6 creedmoor chambering problem

[Remmy223]

I recently started having trouble chambering my loads in my 6 creedmooor. The rifle is an American rifle company nucleus (gen 1) with PVA barrel. I'm loading 105 hybrids in Lapua brass. The brass has been annealed, full length resized ( shoulder bumped ~.002-.003) and bullets seated to mag length. I have been shooting this load for a few years thru this rifle without any issues and out of the blue I'm having to push the bolt really hard to get it to close and sometimes it will not close at at all. The rounds that I'm able to fire are hard to extract even though my load is pretty mild with H4350. I pulled the firing pin assembly and can chamber a resized piece of brass without any issues so I don't think it's a headspace issue but when I try to chamber a loaded round with the firing removed it will not chamber. I also tried seating a bullet another .030" deeper and still the same results. Any ideas?

 

[K22]

Use a sharpie and mark the bullet to determine where the interference is occurring.

What condition is the throat and free bore area of the rifle. Is there any excessive carbon built up?

Have you measured the maximum base to ogive in your rifle for that bullet? If so, have you seated far back enough so the bullet does not engage the lands allowing for variations in bullet ogive.

Is the bullet reasonably straight in the case. Do the roll test on a tabletop.

Have you tried another bullet?

 

[whatsupdoc]

Try new brass, your brass may have expanded at the base and the resizing die is not moving it back.

Mark the case .200 above the base with a sharpie, try to chamber it and see if there are any marks,

 

[Walt Krafft]

Have you trimmed your cases?

 

[Hal]

Do you have a carbon problem ?

Hal

 

[Remmy223]

It was a carbon buildup, what a pain that was to remove! Thanks for the help, very much appreciated!

 

[rijndael]

Try new brass, your brass may have expanded at the base and the resizing die is not moving it back.

It can also be at the Case Shoulder Junction. I just had an issue with my 4th fired brass in a Creedmoor. It didn't want to go in the last 1/4". Turns out, it was the CSJ not getting enough sizing.

 

[6.5 forever]

Try new brass, your brass may have expanded at the base and the resizing die is not moving it back.

Mark the case .200 above the base with a sharpie, try to chamber it and see if there are any marks,

Try this. Also make sure your lugs and recess are free of carbon. Might need a good cleaning.

Edit. Sorry I didn't read to the end before I posted.

 

[spudgun]

Sounds like you found your problem, good for you.

My 6mm CM in a Savage action was giving me the same issues as you.
Bought a SB die and bumped the shoulder and all is good now.

 

[Bula79]

My issue was donuts with the loaded bullet expanding the rear of the case neck