Simple tip for cartridge concentricity

[22BRGUY]

No wonder the general population refers to us as "gun nuts". I wonder how many of the current world records, or any of the previous ones, were scored using weight-sorted primers?

Read this article.

http://www.angelfire.com/ma3/max357/houston.html

Here was a guy who could put all bullets through the same hole tiny, every time, for months on end. And he didn't weigh primers, in fact he said powder charges only "bracketed within a couple of grains" were sufficient. He never found the type of primer made any difference but used 205M because everybody else did, seated them with the cheap Lee hand tool, and was unable to detect any accuracy variance resulting from seating pressure. Read the whole article to glean what he did find was critical (you might just be surprised, if not a little skeptical.)

However, I'm not saying there's only one formula (his) for ultimate accuracy. Why was this mythical chap King, with such a consistently accurate rifle and load, never able to produce results in competition? (He walked away after a relatively short campaign, in disgust.) Answer: He could never get the hang of wind doping. Period. Indoors, he might well have been unbeatable. Outdoors, he discovered he was just another "nut behind the butt", and not nearly the most capable. There's a lesson in there, somewhere.
-

Thanks for great article Brian

 

[lurcher]

I watched a video a few years back on precision reloading from this guy http://richardscustomrifles.com at the time it was useful for me coming to grips with wilson dies. Anyhow he held to the same idea that there were two crowns. He did not use a chamfering tool inside the case neck instead he outside chamfered and merely polished the inside edge with steel wool. I think the idea was that with boat tailed bullets there was no need to chamfer at all?? I have tried this and at least at the neck tension I run (lee collet neck die), checking with a sinclair runout thingy I see very little runout. Pulled projectiles don't seem to have a lot of scoring either

 

[Joe Salt]

Brian Great read thank you. Guess I'm just another nut behind the butt. But I do weigh primers. and everything in between. And I use gauge pins to check my neck tension.

Joe Salt

 

[MagnumManiac]

Most ridiculous theory I have ever heard in my life.
The case mouth doesn't release a bullet while it is still in contact with it, the case neck EXPANDS to release a bullet, the amount angle of the chamfer can, and does, only effect the seating of said bullet.

How in the world is a differing degree of chamfer going to effect a bullet on it's journey down the bore?
This is the job of the leade and throat.
The neck expands so soon after detonation of the primer, the bullet is free to move into the leade fairly early in the ignition process.
Even a crimp only delays the bullets movement by a millisecond, and that crimp is often not fully ironed flat by the pressure in the chamber, which is even evident on uncrimped rounds where the very end of the case mouth curls inwards ever so slightly on fired rounds.

*Facepalm*

 

[Tacticaldonkey]

I like the K&M which offers the steepest cutting angle I have ever seen at 7deg. plus it has adjustable depth control also.

http://kmshooting.com/tools/case-neck-tools/case-neck-chamfer/large-6mm-338-reamer.html

What calibers have you used this on? Wondering if it will work for 308 and so to be 6.5-haven't decided yet caliber, thanks.

 

[Terry]

I bought the RCBS VLD tool, it is a piece of SXXX. It does not cut, just rubs the neck.

Contact them. They have excellent customer service.
They have never let me down. They have exceeded my expectations often.

Terry

 

[zipollini]

What calibers have you used this on? Wondering if it will work for 308 and so to be 6.5-haven't decided yet caliber, thanks.

I use it with my 6XC loads.

 

[Brians356]

Brian Great read thank you. Guess I'm just another nut behind the butt. But I do weigh primers. and everything in between. And I use gauge pins to check my neck tension.

Couldn't survive without my pin gages! Find new uses for them all the time, and not just for reloading.

 

[Brians356]

Most ridiculous theory I have ever heard in my life.
The case mouth doesn't release a bullet while it is still in contact with it, the case neck EXPANDS to release a bullet, the amount angle of the chamfer can, and does, only effect the seating of said bullet.

How in the world is a differing degree of chamfer going to effect a bullet on it's journey down the bore?

I'm rather with you on this, but I'll play devil's advocate here, and think "outside the box":

1. It's possible the benefit is actually derived when the bullet is seated. (After all, loaded round concentricity was initially mentioned by the OP, and there could be neck wall stresses, etc. Who knows?) But then the OP leaped off into the discussion of "point of departure" at launch time, etc.

2. It's just possible the chamfer angle somehow affects how the hot expanding gases interact with the base of the bullet, even after the neck has fully expanded. There would be a slightly different internal shape to the cavity just behind the bullet, for one explanation. Far-fetched concept? Probably, but there it is.
-

 

[Tommie]

Lovely. ANOTHER variable to obsess over...

I love this stuff.

 

[JarheadAZ]

Omigawsh... (plants face...)

 

[vmaxpro]

Hell I dont even use a chamfer tool I use these.

 

[vmaxpro]

Heres the chamfers

 

[GrocMax]

Don't be ridiculous......it is common knowledge that you should be weight sorting ball powder granules...throw away that stick crap!

I like to sort mine so one lot is all ball, and the 2nd lot is all the flattened balls

 

[Steve Ladino]

I'm rather with you on this, but I'll play devil's advocate here, and think "outside the box":

1. It's possible the benefit is actually derived when the bullet is seated. (After all, loaded round concentricity was initially mentioned by the OP, and there could be neck wall stresses, etc. Who knows?) But then the OP leaped off into the discussion of "point of departure" at launch time, etc.

2. It's just possible the chamfer angle somehow affects how the hot expanding gases interact with the base of the bullet, even after the neck has fully expanded. There would be a slightly different internal shape to the cavity just behind the bullet, for one explanation. Far-fetched concept? Probably, but there it is.
-

No not far fetched....everything begins with the "What if - Ah Ha " gift of thinking, without it we would still be eating bugs and plowing dirt with sticks .