Headspace question

[Varmint Hunter]

I'm working with a 6.5PRC with a new Bartlein carbon bbl. The Lapua brass has been fired 5x. Using the Hornady headspace guage I get 1.6425" on fired cases. Resized cases measure 1.6410", allowing for about .0015" of clearance. All the brass has been trimmed to be less than SAMMI max case length.

The problem is that cases don't chamber freely. I can close the bolt but there is some resistance that I'd like to eliminate. FWIW - the reamer used is the 6.5PRC-AW. What is causing the chambering issue?

 

[Critter Picker]

Have you checked neck thickness?

 

[Mike D Texas]

What sizing die are you using?

 

[HandgunHTR]

If I read your post correctly, your brass has been fired in another barrel 5X times. If so, then you probably have to size your brass some more for the first firing in the new barrel. The Hornady tool is just a comparator. It is just measuring a before and after. Your "before" is based on the headspace of another barrel.

Personally, I would anneal the brass, bump the shoulder back 0.004", and then see how it chambers. If it still sticks, push it back 0.001" until it doesn't and then fire it in the new barrel to find its "before" measurement.

 

[26Reload]

Are you testing a naked bolt(as in no firing pin or ejector) and still getting interference?

 

[FireFlyFishing]

How about firing some factory loads and do some comparisons. My guess is your cases are a touch chunky down at the web.

 

[Varmint Hunter]

Additional info - Brass was bought new and only fired in my rifle. Dies are Redding Type S FL dies. I use the Types S FL dies for reloading for almost all of my rifles which are all.

Not chambering with a "naked bolt".

 

[26Reload]

I'd test the naked bolt before doing anything drastic.....that should tell you if there's a chamber or brass issue...

Besides..where's some pics of an inked up piece of brass showing us rub marks....

 

[Taylorbok]

was the brass fired in this barrel or a different one cut with the same reamer?

 

[MagnumManiac]

My guess is this is not a headspace issue but an expansion line issue.
Have you measured the diameter of your cases .200" from the base?

Cheers.

 

[Barrelnut]

How about firing some factory loads and do some comparisons. My guess is your cases are a touch chunky down at the web.

^^^ This ^^^

You need to use a micrometer and measure at the web line of fired and unfired cases and see if that is growing. You may find that the die is not sizing the case down enough at the web and it is growing in diameter after each firing. A cheap digital micrometer off Amazon will work. You can get a little clamp/stand for them too so it makes it easier to get good measurements.
I seen reports that 6.5 PRC chambers are tight. I believe Alex Wheeler has a special reamer to fix it.

 

[lancetkenyon]

If you are feeling the drag at .0015", Bump to .003". The problem should go away.

 

[Barrelnut]

Never mind. Just saw it "6.5PRC-AW"

 

[MagnumManiac]

Are you testing a naked bolt

Ooooh, I love a naked bolt when testing brass on bolt fall.
Great advice there @26Reload.

Cheers.