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6BR taper in neck

So it's happening during the sizing operation? If you have pins that are a tad bigger, what do they do in a fired piece of brass, eliminating the sizing operation, the od should be straight, or as straight as the chamber. What happens with roughly a .245ish pin and a couple +/- of whatever just fits in the fired case?
edit....2445. Does the fired case have the taper, too?
fwiw, I get a distinct bell mouth when I neck from 6.5 to 6mm for a 6 Grendel but it completely goes away after the first firing.
Fired case does not have taper . .2445 goes all the way , .245 doesn’t start . So yes I guess it’s the sizing operation . I have competition shell holders so only bumping shoulder maybe .002 . Using Redding Type S Full length die . I have a couple other bushings to try . Sounds like bushing ??
 
Fired case does not have taper . .2445 goes all the way , .245 doesn’t start . So yes I guess it’s the sizing operation . I have competition shell holders so only bumping shoulder maybe .002 . Using Redding Type S Full length die . I have a couple other bushings to try . Sounds like bushing ??
Yes, it does to me. I've never had one but I've heard others speak of bushings that had taper to them. Interested in what you find either way. Flip the bushing over and try it.
 
Well thank you for suggesting I check fired case . Tonight when I get home I’ll size with a different bushing and check for taper . Thank you for the help !

Mark
You're very welcome but just flipping the bushing will pin it down to that alone. I'd do that and it's free.
 
You're very welcome but just flipping the bushing will pin it down to that alone. I'd do that and it's free.
Something is definitely screwy . Work a lot so not a lot of time . What I did was size a case with same bushing I’m getting taper with and taper repeated . .240 went, .241 went half way and .242 wants to start . Took bushing out and installed a .001 smaller Redding bushing and .238 goes all the way , .239 goes about half way and .24 starts .

What the hell ?????

I know I can be a little slow (Lol) and stubborn , but when I first started reloading I was using a Wilson neck sizing die and instructions said no need to lube neck .
So now with full length bushing die I lube body only . Could this be the issue ?
 
6BR should not be this difficult.

I think you caught a case of the "donuts". A worn out (or poorly spec'd) "no-turn" reamer can essential be a neck-turn reamer. I would skim them and trim them all. I would also send a 3-times fired case to Harrell's for a new die.

Flip the bushing over and try it.
Did you ever try this?
 
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6BR should not be this difficult.

I think you caught a case of the "donuts". A worn out (or poorly spec'd) "no-turn" reamer can essential be a neck-turn reamer. I would skim them and trim them all. I would also send a 3-times fired case to Harrell's for a new die.


Did you ever try this?
I tried a brand new Redding bushing and taper is still there .
 
I always lube the neck and the body when using a bushing style die, or a standard type die.

I would expect you to get scratches in a longitudinal direction on the neck without lube.

Have you cleaned your bushing that is giving you taper?


I just now checked a fired 6BR, and then sized it. Case has at least 10 t0 15 firings on it. Chamber neck is .272, cases are not neck turned, my JGS reamer only did one barrel before this one.

As fired there is a slight taper on the neck OD, about.0004. This is expected as the case supports the neck and the open end does not support it
After sizing in a Whidden bushing die, with a Redding TiN bushing, there is a bit more taper, as you do not size all the way to the case-neck junction, and there is a slight radius on the bushing. Taper from open end to where the bushing stops is about .0008.

I experienced the same result with pins. One goes in all the way, one (.001 larger) stops at the donut, and the next .001 larger almost starts in the case mouth.

All these dimensions are very hard to measure, as the neck is never round, the case walls vary as they are not turned, and the case develops a donut due to brass flow. The Starrett mic I use has a .234 diameter spindle, and the neck is only about .290 long, so it is always measuring almost the full neck length.
To determine the taper, I set the mike at the diameter near the mouth, and slid it towards the case body, where it stopped I opened the mic to read at that diameter.


In my case, the donut is not a problem as my bullet base is above the donut by about .06/.07.

So, you are not alone in your situation, and I do not believe there is a problem.

Look at it this way:
First pin doesn't count, as it is going through the donut, which should not be there anyway. Get rid of the donut, or have your bullet stop above it where it does not effect you.
Second pin fits, at least to the donut, that's your size
Third pin wont go in the mouth, as it should not.
 
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I always lube the neck and the body when using a bushing style die, or a standard type die.

I would expect you to get scratches in a longitudinal direction on the neck without lube.

Have you cleaned your bushing that is giving you taper?


I just now checked a fired 6BR, and then sized it. Case has at least 10 t0 15 firings on it. Chamber neck is .272, cases are not neck turned, my JGS reamer only did one barrel before this one.

As fired there is a slight taper on the neck OD, about.0004. This is expected as the case supports the neck and the open end does not support it
After sizing in a Whidden bushing die, with a Redding TiN bushing, there is a bit more taper, as you do not size all the way to the case-neck junction, and there is a slight radius on the bushing. Taper from open end to where the bushing stops is about .0008.

I experienced the same result with pins. One goes in all the way, one (.001 larger) stops at the donut, and the next .001 larger almost starts in the case mouth.

All these dimensions are very hard to measure, as the neck is never round, the case walls vary as they are not turned, and the case develops a donut due to brass flow. The Starrett mic I use has a .234 diameter spindle, and the neck is only about .290 long, so it is always measuring almost the full neck length.
To determine the taper, I set the mike at the diameter near the mouth, and slid it towards the case body, where it stopped I opened the mic to read at that diameter.


In my case, the donut is not a problem as my bullet base is above the donut by about .06/.07.

So, you are not alone in your situation, and I do not believe there is a problem.

Look at it this way:
First pin doesn't count, as it is going through the donut, which should not be there anyway. Get rid of the donut, or have your bullet stop above it where it does not effect you.
Second pin fits, at least to the donut, that's your size
Third pin wont go in the mouth, as it should not.
Bullet doesn’t contact shoulder neck junction . But it’s a gradual taper from top to bottom . Yes I have those vertical scratches . I’ll start lubing neck .
 
Looks like it's trying to shoot very well. From a right hand twist barrel, there's not a wind condition that will make groups form up and to the right. Looks like you have some of that going on. That can be tune and it could be gun handling, etc, but not generally wind. I'd work on the load just a little bit. Looks like that rifle has a ton of potential to shoot and you're close. Lots of factors and one group leaves a lot left unknown. but keep up the good work. Bottom line though, if you consistently get groups that go up and right or down and left, it's probably tune. If it's just on occasion with a given load, it's probably something in your gun handling or rest setup. Definitely not too shabby!:) It's trying to shoot so I'm doubting the neck thing is a problem. That's why I asked about how it shoots.
 
Looks like it's trying to shoot very well. From a right hand twist barrel, there's not a wind condition that will make groups form up and to the right. Looks like you have some of that going on. That can be tune and it could be gun handling, etc, but not generally wind. I'd work on the load just a little bit. Looks like that rifle has a ton of potential to shoot and you're close. Lots of factors and one group leaves a lot left unknown. but keep up the good work. Bottom line though, if you consistently get groups that go up and right or down and left, it's probably tune. If it's just on occasion with a given load, it's probably something in your gun handling or rest setup. Definitely not too shabby!:) It's trying to shoot so I'm doubting the neck thing is a problem. That's why I asked about how it shoots.
I have a feeling that high to right shot was the nut on the handle !
 

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