BeerBorg

So when I was getting my grain for my Mosquito Chaser IPA it calls for 1 lbs of Crystal 40L but the LHBS was out of 40L and suggested that I use 8 oz of Crystal 20L and 8 oz of Crystal 60L to substitute for the 40L. Without much thought I went ahead and did that but I was thinking later does that really equal 40L?

What say the Borg? Also are there other grain substitutions that you have used for grains you needed in a recipe?

I've had this chart bookmarked for years and it's done me well the few times I needed a substitute.
http://www.brew.is/files/malt.html
The attached pdf is also very close to the link above but I think you're ok. I don't know how much base malt you have but if it's a pretty standard amount, those small amounts won't matter.
Brew, ferment, drink and repeat!

20+60 doesn't equal 40, but (20+60)/2 does. And that's really what you're doing here. You're using half as much of each to average out to 40. It's not exact, but it's close.

Color should be about right. Flavor might be slightly different. Does it matter really? Probably not unless your using large amounts.

This is making my head hurt.