HELP!! Carbon buildup on neck

[jonny315]

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?

 

[varget204]

Are you annealing case necks,looks like neck is not seating fully,allowing carbon to go around neck,Have seen a lot of barrels w/ borescope,fire cracking like that is usually approx at 900- 1000 rounds,guess it's a barrel burner

 

[jonny315]

No I’m not annealing, just straight factory brass. Your seeing cracking? Damn I thought 300 prc was supposed to be good on barrels

 

[Martin52]

Anything related to the case neck mouth ? Maybe it hit a hard surface on ejection, but there's a lip there.

Otherwise, was the chamber dry ?

 

[6MMsteve]

bad chamber job prolly..jmho

 

[rammac]

What powder are you using, maybe you need a slightly slower powder.

 

[338 dude]

Sooty necks are usually a sign of a low powder charge

 

[D Coots]

Annealing is overrated for casual shooting and in some competitions, especially if you're not turning necks. That's not your problem IMO.

 

[243winxb]

Powder issue is my guess. Use a double based powder ( IMR 7977?) load near maxinum. Or may be another issue? Use a mag primer.https://forum.accurateshooter.com/threads/strange-dent-in-fired-case.4016999/

 

[JMayo]

My 30br looks that way. 6mm the whole neck is dirty.
Shells seal at the shoulder ...
I have to make sure chamber is dry after cleaning to stop sticking.
A sealing bore guide is important.

Bortec is really sticky.

 

[jonny315]

Anything related to the case neck mouth ? Maybe it hit a hard surface on ejection, but there's a lip there.

Otherwise, was the chamber dry ?

Yes it was

What powder are you using, maybe you need a slightly slower powder.

Reloder 26, 74.5 g cci magnum primers getting 2975-3000 FPS 220 eldx bullet

 

[jonny315]

bad chamber job prolly..jmho

Proof said they would re-cut the chamber for me thinking the chamber might be too tight?

Powder issue is my guess. Use a double based powder ( IMR 7977?) load near maxinum. Or may be another issue? Use a mag primer.https://forum.accurateshooter.com/threads/strange-dent-in-fired-case.4016999/View attachment 1206293View attachment 1206297View attachment 1206298

These loads are near maximum with re26, problem is it’s tough to find any other powder right now

My 30br looks that way. 6mm the whole neck is dirty.
Shells seal at the shoulder ...
I have to make sure chamber is dry after cleaning to stop sticking.
A sealing bore guide is important.

Bortec is really sticky.

thats a good idea I’ll give that a try

 

[243winxb]

Reloder 26

Looks double based with some Nitroglycerin. No Alliant data for 300 prc?. Hodgdon burn rate looks the same.

 

[jonny315]

Looks double based with some Nitroglycerin. No Alliant data for 300 prc?. Hodgdon burn rate looks the same. View attachment 1206310

According to burger bullets Reloder 26 is between reloader 23 and reloader 19 they tell me it’s much faster than people think.

 

[JMayo]

Using the burn rate chart is not a good resource to pick what to shoot. Use a manual for the bullet or case.
An example in pistol powder is tightgroup and universal ....way apart but both work great in the same gun and the ones inbetween
don't.

 

[243winxb]

Using the burn rate chart is not a good resource to pick what to shoot.

Agreed, but usefull. Hodgdon has data for IMR 4955 and covers bullets from 150 grs to 212 grs. This burn rate is better suited to the heavier bullets. IMR 8133 Hodgdon Data.

May not be powder at all? We can only guess.

Wait for an experts. (Not i)

 

[jpretle]

I concur w/ 338 dude, on this one.

 

[jonny315]

Sooty necks are usually a sign of a low powder charge

I concur w/ 338 dude, on this one.

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

 

[6MMsteve]

I had a 308 barrel that I took off a savage and gave to a buddy, but after I took it off I used it to Lap my lugs in on another action, put a fired case in the 308 barrel and screwed it in with light pressure against the bolt face and lapped the lugs took it off and so on..then my buddy wanted a barrel so I put the 308 on his action and he took it home could not get it to extract..but I had forgotten I used it to lap, causing a negative area in the chamber. we borescoped the 308 barrel and it had a small area that looked funny, so I had a 06 barrel new we put it on shoots great..extracts good..sometimes it can be a chamber issue, sometimes not

 

[338 Mollett]

How far are the bullets seated into the case neck?