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.
| 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 Type | Height Min | Height Max | Diameter Min | Diameter Max |
|---|---|---|---|---|
| Small Rifle/Pistol | 0.1150 | 0.1260 | 0.1745 | 0.1765 |
| Large Rifle | 0.1230 | 0.1360 | 0.2105 | 0.2130 |
| Large Pistol | 0.1150 | 0.1260 | 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.
