The rifle is a .303. I do have qualms about shooting it, but only because I am a collector and it is in nearly new condition. I'm not a big fan of shooting nearly new 100 year old rifles when lesser specimens can be shot. The Ross M-10/MkIII action is one of the strongest ever made. To compare it to a modern action, with its multiple locking lugs it most closely resembles the Weatherby MKV action. Around 1915, E. Crossman did some destruction type testing on Ross, Mauser and other actions. One method of attempted destruction testing was to fill the Ross case (.280 Ross case - about the same case capacity as the 7mm magnum) with pistol powder. He was meticulous in filling the case, tamping it down to pack more powder in etc. until it was as full as he could get it. He then loaded a bullet and also GREASED the case. He could not get the action to blow (not the case with the other actions he tested). So, it is ironic that there is persisent mythology about the Ross action being weak. With regard to the bolt blowing out, this is specific to the M-10/MkIII action. It was primarily reported in the military service of the MKIII - not any of the previous Ross Sporters or military rifles. It was reported that if you disassembled the bolt and then reassembled it incorrectly, with enough force you could push it forward into the action. As the bolt was reassembled incorrectly, it would not engage the locking lugs. Supposedly, a chambered cartridge could be fired and as the bolt locking lugs were not engaged, the bolt would shoot straight back (into the shooter's face). This is not something I fear at all. I say this because it is very easy to know if your bolt is engaging or not. If you watch closely as you push the bolt fully forward, you can easily see that it is full closing and the locks lugs are turning. By the way, nearly all Ross rifles were made in Quebec, Canada. Some early ones were made in the United States, or at least the receivers were. I can post some pictures of these as well. The intended use of the sporters was big game hunting. The .280 Ross caliber, of Charles Ross' design of course, was intended to shoot point blank to about 600 yards without sight adjustment. I have talked to several hunters who have hunted with .280 Scotch Deerstalkers and they report phenomenal accuracy and performance. As I have stated, this cartridge was way ahead of its time. Here were are, 100+ years later and I can't think of a cartridge of close bore size that is a significant improvement.
