I have been full length resizing my 6.5 creedmoor brass. I am trying to take some advice from people and I am trying to just bump the shoulder back .002. I have set up my die but I am not getting a consistent measurement. The measurements are ranging + or - .002 on the extreme. Why am I not getting the same measurements every-time.

Work hardened brass? How many times have you reloaded this,brass???

quote:

Originally posted by JTEX:
Work hardened brass? How many times have you reloaded this,brass???

3 maybe 4 times

First off, how are you measuring this?

You need to use the same comparator inset placed the same way.

I’m assuming it’s the same rifle you are shooting them out of.

If it’s different rifles, the precise chamber length isn’t identical.

If you are moving the comparator around it won’t be the same overall, but should be similar once you’ve zeroed it with the same comparator insert.

What equipment and procedure are you using?

With mine, I’m using Sinclair comparator and insert and once tightened down I zero it.

I then take an average of 5 readings.

I then reset the die so that it shows 0.002 reduction to the shoulder for a bolt gun, tighten it, and then take 5 more and average to make sure it’s right. My calipers will read to 0.0005.

Usually they are within .0005 of each other.

It will give screwy results if you are trying to base it off one case and you have a mixture of brass from different guns.

If you have a long chamber, shorten it by .002, and there are some that were fired in a chamber that is .003 shorter, then you will see variance all over even with perfect technique.

The most common screw up I’ve seen involves changing comparator inserts and not rezeroing each time. I’ve seen considerable variance with just changing or removing and reinstalling the comparator body or insert.

Brass is so ductile that you can never get perfect results. Especially fired brass as you are using. Chasing tails.

No trying to be a smartass, but is +/- .002" really that big of a deal ? I don't think it is.

quote:

bike8300
posted 17 April 2022 13:00
I have been full length resizing my 6.5 creedmoor brass. I am trying to take some advice from people and I am trying to just bump the shoulder back .002. I have set up my die but I am not getting a consistent measurement. The measurements are ranging + or - .002 on the extreme. Why am I not getting the same measurements every-time.

At the risk of misunderstanding your question I assume the shoulder bump is desirable to get a less firm feel when chambering rounds, yet still have a close chamber fit...??
As dpcd says the ductility of brass makes a consistent shoulder bump this precise almost impossible.
If you have set your die and already get the right "feel" when chambering that may be all you need. I am talking hunting rounds here, not benchrest.
Personally, when first setting a die ( I always use FL ) I turn down in about 1/8 increments until I'm happy with the "feel" of a chambered case. I look for a snug, not tight fit. Then I set the die and shoot that brass. Usually I find after a few cycles of shooting and FL sizing that the brass starts to feel tighter upon chambering. It's not neck stretch as I trim to length after each firing. At that point I turn the FL die down further by another one or two 1/8 turns, set it there and that's usually the final adjustment for that particular chamber. I can get up to 20 loadings in a batch of brass ( I use Norma ) before losses occur. I couldn't tell you the actual adjustment measurements as I never measure any. I go strictly be feel and it's always worked for me.

Why are you attempting to do this?

quote:

Originally posted by Saeed:
Why are you attempting to do this?

This

I start with one fired case, seat the case out a good bit or at least to the point it won't feed, then neck size a tad at a time until I get just a snug fit on closing the bolt, the seat the bullet just a tad more, Scientific?? maybe, maybe not but it sure works when tweeking accuracy, good on targets and varmints.

Also you can smoke the neck and shouder to tell where your at on the neck and shoulder..

BTW .002 is non critical, and your overthinking your reloading, ain't gonna happen..same with trimming cases with a rotory trimmer..you have a lot of leeway..

I wouldn't advise hunting with such, I would set my neck sizinf with a blackened neck to the shoulder, test it and be sure it slopped right in the chamber..or probably full lenght resize, In really accurate rifles it may or may not increase accuracy to bump that shoulder..

Nothing on this subject is written in stone..

What type and how much lube are you using?
Lube build up / removal in the shoulder will effect how far / not the shoulder is moved as well.

Do two things

1)...Remove the piece of junk sizing ball from your FS die and use sizing a mandrel to finish the neck ID
2)...aneal

Lube is important (on the shoulder. a wax is best). Also, dwell time is important. Wait a couple of seconds with the ram all the way up, before pulling the case out. Regards, Bill.

quote:

Originally posted by Bill Leeper:
Lube is important (on the shoulder. a wax is best). Also, dwell time is important. Wait a couple of seconds with the ram all the way up, before pulling the case out. Regards, Bill.

I never lube necks or shoulders