Old load now shows pressure

[Jon Lester]

63.5g of RL22 has been my 7wsm load since GAP sent me the rifle. As of late I am seeing pressure signs,sometimes in a big way. Same scale ,same bullet (180s), same temp and station press, same seat Depth. Yesterday I had to back down to 61.8g to get a consistently easy bolt lift. It is still shooting tiny bug holes.
Any Idea What Gives?

 

[Guest]

Re: Old load now shows pressure

It was long ago but, I've had it happen as well. Went back and pulled 5 rds an found they weighed more than they started life at. Took a new can of powder, weighed out 10 charges and let them set. 10 days later I reweighed them, they all added approx. 1.3 grains which I believe was H2O. Then when they were fired, just that little extra steam pressure put me over the edge. Not enough for a bolt marking or primer issue, but I could tell the diff in bolt lift.

A carbon ring in the throat will do the same thing just as slow.

 

[Jon Lester]

Re: Old load now shows pressure

I pulled 10 and they were on the money.Gonna have to pull apout 180 more.

 

[Guest]

Re: Old load now shows pressure

Have you checked for a carbon ring?

 

[Rthur]

Re: Old load now shows pressure

Is this a new lot of RL 22? I have heard of powder lots being hotter or cooler than your previous lot.

 

[Jon Lester]

Re: Old load now shows pressure

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Gunfighter14e2</div><div class="ubbcode-body">Have you checked for a carbon ring? </div></div>

NO where?

 

[Guest]

Re: Old load now shows pressure

In the neck area, throat, and just in front of it sometimes.

If there's one there, you can remove it with a std bore brush. After you have done your normal cleaning, take a good "Clean" bore brush and soak w/ carbon cleaner or carbon solvent you normally use. As your exiting the chamber and getting into the neck bore an throat twist it around and around as you very slowly go forward into the rifling then just push it normal out the crown end. Next take a clean dry patch an push it threw. If she's dirty or black you have a carbon ring. Elbow grease and about 5-10 minutes of the same will remove it.

 

[Guest]

Re: Old load now shows pressure

A carbon ring can build very slow depending. When you get one building in the case neck area, the normal space the case neck expands during firing for bullet release is lost. This will start adding pressure at a slow rate and is not always felt in the bolt when putting a round in battery.

 

[jeffbird]

Re: Old load now shows pressure

Jon,

I had the exact same thing happen with RL22 in my first 7wsm. As Gunfighter is suggesting, it turned out to be powder residue buildup.

The fix that worked best and easiest for me, although not the quickest, was to push several patches of Hoppe's Benchrest (not Hoppe's regular stuff) through and let it soak overnight. The next day I pushed another patch wrapped around a nylon brush through and it looked like mud coming out there was so much residue. That fixed the problem.

I changed over to MagPro and have not noticed as much of a residue accumulation, but I stay on top of it better now also.

 

[bm11]

Re: Old load now shows pressure

This is very similar tl the issue I am having with my rifle. I think maybe a more intense cleaning is in order.

 

[jonbearman]

Re: Old load now shows pressure

JB Bore paste or iosso or similar will remove the carbon ring also.I have used jb for years and it doesnt hurt the bore.You have to patch out the paste and use some kroil or butch's to push some real wet patches through it to make sure you get all the residual jb out.I also use brakeclean as a final rinse.Dont get it on the stock.