Which one?
There are 2 different M-pro 7 cleaners, one primarily for carbon, but with mild metal disolving abilities (M-Pro 7 gun cleaner), & one primarily for removing jacket fouling, (M-Pro 7 copper remover).
Neither contain ammonia & so both can be left in the bore for long periods without concerns. Because neither has ammonia some don't think its really "cleaning metal" due to the lack of blue/green patches, but that's just a side efffect of ammonia dissolving copper. As the M-Pro 7 uses different chemicals the dissolved metal is black in the patch, but its still copper solution, it just isn't green/blue copper solution!
The idea is that metal & carbon form a kind of layer cake of deposits. M-Pro 7's trick is to alternate the cleaner with the copper solvent to get at the next layer till its clean. Both are drain/septic safe & organic so the smell is minimal & you can clean your brushes & jags with tap water!
They also market their own brand of gun oil, but I haven't tried it yet.