Switching Ammo in Same Barrel

[JBHorne]

Is it bad to switch ammo varieties in the same barrel?

Here's an example: I want to use cheap surplus 5.56 55gr ammo when plinking out in the desert, but on the range use something like a Black Hills 77gr Sierra MatchKing.

Will running the surplus ammo hurt the barrel or cause pitting, copper fouling, etc. and lessen the accuracy of the MatchKings?

What do you guys think about mixing the suplus with Moly-coated black hills? Should you not use other ammo after shooting with moly?

Some say to pick an ammo, zero it, and never change types after you find that "sweetspot" for your particular rifle. However always shooting the MatchKings would get quite expensive when bump-firing in the desert!!!

Thanks!

[fredj338]

Sure your accuracy will vary & even POI, but bump firing isn't really an accuracy thing is it. I also stay away from mixing moly & reg. Moly bullets like to be shot in a bbl. that has a coating of moly left in it. So shooting moly after jacketed & vis versa results in poor accuracy.

[griz]

I avoid mixing lead and copper jacketed in the same session without cleaning the bore between them. Shooting copper jacketed after lead results in the lead being glazed into the grooves and takes some serious cleaning to get out.

[JBHorne]

Originally Posted by fredj338

Sure your accuracy will vary & even POI, but bump firing isn't really an accuracy thing is it. I also stay away from mixing moly & reg. Moly bullets like to be shot in a bbl. that has a coating of moly left in it. So shooting moly after jacketed & vis versa results in poor accuracy.

My point with bump firing was not necessarily an accuracy issue but a cost factor. I should have put it this way: In the desert where I could care less about accuracy and groups and just want to hit cans and such, I will use the surplus 55gr stuff, but at the range I want ammo thats good for a couple hundred meters.

Originally Posted by griz

I avoid mixing lead and copper jacketed in the same session without cleaning the bore between them. Shooting copper jacketed after lead results in the lead being glazed into the grooves and takes some serious cleaning to get out.

OK, so the best way to do this would be to get the Black Hills non-moly coated. Also make sure I don't mix-match between sessions and give it a thorough cleaning afterwards.

Is there anything else I should know, or would you avoid mixing ammo types period?

Remember that the surplus is 5.56 and the BH is .223. I don't know if that effects the barrel at all, even though it can shoot both.