Cause of my over pressure and accuracy in my 25-06 and Creedmoor?

[PLhunter]

Two of my rifles have been showing pressure with previously safe loads. For the 25-06 I assumed case welding as the cases were ultrasonic cleaned and had sat for a couple years. But a bump test on the seater had no resistance. For my creedmoor I have had some difficult bolt lift at what should be safe loads. What was interesting was when I conducted a jump test developing a load. I was using 44.7 grains of Staball and was testing a .05 jump and a .07 jump with Peterson brass and 125 grain badlands. The .07 jump was fine. The .05 jump was extremely difficult bolt lift. I had just put the gun into a new stock and was wondering if action flexing could have played a role. My vote scope arrived today and the first photo is the 25-06 and the second is the creedmoor. The creedmoor had recently been vigorously cleaned as I suspected this issue. Clearly it removed some but not all the carbon in the throat. My 25 year old 30-06 looked brand new.

 

[Tanner]

I’ve had an issue once or twice after cleaning barrels, the first few rounds post cleaning exhibited extremely high pressure with proven, sub max loads. I’m not sure if it was due to moisture still leftover in the chamber or debris that was not removed but significant ejector marks and stiff bolt lift occurred.

Just another great reason to not clean barrels.

 

[PLhunter]

I’ve had an issue once or twice after cleaning barrels, the first few rounds post cleaning exhibited extremely high pressure with proven, sub max loads. I’m not sure if it was due to moisture still leftover in the chamber or debris that was not removed but significant ejector marks and stiff bolt lift occurred.

Just another great reason to not clean barrels.

The high pressure loads were more than a couple rounds in and continued. Guns that develop carbon rings with signs seem to be the exception to that rule.

 

[dieselchessy]

You sure 44.7 grains of Staball (6.5?) is not overpressure with the 125 Badlands? Them are solids with a fairly long bearing surface. The jump and momentum probably help with engraving force.