Here is a table of the minimum and maximum primer pocket and primer dimensions. Surprisingly this data isn't too easy to find, so I have done the research for you. Dimensions in inches.

Primer pocket dimensions and tolerances
Pocket Type Depth Min Depth Max Diameter Min Diameter Max
Small Rifle/Pistol 0.1170 0.1230 0.1730 0.1745
Large Rifle 0.1250 0.1320 0.2085 0.2100
Large Pistol 0.1170 0.1230 0.2085 0.2100
Primer dimensions and tolerances
Primer Type Height Min Height Max Diameter Min Diameter Max
Small Rifle/Pistol 0.1150 0.1250 0.1745 0.1765
Large Rifle 0.1230 0.1330 0.2105 0.2130
Large Pistol 0.1150 0.1250 0.2100 0.2120

It's interesting to note that while small pistol and small rifle primers are exactly the same size, the same is not true of large pistol vs large rifle. I have heard of people substituting small pistol and small rifle primers during desperate times, but one should always be careful of pressure increases and the potential for pierced primers if one resorts to such extreme measures. It's always best to use components as they were intended.

Another notable fact is the overlap in tolerances. The largest primer is taller than the shallowest pocket, and the loosest in-spec pocket is the same size as the smallest in-spec primer. It's for these reasons that we sometimes run into so much frustration with certain brands of brass and primers.

Stop guessing about your primer pockets, know for sure with the Swage Gage for small and large primer pockets.