Found Source: 3/8" 7075 Hex

[Cory]

Originally Posted by Gray Adams

We bought some 3/8" hex 6061 this season, and other than the fact that it was a poor material choice, it was 10 thou oversize. We couldn't use it at all.

If you find out the tolerances on the stock, it would be a whole lot more appealing.

It is not .010.

If it's from Fry Steel, who was the previous common supplier in CA, it's more like +.002/-0. Sometimes it fits in hexes great for us, sometimes it requires a light hit with the scotchbrite belt.