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Topic: 6mm CM Barrel Replacement (Read 702 times) previous topic - next topic

6mm CM Barrel Replacement

I had just over 1100 rounds down the Shilen 6mm CM barrel.  It was starting to not shoot well so I thought I better look at the throat and the lands.  There are a couple shots of the area just beyond the neck juncture and a couple of what the lands look like.  I think this is the worst barrel that I've been responsible for creating.  I did a lot of load development with this barrel as it was the first 6CM that I shot.  I hope to get a more productive life out of the next one.
Bob
If everything seems under control......you're just not going fast enough

Re: 6mm CM Barrel Replacement

Reply #1
Looks kinda nasty. It would be interesting to see some pics of those same areas after all of the carbon was scrubbed out.

Re: 6mm CM Barrel Replacement

Reply #2
Looks kinda nasty. It would be interesting to see some pics of those same areas after all of the carbon was scrubbed out.
 
Jerry, I saw the carbon as well.  I didn't do a thorough cleaning the last time since I was not expecting to keep the barrel in service.  I did a quick pass to get the gross stuff out.  But if you think it would be worth it and may indicate that the barrel is still serviceable, then I'm willing to invest the time and complete the cleaning.  What really concerned me was how washed out the lands were...they looked in pretty back shape.  But once you got a bit past the start, the rifling looked in pretty good shape.
Bob
If everything seems under control......you're just not going fast enough

Re: 6mm CM Barrel Replacement

Reply #3
Pm sent..
Grant

Re: 6mm CM Barrel Replacement

Reply #4

Jerry, I saw the carbon as well.  I didn't do a thorough cleaning the last time since I was not expecting to keep the barrel in service.  I did a quick pass to get the gross stuff out.  But if you think it would be worth it and may indicate that the barrel is still serviceable, then I'm willing to invest the time and complete the cleaning.  What really concerned me was how washed out the lands were...they looked in pretty back shape.  But once you got a bit past the start, the rifling looked in pretty good shape.

You might check with Grant regarding his recent experience.

Re: 6mm CM Barrel Replacement

Reply #5
I'm pretty sure Grant is telling him that now.

Re: 6mm CM Barrel Replacement

Reply #6
We have a plan....stay tuned for an update.   :D
Bob
If everything seems under control......you're just not going fast enough

Re: 6mm CM Barrel Replacement

Reply #7
Need to see the “after” pictures. 😊

Re: 6mm CM Barrel Replacement

Reply #8
Need to see the “after” pictures. 😊
 
 I got up this morning with a mission....once if finished my coffee.

As I had mentioned, the initial pictures were done after a very cursory cleaning.  What I was looking at was all of the firecracking....which looked pretty bad. 

First off, I really appreciate the 'gentle' prodding from Jerry and Grant....nicely done !!

I broke my next steps into two.  First, I was going to go thru my normal regiment of cleaning which is using Boretech  Eliminator, Cooper cleaner and finally the Carbon Remover.  I use a nylon brush with each product and end with a light oiling and final dry patch.  I wanted to see how this looked as a good baseline.  Those pictures are attached to this post.  As you can see, the carbon cleaned up nicely in the neck area but the throat and lands still looked to be in bad shape.

The second step was to follow the guidance provided by Grant to be more aggressive and use Kroil, JB Paste and a bronze brush....and put your back into so to speak.  I did that and did a final wash with Kroil before drying and final light oiling.  Those pictures are shown in the next post.
Bob
If everything seems under control......you're just not going fast enough

Re: 6mm CM Barrel Replacement

Reply #9
Need to see the “after” pictures. 😊
 
 Here are the pictures after the Kroil/JB Paste and elbow grease treatment.  I must say, I was surprised at how well this all cleaned up.  This was accomplished by a combination of full strokes of the brush thru the barrel and back.  I then did a number of short strokes just in the first 8" or so to focus on the throat/lands.

I hope this helps some others in their approach to barrel cleaning.  A couple learnings for me:
1) My normal regiment is probably good for most cleanings
2) Keep an eye on the throat and if it starts looking rough, then a periodic Kroil/JB Paste cycle should be done.

Again, a big thanks to Grant and Jerry for their guidance and coaching......
Bob
If everything seems under control......you're just not going fast enough

Re: 6mm CM Barrel Replacement

Reply #10
 :D
Grant

Re: 6mm CM Barrel Replacement

Reply #11
Looks like a different barrel.  :o
Grant is the "barrel whisperer"

Re: 6mm CM Barrel Replacement

Reply #12
Plan on giving that barrel about 20 rounds before assessing if it will still perform for you. 😊

You may have to adjust your seating depth because you have removed a lot of hard core carbon from the anterior of the lands - probably somewhere in the neighborhood of 5 thousandths.

It will also rebuild that carbon faster then it did when new.

Take  home message: never try to read fire cracking through a layer of carbon.

Re: 6mm CM Barrel Replacement

Reply #13
I've been mostly concerned about the carbon ring and no so much on the lighter carbon build up.  So do you recommend getting all of the carbon out at each cleaning or is some build up OK?
Bob
If everything seems under control......you're just not going fast enough

Re: 6mm CM Barrel Replacement

Reply #14
I agree with jerry.. it will take 15 or 20 rounds for it to come back in.. i didnt have to change my seating depth on the rifles i cleaned like that but they all had a long jump to the lands any way.. i find with a long jump that seating depth is more forgiving than being up there close to the lands..

Just hope it comes back in for ya and shoots good again for a few hundred more rounds..

I do have a question for ya bob.. you have probably told me before but what speed are you running this barrel..
Grant