Let him know you're interested, _if_ the gun is working properly. Ask him if he will let you shoot it, and meet him at the range whenever it's convenient for both of you. First, settle on a price, assuming you buy the gun. Make the purchase contingent on the gun working- no workee, no buyee.
Bring a few different brands/loads of ammo in the proper guage/size- field/trap loads, 2 3/4 inches. Bring your cleaning gear, INCLUDING a new 10/12 ga. bronze brush and some 4/0 (0000) steel wool. Bring your favorite gun oil too. Bring an old towel, rug or mat to lay out parts on while working on the gun, there will be no really tiny parts but you want to keep everything clean.
Ask him to show you the process to field strip the gun, if you don't know how. Alternately, if you are familiar with the gun, and know how to fieldstrip it, ask to use it at the range by yourself. Inspect the ejector after you remove the barrel, look for wear, chips or breakage. The ejector on my 1970s Mohawk 48 only protrudes from the barrel extension about 1/16 of an inch or so, it is square shouldered at the top and along the front and bevelled at the bottom.
When the gun is field stripped, clean the chamber using one section of cleaning rod, with the new bore brush wrapped in some 4/0 steel wool and dampened with whatever bore cleaner/solvent you use. The bore should not be an issue, you can inspect it when you inspect the chamber but you want to concentrate on cleaning the chamber. Run the steel wool wrapped brush back and forth several times in the chamber, clean it out with a rag and inspect. If it still looks rough, do it some more.
Also clean the outside of the magazine tube with solvent and a rag. If there is surface rust (unlikely, but I have seen it) the 4/0 steel wool, dampened with oil or solvent, will remove it without damaging the underlying metal. Make sure you get 0000 grade steel wool, tho. Lubricate the outside of the magazine tube lightly. 'Turn' the recoil spring through your rag to clean it also.
Make sure all the recoil parts are in the proper position when putting the gun back together and that the friction piece is not chipped or gouged so that it exerts too much pressure. After the gun is reassembled, lubricate the area behind the extractor where it is contacted by the extractor plunger. You want to get some oil back to the extractor spring and free up any binding in these parts caused by congealed lubricant/dust etc. Don't let the bolt slam closed on a long recoil action gun that is not chambering a shell, especially when the barrel is removed- that can damage parts.
It could be there are problems with the trigger plate assembly that will affect how the gun runs, and it could be the bolt return spring/plunger/tube that extends out the back of the receiver and into the stock has problems. Sometimes one of the arms from the back of the bolt to this plunger will break too. That can be seen if the trigger plate is removed from the gun and the bolt closed slowly, that will give you a chance to put a drop of oil back into the plunger tube also. While the trigger plate assembly is out, inspect it for proper function also. Do not release the safety and pull the trigger when the trigger plate assembly is out of the gun- it can spontaneously disassemble itself or break parts. Make sure nothing in the trigger plate assembly is interfering unduly with the bolt- it is of course the bolt that re-cocks the hammer when the gun cycles, so there is contact.
With the gun properly cleaned and lubricated and assembled with all parts in the proper relationship it will fire and function properly if there are no mechanical problems. If you know someone who is familiar with the design you might wish to consult them during or before this process. If the gun still fails to eject after a good cleaning and after using a variety of ammo, you will likely want to call off the sale. Long recoil operated guns run with a number of counterbalancing forces and spring pressures and a lot of things can interfere with their proper functioning.
Most often these things are lack of cleaning/maintenance, improper assembly for the loads being used and 'wrong' ammo. But any mechanical device can fail due to broken or worn parts, and it can sometimes be expensive to get them running again.
But if you can get this one running with a simple cleaning and/or substitution of different ammo, you'll have a good gun- the weight-forward aspect of the design makes it swing really well.
hth,
lpl/nc