This may be a dumb question, but is there anything keeping me from putting a 4" slide ona 5" XD40. The frames look the same, but I don't have one to compare. Would be nice to have a slightly smaller weapon when out and about.
I don't know exactly what's different but it's not designed to be able to do that. I'm sure it won't just magically work. If it did, Springfield Armory would be marketing it as such and jacking up the prices.
Sig has a gun like that now with interchangeable barrels, slides, and grips.