Barrel slowing down?

[rhovee]

I shot a 1 shot string with progressive charge weights last week. Now I have cleaned the rifle and have three shot groups loaded up from 61.3-62.1 in .3 grain increase. Plan is to shoot at 200 and look for groups landing on same plane horizontal. I just need it to stop raining.

 

[rhovee]

Man it doesn’t matter how much powder I put in the case it doesn’t want to get back to speed. Tested today and 60.2- 60.7 used to be 3070.
61.7-3020
61.9-3013
62.1-3013
62.4-3029

 

[Rsadams]

Your post says 70 degrees and 30 degrees correct..? Are you just seeing the swing in powder sensitivity to temps..? Try useing some foaming bore cleaner with the barrel pointed slightly down and on a paper towel , just let it sit , if blue starts coming out , then it's still copper fouled..

 

[rhovee]

The testing I did today was same temp and conditions as in the fall. The 70-30 was just to test the stability of Reloader 26. Have you seen a barrel do this with excessive copper fouling? I cleaned the barrel very well before this trip using bore tech eliminator brushes wet patches. Did it 3 different days to try and get everything out.

 

[rhovee]

Well I think I figured it out. Doughnuts! I was playing around with fired brass and slid a bullet down and it hits a wall. Tried to push very hard and could barely get it in there. Guess who bought an inside neck reaming tool! Learn something new.

 

[Rustystud]

It has been my experience that barrels do one of two things:
Premium barrels often change little and usually speed up 100 fps within the first hundred rounds, the level out until they beging loosing velocity.
OEM barrels generally loose velocity from the get go.
Of course there are exceptions.