Mating Bushmaster Carbon-15 lower and M4 non-carbon upper question

Any issues in using a Bushmaster Carbon-15 lower with a Bushmaster M4 non-carbon upper? Use for light range duty - 500 rounds per year.
Thanks, Bill

Can't imagine there'd be anything wrong with that, the lower just holds some parts together, it isn't a very high-stress piece of equipment.

Thanks NG VI - I had assumed it would be ok and thanks for the confirmatory input.

Regards, Bill

I saw one of these Carbon 15 rifles today for the first time. Really impressed with how light it is.

Anybody here actually put a different upper on the carbon 15? I am specifically thinking a .300 blackout upper for hunting season.

I have a top load carbon 15. Is it ok to simply change the lower to modify to mag feed?
I apologize for my ignorance, newbie.

First to address my own question. I called bushmaster they said no problem it's all built to the same space other than the barrel nut.

@numbuts: I dont know of a top load model you might be thinking if something different.

Newbie; could that be a kalifornistan version with a bullit button?