removing inside neck donuts?

[Mooster1223]

I'm shooting a wildcat 300 NM 40° Improved and have pressure cropping up when I shoot brass that has been shot 3 times. It is a .338 neck and I turn brass to .336 for the initial firing. I then resize and head back to the turner to "clean up" the necks and leave it at the previous dimension. I barely remove any material on the second turning.

What I THINK is happening is the brass is initially fired and the shoulder does not FULLY form. I fire the second time and the brass now has it's final shape but on the third firing, the same load that I fired the second time shows pressure with a shiney head stamp. I have no ejector so I can't look for that mark on the case head.

When I measure the diameter at the neck/shoulder junction, I get 0.337 - 0.3375" with a bullet seated. Before seating, I get 0.334" after sizing in Neil Jones dies. The boat tail is being seated below the neck/shoulder junction.

I use a 21st century neck lathe to turn the necks. Is there any way I can get an oversized expander and mandrel and force the donut to the outside and cut it off with out having to ream the inside of the necks? I'd like to keep my current dimensions and neck tension.

Thanks.

 

[Keith Glasscock]

I tried expanding and turning again on my 308....

It didn't work. I'll be buying a neck reamer soon.

 

[Mooster1223]

Well, I called MSC today and ordered 3 HSS reamers covering a 0.003" spread. I'll resize the brass and chuck the reamer in a cordless drill and ream away. I have no idea how i'm going to keep the reamer parallel with the necks. I HOPE the cutter will "self align" with the necks and not chew them up. First time for everything.

 

[Keith Glasscock]

I'm going to give the Wilson inside neck reamer a try. In theory, it should remove the donut and not mess with the neck alignment. We'll see.

If you are using a bushing die, you can also just size part of the neck above the donut. It isn't an elegant solution, but it does work for me. My test rounds with that technique netted .3 MOA at 300 yards with most of the size being my fault (bad wind reading).

 

[Bert]

K+M makes a mandrel to cut the donut out. Take a look at there web site.

 

[expiper]

turn your brass a lil' thinner......002 is not enuff clearance.....003-.004 is much btr....and if you can deepen the FB and get the bearing surface of the bullet above (up out of ) the donut, the problem will be solved...Roger

 

[Mooster1223]

turn your brass a lil' thinner......002 is not enuff clearance.....003-.004 is much btr....and if you can deepen the FB and get the bearing surface of the bullet above (up out of ) the donut, the problem will be solved...Roger

I'm trying to keep expansion and contraction to a minimum to avoid having to anneal. I don't know if it will work but, thats my reasoning for 0.002". The barrel has been Nitrided so throating is not an option at this point.

If you are using a bushing die, you can also just size part of the neck above the donut. It isn't an elegant solution, but it does work for me.

My "bushing" also bumps the shoulder so, that isn't an option.

 

[bozo699]

Well, I called MSC today and ordered 3 HSS reamers covering a 0.003" spread. I'll resize the brass and chuck the reamer in a cordless drill and ream away. I have no idea how i'm going to keep the reamer parallel with the necks. I HOPE the cutter will "self align" with the necks and not chew them up. First time for everything.

Mooster1223,
You can push that donut out with a mandrel and then turn it off, I would highly recommend NOT trying to neck ream with a drill, they will not self align until at least they are in the neck aways and then it will be to late,..the brass will be ruined!! You can use the reamers though, Get yourself a Wilson case holder that will hold your case, wrap paper or emery cloth around it and chuck it up in a lathe, put the ream in the tailstock chuck and you will be able to remove your donuts, after doing that I like to use steel wool or Scott's brite and polish the inside of the neck, make sure you remove all brass and steel wool from inside the case before reloading.
Wayne.

 

[Mooster1223]

Mooster1223,
You can push that donut out with a mandrel and then turn it off, I would highly recommend NOT trying to neck ream with a drill, they will not self align until at least they are in the neck aways and then it will be to late,..the brass will be ruined!! You can use the reamers though, Get yourself a Wilson case holder that will hold your case, wrap paper or emery cloth around it and chuck it up in a lathe, put the ream in the tailstock chuck and you will be able to remove your donuts, after doing that I like to use steel wool or Scott's brite and polish the inside of the neck, make sure you remove all brass and steel wool from inside the case before reloading.
Wayne.

Thanks. I have the little do-dad from 21st Century that is designed to be chucked up in a drill and then there is an o-ring that seats in the primer pocket. You hand tighten the locking collar. Can I presume that this will work to chuck the brass in the lathe? I am also planning on sizing the brass before reaming the necks as well.

 

[bozo699]

Mooster1223,
You can push that donut out with a mandrel and then turn it off, I would highly recommend NOT trying to neck ream with a drill, they will not self align until at least they are in the neck aways and then it will be to late,..the brass will be ruined!! You can use the reamers though, Get yourself a Wilson case holder that will hold your case, wrap paper or emery cloth around it and chuck it up in a lathe, put the ream in the tailstock chuck and you will be able to remove your donuts, after doing that I like to use steel wool or Scott's brite and polish the inside of the neck, make sure you remove all brass and steel wool from inside the case before reloading.
Wayne.

Thanks. I have the little do-dad from 21st Century that is designed to be chucked up in a drill and then there is an o-ring that seats in the primer pocket. You hand tighten the locking collar. Can I presume that this will work to chuck the brass in the lathe? I am also planning on sizing the brass before reaming the necks as well.

I have the same tool that John makes, it works great for what it was built for but I don't think it would work for this as the brass could still move, it needs to be held centered and solid.

If you size your brass first you will remove way to much brass with a standard inside reamer but you ordered reamers so if you took that into account you will be okay.
Remember though when the brass comes out of your chamber it is very concentric and after you size it, it may or may not be perfect, if you induce runout in it with the resizing then when you inside ream the neck you may create more problems, just something to think about.
Wayne.

 

[Mooster1223]

I have the same tool that John makes, it works great for what it was built for but I don't think it would work for this as the brass could still move, it needs to be held centered and solid.

If you size your brass first you will remove way to much brass with a standard inside reamer but you ordered reamers so if you took that into account you will be okay.
Remember though when the brass comes out of your chamber it is very concentric and after you size it, it may or may not be perfect, if you induce runout in it with the resizing then when you inside ream the neck you may create more problems, just something to think about.
Wayne.

I'll have to try the fixture in the lathe and measure the outside of the neck while turning. The item I have is not what is on the lathe. It is a "fixed" holder with interchangable locks. It'll either work or it won't.

I had Neil Jones make me a set of dies but, I haven't checked any loaded rounds for concentricy. I understand what you're saying and I'll check for that on a few pieces of sized and fired brass before I start in. I ordered the reamers with the intention of sizing the brass before reaming. They will be here tomorrow so, if I can get on my buddies lathe tomorrow night, that would be ideal.

 

[bozo699]

I have the same tool that John makes, it works great for what it was built for but I don't think it would work for this as the brass could still move, it needs to be held centered and solid.

If you size your brass first you will remove way to much brass with a standard inside reamer but you ordered reamers so if you took that into account you will be okay.
Remember though when the brass comes out of your chamber it is very concentric and after you size it, it may or may not be perfect, if you induce runout in it with the resizing then when you inside ream the neck you may create more problems, just something to think about.
Wayne.

I'll have to try the fixture in the lathe and measure the outside of the neck while turning. The item I have is not what is on the lathe. It is a "fixed" holder with interchangable locks. It'll either work or it won't.

I had Neil Jones make me a set of dies but, I haven't checked any loaded rounds for concentricy. I understand what you're saying and I'll check for that on a few pieces of sized and fired brass before I start in. I ordered the reamers with the intention of sizing the brass before reaming. They will be here tomorrow so, if I can get on my buddies lathe tomorrow night, that would be ideal.
[/quote
Neil Jones are the best you should be okay, if your 21st holder doesn't work like you want, ask your buddy if he has a 6 jaw chuck, you could wrap heavy paper around your brass and lightly chuck it in the 6 jaw
(if the case walls are straight enough) and you should be able to do it that way as well, best of luck to you my friend, let us know how it turned out, oh, check your neck wall thickness after reaming one or two to make sure it is going in straight and true.
Wayne.

 

[Mooster1223]

I ran the 0.306" reamer in the sized cases and it doesn't touch the necks anywhere other than the donut. I ran it in by hand so i could feel it working. I also purchased a 4&5 reamer which are too small for even the donuts. I'm going to see if I can return them for a 6.5 & 7 thou.

Went out today and shot some test rounds and, so far, so good. I'll post if/when I get some larger reamers. I still want to chuck the cases in a lathe and "play".

 

[Catfish]

I have a Forster case trimmer inside neck turnner. The reamers for 6 mm and 22 cal. are easy to pick up but others are harder to find. If your useing a neck bushing die you will have to drop .002 after you inside neck turn a couple of time. If you shoot a hot rod you really need to check for the dount because it will raise presure a bunch.

 

[Scott Harris]

Moose,

Just my opinion here, but the problem with reaming is you aren't doing anything to eliminate future problems from the shoulder flowing into the neck on subsequent firings. Otherwise, neck reaming would be a good option. Since it does not address future problems I believe outside neck turning and cutting into the shoulder is a much better option. You push the donut outside with the expander mandrel and then turn into the shoulder to prevent future problems. I had 243WIN brass that was previously turned, but not into the shoulder. I developed donuts and tried turning again to remove them. I was able to avoid touching any part of the neck and removed the donut. This time I took a healthy chunk out of the shoulder and never had the problem for the remainder of the brass life. Another tip is to get a cutter with the same angle as your brass neck-shoulder junction: like 21st Century sells. This will allow you to cut higher into the shoulder without risk of overdoing it. Cutting higher into the shoulder ensures the problem will not return.

 

[lurcher]

Do any other manufacturers like k&m make cutters with various angles to suit different calibers? Sounds like a good idea

 

[Mooster1223]

I am using the 21st cent lathe. My initial turnings, I did not get far enough into the shoulder because this is an ai chamber. I have the 40 degree cutter but, the parent case has a 20 degree shoulder.

My second run of cases, I went further into the shoulder than before but, its not ideal because he cutter does not match the shoulder angle initially. At $2 per case, i'm trying to save my first batch by reaming.

When I do my second turning on formed brass, I am cutting into the shoulder a little deeper. Hopefully, reaming and cutting deeper will keep them down to a minimum.

 

[fguffey]

Mooster1223, I disagree, I have said do-nuts can be caused by bad habits, not a problem but when I disagree it brings out the ugly in some, do-nuts that are not caused by bad habits happen by design then there is the failure of understanding what causes do-nuts.

http://www.midwaysverige.net/RCBS-Neck-Reamer-Die-25-300-Winchester-Short-Magnum-WSM


F. Guffey

 

[jo191145]

[/quote]

My "bushing" also bumps the shoulder so, that isn't an option.
[/quote]


Odd, I never heard of a bushing bumping shoulders.
Shoulders are usually bumped by the die with the bushing being adjustable in depth.
What kind of dies are you using?

 

[fguffey]

“My second run of cases, I went further into the shoulder than before but, its not ideal because he cutter does not match the shoulder angle initially. At $2 per case, I'm trying to save my first batch by reaming”.

”When I do my second turning on formed brass, I am cutting into the shoulder a little deeper. Hopefully, reaming deeper will keep them down to a minimum”.

and a smith built a wildcat, went to the range and fired 5 rounds, then removed the bolt and checked the bore, no light coming through, he checked his last fired case, no neck, then he checked the first 4 cases fired, no necks on any of them, and he said to me “This wildcatting and getting information off the Internet is not what it is crapped up to be”, I offered to get involved, but, at that time he was not interested and did not care.

F. Guffey

There is a die that uses a bushing, I call it a ‘do-nut’ making die, it does not make donuts by design but when the user/owner gets fancy with the adjustments, ‘there they are’.