I'm comparing different budget ARs and I'm really curious whether the M&P15 Sport II's buffer tube is made of 7075 or 6061. I can't see to find the answer anywhere. Does anyone know?

Also, if it is 6061, is it something worth upgrading to 7075, or does it really not matter?

Thanks!

I don't know what S&W uses. It's not something I would worry about. IMO, you should have a spare either way. 7075 is obviously better so get that for a spare.

I've personally only seen one buffer tube destroyed. My buddy rolled his patrol car 3 times. His Bushmaster was riding in a vertical rack. Tube was toast. I replaced the tube and it was back in action. I don't recall what aluminum it was and it wouldn't have mattered.

Oh I see. That's very interesting. Thanks for the reply! As far as spare tubes go. Do they require a spare castle nut and end plate as well, since the original end plate is often staked?

You can reuse the endplate and castle nut, but you should have a spare as well. A spare everything, IMO. These are fairly inexpensive parts to have on hand.

Very true. Awesome, thanks for the advice man!