I did it my way, a lot cheaper. Here is my 7x57 Mauser I built more than 20 years ago. A 1912 dated commercial B Mauser on an intermediate action fell into my hands. As the barrel was completely rusted out, I had it rebarreled to the original caliber. As at that time I did not like the early Mauser factory stock shape and did not want to damage it, Istored it and the original open tangent sights away. I made this using stock from a cheap preshaped/inletted one, extensively reshaped by me without a useless cheekpiece , only to my then taste and fit. The pg cap is steel and the foreend tip buffalo horn. The barrel is 21", weight without the prewar Zeiss Zielsechs scope 7.16 lbs = 3.25 kg. The original stock shown below. It is not a Rigby, but built on the same action.

My 9.3x62 once was a 1938 vintage type B Mauser that was rebarreled from 8x60 before it came to me abot 12 years ago. The quite heavy barrel by Haemmerli is 24.5". The original stock, shown below, is ok and in very good shape. At that time a gunsmith friend gave me a preshaped/inletted Mauser stock that had turned out to show too little figure for his high-grade custom rifles after machining. I decided to make it into an using/knockabout stock to save the original one from wear and tear. Admittedly, I shaped it somewhat after a .350 Rigby in my gunsmith's friend collection, sans cheekpiece too. The scope is a 1.5-6x Hensoldt Diavari, the peep sight an original Rigby. Weight is 8.42 lbs = 3.82kg. Though it is not a .350 Rigby on a Mauser Magnum action, using a 225gr bullet at 2625 fps, but merely a 9.3x62 on a standard length Mauser action, both hunter and animal will be hard-pressed to notice a difference if it is loaded with a 232gr bullet at 2650fps.