Simple question---Can a gun stock size blank be too heavy? I have a blank that is 4" x 6-1/2" x 52" and it weighs 30.5 pounds.

Sounds more like a fence post than a stock blank..the thicker it is, the more issues there may be in the drying/curing

Can it be too heavy and still be wood?
No. Will your finished stock be too heavy for you?
Only one way to find out.

If you look at the photos in Custom Rifles I posted of the pre-64 Model 70, the blank I used for that rifle weighed over 26 pounds when I bought it, green. By the time I used it the weight had dropped to just over 11 pounds. How dry is your blank?

That is a big stick of wood. You could calculate the cubic inches and compare the weight/density to other standard stock hardwoods if you are concerned. It's an awful lot of work to shape a stock from it and decide later it's too heavy...

As I read the blank dimensions... it is 4"thick. That would cause extra weight. You say in your ID you are in the PNW. Relative humidity plays a part. Portland, OR kept my wood at 18% even after 10 years of "drying". May I suggest, IF the blank is 4" thick..... you get 1" off the blank in thickness and weigh it again. Great length for a Mannlicher stock!

This blank was cut in the 1930's. There is no written documentation but this blank was given to me from a very good friend who's grandfather
claims it came from the Henry Ford estate.
It should be dry!

Walnut can weigh 35 - 40 lb. cuft
If your blank is rectangle it's about 3/4 of a cuft.

Curious... Assume this is black walnut?

This was labeled Rosewood. It is as dark as any walnut that I have seen. I could post pics if needed.