N-140 Decoppering Agent and Clean bore shots?

[Stumpy1]

Hi All,

Myself and a couple others are seeing something with the new formulation of N-140 and clean/cold bore shots that has me scratching my head.

Details:
223 rem
85.5 Bergers
CCI450 primers
30" Bartlein 7 twist 5R barrel (new, with ~450 rounds on it now)

With a clean cold bore, the first half dozen or more shots are literally all over the place, like nothing I have seen before. Once I get 6-10 shots downrange, the rifle shoots just fine, and then in subsequent matches (cold bore, but not clean), it is OK again -first shots on call.

When cleaning, I notice what I suspect is the decoppering agent throughout the entire bore. My suspicion is that until the decoppering agent is evenly distributed through the bore, it is affecting the group.

I intend to try a known good load of H4895 in that barrel (clean of course) but was wondering if anyone else has seen something similar.

Thanks!

Frank

 

[Jdne5b]

Are you starting with a clean\bare metal dry barrel?

I've been using spray graphite after a deep clean. Cold bore shots are very close, inside half moa of the following shots. N140 and N150.

 

[fatelvis]

I suspect is is like using CFE223 or RL16, you need to "lay down" the copper preventing layer before shooting for record. The beauty of the layer is it allows much more shooting between cleaning. I allow >10 shots to season the bore before shooing for score. I don't advise using it if you clean your bore religiously after each match. Good shootin to ya!

 

[Laurie]

When I shot 223 in F/TR with 90s a lot (two different New Zealand True-Flite 1 in 7 Heavy Palmas and a Bartlein 1 in 7.5), that behaviour was the norm and I'd need at least four foulers, preferably five. That was with Alliant Re15 in the True-Flites and Viht N150 in the Bartlein, definitely not 'copper erasers' back then. (N150 is now, though.)

I think it just goes with the [223 heavy bullet] territory with some barrels.