smicha, the R-1 is now available in 338, but so is the Browning BAR. The BAR is tried and true.
It seems that the R-1 can be accurate, but they are finicky as to what they like to shoot well. The BAR can be had with the BOSS system and can be tuned to shoot well with most ammo.
So for the price and the features, I'd probably have to recommend the BAR over the R-1. The only advantage I can see with the R-1 is that it is lighter. But the BAR is not overly heavy either, so it's a find rifle and I know very few men or women that own one that have said anything bad about them.

I do like my R-1, but I am a gunsmith and I have lots of experience with hand loaded ammo, so I was able to find loads that were acceptable accurate in a few hours of load development. For hunters who are not hand loaders, and those that don’t have time or facilities to work up loads, I’d still be force to recommend the Browning over the Benelli.
The BARs can be had in may other calibers. They have the BOSS available, and you can get every version in left hand.. The stocks can be shortened to fit shorter shooters. They are generally accurate. Benelli has some stiff competition from Browning. That’s for sure!