Stubborn Fouling in Last Inch of the Barrel

[Bucksdeermanager]

Hi All,

I have a 20" .308 barrel that seems to get a build up of very stubborn fouling (carbon) in the last inch of the barrel. Any ideas what could be causing this? Is it the load, the moderator, the barrel itself? For context, it is a very new barrel, shooting 150gr bullets using N140 powder with a very short and compact moderator on the end.

TIA

 

[Andyquadra]

DO you leave the moderator on all the time?

 

[bluesako]

i would use some jb compound first and get it clean, then shoot it without the moderator on , if it doesnt foul up put moderator back on and shoot it, if it fouls again, then its your moderator you should be checking, ive seen this a few times, and its always been the moderator gl bs.

 

[Ratwhiskers]

You fail to mention as to your normal cleaning pattern, do you use a brush (nylon/bronze) or patch, and what fluids are you using?!

At this stage l am inclined to agree with bs as to the possible problem, and as Andy has asked, do you leave the moderator on the barrel between outings?!

 

[Bowland blades]

That will be leaving the moderator on then i guess ? get it chopped and re-threaded with a nice crown , it will love you for it ! just done one myself that was bought second-hand unseen , transformed it !

 

[Drum123]

I have a sl5 that I use on a 243 which even after 4 or 5 shots leaves a very stubborn carbon deposit in the last half inch and particularly the crown area , the Pes t12 and two dpt's I use on my other 3 rifles don't do this.I take my cf mods off when I get home so I come to the conclusion its the design of the mod that causes it in my case.

 

[Ronin]

Not necessarily any failure of the op

Rather than JB try Losso - less aggressive and apply with a patch over a nylon brush

 

[Bucksdeermanager]

DO you leave the moderator on all the time?

No, the moderator is taken off immediately after use.

 

[Bucksdeermanager]

i would use some jb compound first and get it clean, then shoot it without the moderator on , if it doesnt foul up put moderator back on and shoot it, if it fouls again, then its your moderator you should be checking, ive seen this a few times, and its always been the moderator gl bs.

Very interesting, thank you! I’m inclined to agree it’s the moderator as I shot the rifle for a while before I got the moderator and never had an issue.

 

[User00040]

Hi All,

I have a 20" .308 barrel that seems to get a build up of very stubborn fouling (carbon) in the last inch of the barrel. Any ideas what could be causing this? Is it the load, the moderator, the barrel itself? For context, it is a very new barrel, shooting 150gr bullets using N140 powder with a very short and compact moderator on the end.

TIA

3 options:

1. Ignore it amd stop worrying

2. Cut that section of the barrel off and make it 16"

3. Robla Solo Mil, this is the strongest cleaner you can buy which contains ammonia, so be careful!

 

[Bucksdeermanager]

You fail to mention as to your normal cleaning pattern, do you use a brush (nylon/bronze) or patch, and what fluids are you using?!

At this stage l am inclined to agree with bs as to the possible problem, and as Andy has asked, do you leave the moderator on the barrel between outings?!

The rifle is cleaned after each firing with a bronze brush, patches and Napier rifle cleaner. The moderator isn’t left on the rifle between outings.

 

[Bucksdeermanager]

That will be leaving the moderator on then i guess ? get it chopped and re-threaded with a nice crown , it will love you for it ! just done one myself that was bought second-hand unseen , transformed it !

I don’t leave the moderator on. The fouling can be removed with a heavy clean and the crown is fine. I just wondered what could be causing the issue.

 

[Bucksdeermanager]

I have a sl5 that I use on a 243 which even after 4 or 5 shots leaves a very stubborn carbon deposit in the last half inch and particularly the crown area , the Pes t12 and two dpt's I use on my other 3 rifles don't do this.I take my cf mods off when I get home so I come to the conclusion its the design of the mod that causes it in my case.

I tend to agree. Interesting as the SL5 is a similar size to the moderator I’m using and is quite short!

 

[Bucksdeermanager]

Not necessarily any failure of the op

Rather than JB try Losso - less aggressive and apply with a patch over a nylon brush

What is ‘op’?

 

[Bavarianbrit]

What is ‘op’?

Original thread poster.

 

[Drum123]

I tend to agree. Interesting as the SL5 is a similar size to the moderator I’m using and is quite short!

Not sure it's much to do with the size of mod as such, I've an end of barrel dpt which is similar size , dimensionally, and that dosn't leave the crown in a mess. I'd always assumed it was something to do with the proximity of the crown to the first baffle or something along those lines.

 

[bluesako]

Very interesting, thank you! I’m inclined to agree it’s the moderator as I shot the rifle for a while before I got the moderator and never had an issue.

i hope you get it sorted, it might be worth getting your moderator checked out by a gunsmith just for piece of mind, i always get my mods fiited by a gunsmith gl bs.

 

[Mike L]

i always get my mods fiited by a gunsmith gl bs.

As a newbie, is this a ‘thing’?, I just screwed my moderator on until it was tight, is there more to it?

 

[User00040]

As a newbie, is this a ‘thing’?, I just screwed my moderator on until it was tight, is there more to it?

Most rifles did not come screwcut until relatively recently.

 

[palo]

I think its the mod causing the fouling.
I had the same problem with my 308 when I used my jet z compact mod.
I just gave it a good cleaning after shooting.