It’s the factory one and that’s how they are supposed to fit. They fit further down on m4geries because they have a longer barrel than the real deal because of NFA so the distance from the lug to the muzzle is off.
Looks wise the m9 is boss. I think the m7 is a better actual bayonet. M7 is full tang thinner blade so it’s easier to to poke in things and is more lively in the hand unmounted in my opinion. Also many users of m7 pattern bayonets didn’t follow the US Army in replacing it with the m9. I think the air force stayed m7 the Marines went with their own thing and I want to say Israel stayed m7 but I haven’t done much research on that and could be wrong.
The m9 is not full tang and it is very wide. I think the movie Rambo inspired it’s design and adoption
. It’s heavier and it’s scabbards bulkier. On the plus side it’s scabbard has a built in spot for a sharpening stone and has a wire
cutter built in. I never used the wire cutter while I was an infantryman (we only checked them out once maybe twice from the arms room in 4 years they have a reputation of not being joe proof with them breaking when used for prying because of its design and bayonets aren’t that useful) some NCOs I served with had however and said the bayonet / scabbard wire cutters were trash that barely worked.
My m7 is beat up with lots of knicks on the blade I’m guessing the joes who served with it chopped all sorts of stupid shit with it and I’d like to get a more pristine example someday so it’s definitely my favorite out of the two.