Phil, mainly I base the "front-heavy" comment on my own experience and reading any number of similar comments over the years. Look at most any target rifle made to be fired off-hand.

http://mlhunter.com/prod01_rifleguide1.htm paragraph on overall length.

http://www.muzzleblasts.com/vol4no1/articles/mbo41-1.html

Just a couple of quick references google turned up.

My neighbor bought a cheap little CVA sidelock (Bobcat I think) .50 caliber. The rifle was incredibly light but the balance point was too far forward. Isuspected it was going to kick like a mule with any serious load and his first shooting session confirmed that suspiscion. So I took his buttpad off and filled the hollow stock with gray packing foam and 2 lbs of sinker lead, using strategic SWAG positioning. The rifle then balanced more like a modern piece and hehas told me thefelt recoil was greatly reduced.