Handlebar size and bar ends

[Razorburns]

Totally confused here.

Bought some new handlebars and bar-ends. 7/8 inch aluminum bars, appropriately sided bar-ends. Good so far. Pretty stoked to go out today and install them.

The only problem is: While the outside diameter of the bars is in fact 7/8 inch, the INSIDE diameter is roughly 1/2. The bar ends totally don't fit inside. I have 1/2 rubber expansion plugs I purchased at the hardware store that will work.... but the bar ends have a shorty flange on the inner edge that is supposed to go in the end of the handlebars.... and it simply will not.

Did I get the wrong sized bars, the wrong sized bar-ends or maybe do aluminum bars have thicker walls than steel? I'm kind of assuming that the bar-ends are intended to fit into STEEL 7/8 bars.

Any insight is much appreciated for this confused newbee.