What do you think about building a 5.45x39?

[refryguy]

I have the M&P15R which is 5.45, its a great gun. Problem is that a lot of the rounds, especially the cheap ones are highly corrosive. I don't know anything about reloads so you would know if you'd have that problem with reloads more than me.

[5.45x39]

I like it. I've only shot corrosive ammo in it so far, and cleaning really isn't that tough. It will pay for itself pretty quickly when you consider the price difference between 5.56 and 5.45.