The Gun Counter

I see lots of posts and articles about building a rifle for a specific caliber. But I've always wondered - within a certain range of calibers, why not build one good lower, then have different uppers for those other calibers?

Which are the calibers you do that with? I'm assuming magazine differences would affect that to a degree?

For example, if you have a 5.56 gun, can you just plop on a 9MM upper and use different magazines?

Fire away!

Lowers and parts are pretty cheap these days.... If you have something like a registered SBR lower that you want to have multiple uppers for it makes more sense.

Me, I have one complete upper and multiple lowers including two SBRs.

Weetabix wrote:I see lots of posts and articles about building a rifle for a specific caliber. But I've always wondered - within a certain range of calibers, why not build one good lower, then have different uppers for those other calibers?

Which are the calibers you do that with? I'm assuming magazine differences would affect that to a degree?

There are dozens of calibers you can do it with. But like NPR stated, in the days of $200 complete lowers, it's not really the best way to go.

I too have dedicated lowers for all my uppers, but theoretically I could use the same lower for all by 5.56, 458 SOCOM and 300 Blackout uppers -- they use the same magazines.