Different powders while load testing.....

[RottenII]

Just curious if there is something to it. I thought I read a while back that when load testing and switching to a load with a different powder that it can affect the first shot after the switch. Never made any sense to me but yesterday I was doing some load testing with .308 at 300yards and I switched from my Varget loads to some using RE15. When going back to Varget the first shot was way right and then the rest settled down and grouped fine. I can usually call one when its that far off. Coincidence or has anyone else had this happen?

 

[BoydAllen]

Different powders lay down different fouling in the bore. I think that that is the reason for what you are seeing. If I were going to do an important test that involved more than one powder, I would do a light cleaning between powders and allow some shots to refoul.

 

[RottenII]

Thanks Boyd. Wasn't sure if it was just internet myth or something I dreamed up :

 

[CatShooter]

I would think that it would be most prominent when switching loads with powders that have very different chemestry - like Varget and RL-15 (or a ball powder).

When I shoot similar powders in load testing, like H-322, BenchMark, and 8208, I do not see any of this.

 

[RottenII]

I checked my targets and there was no issue going from Varget TO RE15...but the otherway around was sure noticeable. Usually if I really shank a shot like that I know as soon as it leaves but they all felt "good".