Uneven Shoulder Bump?

[getoffmylawn]

So I recently got a Redding instant indicator and really like it. One thing I've noticed since I started using it is that if I check headspace on a single piece of brass, then rotate the brass in the shell holder, the indication may vary .001-.002. I never noticed it when using the Hornady comparator kit with calipers but now that it has been brought to my attention, I checked and sure enough, I'm getting the same variation. I'm using a Redding competition die set and t7 turret press. Brass is hornady. Is this normal? If not, what may be the cause?

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[spife7980]

What calipers are you using? My hornady ones did that until I went to mitutoyos. I would just spin it until I got the smallest reading. Took some finagling each time but it worked.

 

[getoffmylawn]

I'm using a starrett digital micrometer with the Hornady comparator. I'm leaning towards it not being the measuring instruments since both the starrett and Redding dial are showing the same variation.

 

[918v]

I use a pistol case has a comparator. I spin the two cases in between the caliper jaws and once they settle down I get no variation.

 

[Milo 2.5]

There's a certain amount of flex in a T-7, double pump a few cases while rotating 180 degrees, see what happens.

 

[getoffmylawn]

There's a certain amount of flex in a T-7, double pump a few cases while rotating 180 degrees, see what happens.

Will give this a shot. I will also probably try the o-ring trick on the shell holder and die.

 

[buffybuster]

There's a certain amount of flex in a T-7, double pump a few cases while rotating 180 degrees, see what happens.

This. The turret is going to tilt ever so much.

 

[Milo 2.5]

Will give this a shot. I will also probably try the o-ring trick on the shell holder and die.

One other thing to try, move die to a diff hole, a lot going on making that turret head, I had one out of spec, seemed to do about what you are experiencing.

 

[shootnrelease]

Try it with once fired brass, if no success maybe a standard f/l sizing die, ...