Sizing Dies and Barrel Change

[Packfan]

I just put in a new 6.5 CM barrel and am having issues with my reloads. (All factory ammo is fine.) I am using a Forster full length 6.5 CM sizing die that was modified by Forster to provide a .002 shoulder bump with my old barrel. (I sent the die and 5 fired cases to Forster).

With these dies and the same press settings, with the new barrel I initially got a stiff bolt lift with a click at the top on relatively mild loads. This was with similar headspace comparator gauge measurements as before. I adjusted the die down to fully cam over and now only get the bolt click at the top.

For comparison, I sized some rounds with a full length RCBS 6.5 CM die, and don't experience either issue. As the shoulder measurements and trim length check out, I think the bolt click may be caused by the Forster die not sizing the base of the case sufficiently for the new barrel? But I am unsure?

The old barrel was an X-Caliber chambered by MPA and the new barrel is a Krieger chambered by Keystone Accuracy. I am going to keep using the RCBS die for now, but I am curious whether sending the Forster die back for another adjustment is worth the time and effort.

Thanks for the help!

 

[918v]

Did you measure the body diameter of the fired cases out of the new chamber vs your sized cases?

 

[Edsel]

I think the bolt click may be caused by the Forster die not sizing the base of the case sufficiently for the new barrel? But I am unsure?

Quite possible, had this same problem myself.

I had to “reset” this batch of brass with a Forster Small Base FLS die to share them between my bolt guns, despite identical comparator measurements.

 

[Dolomite]

Base size between the 2 chambers could be the issue which is causing clickers or the die is not sizing the base enough. measure the brass with clickers the brass without clickers at the .200 line and is there a difference? Compare than to the sized cases from each die, is it being sized at the base?

 

[Packfan]

Measuring the base consistently is tough, but fired cases are approximately .001 larger at the base than those sized with the Forster dies. Factory cases appear to be another .001 smaller. I don't have measurements for the RCBS sized cases.

 

[Packfan]

Base size between the 2 chambers could be the issue which is causing clickers or the die is not sizing the base enough. measure the brass with clickers the brass without clickers at the .200 line and is there a difference? Compare than to the sized cases from each die, is it being sized at the base?

I guess it could be both the chambers and the die, but what leads me to believe it is the die, is that the RCBS die works perfectly. No clicking and bolt lift is dead on.

 

[918v]

I guess it could be both the chambers and the die, but what leads me to believe it is the die, is that the RCBS die works perfectly. No clicking and bolt lift is dead on.

When you measure the RCBS sized cases you’ll know right away.

 

[Dolomite]

I guess it could be both the chambers and the die, but what leads me to believe it is the die, is that the RCBS die works perfectly. No clicking and bolt lift is dead on.

I guess you answered your own question. Keep using the rcbs die.

Give Forster a call and tell them what’s happening maybe they can adjust your die somehow.

 

[Packfan]

I guess you answered your own question. Keep using the rcbs die.

Give Forster a call and tell them what’s happening maybe they can adjust your die somehow.

Will do. The RCBS die is consistent with factory ammo at the base (Hornady 140 ELD-M Match). The Forster die is not quite getting there.

I wouldn't think .001 would make a difference here, but it may be as my headspace measurements are consistent for both dies. I think Forster shortened the die to increase the shoulder bump last time. I wonder if that could be having an impact.

Thanks again.

 

[918v]

Shortening a die does not make it size less.