Bushing die runout redux

[Tesoro]

I bought a set of Redding compet for my new 20 Practical. I had read various posts over time about people getting horrible neck runout issues with these dies. Obviously those instances were caused by some kind of 'operator error' like sizing down in too large increments etc.

The other day I started sizing a batch of new 223 LC brass and after about 40 I took a break and decided to check neck runout. It was all over the place from none to 4 tho. I said what the heck and started checking all sorts of things but no luck and even started thinking about a lee collett die!

And then I found the culprit..most of the new brass had a very slight hump/burr on the outside of the neck. Maybe this was formed from the cut? I am not sure how new brass is made. Anyhow I got out the de-burring tool and that fixed the problem and i was back to max 1 thou runout. I get better than that on fireformed cases with busging dies and my coax

There was one thing I noticed that was different when sizing the non de-burred brass and that was noise. I would get some squeaks on extraction even though I had plenty of lube. I attributed this to having steel bushings. But once I deburred i never heard another squeak.

Anyhow just a tip for new users of bushing dies.

 

[TheCZKid]

I bought a set of Redding compet for my new 20 Practical. I had read various posts over time about people getting horrible neck runout issues with these dies. Obviously those instances were caused by some kind of 'operator error' like sizing down in too large increments etc.

The other day I started sizing a batch of new 223 LC brass and after about 40 I took a break and decided to check neck runout. It was all over the place from none to 4 tho. I said what the heck and started checking all sorts of things but no luck and even started thinking about a lee collett die!

And then I found the culprit..most of the new brass had a very slight hump/burr on the outside of the neck. Maybe this was formed from the cut? I am not sure how new brass is made. Anyhow I got out the de-burring tool and that fixed the problem and i was back to max 1 thou runout. I get better than that on fireformed cases with busging dies and my coax

There was one thing I noticed that was different when sizing the non de-burred brass and that was noise. I would get some squeaks on extraction even though I had plenty of lube. I attributed this to having steel bushings. But once I deburred i never heard another squeak.

Anyhow just a tip for new users of bushing dies.

I'm dealing with runout issues on my 20 Practical brass I'm sizing. I'm wanting to understand what you are meaning, as the hump or burr, where you found it, and if you just did chamfer and deburr before the start of sizing, is that what solved the issue?

 

[mike06]

Always chamfer and deburr before resizing to avoid burrs hitting die neck area or bushing. Chamfer the case neck inside and out.

 

[Uncle Ed]

Always chamfer and deburr before resizing to avoid burrs hitting die neck area or bushing. Chamfer the case neck inside and out.

100% correct and very good advice.

I was sizing some once fired 7.62 Lake City cases that had the bullets crimped. The sized case before trimming had double the case neck runout because of the inward crimp at the case mouth and expander "pull". Once the cases were trimmed and chamfered and sized again the neck runout was greatly reduced.

So the un-chamfered case mouth can cause the bushing to tilt sliding over the uneven case mouth.