Carbon fouling on bolt body

[Ronin75]

I have been noticing a fair amount of carbon residue on the bolt body of my 308 win. The rifle had a bartlien carbon wrapped barrel recently installed.
What I have notice is after approximately 10 rounds I have enough carbon residue where the bolt is starting to feel sticky as I work the bolt. I was told that I need to adjust the seating due so that It travels lower on the case neck.
I looked at recently fired cases and noticed the the residue appears to start about an 1/8" from where the shoulder and case neck meet. Any input would be appreciated.

 

[ShtrRdy]

Is the ammunition hand-loaded or factory?

 

[Ronin75]

Hand load , 168 HPBT, velocity 2675, Varget powder, WLR primers

 

[243winxb]

Low pressure may do it. A shorter COL Or More neck tension/bullet hold, * may reduce soot?

A crimp if all else failes.

A barrel chambered out of spec *, long throat, big bullet jump, not wanted.

THROAT

The tapered portion of the bore of a barrel, immediately ahead of the chamber which is sized to provide clearance for the bullet of the loaded cartridge. Also referred to as Leade or Ball Seat and is associated with Free Bore.

 

[ShtrRdy]

I was guessing possible low pressure load but that velocity sounds pretty good for that combination.

Would you please post a picture of a typical case and the bolt showing the carbon build up?

 

[243winxb]

velocity 2675

Whats the barrel length? Hodgdon 2731 @ maximum , 24" bbl.

 

[Coyote Shadow Tracker]

Sounds like gases are escaping around the case neck after the bullet leaves and the gasses continue around the neck, case & chamber to your bolt.
You should not have any carbon on your Bolt unless this is a AR.
Does your brass have carbon on them? If so you may have an out of speck chamber.
Did you measure a fired case for re-sizing?
I would definitely have the gunsmith that chambered your barrel (or another GS) check out your chamber and give them fire brass.
Gas should not escape from the bullet neck in the chamber to the Bolt.

 

[243winxb]

Supressed AR?

 

[Pdyson]

Definitely not normal on a bolt gun, it's gotta be a gas gun. Is your brass is black and sooty? Low pressure light loads can have that affect. but those velocities rule out low pressure. I'd say chamber defect but it would show on the brass, possibly even making it impossible to resize and reload. I Don't understand the advice given to you though. I can't imagine how a seating die or even a sizing die could make a difference. Even if it barely held the bullet. I'd take it to the gunsmith. I may be wrong but I'm thinking that much gas leaking is dangerous

 

[Bob Wright]

Most of my 7RM sooty necks, shoulders were from brass that needed annealing and had varying neck wall thickness. Once I fixed those issues, the neck could seal the chamber quite easily and no more fouling the necks.

 

[Ronin75]

All the brass is once fired Hornady brass used in there Amax loads. This is a Remington 700 short action

 

[Bob Wright]

All the brass is once fired Hornady brass used in there Amax loads. This is a Remington 700 short action

The action length makes no difference. Factory brass varies quite a bit. That neck has to seal. Right now it's not. The carbon pattern will also show where thick or thin areas of the neck are. How much is determined by measuring it.