enough freebore to seat bullets out far enough in the case to avoid the neck shoulder junction. Nowadays I order my reamers with a sufficient amount of free bore to avoid the neck shoulder junction. How quick the donut comes back depends on how much shoulder bump you use on each firing of the brass. You can also avoid the donut somewhat by cutting into the shoulder when neck turning. How high it goes up the neck again depends on brass movement from sizing or pressure. I've experienced that the donut moves higher and faster with the high pressure cartridges.

 

[AlNyhus]

The Wilson setup works great for dealing with donuts....have used it for years. Determine what size reamer you need by measuring the neck I.D. with a pin gauge and order the appropriate size reamer from Wilson.

You can also make a bushing and use a chucking reamer of the correct size.

Good shootin ' -Al

 

[Chris Edmondson]

I recently employed a Wilson reamer for well-fired 6mm BR Lapua brass that'd developed substantial donuts. One half of the cases had been neck turned, the others had not. Since I seat bullets well above the donuts, I never worried about them. Once I started expanding necks after compressing them with a bushing, that's when I wondered about the donuts; the bullets may never see them but the expander will. It'd be one thing if the donuts were uniform, but there's no way to know for sure, until the donut gage is invented and perfected .

De-'nutting the cases with the Wilson reamer was about as much fun as my last root canal, most likely I'll revert to bushing-only neck sizing and ditch the expander.

 

[markm87]

I'd love to ream some of my 300 WM necks. I have RWS brass which lasts very long due to the beefy web area, but some of it is donut city. I load 225s so the bullet is seated well past the donut.

 

[Bill Norris]

I'd love to ream some of my 300 WM necks. I have RWS brass which lasts very long due to the beefy web area, but some of it is donut city. I load 225s so the bullet is seated well past the donut.

The 30 Cal. Wilson Neck Reamer part # is WILINR030

L.E. Wilson Inside Neck Reamer 30 Caliber (.311-.3115 Finish)
$40.48 EA

@ PrecisionReloading.com

 

[nmkid]

When using "donut cutters" or reamers to remove donuts, does the action of removing the donuts weaken the neck in any manner?

 

[Bill Norris]

When using "donut cutters" or reamers to remove donuts, does the action of removing the donuts weaken the neck in any manner?

I'm just now beginning to work with these so not real sure of all the details but from seeing the amount removed from the inside of the necks I doubt if there was enough removed to do any harm The micrometer only showed .001 - .0015 difference with before and after.