Neck Reamer Die

.257roberts

What is it and what does it do? A Forum member suggested neck reaming .220 Swift brass instead of trimmer reamed or outside turned. Is there anything different that needs to be done to .220 Swift brass as opposed to other rifle brass?

nononsense

.257roberts,

Q: What is the difference between neck turning and neck reaming?

A: Neck turning removes metal from the outside of the case neck and uniforms the neck wall thickness at the same time. Neck reaming removes metal from the inside of the case neck but does not make the case neck wall thickness more uniform.

Outside neck turning is done with the neck controlled on a mandrel inside the neck and uniforms the neck wall thickness. This insures that the bullet will be held by an even or uniform tension which is an enhancement for accuracy.

Inside neck reaming merely removes a specific amount of material from the inside of the neck leaving the neck wall uneven in thickness. That means that the neck will not hold the bullet with uniform tension and it will not be as accurate. Inside neck reaming can be accomplished by using a press mounted die just like a reloading die or on a horizontal case length trimmer with a die that controls the outside of the case while using a reamer on the inside of the neck.

"Is there anything different that needs to be done to .220 Swift brass as opposed to other rifle brass?"

No. The .220 Swift cases can grow in length when fired due to the very gradual shoulder angle and can require slightly more frequent length trimming. If you have an accurately cut chamber that will tolerate minimal neck turning and benefit from it, I'd opt to turn the outside. The only time I use a reamer on the inside of a case neck is when I get a donut that needs to be removed.

If you have a factory rifle chambered from the factory there is very little you can do. I would concentrate on neck sizing and watching the case length. Then work up a load that your rifle likes.

Best.

.257roberts

Thanks for the informative answer. I,ve been reloading for about 7 or 8 months now, and still run into problems frequently. This forum answers alot of questions I come up with. Thanks again. Robert

336marlin

The suggestion was to neck ream with a die and reamer instead of using a trimmer mounted reamer or outside turning. As Mr Nononsense was refering to a trimmer mounted reamer, the cutter is guided by the case mouth and if you have uneven neck walls to begin with, you end up with uneven neck walls; that when sized result in an eccentric bullet alignment with the bore. The problem with neck turning is that you don't turn all the way to the neck shoulder junction as this is recommended and is also a critical area. Where you leave off turning, a step or variation in thickness is left; and when the case is run through the size die this pushes the thicker area inside and creates what is referred to as a "do-nut" on the inside at the base of the neck, envision this. With a neck reaming die, the case is held in a sizing chamber closely matching that of the sizing die. The reamer is guided down through a closely machined concentric(with the neck area inside) hole in the top of the die. You end up with full length uniform walls and a case mouth centered to perfectly align the bullet with the bore. This is the best method I've found. Most die makers offer these but are not usually seen listed in the catalogs.

nononsense

336marlin,

You might do better to read my post again but this time paying attention to the details and stop making assumptions.

Inside neck reaming is passe and no one interested in concentricity and accuracy bothers with it except to remove a possible donut. Check with those of us who shoot benchrest and long range target competitions. We have the answer.

Best.

mrbruce

When you make that first cut into the shoulder like it's supposed to be done the donut problems is not so bad, and no one in there right mind uses a reamer to remove material on the inside of the neck, because it don't solve much other than removing the donut, and if your using the correct tool that takes care of the donut anyways.....

336marlin

Mr. "nonsense"
Your post is right on but didn't explain the reaming die to the gentelman, just your theory. Neck turning is by far the most used method and is needed to control neck thickness in custom chambers. The reamer and die set-up is mainly useful to maintain neck thickness for the commercial rifle. By the way, which one of these is you?
http://www.pa1000yard.com/results/results.php?cls=Heavy+Gun&week=3&sortby=Score&showshoots=Yes&tops=Yes&topct=10

Reloading practices over the years have evolved from theory. When a particular theory applied in a particular situation happens to work it becomes an accepted method that might or might not be needed or even work for you. This in no more evident than in cartridge design. Many new designs have come out even with theories of shoulder shapes that reduce chamber pressures. If you suspect one of these theory's might help you by all means try it. Get lots of reference material and read a lot about reloading and apply what is needed in your situation. Though bench rest is a test of a "hybrid" type rifle, reloading for it is different than for your Ruger KMVT. Reloading for a "bench rest" rifle that will most likely shoot anything that is thrown together might lead one to believe that the way he's reloading for it will work for anybody else's rifle. Be well read about all aspects of reloading and not just what works for a specialized group of individuals. By the way I also shoot long range with a custon rifle built by Alex Hoyer an original long range Gunsmith. I don't use the same methods reloading for it as I do my varmit rifles. When a case is sized and fired it is irrelevant as to whether the material was removed from the inside or outside. It may take someone familiar with machining practices to understand this.

nononsense

336marlin,

Thank you for your response and your opinions, stated and implied. I love entertaining posts!

You make a great point for the teachers of this world, there's still a lot of work left to do.

"It may take someone familiar with machining practices to understand this."

You'll excuse me while I get back to work. I need to get something productive done.

Have a nice day!

Best.

bigcitybill

.257, Thinning case necks, from the inside or outside, only helps if you're shooting a tight necked chamber. If it's a factory rifle, the chamber neck diameter will be several thousandths of an inch larger than your loaded round. Making the loaded round neck diameter smaller only increases the slop. Shooting fire-formed cases that have only been neck sized will probably get you better results. There are lots of cartridges with body taper and shoulder angle similar to .220 Swift so nothing special required UNLESS you shoot hot loads and reload the cases multiple times. Then you should keep an eye on maximum case length.

.257roberts

Thanks for the info. Bigcity, all of your alls input has really helped. Thanks, Robert