They are sized for the different calliburs but I don't know if any of them are the same ie 30-30 and 32 special, I do know there was quite a gap when I tried to use a really nice piece of wood off a 45-70 on a 35 rem 336. Hopefully someone else can jump in with more wisdom on this one.
Well I'm looking for a walnut forearm for a Model 375 Marlin, and was just thinking if they were different for all the different calibers. Or are these forearms available? The one I have works but the wood is all broke up where the forarm cap meets Thanks for your reply !
A forestock for a 30-30, and 35rem are the same barrel taper configuration and will fit the 375.
The barrel config gets fatter with the 444 45-70 & 450 due to the increased bore diameter.
I suggest you call Gun Service at Marlin and tell them what model rifle you have and they will help you. I don't know the price, but it shouldn't be much. be sure to tell them if yours is a barrel band or capped forestock.
Another place you can try is Brownell's and Gun Parts Inc in West hurley N.Y.
Hope this helps.