Model 121 won't lock up

[rdoane]

Have a .22 cal Model 121 pump with ww stamped on the barrel and # 146417 apparently made in 1949 or 50.
I lost the bolt assembly and purchased used bolt assy with a round firing pin from Numrich.
The new (to me) bolt will not lock up.
Do I have the wrong bolt for my rifle or is their another problem? I read some tips about removing some metal from the carrier but am reluctant to do that for fear of ruining that part.
Any help would be greatly appreciated.
Rog

[admin]

No it's probably not the wrong bolt but all I'd risk saying is you need a gunsmith, I know it's not a big help but I believe that is really the right answer vs you fixing it with suggestions

[rdoane]

Thank you for the advice. I will take it to a gunsmith.
Rog