Evidently you know little about the Carcanos available at that time by mail order. Most were new, made at Benicia aresenal by...Beretta.....the rifles are smooth in action and fast on repeat shots. Color case hardened bolts and blue steeled recievers. The raceway for the bolt is simple and easy to use. The cock-on-close makes fast follow-up shots easy.
The 6.5 Carcano is a light recoiling medium range cartridge designed for one purpose. Penetration at medium ranges. (200-350 yards)
Could Oswald fire 3 shots at a max distance of 600 FEET in what has been determined to be approx. 8 seconds? Of course.
Wearing this contraption for his bad back only held him upright. The reaction you see is the interuption of the muscles needed to stay erect using this thing. Notice in every picture/film Kennedy is leaning forward in the seat as the motorcade rolls along.
Actually the Carcano is one of the worst military rifles ever. They are generally fairly roughly made. I have owned several of them.
Having said that, they are still an effective rifle, fully capable of doing the job.
Now all these experts who keep saying Oswald was a real sharpshooter are all wet. He barely qualified and I think they gave him the designation of marksman or maybe sharpshooter, I can't recall off hand, which is a bit of a misnomer as it was the lowest grade the Marines gave for someone who qualified. I have read more than once that he failed to qualify on his first attempt, tho I don't know if that is true since so much misinformation is out there.
Now shooting is something I have done all my life and it is one of the few things I really know. Yes, Oswald's shots were possible but really difficult even for a good shot. The fact that it could have been done is enough to make it possible tho. The fact that it was difficult is enough to make one suspicious.