There are several (5) in our hunt camp. The very, very most common calibre is .308. If it is good condition, they commonly sell for between 4 and 5 hundred. They were chambered in other short calibres as mentioned above and command much higher prices accordingly.
As mentioned above be aware there was a firing pin recall on the 100's about 15yrs ago. Some of the model years had steel gas system components which were very prone to rusting. They are tricky to disassemble, and even trickier to reassemble especially if you have taken the bolt assemble completely apart. Watch very carefully the orientation of the bolt parts when you are taking it apart.
Make very sure you are holding on to trigger assembly when you push out the pin in the slide assembly or you will have springs and subsequent parts all over the room.
You will know if you got it wrong as you either won't get it together at all,or it will go to gether and the bolt won't slide back.
The clips sell for whatever the market will bear 50 to 100 bucks apiece!!
They are an excellant gun. But like any auto loader are more prone to jamming. In the case of the 100 in my 44 yrs of experience with one keep it very clean which includes the clips. If you shoot it, clean it that night, the gas system will condensate in colder weather and rust. Clean the crap out of your clips and wipe off your shells and lightly oil them everynight during the hunt.
Every single time I have had issues with mine it has been dirty dry shells hanging up in the chamber and not letting the bolt head completely turn home. When you load it always let the bolt slam shut to make sure that bolt head turns. If you let it down gentle as to not scare away the deer 9 times out of 10 that bolt head won't turn over and she won't fire when Mr.Buck steps out for a look at you. "Ask me how I know this"!! So wiping down your shells every morning with an slightly oily rag greatly reduces this issue.
My Dad bought mine new in 1960 and she is still going strong.
Getting a little off topic here but I thought I would give you the whole speil.