Increase in pressure?

[tim_w]

Something to consider. If starting with a fresh bottle/jug of powder, that powder has a particular amount of moisture in it. It weighs a certain amount of weight for a set volume. If that powder looses any moisture the the same weight as before now has more volume. If you're not capping your powder containers tightly or your leaving your powder in the powder hopper it is loosing moisture/weight and the volume of powder in your case is increasing. Return your powder to it's tightly capped container immediately after each loading session.

For that reason I never fill my powder measure full and never leave it out any longer than I am actively using it. Even if I step away for say an hour it gets sealed up. First time I saw a huge variation was top node using RL10x. It can work to your advantage in some instances as it changes the combustion rate. In my 6.8 load I got better vel for a given pressure after I let it dry out for a couple days. But it's the exception.

 

[tim_w]

I'll take a shot at it…along with throat erosion, copper fouling, and fired-cracking. (Not my photo, but a decent depiction)View attachment 399244

I have found carbon rings in front of the case necks when people have trimmed cases to min SAAMI rather than based off their own chamber's neck length dimension. Creates almost a neck crimp into the bullet. Similar to running too long of a neck from lack of trimming. Pop goes the primer.

 

[2buffalo]

Alright guys. Here's a video. Anybody see a carbon ring or anything else out of the ordinary? Other than a dirty barrel?

I don't see a penis either...

 

[Dot_3]

This is where I just cleaned one out. This is right there where the chamber ends and the freebore begins. That's where you're looking. If the carbon ring was still there it would look almost like my little squiggly lines. It would literally be a buildup of carbon running around the circumference of the bore. Can't really be seen without the side view mirrors unless it's really bad. I deal with them regularly. I'm too lazy to reset my trimmer, which I think is part of why I get them.

 

[Dot_3]

Btw: I've never used an abrasive on anything. I use CLR to bust up carbon. I'm conscious about how long it sits and I have not etched anything. It takes some elbow grease, but so do abrasives.

 

[Ucsdryder]

Btw: I've never used an abrasive on anything. I use CLR to bust up carbon. I'm conscious about how long it sits and I have not etched anything. It takes some elbow grease, but so do abrasives.

CLR scares me.

 

[Dot_3]

Abrasives scare me. Lol

 

[slowshot18]

Your borescope really needs the reflectors on the end of it to verify if a carbon ring is present or not.
I way I have removed carbon ring is by using boretech carbon remover (eliminator works too, just not as good). Soak a couple of patches in the carbon remover, bundle them up and shove them in the chamber. Push them in with a jag. They will usually stop around where the lands start. Let them sit for a few hours. Remove with jag from the muzzle to the chamber. Patch out, re-check with scope, and repeat if necessary. Letting the soaked patches stay is the key. I'm leery of any abrasive cleaner as you can do more harm than good.