Neck turn or inside ream?

[Mk42gunner]

I am preparing to convert some .308 Win cases to .30 BR. I do have some of the Remington BR brass, still in .308 form, not sure what the neck thickness on that will be but I am almost certain any formed from regular .308 will have a very thick neck.

I do have one of the sets for neck turning on the Lyman case trimmer, I played with it a few years ago and wasn't too pleased with the results.

The chamber cast I did before installing the barrel gives me a neck diameter of .332", so I have been thinking about the easiest/ best /cheapest way to do this operation.

So far the cheapest option is to learn how to make the Lyman unit work.

Next cheapest seems to be buying an inside neck reamer for a Forster case trimmer (I do have one of their trimmers).

Then we get into the Sinclair tools.

I have never had a tight necked chamber before, although I did run into this problem years ago when forming 7.65x53 from .30-06.

Looking for opinions, I'm not in a hurry on this build.

Robert

[stubshaft]

If you are interested in just forming brass so that you have something to shoot, then you can try one of the inside case reamers. If you are interested in shooting accurate ammo, then you will invest in an outside neck turner. The initial investment may seem high, but you can use it to turn all of the other calibers you shoot by purchasing mandrels and shell holders. Either way you only have to turn the necks once. If you want an "eye opening" experience, try and take a light cut on factory brass and see how far out of round it is!

[BJung]

I like my neck turning tool. The first thing I learned is that after I expanded case necks with a mandrel and turning it over a concentricity gauge is that certain brands are more concentric than others. It's not just the neck but the whole body. I found Lapua brass as the most concentric.

[wilecoyote]

...Next cheapest seems to be buying an inside neck reamer for a Forster case trimmer (I do have one of their trimmers).Then we get into the Sinclair tools.

Handloading for competition by Glen Zediker is the best source about this matter, imho_
for what is worth, my tools of choice are the Sinclair NT 1000 to outside neck turning and the Forster case trimmer conversion to ream the inside_

[414gates]

To thin the neck walls, you need a neck turning tool.

An inside reamer is for removing donuts.

I chose the Hornady neck turner.

Results are excellent. It can be powered by a cordless screwdriver.

A drop of cutting fluid on each neck prevents the cutter overheating.

[BJung]

I use Sinclair tools. The only tool I wish they'd improve is their meplate trimmer

[AntiqueSledMan]

Hello MK42gunner,

The problem with a reamer is the fact it will follow the hole, so if your neck walls vary before reaming they will vary after reaming as well.
By turning the neck as it's supported on a mandrel, your necks will be the same thickness everywhere.

AntiqueSledMan.

[pworley1]

I have found that turning the necks works best for me.

[country gent]

Youve started in the right direction with the chamber cast getting the neck dia of your rifles chamber. Now size a dew cases to 30 br and measure the wall thickness.
wall thickness X 2 + bullet dia = loaded round neck dia. This is the number you want as it is a direct to the neck dia. your Loaded round neck size should be .001 under the rifles.

I have one wildcat here that when formed the neck is part of the body and very thick. I do both a neck ream ( to remove most of the excess ) and then a neck turn to true and bring to size. Its easier to remove the bulk of the material with the reamer then true with the turner. ( I usually end up with .006 -.007 to remove) a lot to trmove in one pass with a turner by hand.

I use a sinclair style tool I made in a drill press for the neck turn. If you can size small and expand in a sizing with the turners mandrel the spring back gives a perfect fit on the mandrel when turning.I shoot for .001 in a side for neck turning. With the neck ream and size on mandrel after neck turning wall thickness is usually around .0001 in size and consistency. Always remember you need a small amount of clearance for the neck to expand and release the bullet. A small amount of lube on the mandrel helps and a small amount of lube on the neck helps lubricate the cut. I use a small pan of unsalted lard for this, just a shallow dip before turning. This keeps brass from adhering to the mandrel and extends cutters life and the finish of both the turned neck and reamed surface.
The ones using tight necked rifles may be as low as .0005 clearance between neck and loaded round.

[243winxb]

My Lyman Universal case trimmer, outside neck turner attachment works ok. I turn factory brass for factory chambers in 223, 243, 6.5CM. Turning attachment has been discontinued by Lyman.
If needing to remove a lot of brass, multiple passes will be needed.

Inside neck reaming should be done while neck is held in a die, for best results. None currently made that i know of?

So, ream, but leave enough brass to finish by outside neck turning.

All depends on how much brass needs removed?

[racepres]

I was taught to fireform, all wildcats. Formed with COW and wax plug should tell how much to Turn Off the neck.
BTW, FWIW, I use the Lyman..

[ndnchf]

I have neck turned brass on my lathe with very good results. I don't think anyone would argue that it is the more uniform of the two methods. But I've also had very good results with neck reaming. It all depends on what your goal is. I'm not a bench rest shooter, I'm not looking to shave a 1/10" off my group size. My interest is making long obsolete brass to get antique rifles shooting again. One example that has proven very good for me is a #2 rolling block in .32 extra long rimfire. Using a centerfire breech block I make brass from .327 Federal magnum. But it is too thick in the neck. Years ago I had Forster make me a .299" neck reamer to accept the heel type bullet it uses. This rifle is over 130 years old. Despite my aging eyes, it shoots exceptionally well with iron sights and my neck reamed cases.

So yes, neck turning is more accurate, but neck reaming can still give very satisfactory results too.
Steve

[uscra112]

Lathe. Not hard to set up and does a masterful job. Last batch I did on an Emco-Meier Unimat 3, sitting at my desk.

The Wilson tools are the only ones I know of that can inside ream and keep the wall thickness uniform. With a lathe, you can hold that to a "tenth" with almost no effort at all.

[racepres]

Lathe. Not hard to set up and does a masterful job. Last batch I did on an Emco-Meier Unimat 3, sitting at my desk.

The Wilson tools are the only ones I know of that can inside ream and keep the wall thickness uniform. With a lathe, you can hold that to a "tenth" with almost no effort at all.

Quick...how Superior is the $$$ Lathe method to the Lyman tiny lathe type...with a Mandrel??
Inquiring minds want to know..

[BK7saum]

Ream to make usable cases. For best accuracy, neck turn. If I am going to the trouble to "work" on a case, Id just as soon neck turn and know that they are the best cases i can make.

[Mk42gunner]

Okay, you guys have convinced me that my first thought, neck turning, is the way to go. I'll break out the Lyman attachment and start playing with it on some junk cases from the scrap bucket, wouldn't want to destroy any good cases.

Thinking back I may have tried to take too heavy a cut when I first tried neck turning; and since all I had at the time were standard factory or milsurp chambers, it really was an unneeded step.

I can see that I am going to have to order a real set of dies for this cartridge, so I may as well order a forming die while I am at it. So far I have managed to cobble together some dummies with a combination of M- and 310 dies.

Cash outlay so far has only been slightly over $500 to get to a rifle/scope combo in fireable shape. Still a single shot, but I have a few ideas on how to make a long action Savage work with an extremely short round.

Robert

[357Mag]

MK42 -

Howdy !

IMHO - you'll likely have to do both inside neck ream and outside neck turn.

The substantial shoulder shove downward on the .308 case, will result in the wildcat case's shoulder radius and lower necks being thicker inside.... than the upper part of the final case; necks. That in itself drivers the need to inside neck ream.

The outer neck side walls will also very likely be irregular or non-uniform in their thickness.... even if only slightly. The fix for that is an outside neck turning, even if only a " skim trim ".

I say these things after doing case forming like:
- making .22BR case's out of .308Win basic
- forming a 6mm wildcat sized between a 6PPC and a 6BR.... starting out w/ .35 Remington basic
- and ...forming a new 6mm wildcat using 7 X 64 Brenneke..... to fit a chamber cut by running a 6mm reamer in " short '.... for a .466" base diam.


With regards,
357Mag

[uscra112]

Soooo, once the neck O.D. is rough formed, measure the I.D. at the mouth. Run an ordinary chucking reamer of that diameter in to make the neck I.D. a cylinder, (ignoring concentricity for the moment), then make or buy a mandrel of that diameter for your O.D. tool and turn to bring the neck wall down to your spec, and make it concentric, yes? Then expand the neck to the required I.D., load and fireform.

This would be a strong incentive to use a lathe, because you can make your mandrel precisely to a light press fit. Keep it in the chuck so it's running dead true, push the case onto it with the live center, up to a shoulder that stops it on the case mouth. Friction will drive the case. Turn the O.D., then yank the case off and repeat. I've never done a conversion where I needed to ream, but the lathe method has always been the most precise way for me. The neck-turner gadget that came with my manual trimmer hasn't been used in years.

[243winxb]

Okay, you guys have convinced me that my first thought, neck turning, is the way to go. I'll break out the Lyman attachment and start playing with it on some junk cases from the scrap bucket, wouldn't want to destroy any good cases.

Thinking back I may have tried to take too heavy a cut when I first tried neck turning; and since all I had at the time were standard factory or milsurp chambers, it really was an unneeded step.

I can see that I am going to have to order a real set of dies for this cartridge, so I may as well order a forming die while I am at it. So far I have managed to cobble together some dummies with a combination of M- and 310 dies.

Cash outlay so far has only been slightly over $500 to get to a rifle/scope combo in fireable shape. Still a single shot, but I have a few ideas on how to make a long action Savage work with an extremely short round.

Robert

The Lyman requires FL sized brass, before turning. . The necks inside diameter may need a smaller pilot to fit inside the case neck/mouth? May have to adjust the pilot diameter?

[racepres]

Soooo, once the neck O.D. is rough formed, measure the I.D. at the mouth. Run an ordinary chucking reamer of that diameter in to make the neck I.D. a cylinder, (ignoring concentricity for the moment), then make or buy a mandrel of that diameter for your O.D. tool and turn to bring the neck wall down to your spec, and make it concentric, yes? Then expand the neck to the required I.D., load and fireform.

This would be a strong incentive to use a lathe, because you can make your mandrel precisely to a light press fit. Keep it in the chuck so it's running dead true, push the case onto it with the live center, up to a shoulder that stops it on the case mouth. Friction will drive the case. Turn the O.D., then yank the case off and repeat. I've never done a conversion where I needed to ream, but the lathe method has always been the most precise way for me. The neck-turner gadget that came with my manual trimmer hasn't been used in years.

I can certainly see how a custom diameter Mandrel would be beneficial.. I also understand the "donut" inside at neck to shoulder junction.
I'm thinking (maybe rightly, maybe wrongly) that a slightly small inside ream, after forming, then expander, then neck turning against mandrel, Custom of Standard. Probably as good as I can do with the tools at hand.. I personally do Not prefer a lot of "room" between Fired and resized necks.. Got me to wondering now...if Fireforming actually removes the donut??? gonna Check that...somehow.