turning 30BR brass to neck-shoulder junction

T

tiny68

Member
Ok. Rookie questions again. One of you guys need to move closer to me.

I am turning some 30BR for a new barrel I just installed. My old 30BR barrels were 0.332 and 0.333 necks. The new one is a 0.330 neck. I am using a K&M neck turning tool. I expanded and turned 50 brass down to 0.0105" thickness. I turned them in one pass. Didn't seem like too much (feel free to tell me I am wrong). I actually did this 8 months ago when I got the barrel. When I went to chamber a piece of brass, the bolt wouldn't shut. I realized that I hadn't turned in back close enough to the shoulder junction (right of pic). I adjusted the tool and went to I was just cleaning up the shoulder (left of pic). Is this too much? How do you know when to stop?

Thanks, Tim

brass2.jpg
 
Using a small jewlers saw,or dremel, you can cut that case in half .
before returning the rest of the cases. My guess is that it is deeper
in the shoulder than needed. Not all 30 caliber bullets are .308, some are
bigger. 10 1/2 thou could be thick with some bullets in a .330 neck
 
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Tim, I have not used the K & M, but your recuts look way to deep into the shoulder. You should have a .10 neck thickness x 2 plus .308 = .328, loaded round for a .330 necked chamber. I suggest making your cut a little deeper but not going any further towards the shoulder. Even if you end up with the "dreaded donut" at the neck/shoulder junction. Ther aren't any light weight .30 cal. bullets that should seat far enough into the case to be effected. JVH
 
Bob Kingsbury said:
Using a small jewlers saw,or dremel, you can cut that case in half .
before returning the rest of the cases. My guess is that it is deeper
in the shoulder than needed. Not all 30 caliber bullets are .308, some are
bigger. 10 1/2 thou could be thick with some bullets in a .330 neck
Click to expand...

Yes, the cut looks a little deep, but as Bob suggested sectioning would tell you for sure.

Another method would be take another case and make the cut in .005-.010" increments until the case just chambered without interference and then go another .005"...........Don
 
I feel you are doing the correct cut into the shoulder. I just can not see how you will ever create a donut like that. I always cut slightly into all my neck turned brass, no donuts ever that way. I used the K&N for a lot of neck turned cases, now I use the great Pumpkins tool and it does make it easier. That K&N did make for some tired fingers, but is a good tool.:D
 
Tiny,
I had a similar question when I started turning my 30br brass...how much to turn off and how far down.
The best that I can tell you with regards to how far down, now having the opportunity to see Ron Hoehn's pre-prepped brass, is that the angle on the K&M cutter is just right for the shoulder. In other words allow the beveled angle on the cutter to make its mark into the shoulder but no further.
Once you turn the donut off, you are maybe going to go another couple hundreths at the most further on the case. What I did was to turn, try to chamber...no fit, go down a bit further in .01 increments (this was done by eye only. If you have a means of measuring go for it) until the brass would chamber.
Then you want to seat a bullet in an unprimed/no powder case and measure the OD at the pressure ring with a good mic. What I aimed for was .002 clearance, or a loaded diameter of .328. Then try to chamber it. I ended up turning down to .0010 or less depending on the bullet used. The Hoehn brass is .0092, and I am using BIB's with a .0008 pressure ring.
If you used the K&M expandiron, as I did, some of the necks are WAY out of concentricity (you could turn all day and they wouldn't go...we're talking .020 out of round), and it may help to run them through your FL die once or twice.

It might just be the camera angle that makes the cut look deeper than it really is, but your cut does not seem that far off the mark. If you look at the piece on the right, there is a subtle area just below the cut edge that is a little bit darker than the rest of the brass. You will most likely turn that off and your cutter will start it's bevel cut. I say cut, chamber, cut, and chamber until it fits. Then you'll know.

Good luck,
Mike
 
Question

Did you run the case through your F/L die before trying to chamber the case?

GW
 
Gary Walters said:
Did you run the case through your F/L die before trying to chamber the case? GW
Click to expand...

Sure.

____

I can't feel any groove on the shoulder above and below where I cleaned them up. I think I am good. I will just make about 20 to have to shoot at the match next weekend and then will let the pros give me the ok.

Thanks, Tim
 
Gary ...

Gary Walters said:
Did you run the case through your F/L die before trying to chamber the case? GW
Click to expand...

I had a similar problem with my 6PPC brass but was fortunate to have a F/L die that Billy Stevens had sent me before fire forming. Once I ran it through the die the cases seated easily.

However ... what if someone was going to order a 30 BR Harrell's or Neil Jones die and needs to send in two to three cases that have been fire formed twice before a F/L die is made ???

Is it acceptable to borrow someone's 30 BR die, like a Redding Type S to push the shoulder back ??? Art :)
 
tiny...the case that has the cut into the shoulder area will be just fine...a couple of firings will iron it out...I have at least 75-100 30BR cases cut the same way and all have been fired at least 12-15 times and never had a separation...don't worry....
 
Tim,
I think the cut looks fine but for a .330 neck I believe your loaded neck diameter is going to be a little larger than ideal. I think your cutter should be set for more like .010" maybe even a little less depending on size of your bullets pressure ring.

Dick
 
Dick Grosbier said:
Tim,
I think the cut looks fine but for a .330 neck I believe your loaded neck diameter is going to be a little larger than ideal. I think your cutter should be set for more like .010" maybe even a little less depending on size of your bullets pressure ring.

Dick
Click to expand...

Dick,

The necks are right at 0.010". I loaded up some 118 Cheeks and they measured 0.328" with a bullet seated.

Tim
 
Could be some mike squeasing here.
.328 less .010 twice makes .308 on the nose.
I have never seen a flatbased bullet measure exactly .308
 
steve stanley said:
The cut looks about perfect to me also, If it's too deep I've been shooting screwed up brass for a long time. :) Steve
Click to expand...

Agreed..........

Tim, the earlier post about donuts in a 30 where the bullet heal will be no where near the shoulder/neck junction... Yep, no worries.

Your case on the left looks just right, ready to fire and cut X's;)...

The necks are right at 0.010". I loaded up some 118 Cheeks and they measured 0.328" with a bullet seated.

Tim

Good... .001 clearance per side of loaded round... That'll do.

cale
 
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