A former co-worker of my wife has asked me to help put a value on her late husband's cartridge collection. I won't be able to look at the collection until I go back home pheasant hunting in about a month and don't know how extensive the collection is. Are there any references that would help determine value?

If it is more than a shoebox filled with old bullets then you probably need to track down a member of the International Ammunition Association in your area , and seek informed advice from him/her. Ammo collecting is a specialized field , and if you dont know what you have to start with you wont realize its true value.
Having said that , 90% of the value will be in 10% of the cartridges , the rest you will need to give away as a package deal.

Best of luck.

Well said Muzza. I can't agree more.

Sendaro

Yes,sad though it may be,most others do not not treasure our collections as we do.When left to widows the problem increases greatly. As an example: I have a 1964 corvette painted pink that I want $30,000 for it. Now it might be worth that to me but now we have to find another that has that same interests + be in the price range. Basic story is 'what the market will bear'No one wants to lose a potential fortune. I know a friend that did an estate sale a few years back,come to find out that their china set was worth over $100.00 a plate,their silver service was beyond belief...anyway you get my point.I don't think that a cartridge collection would be in the same realm however with collectors one never knows.