Neck turning or reaming - I need an education

[Aloxite]

I've been reforming some military 30-06 brass to 8mm Mauser brass. I picked up a Forster trimmer and see that I can use it for either neck turning or neck reaming. From what I can glean online the neck reamer is used on fired brass that has not been resized. The neck turner is used on resized brass. The neck reamer is less expensive if I'm just buying for one caliber. The neck turner costs more but will make sense if I need to do 2 or 3 different calibers.

So I could use an education here. What are the pros and cons of the two methods? If I go with neck reaming should I fireform the brass with cream of wheat or something before reaming? Or what would you recommend?

Or should I skip both and just chuck the brass into a Lee lockstud in a drill press and hit it with a file or emery cloth?

[.22-10-45]

Hello, Aloxite. Not sure your reason for either neck turning or reaming. If it is for accuracy inhancement..the neck turning will give more concentric neck wall thickness..a reamer will always follow a hole. But alot depends on your chamber. If all your trying to do is equalize neck wall thickness..thats fine & 100% clean-up all around isn't needed. But if your chamber is a factory or military..and by turning the necks you believe greater accuracy will be gained..be aware with these generally oversized chambers..there comes a point where your neck turning will increase tolerances.

[stubshaft]

As already stated neck reaming will follow the hole. I ream usually to thin necks out when reforming brass as long as I have the reaming die as part of the set.. For more precise thinning of the neck or reforming cases without the ream die then turning is what I do. I shoot a few cartridges where I neck ream and after shooting just deprime and seat a new bullet in the case. I also use it to take a couple of thou off of certain cases in accurate guns. Turning or reaming a 44 mag or 45 lc would not be beneficial. But it is eye opening to see how uneven a case neck is by just taking a light cut with a turning tool.

[midnight]

Reaming or turning depends on your needs. If necks are thicker on one side than the other, they will still be that way after reaming. You turn necks to get them concentric as well as to thin them. I turn necks on a 219 Donaldson Wasp. The necks must be thinned because the neck is formed from what used to be the body of a 30-30 case. Because neck thicknesses vary, I prefer to turn rather than ream. All the books tell you to ream the Wasp but I think that is just because it is easier. Turning is more expensive than reaming because you need a very good fit on the mandrel. You can size the case and Sinclair sells an expander mandrel that will open up the neck so it fits the turning mandrel perfectly.

Bob

[Aloxite]

The only reason I'm looking at neck turning / reaming right now is really for safety. My concern is that by reforming Lake City military 30-06 to 8mm JS I will end up with a neck that is too thick. I don't want to create a situation where the neck cannot expand enough to release the bullet properly when fired. I figure that might push the pressure up too high.

I may be over thinking this but I want to err on the safe side. The only 8mm Mausers I am going to be loading this for are military rifles. I've got a Czech VZ-24, a Yugo M48 and Turk K. Kale. For now I will be loading for the VZ-24 and the M48. Maybe someone with experience with these rifles can shed some light as to if the chambers are generous enough to handle the thicker neck.

I guess I should really start by figuring out exactly what dimensions the chambers are. Would measuring the necks of fired brass tell me what I need to know? If not I suppose I can make chamber casts.

[Doc Highwall]

What is the neck diameter of a loaded 8mmJS vs Fired.

Then load your 8mm bullet into the reformed case and see how that compairs in neck size to the factory cartridge.

Thinning case necks allows the case neck to expand larger in the chamber, meaning that you will have to size them down more at each reloading overworking the case necks.

[beagle]

Turning and reaming both have the same affect....to thin the neck. Turning has the additional benefit of making the neck thickness consistent if the brass is consistent enough. Some R-P brass is **** as far as consistent neck thickness.

It depends on the equipment you have and how much time you want to spend on the project. I own a Forster turner and love it. I also own a Forster trimmer and use it to ream the necks on my .458 X 2" cases.

I'm leaning toward the neck turning for your application if it were me./beagle

[tonyjones]

Necking up .30-06 brass to 8 mm will, if anything, make the case necks thinner. Necking down will make them thicker. I do not trust chamber casts made from Cerrosafe. Dimensions from the casts can and do vary quite a bit. I recommend that you make a lead neck/throat swage. This and bore slugs will tell you what you need to know.

Regards,

Tony

[flounderman]

the 8mm is bigger than the 06 so expanding the 30 cal neck to 8mm will make it thinner. why would you want to ream? shoot a fireforming load and check the fit of a bullet in the neck. if it is tight, it probably needs to be reamed. I doubt that it will be tight. cases like the 243-06 need reaming because you are compressing the brass into a smaller cylinder. opening a case to a bigger caliber, should not need the necks thinned. you probably should anneal the cases before you make 8mms out of them. you will trim the cases and could get into an area of the case that is not as annealed as much. I'm not sure how much shorter the 8 is than the 06. I have seen the base of the case swell using 06 brass in an 8 chamber. every chamber is different. could have an 8mm-06 made out of it and probably get a better throat.

[Aloxite]

Much of the 8mm neck isn't formed from the neck of the 30-06. Quite a bit of it is formed from the shoulder of the 30-06. So I'd guess the tip of the new neck is thinner than the base of the neck. This picture shows (from left to right) formed and trimmed 8mm, formed and not trimmed 8mm, 30-06 and factory R-P 8mm.

http://i222.photobucket.com/albums/dd229/aloxited_photos/8mmbrass.jpg

[plainsman456]

I have formed some 30-06 to 8 MM and have not had to ream or turn the necks.
I even did some 270 brass but it was much harder to get them to open up.
You will get the formed shoulder when you fire them the first time,just don't trim them too short before you fire them.

[MtGun44]

I see no particular need for either. Both are relatively unusual procedures that occasionally
are needed to correct issues like neck assymetry or dramatic neck thickening from case
reforming.

Suppose you were making .22-250 cases from .358 Win brass. You are going to take a nice
normal .35 cal neck down to .22 cal. This will dramatically thicken the necks. Think of how
much brass there is in a normal .35 cal neck and then jam all that same brass down into
an outside diam appropriate for a .22 cartridge, and you will have too much brass, so the
neck will be too thick. In this case, you would almost certainly need to ream out the extra
brass.

In your case, you are barely changing and you are stretching the neck, so it should wind
up THINNER, and should be fine.

Bill

[Rhoa4396]

I have an XP-100 that was re-chambered from 7mm benchrest to 7/08. I took Lake City 7.62 NATO brass and ran it thru some custom dies I had made by Redding off a casting. I also bought a Forster lath and had them make a neck reamer to provide a .001" interference fit between my bullets and the inside neck of a sized case. If I had neck turned, there is a section at the base of the neck/shoulder inside of the case that will be too thick. A neck turner won't get to it. By neck reaming my reformed cases the neck reamer gets all the way down inside and eliminates the thick area.

I can drop a bullet into a fired case and it will fall right thru. OTOH, if I take a bullet and push it part way thru neck without dropping it, I can pick up the case by the bullet and it will be suspended on a cushion of trapped air. If I gently pull down on the fired case and let it go, the case will bounce up and down like a spring from the trapped air. I think I got a good fit.

I thought about turning the outside first to get everything concentric and then doing the reaming for final fit, but this was for IHMSA back in the '80's and since we used open sight I figured I wouldn't be able to tell the difference anyway. The gun was probably more accurate than I was back then, and definitely more accurate than I am today.

Ken R

[Aloxite]

I am amazed at the depth and breadth of knowledge and experience on this site. Thank you for all of the insight. Looks like I can safely give it a go without working on the necks. I was mainly worried because I was using military brass. They just have such a nice blank canvas for some sort of headstamp re-marking.

[Hip's Ax]

As previously stated, take one of your formed cases, seat one of the bullets you are going to use then measure the loaded neck diameter and compare to the know proper diameter. That will tell you if you need to ream or turn.

[scrapcan]

there is another reason as mentioned by Rhoa4396 above to inside ream. That would be the donut that is created when forming necks. one may need to ream to get rid of the donut at the junction of neck and shoulder, and you may have to also out side turn to get consistent thickness.

But as others have said there are many reasons for one of the other.

[Hip's Ax]

there is another reason as mentioned by Rhoa4396 above to inside ream. That would be the donut that is created when forming necks. one may need to ream to get rid of the donut at the junction of neck and shoulder, and you may have to also out side turn to get consistent thickness.

But as others have said there are many reasons for one of the other.

I have a 6BR 300m free rifle and I get doughnuts inside the base of the neck after first fire. I decided I'd rather ream them out rather than neck turn.

I bought a whole Forster rig without reading enough, the 6mm reamer is actually a few thousanths larger then I wanted, this is standard in neck reamers. I then wound up buying a whole Wilson set up as Sinclair stocks some of the popular custom size reamers, a 0.244" takes the doughnuts out and leaves the rest untouched.

Wish I had done my homework first, this was an expensive lesson. :(

[scrapcan]

Hip's Ax,

I understand exactly what you are saying. I was there also. had a bunch of cases that were unusable. A good friend of mine spent a considerable length of time re grinding the inside neck reamer for me. Good thing was I was not trying to compete with teh rifle, I was jsut trying to make an old obsolete cartridge shoot in a rather nice old gun.

learned alot from that experience and have used that hard earned knowledge a bit since.

I think your sharing here has helped someone else not have to make the same expenditure in learning that we have.

[tdgarry]

I have an XP-100 that was re-chambered from 7mm benchrest to 7/08. I took Lake City 7.62 NATO brass and ran it thru some custom dies I had made by Redding off a casting. I also bought a Forster lath and had them make a neck reamer to provide a .001" interference fit between my bullets and the inside neck of a sized case. If I had neck turned, there is a section at the base of the neck/shoulder inside of the case that will be too thick. A neck turner won't get to it. By neck reaming my reformed cases the neck reamer gets all the way down inside and eliminates the thick area.

I can drop a bullet into a fired case and it will fall right thru. OTOH, if I take a bullet and push it part way thru neck without dropping it, I can pick up the case by the bullet and it will be suspended on a cushion of trapped air. If I gently pull down on the fired case and let it go, the case will bounce up and down like a spring from the trapped air. I think I got a good fit.

I thought about turning the outside first to get everything concentric and then doing the reaming for final fit, but this was for IHMSA back in the '80's and since we used open sight I figured I wouldn't be able to tell the difference anyway. The gun was probably more accurate than I was back then, and definitely more accurate than I am today.

Ken R

Ken,
I just started IHMSA with a .22 T/C Contender. I am ready to jump into Big Bore and just bought an XP-100 in 7/08. Any insight on makeing the brass and what I need to buy to do it. I have cast and shot literally millions of straight walled pistol bullets, however this bottleneck cartridge making is all new. I ordered the Lyman 7mm Silhoutte mold and a .285 die for my Star LubriSizor. Now I need some Help.
Tim

[Doc Highwall]

You could neck up Lapua 243 brass to 7mm08 for high quality brass.

7mm08 brass can be bought and does not have to be made.

[Rhoa4396]

Ken,
I just started IHMSA with a .22 T/C Contender. I am ready to jump into Big Bore and just bought an XP-100 in 7/08. Any insight on makeing the brass and what I need to buy to do it. I have cast and shot literally millions of straight walled pistol bullets, however this bottleneck cartridge making is all new. I ordered the Lyman 7mm Silhoutte mold and a .285 die for my Star LubriSizor. Now I need some Help.
Tim

Hi Tim,

I can tell you what I did that seemed to work for me. I started out with a bunch of Lake City 7.62 brass that I deprimed, cleaned, sized, trimmed, and then deburred and contoured the flasholes on. I weighed the casses and selected 110 that were the closest in weight. (I don't remember anymore is they were the same or withing .1 of each other) I only shot J word projectals at the time. I started out with Sierra 7mm 168gr HPBT Matchking's. Eventually I started shooting my own swaged 7mm bullets instead which I turned out on Corbin dies. With the cases sized in Redding dies I ordered I had Forster turn out a custom reamer that bored the neck out to .283. I figured this would give me .001 interference fit between my bullet and the case. I used a bullet seating gauge and would seat my boolets just shy of the landings. Although Sierra MatchKings were good, I found there was slight differences in the hight of their ogive. I found that my own swaged bullets were more consistant. My own were rebated tail open points. I had several sizes that worked well for me, but tended to like the heavier bullets for shooting steel. My choice of powder was Hogkins 4895.

I gues my biggest thing was consistancy of the brass and seating of the bullet. My loads were raised just to the point of causing the neck to give a good gas seal and no more. I never really saw any lengthining of the brass. I would always run them thru my lathe but the cutter would "just" leave a faint mark on the edge and no more.

I never tried shooting cast boolits in my XP so you will need somone elses help with that. Not sure if any of that helps but writing about it is making me want to dig the XP out and do some more loading for it. (grin)

Ken