351 Power,
Not all of the P14's have the hole under the rear sight, I have a Remington P14 without the hole. Another P14 that had the hole which I left unfilled, A 1917 with the hole that I took a great deal of time fitting a piece of steel in the hole and the epoxying it in place. the hole didn't bother me enough to fill it after all the time I spent on filling the hole on the 1917.
I contour the rear bridge to use the Model 70 one piece base by Leupold or Redfield. It is much easier if the barrel is not on the action when doing this.
1. You need a level place to set the receiver on when contouring the rear bridge to check for level. I use a 360 degree swivel vice that I set to level.
2. Grind on the rear bridge, then place the receiver on the level surface, place the scope mount on the receiver, place a short level on the top of the mount, keep checking and grinding on the rear bridge of the receiver until the level shows that the base is level.
3. once you are level, drill and tap. On these I modify the base to use 8-40 vs the supplied 6-48 screws since they hold up much better under recoil with the calibers I used on these actions, .338, 375, .458 for example
Be careful and don't grind too much off at one time, if you grind too much you will have to shim the rear of the base on the bridge. Don't do any grinding on the front receiver ring period.
I have installed two piece bases on a P14 just for my satisfaction and I got a perfect job, but the one piece base is much easier to install. Since I do this for a hobby I don't have to worry about paying $60 per hour for the work.
Tools needed, Hacksaw for rough shapeing, grinder with course stone, polishing wheel for final finish. Actually you can do it with a grinder alone, and hand files.
Note: If you use two piece bases for any heavy recoiling round like the .375 and .458, absolutely use the 8-40 screws to hold the bases on the receiver, the 6-48 screws are just not up to the task, particularly if you use some of the heavier scopes on the market today. The heavier the scope the more stress on the base, screws and rings. As I said earlier I perfer the 8-40 screws on all the P14 or 1917's since these are actions for the big boomers.