Best way to turn 30BR necks a 2nd time?

K

Kyle Schultz

Member
My 30BR chamber has a 0.330" neck. My brass was initially neck turned to +/- 0.0096". My loaded rounds (BIB 112gr) measure +/- 0.328” so I have about 0.002" of clearance. While the gun is shooting fine, I've wondered about skimming the necks a 2nd time down to 0.0091" and thereby increase the clearance up to 0.003”.

I use K&M tools. My .30cal expander measures 0.3086" while the pilot measures 0.3074". My fired cases fit loose on the expander which makes sense since theoretically a fired case would have an neck ID of 0.3108". My Harrell's resizing die only sizes the upper half of the neck. That's fine for normal reloading but in a situation where I need to reduce the entire neck length down prior to expanding out for neck turning, that won't work. K&M sells larger expander and pilot mandrels. 0.311” and 0.32” are the next sizes up. My hesitation relates to what happens after I neck back down after reszing. The bottom portion of the case neck will be oversized compared to the chamber neck.

Will that cause chambering issues? Is there a better procedure for turning the necks down to 0.0091”? Thanks
 
I did/do exactly what you are talking about. I also was worried about the resized portion being different. Here is what I did:

Fire all the cases - do not resize
knock the primers out
Clean - I use ultrasonic cleaner. You'll want the inside of the necks to be clean.
Trim all to length
Talk to Roger at K&M and he can specially grind some pilots that will just fit inside your necks. You will have to send him some cases.
Turn to your desired thickness.

I had him grind me .306, .307, .308, .309, and .310 pilots.

Hope this helps.
Just my opinion - .002 neck clearance is a pretty good number to be at.

Stanley
 
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One item that you might run into if you get specially made pilots.

If you used an expander mandrel to expand your necks - you will find that the inside of the case necks are not parallel with the outside of the necks. They are slightly "funnel shaped" (Al Nyhus) I inside neck ream my cases after expanding to get rid of this funnel. This is all done before the first turning. I have never inside neck reamed after firing a case - but others have told me this kills accuracy. The point is - if you did not inside neck ream, then getting a pilot to fit your fired cases might be a little trickier. Just something to watch for.
Speaking from experience - when/if you decide to pursue this - you might want to only do 5 cases, or so, and see if they shoot better than the brass you currently have. If so, great - continue on with the rest of them. If not, then you only ruined 5 cases.

Good luck with this project. Let us know the procedure you use and how it turns out.

Stanley
 
Thanks for the feedback.

I hadn't thought about skipping the expander step and fitting the fired cases on the pilot mandrel. One possible concern with that procedure is that any inconsistencies from the 1st neck turning will not be pushed to the outside to be skimmed on the 2nd pass.

The gun is shooting well as it is. I'll likely leave things alone for now. Good luck!
 
The thing I don't understand

is why your expander doesn't produce a neck ID that is a close fit over your neck turning mandrel. That is the way my Nielson works...a nice snug fit over the turning mandrel. --Greg
 
glp said:
is why your expander doesn't produce a neck ID that is a close fit over your neck turning mandrel. That is the way my Nielson works...a nice snug fit over the turning mandrel. --Greg
Click to expand...

Fired case neck ID is set by chamber neck less the case neck thickness times 2. After the cases have been thinned once, the fired case neck ID is bigger than it was for virgin brass. That's why the fired brass fits loose on the stock expander.
 
If you follow Jason Stanleys advise you will have great results.

I'll add one thing to Mr Stanley's method.

Hone a radius on your K&M cutter to match the radius of your neck & shoulder radius. "See Attachment"

Also your neck chamber dia. is probably .3303 to .3305 therefore you may already be at .0025 clearance.

I'm currently turning my necks to .0095 so far it's showing good results.

cutter.jpeg

Russ
 
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Pardon me

TX_Oilman said:
Fired case neck ID is set by chamber neck less the case neck thickness times 2. After the cases have been thinned once, the fired case neck ID is bigger than it was for virgin brass. That's why the fired brass fits loose on the stock expander.
Click to expand...

I missed the "second time" turning issue.
 
In my opinion, having done quite a few of them,

it is most important to make certain the insides of the necks are absolutely clean, to include removing the layer of patina. I would also not second cut any until they had been fired a couple of times after having been annealed. I think the whole thing would go a lot better then.

Pete
 
TX_Oilman said:
My 30BR chamber has a 0.330" neck. My brass was initially neck turned to +/- 0.0096". My loaded rounds (BIB 112gr) measure +/- 0.328” so I have about 0.002" of clearance. While the gun is shooting fine, I've wondered about skimming the necks a 2nd time down to 0.0091" and thereby increase the clearance up to 0.003”.

I use K&M tools. My .30cal expander measures 0.3086" while the pilot measures 0.3074". My fired cases fit loose on the expander which makes sense since theoretically a fired case would have an neck ID of 0.3108". My Harrell's resizing die only sizes the upper half of the neck. That's fine for normal reloading but in a situation where I need to reduce the entire neck length down prior to expanding out for neck turning, that won't work. K&M sells larger expander and pilot mandrels. 0.311” and 0.32” are the next sizes up. My hesitation relates to what happens after I neck back down after reszing. The bottom portion of the case neck will be oversized compared to the chamber neck.

Will that cause chambering issues? Is there a better procedure for turning the necks down to 0.0091”? Thanks
Click to expand...

I don't understand why you would want to take it down to .0091 from .0096? The chamber probably in all reality is 330.3-4. You said your loaded rounds are running 328.00 and the rifle is shooting fine so why mess with it. If it ain't broke don't fix it.
 
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First, thanks again to everyone for your advice and comments.

I went back and rechecked the numbers. My fired cases are running 0.3303" to 0.3305" so as Russ and others suspected, my chamber neck is slightly larger than the nominal 0.330".

Loaded rounds are consistently 0.3281". My BIB 112s are 0.3087". That's suggests a case neck thickness of 0.0097". P1ZombieKiller prep'd all my brass and he did a wonderful job nailing the 0.0096" spec.

So, as best as I can tell, my current clearance is approximately 0.0023". The gun is shooting fine and as long as it continues to do so, I'm not going to tinker with the brass.

Good luck to all!
 
TX_Oilman said:
First, thanks again to everyone for your advice and comments.

I went back and rechecked the numbers. My fired cases are running 0.3303" to 0.3305" so as Russ and others suspected, my chamber neck is slightly larger than the nominal 0.330".

Loaded rounds are consistently 0.3281". My BIB 112s are 0.3087". That's suggests a case neck thickness of 0.0097". P1ZombieKiller prep'd all my brass and he did a wonderful job nailing the 0.0096" spec.

So, as best as I can tell, my current clearance is approximately 0.0023". The gun is shooting fine and as long as it continues to do so, I'm not going to tinker with the brass.

Good luck to all!
Click to expand...

Good decision!:cool: Like Jackie, I turn to 0.0098" wall-thickness, and, through thick & thin, have never looked back.;) Keep 'em ON the X! RG
 
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