This should have all the information you need: http://www.homebrewtalk.com/f11/how-...n-needs-123585
. From Bobby M's post on top of page 2 there is also this info:
Each quart of mash tun capacity can handle:
Max grain @ 1.25qt/lb = .6lbs
Total strike .1875 gallons
Total in tun .2435 gallons
FYI, HBT has a pretty good search function. This is one of those questions that gets asked multiple times per day. Nothing wrong with asking, but you can find a lot of the information you need by searching. Good luck.