Neck Turning vs Neck Reaming

[C.E.Smith043]

Ive always wondered why ive never heard more about neck reaming. You hear many that neck turn the outside but very seldom do you hear about reaming the inside.

Is neck reaming beneficial to accuracy or is it something that is taken care of thru the sizing process?

 

[David Christian]

@C.E.Smith043, I do both. Outside neck turn post fireform then after another 5 firings to clean them up a bit.

I use a gage pin to ream the inside every reload, just before dropping powder and seating a bullet.

 

[Kevin1911]

@David Christian: Very neat- is that a collet bullet puller holding onto a gage pin? If so, does it hold the gage pin straight/perpendicular enough relative to the case?

@C.E.Smith043 I have been wondering the same; I'm assuming you're thinking of not just expanding the interior of the neck to push irregularities outwards (like using an expander die the way David is) but instead cutting some brass on the neck interior?

 

[C.E.Smith043]

@C.E.Smith043 I have been wondering the same; I'm assuming you're thinking of not just expanding the interior of the neck to push irregularities outwards (like using an expander die the way David is) but instead cutting some brass on the neck interior?

Correct

 

[Straightshooter1]

Ive always wondered why ive never heard more about neck reaming. You hear many that neck turn the outside but very seldom do you hear about reaming the inside.

Is neck reaming beneficial to accuracy or is it something that is taken care of thru the sizing process?

You might like to take a looks at this old article (particularly the bottom of page 6) for what the legendary Virgil King said about it:

http://2poqx8tjzgi65olp24je4x4n.wpe...-shooting-magazine-special-edition-1-1993.pdf

 

[lotech]

No firm rules on anything handloading related, but I've never seen a need to ream a case neck; neck-turning has always been satisfactory.

 

[Straightshooter1]

No firm rules on anything handloading related, but I've never seen a need to ream a case neck; neck-turning has always been satisfactory.

Likewise, I've never reamed or turned the inside of a case neck and have been satisfied with my results. I guess, like with hand loading, it depends on just what the objective is and how far one want to go with the effort. On thinking about how the variations tend to be moved to the inside upon the firing of the cartridge, it seemed to me to be a good thing to do, but it seems like a lot of effort for a low return (in my case, anyway). Instead of turning the inside, I figured I could squeeze the necks with a Lee collet die to even things out to some extent before turning the outside. This seems to work well enough.

 

[BoydAllen]

@C.E.Smith043, I do both. Outside neck turn post fireform then after another 5 firings to clean them up a bit.
View attachment 1111873
I use a gage pin to ream the inside every reload, just before dropping powder and seating a bullet.
View attachment 1111872

I think that you are a bit confused on terminology. One cannot ream with a pin gauge. Reaming is a cutting operation and is done with a reamer, that has flutes, with cutting edges. I am not saying that what you are doing is not beneficial, just that your word usage is incorrect. BTW, very nice pictures, and if the collet holds the pin gauge straight, I really like the idea.

 

[BoydAllen]

On reaming vs. turning....I have done the experiment, and a good neck micrometer will show you the difference in neck runout, which is why people turn rather than ream. The one exception is for remediation of doughnuts. Then, it is usually done after a number of firings, and not as a substitute for an initial turning.

 

[David Christian]

@BoydAllen, thanks for the terminology correction. I am expanding, not reaming.

@klloyd, yes bullet puller collet holds the pin straight. I slightly grind one end of the pin to allow for easier insertion and the Hornady Lock-N-Load die bushings provides enough float for easy alignment as well.

 

[varget204]

The pin gages do not ream the inside of case,one is just forming inside diameter to the gage,Neck reaming,will cutt ID to specific deminsion,it will be concentric and it removes Donuts inside case neck,then neck turn outside after reaming

 

[47WillysGuy]

I reamed about a hundred 220 Swift cases that shoot fair. And after test firing the reamed cases, I threw them all away. I wouldn’t advise reaming case necks.

 

[357Mag]

C.E. -

Howdy!

There’s also sometimes a need to do an inside neck ream when forming wildcat cases that require a ( significant ) “neck down”.

My custom RCBS case forming die set for my .22-35Remington includes a case holding “die” and associated inside neck reamer, to allow performing the ream function after case neck down from .358l cal to final .224” cal.

When forming wildcat cases based on 7 x 64 Brenneke brass, I have formed 4 different caliber wildcat cases using just one “ form die”; and using both inside neck ream and outside neck turn to arrive @ final,caliber and neck wall thickness desired. I have a rifle chambered to shoot the
6mm variant, which I call “DEEP 6”.


With regards,
357Mag

 

[carlsbad]

I've toyed with the idea of building a neck reamer. Because of the lack of hoop strength of the necks, the only way to really do it accurately, that I can come up with, would be to use a sizing die. After sizing, while still in the die, a neck reamer could be inserted. This would be especially effective in addressing the donut.

I think this could be set up by mounting the right reloading press on the table of a Bridgeport.

--Jerry

 

[DJSBRS]

IMO, inside neck reaming is not precision process due to cutting with a fluted reamer on the inside and with no support of the neck on the outside during the reaming process. There are those that are expecting better than .0002 neck thickness variance in their benchrest requirements. Considering that the necks thickness are not perfectly true and consistent uniform inside and out from the factory, one will have to cut the high and lows from both inside and out by some precision process to obtain that goal. The outside neck is usually turned for consistency utilizing an inside support mandrel during the turning truing process.

If you take any new brass with magnification, look at the inside of the neck before expanding and look again after expanding, you will see that the expanding mandrel does NOT make 100% contact all the way around and down after the expanding process. There are high and low on the inside as well.

The real practical question is "how do you turn the inside for 100% cleanup with outside support as not to move the neck wall as the cutting begins.

With all that said, I do believe after firing the pressure pushes more of the inside of the neck into the neck for more inside consistency.

Just my 2¢ worth of thought.

DJ

DJ's Brass Service
205-461-4680

 

[SDDasher]

The objective of neck reaming is to remove the donut, however because of variances in neck walls it is not a practical way to do it. Neck turning or as I prefer to call it, neck uniforming, is a more practical way of removing donuts. Here are 7 RSAUM cases after removing the donuts.

View attachment 1112043

Here's a video that I made that you may find relevant.

Joe

Joe,
Thanks for the video and information. Is the collet die that holds the mandrel made by your gunsmith commercially available?
I am currently experimenting with new Peterson 284 Winchester brass and would like to employ some of your prep suggestions. I’ve used Ben Steinholt’s method for years on the 6 Dasher and 260 AI so have a pretty good feel for the importance of neck tension.
TIA

Wes Cummings

 

[SDDasher]

IMO, inside neck reaming is not precision process due to cutting with a fluted reamer on the inside and with no support of the neck on the outside during the reaming process. There are those that are expecting better than .0002 neck thickness variance in their benchrest requirements. Considering that the necks thickness are not perfectly true and consistent uniform inside and out from the factory, one will have to cut the high and lows from both inside and out by some precision process to obtain that goal. The outside neck is usually turned for consistency utilizing an inside support mandrel during the turning truing process.

If you take any new brass with magnification, look at the inside of the neck before expanding and look again after expanding, you will see that the expanding mandrel does NOT make 100% contact all the way around and down after the expanding process. There are high and low on the inside as well.

The real practical question is "how do you turn the inside for 100% cleanup with outside support as not to move the neck wall as the cutting begins.

With all that said, I do believe after firing the pressure pushes more of the inside of the neck into the neck for more inside consistency.

Just my 2¢ worth of thought.

DJ

DJ's Brass Service
205-461-4680

Darrel,
To what you are suggesting, I recently turned the necks of some new Peterson 284 W brass and to make a long story short fired it with no issues testing loads. However, upon reloading and firing on the second go around the bolt was noticeably more difficult to lift at the top.(Panda F Class Action) upon remeasuring the neck wall it had uneven high and low spots and some brass flow into the neck junction.
Using Joes suggested method by accident I reuniformed the piece of once fired brass removing a fair amount of clean up off the neck and shoulder junction. This would concur with your observation. My dreaded fear is not knowing if the brass (now uniformed twice) will need additional uniformity on each subsequent firing. Ha!

 

[WayneShaw]

The popular 30BR is a prime example of the difficulty removing the donut inside. Taking the 6MM neck up to 30 cal moves a lot of the shoulder into the neck area. Running the expander in the neck a second time, you can feel how tight it is at the bottom of the neck. I always turned the necks in two steps, first to get the thick brass at the bottom of the neck off so it was about the same thickness as the rest of the neck. That relieved a lot of the tightness, then turned to the thickness I wanted. As DJ says, it's not easy getting the neck even from top to bottom. I recently started using some old 30BR brass I had shot many times, and they shot well. But I was now using heavier bullets and had to seat the bullets much farther down the neck than I did with 115-120 grain bullets. You should be able to push a bullet right down into the body, but I had the donut I didn't know I had. I measured the ID of the fired neck down to the donut, and had a chucking reamer that was a good fit. I drove the reamer with a battery drill, and held the case with a Sinclair tool which clamps around the case base, both in hand. This allowed everything to self align, and cutting the donut out was simple and quick. The reamer did not cut into the upper portion of the neck, only the donut.

 

[SDDasher]

Hi Wes,
Kenny Porter (of Porter Precision Products can be reached at kennethp@portersprecisionproducts.com) makes them in a variety of calibers.

Any friend of Ben S. is a friend of mine, I've learned a lot from him over the years. He is a kind soul and excellent shooter.

Joe

Thanks Joe, I will reach out to Ken. He has bushed some bolts for me in the past and is masterful in his work.
I agree on Ben and what a fine gentleman and friend to the shooting community he has been for many years. Thanks again
Wes

 

[fyrewall]

I routinely turn necks. I have noticed when necking down .270 or .30-06 cases to 6.5 the neck turning often removes more brass from one side than cases that have not been necked down. I feel that when the neck turning process is completed my ammo is more concentric inside my chamber - brass & bullet. I also turn necks for my .20 P made from .223 brass. I seat bullets well above the donut for the .20P.