Nothing really harmful with the excess mess Kleanbore primers bring. Everything there is non-corrosive.

I am not familiar with the small rifle primers strengths per manufacturer. I would only consider such a Vari-flame adapter if I could do the same as 209 primers -- meaning find a weak small rifle primer to use -- then the strongest one for rare occasions where the powder is just wet enough that the weak small rifle primer wont fire the powder -- that way I can put a strong primer in & the rifle will fire.

I do this with 209 primers. I use a weak 209 primer - but I always carry around a few of the strongest/hottest.... ie.... Federal 209A's so I do not have to pull my powder & bullet when it wont fire. On three different occasions, I had to resort to the Federals. They did the job - made the gun fireevery time.