HELP!! Carbon buildup on neck

[jonny315]

How far are the bullets seated into the case neck?

The oal is 3.6, the bullet is through the full neck and the boat tail sits in the tapered portion

 

[Eric Bliss]

I have seen this in my rifle and it ended up being either lube in the chamber or on the case or both. I started making sure chamber and ammo are not introducing lube to the chamber and haven't seen the issue since. FWIW

 

[Intheshop]

I'd say "lube" of some sort.

The total loaded neck clearance,tension #'s,and jam, "can" interact in..... hate to say it but,unpredictable ways. Yes,I can get it to repeat but exactly "why" is something of a mystery. Like solder wicking into a heated joint,there's a lot of factors going on in there.... cleanliness is critical in anycase. Good luck with your project.

 

[jonbearman]

I think I would choose another powder that doesnt burn like coal. I would try any powder than that. How much neck tension? Exact recipe of your load using magnum primers I hope. Gavintoobe is the guy to ask the PRC question to? He shoots his a lot. Something isnt adding up/ Are the necks unturned and is it a no turn chamber? Ask who chambered it if for some reason the neck might have been spec'ed wrong. He can measure his reamer. Maybe I am out in left field but start from the beginning and make sure everything is the way it is supposed be .

 

[jonny315]

I think I would choose another powder that doesnt burn like coal. I would try any powder than that. How much neck tension? Exact recipe of your load using magnum primers I hope. Gavintoobe is the guy to ask the PRC question to? He shoots his a lot. Something isnt adding up/ Are the necks unturned and is it a no turn chamber? Ask who chambered it if for some reason the neck might have been spec'ed wrong. He can measure his reamer. Maybe I am out in left field but start from the beginning and make sure everything is the way it is supposed be .

It’s rl26 74.5g 3.6 oal mag cci primers 220 g eldx.
proof research factory shouldered 300 prc barrel. Prefit so factory chamber. Factory hornady brass, non turned.
what do you think of this picture, I just cleaned it with a nylon brush (which seems like it doesn’t work at all) because proof said that if I use a brass brush it would hurt my barrel. I slide in a cartridge pull it out and this is what it does to the bullet.

 

[243winxb]

Barrel may just need a good cleaning? I found this interesting. Google - "accurate shooter barrel cleaning"
I am still using #9 , bronze brush, & Hoppe's benchrest solvent.

The throat may be tighter then normal? Bullets should not get marked like that.

 

[jonny315]

Barrel may just need a good cleaning? I found this interesting. Google - "accurate shooter barrel cleaning"
I am still using #9 , bronze brush, & Hoppe's benchrest solvent.

The throat may be tighter then normal? Bullets should not get marked like that. View attachment 1206446View attachment 1206447

i can soak and clean it, the barrel comes out clean and shiny. then 15-20 rounds later (progressively gets worse) untill it is very hard to push a new shell into the chamber

 

[varget204]

Okay i am in need of an experts opinion. If i clean with a good carbon cleaner the gun shoots great, after about 5-10 rounds i get enough carbon buildup that the shells stick in the chamber and my extractor just slips off, rounding off the butt of the shell. then i have to pop it out with a cleaning rod.
Its a proof carbon barrel with a bighorn action. approx 200-300 rounds down the pipe. any advise?View attachment 1206203View attachment 1206204View attachment 1206205View attachment 1206201View attachment 1206202

Did not mention How much neck tension, Light tension could be the problem

 

[jonbearman]

Maybe that lack of freebore shown by your pictures is the real problem. You have to see the print of the reamer used.

 

[Dusty Stevens]

You have a lot goin on here. First, your dies or your chamber is bad along with brass that needs neck turned- the neck dia stamped on the barrel is probably wrong. Your case has a lot of runout due to bad chamber/sizing die thats whats kicking that bullet to the side making it rub that hard. Necks too thick is whats causing the tightness. Second- use a bronze brush. Youll never clean your barrel without one. Third- if you look at that gunk on your neck thats not carbon that looks like melted plastic. You have solvent or lube buildup somewhere before firing. Look at the carbon on a neck posted above. Its just like a discoloration you cant feel- yours is thick. First thing try some different dies, check your bullet runout. I think your brass may have excess thickness on one side of the neck in a bad way along with a chamber neck way too close to your loaded round dia.

 

[338 Mollett]

The more variables that can be eliminated the more accurate the solution . A cast of the chamber would help.

 

[Texas10]

I would usually agree with that statement but in this case I am using 74.5g of re26, I was getting ejector marks at 75g and the hornady reloading manual for 220 eldx max out at 75.5

Exactly what I'm finding loading the 220 ELDM in 300 PRC Hornaday brass. 75.5 of RL26 was making ejector swipes in a factory RPR. 74.5 was best accuracy.

 

[Texas10]

It’s rl26 74.5g 3.6 oal mag cci primers 220 g eldx.
proof research factory shouldered 300 prc barrel. Prefit so factory chamber. Factory hornady brass, non turned.
what do you think of this picture, I just cleaned it with a nylon brush (which seems like it doesn’t work at all) because proof said that if I use a brass brush it would hurt my barrel. I slide in a cartridge pull it out and this is what it does to the bullet.View attachment 1206437View attachment 1206438

A recent post on this very issue. https://forum.accurateshooter.com/threads/carbon-in-the-throat-what-to-look-out-for.4005755/

 

[hammerjack]

I would check and see if a bullet will slide into a fired case and trim length on brass in case they are too long.