I would love one in .303 myself...... I've only seen one in .303 in a SxS configuration. It was an early 1900s Holland and Holland Royal double, side lock. I couldn't afford it at the time and even now, it would seriously strain my finances to buy it if it was still available, which unfortunately it isn't. There is one new .303 V-C but in over/under configuration locally here for sale, listed as a special anniversary edition and selling at less than 1/3 the price of the H&H referenced above. If it had been in a SxS configuration, it would be adorning my gun vault as I type. I am uninterested in O/U configuration but I expect I will one day stumble into a SxS.

I think the 9.3x74R is a great caliber. The bullets weigh quite a bit more than a .303 and are hurtled along at approx the same velocity as the .303 174 grain bullets, around 2400 fps. Recoil is more, but it can do more if game weight scales upward. The 9.3x74R is very common in many countries in Europe and Africa, but at least in Canada being an old British colony, the .303 is much more common, although not as much so as it once was since the Canadian military moved away from that caliber sometime after the 1950s Korean War.

When I mount a scope on my 9.3x74R Merkel, I can consistently ring the 12" steel gong at 300 yards at the outdoor range I frequent by holding my point of aim on the top of the gong. My longest hunting shot was a lasered 265 yards across a field where I shot a whitetail deer in the brisket and the shot exited the rear quarter using a Barnes 250 grain TSX.

I absolutely love the .303 as well and wouldn't feel undergunned for shooting out to a good 250 yards for most non dangerous game. The one really big thing for me with the .303 is the light recoil..... It is a total joy to shoot, and I could easily see a light well regulated double in .303 quickly becoming a favourite for me.

My thought would be to keep your eyes open and buy a nice rifle that fits you well as the first consideration and maybe be less particular about the caliber. Please do keep in mind that double rifles are funny contraptions that can be cantankerous when it comes to finding a load that regulates well. The 9.3x74R cartridge is most commonly loaded and sold with 286 grain bullets, but my rifle only likes the 250 grain bullets. I had a devil of a time stumbling on the right combinaton that my gun loved. It is not my most expensive double but it is hands down the most accurate and best regulated double that I own now that I have discovered the load it likes. I only mention this because one may need to play with bullets weight, powder type, charge weight, seating depth, and a whole bunch of other reloading trickery to find the magic load. Broader component choice and selection provides more possibilities. Also of note, my factory test target showed a single hole at 50 metres for both barrels using 286 grain RWS ammunition which I haven't managed to find here. Funny it was that when hand loading, I could NOT get any 286 grain bullet to regulate period, yet those Barnes 250s worked miraculously. I do believe there is a pretty wide selection of .303 bullets and weights to select from. Also, do yourself a favour and stick with a rimmed cartridge in a double. Rimless cartridges will and do work well in doubles but it is easier to work with rimmed cartridges in doubles.