7PRC problem. Brand new prefit barrel, reputable smith, bolt wont close on freshly sized new brass

[Mumzergadol]

Just received a long awaited 7PRC prefit from a reputable vendor here.

Prefit for a Curtis Axiom LA previously wearing a 300WM tube from MPA

Forster FL bushing die

New Nosler brass.

I DONT have a go gauge yet, they are all on backorder. its on the way.
I DONT have factory ammo in hand yet, but will try that tonight.

After mounting up the new barrel with a quality torque wrench and appropriate high-presure synthetic grease, I've got an issue.

Dropping fresh brass into the raceway, bolt will close with reasonable pressure.

After running same brass through the FL die to uniform them prior to loading, bolt will only close with a hard push. Enough of a push that to roll the rifle over on a bipod. Enough of a push you can't run the bolt. All the resistance comes in the last 1/8" of bolt throw and requires force to close lugs into the stops.

Dykem on neck and shoulder shows no contact.

Bolt face shows significant brass transfer.

Will be mic'ing everything tonight when i get back from work, but google-fu has uncovered numerous threads about Forster dies inadequately sizing for minimum spec chambers.

is it possible that the die doesn't adequately size case head/web area with my (redding) shell holder ?

i'm a competent, but unsophisticated reloader and could use some guidance on troubleshooting.

thanks

 

[Mike_in_FL]

I'd say you need the head space gauges. Only way to be sure.

 

[918v]

If an unsized virgin case goes into battery more loosely than your sized virgin case then your sizing die popped the shoulder forward by squeezing the case walls. Screw the die down more.

 

[smoothy8500]

Dropping fresh brass into the raceway, bolt will close with reasonable pressure.... same brass through the FL die bolt will only close with a hard push. Enough of a push that to roll the rifle over on a bipod.....

Well, brand new brass SAAMI cartridge headspace spec is usually less than the chamber headspace spec, so something is amiss.

And yes, the die is squeezing the shoulder forward a few thou.

 

[ma smith]

+1 on get your tools together and revisit the issue when you are prepared and in a better place to proceed.

 

[smoothy8500]

Just received a long awaited 7PRC prefit from a reputable vendor here.

What did the vendor say when you asked about this?

 

[918v]

If you can close the bolt on a virgin case then load a few and fire them and get some pre and post dimensions.

 

[Mumzergadol]

Go gauge on the way

 

[FLIGHT762]

A Comparator would help you figure out if it is a shoulder bump length issue. I reload for about 9 Rifle cartridges, a Comparator is a necessary tool. I have multiple rifles chambered for the same cartridge. Getting good measurements is a necessity.

90% of the time for me, a chambering issue was connected to a shoulder datum length issue from the F/L die not sizing the case shoulder back enough from where it was set. That can be caused by the die not being screwed down enough into the press. On rare occasion, a F/L die cannot push the shoulder back enough even at maximum die / press setting. I had a 308 die that wouldn't. I sent it back to the manufacturer who skimmed .008" off of the bottom of the die. The die then worked perfectly.

Only one time, I had a rifle that was so tight chambered, it was a case web issue of the die not sizing the case web down enough on brass fired from a different Rifle. That rifle needed a Redding S/B Body die. That fixed the issue.

 

[high right]

Try trimming the case .005. Had it happen