I would look at the magazine box and follower, specifically the magazine box ( if installed correctly ? ) this happened to me with a new S2 Vanguard follower was too tight and magazine box was installed incorrectly, the OLD S1 vanguards had a welded mag box which you probably could not install wrong because you can't compress the welded end. The New S2 vanguards from what I've seen do not have a completely welded magazine box and CAN BE COMPRESSED TIGHTER on one end not allowing the magazine follower to depress not allowing a cartridge to install or not allow the full magazine case capacity depending upon where the magazine box is bending inwards. Mine came from the factory that way and of course me being me after taking the rifle back to Sportsman's warehouse where I bought it and showed them the problem also. I took it apart and found the problem of the magazine not installed correctly or sitting flush with the action along with a call to Weatherby for a new follower that was too tight which they sent out a new follower. I bent the non welded magazine box back out a little bit and it fit perfectly flush with the receiver. Mine would also push the 3 rd loaded cartridge when chambering a round up and out of the action which was the first indicator there was a problem. My problem was found after a little careful looking at the situation, for the life of me I don't understand why Weatherby went to a non welded box magazine which can cause problems if not installed correctly and mine came from the factory that way. Maybe Weatherby has corrected the problem or have a better inspection or QA process that I'm not aware of, such as inspected by number 5 or so and so, which would include a functional inspection before shipping out. I don't know if they do that or not, Maybe mine was the one that just slipped by ? I know in my case the rifle functions perfectly today and is one of my favorite rifles if not for someone in the process not installing the magazine box correctly.