6br chamber length problem

[gambleone]

I have 6br rem 700 trued action with a bushing job done by Greg T. Seems
the last few times I load for it I have to keep trimming the length back.
I have always trimmed to between 1.555 & 1.560. I trimmed back to 1.555
& chambered it & was tight with bur marks on the edge where it is hitting.
I trimmed it back to 1.540 & it still hits???
Can anyone shed some light on this?

 

[Ggmac]

Is it chambered for 6BR REM or 6 BR norma

 

[gambleone]

6br norma

 

[queen_stick]

carbon ring maybe?

 

[gambleone]

'm going to try & check, although I don't have a borescope.

 

[queen_stick]

both of my 6BR's build up carbon pretty quick with dirty powders (RL15) ... definitely worth checking it out.

I started adding another step to my cleaning process (when I do heavy cleaning every 250 rds or so). Use a 38 cal brush in a drill, with JB Bore paste, and spin it in the neck of the chamber. If there's a carbon ring in there, you'll have to hit it pretty good to knock it out. Not everyone agrees with this approach, just giving you info on what works for me.

carbon ring may not be your problem either... just the first thing that popped in my mind when you noticed a chamber that's oddly short.

 

[gambleone]

I used a thin plastic straw & put it in at an angle & just before the end of the chamber I
felt a rough spot all the way around. I guess it is a carbon ring. I will try what you said queen_stick. I was using RL-15 also.
Thank you, Greg

 

[gambleone]

Well, I used jb paste with a 32 cal brush in the neck area with a drill &
the carbon ring is still there. I read where some use 0000 steel wool on a
6mm brush. Anyone heard of this?

 

[queen_stick]

hopefully someone with more experience chimes in here, who can confirm that what you're experiencing is actually a carbon ring. (I still think it is, but I could be wrong).

You can try chemicals... get a well known carbon remover, plug the chamber with a plug (sinclair sells plugs for this application), then fill up the chamber (from the muzzle) with solvent... let it sit for a couple of days. Then get in there and hammer it again.

Some guys actually use a reamer to clean up the chamber... It has to be the reamer that cut your chamber (or spec'd the same), and at the very least, you should have reamer stop so you don't cut in too far. This would be "last resort" of course...

When I first ran into a carbon ring (very similar conditions to what you're describing, also in 6BR), it took me a while to get it out. I read on this forum, that this problem is often overlooked, and spinning a brush in the neck (with solvent) every time you clean, is the only way to prevent it from building up to a "stubborn mess". Cleaning procedures are like religion, so not everybody agrees with this. It makes sense to me, and I haven't had any problems since I started scrubbing the chamber neck at each cleaning, so I'm gonna stick with it

Here's a thought... cast the chamber with cerrosafe.
I have never personally done this, so I can't really give any pointers/advice on the process. I also don't know if this would be a good way to determine if you have a big ole carbon ring in there. just search youtube or google for 'cerrosafe,' and you'll see plenty of instructive videos.

definitely keep us posted on what you find/do...

 

[gambleone]

I got it out. I wasn't going far enough in to the neck.
I will start cleaning this area better now!
Gotta try & prevent this somehow.
Thanks queen_stick.

 

[queen_stick]

good deal! Glad I could help.

Keep that 38cal brush with your 6mm cleaning stuff
(or whatever brush fits nicely into the neck of you chamber)

 

[lpreddick]

a chamber length space gauge (sinclair sells them) will measure the length of the chamber and subtracting the ease length will give you how much length of the neck portion of the chamber that will form a carbon ring. the shorter this space, the lesser the ring. over trimming of brass can be avoided by knowing this gap. before using you must get all the carbon ring out as the ring could give a false measurement.