I'm thinking about buying a ruger #1 in 416 rigby and was wondering if anyone here has one. I would like to know how well it shoots at 100yds and how bad the recoil is with a factory rifle with no mods.

First you should put a REAL recoil pad on it, not that piece of petrified rubber that Ruger calls a recoil pad.
As for recoil, I used to have a No. 1 in .458 and it was more unpleasent to shoot than any other .458 I have owned. I have owned custom, Mark X, Winchester, Ruger and Savage brands.
It might be the way that the stock fits me, but my No. 1 in .338 is about it as far as they go before I don't enjoy shooting them.

Friend of mine has a NO.1 in 416Rigby and no problem with accuracy. I have one in 458Lott and we both solved the recoil problem or at least made it tolerable by buying one of the Ruger(Galco) leather velcro butt pads. They work quite good and actually look fine plus no fitting of pad required. You can buy them direct from Ruger's "e store."

I had #1's in .416 and .458, but simply found them too uncomfortable to shoot. The #1 is one of my favourite rifles but I find that the stock design is very poor for transmitting felt recoil. My #1 in .375H&H kicks much worse than a CZ in .458Lott, at least to my shoulder.

Accuracy is usually very good with mine, and a little tweaking of the fore-end is easy to do if necessary.

I have both a 416 Rigby and 458 Mag. Ruger No.1
As been stated in a previous post the recoil pad is way too hard. I fitted a Pachmayr Decelerator pad and it made a world of difference. With 400gr. bullets it is very comfortable to fire now. The 458 is a Liberty model so I don't want to change the pad, so I use a Past Magnum shoulder pad for bench work. Offhand it is not bad to fire.