I'm not 100% sure what you are referring to, but I think the “splices” are there to allow mounting a grenade launcher.
So, why do you think your rifle is too short? You could try replacing the butt pad for another inch or so of length. If you need more than that you may need another stock.
A major source of objection to a free economy is precisely that it ... gives people what they want instead of what a particular group thinks they ought to want. Underlying most arguments against the free market is a lack of belief in freedom itself.
- Milton Friedman