Dave,
Kirby did a good job answering your question and I concur with what he said.
I prefer the old style (orginal XP) dogleg bolt handle that has the single shot action. Remington did make a XP-100R which is just a model 7 action with a magazine. For most purposes I like the centergrip stock (H-S or McMillan). I have 3 H-S stocks and have used them the longest. For the big thumpers I believe my preference is McMillan. I should be getting a complete 7mm WSM from H-S at some point. H-S makes their own line of specialty pistols. Kirby reinforced my McMillan stock on my 7mm Dakota. Since the potential of LR is inherent within this post I like the cartridges based off of the 284 Win, WSM's, and of course the Dakota line.
Basically, you are going to lose 200-300 fps in a SP compared to the same chambering in a rifle.
Richard Near (Near Manufacturing) makes a pic base for both the XP-100 and the Savage Striker. I have four of Richard's bases and am very pleased.
My XP-100 chamberings are:
250 Savage AI, 6mm-284, two 6.5-284's (one rear-grip and one center-grip), and the 7mm Dakota. I have other SP's but they different action types.
I use Varget with 100 NBT's on my 250 AI, H-4831 w/115 DTAC's for my 6-284, H-4350 with 140's for my 6.5's, and Retumbo for my 7 Dakota with the 200 grain WC bullet.
SP's are a lot of fun, and add a challenge when hunting/shooting compared to a rifle. Learning to use a LER scopes and find your FOV or a rifle scope and not getting smacked is just one of the things you will come to enjoy. A well built SP has the same accuracy potential as a rifle. Fast shots in the field compared to a rifle are difficult. But you can get going quite quickly prone with a bipod.