Needing to turn necks after X amount of firings

[dkhunt14]

A mandrel pushing the donut out is no different than a seated bullet pushing the donut out; the donut remains a risk.

A bullet won't push the brass out like a mandrel does. After running a .306 mandrel in for a .308 the most you could have is .001 and that is nothing. If you had them annealed, it isn't springing back. Like I said before you got to be careful returning brass. I have seen more then one barrel ruined by shooting a neck down the barrel. This is from guys that are careful and measure real good. Matt

 

[dkhunt14]

Bryan, I was saying about the turning because that is what the picture looked like. It just looked like it didn't take any off the neck. That is the problem with pictures sometimes. A lot of times they help but sometimes they don't show everything. Matt

 

[PMA3]

Tom,

In looking at your top picture of the dasher case ff+2, what is the positive benefit of turning so far down the shoulder? I always thought the max turn below the neck/shoulder junction was to be .020"-.030" or you would start to weaken the shoulder....looks like your at .050"-.060" or more.

Paul

 

[savagedasher]

That is why the correct angle on the neck turning tool is a must. Larry

 

[dkhunt14]

Tom the top picture, it looks like you did a very good job. What neck turner are you using? Maybe people want to know. Matt

 

[PMA3]

Tom,

Your picture does indeed show that the cutter angle and the shoulder are a perfect match.....but, if the purpose of turning necks below the neck/shoulder is to eliminate the "donut", and you can do this with a .020" cut with a perfectly angled cutter, what is the benefit of going an extra .050' or .060" beyond the .020" number?

 

[PMA3]

Thanks Tom, that clears it up for me.

 

[PMA3]

Tom,

Thanks for pictures....always worth a 1000 words. In the 2nd photo, looks like one more firing and the whole neck/shoulder should just blend together.

 

[jsthntn247]

I used to turn new brass then work a load up. Accuracy would be great for a few firings then go bad. I came to find that the build up of brass on the outside of the neck after a few firings was causing an interference fit in the chamber that had .003 neck clearance. I used a full length die to resize the 3x fired brass and shot groups at 300 yards against brass left over from the last match that was bushing neck sized. The full length sized brass was under 1" for 8 shots and the bushing sized was 2.5" with the same load. I repeated the test again with similar results. I will just FL resize from now on and use an expander mandrel to control my neck tension.

 

[fastarget]

Interesting discussion and timely. I turned the necks on the 284 norma brass when new(for a Shehane), I am using a bushing die and .002 tension. After the first firing, I noticed the bushing die not sizing the entire neck, and there was a thickening of the brass, so I turned the necks again to uniform that area and re-ran the brass through the bushing die, with no noticeable change in the dimensions.
1. Other than going to a non-bushing die, should I change my brass prep protocol?
2. The turned brass looks like Tom's pic above.
3. Did I just set myself up for a failure?

Great thread,

 

[fastarget]

Trust me, it is appreciated on the part of a beginner precision reloader.

When I did turning the second time, my carbide mandrel did not feel any different than when the brass was new after the use of the expander die, not even sure that is relevant.

This is once fired brass. I did use a ball micrometer, overall the brass thickness was 2-3thousands more than my target thickness, so I uniformed the brass, that is when I noticed the area thicker since the cutter had to work a little more to shave it.