It's sometimes hard to tell which nocks you are using if you are not familiar with the vast variety out there! And when a manufacturer says they make a "small groove" nock, it is not necessarily the same as another manufacturer's "small groove" nock. You will get the best nock fit and arrow flight if your nock is custom fit to your string. The first step is knowing which nock you are using. Here's a guide to help with identification:
Nocks by Type
Pin nocks
Note: Beiter nocks are only shown in their pin nock form above, however Beiter nocks are made in press fit styles as well. From my experience, these nocks are the most consistent in terms of throat size across their many offerings. It should also be noted that the number 1 and 2 nocks are an asymmetrical design while the hunter nocks are symmetrical.
Press fit nocks
Glue on nocks
Over Nocks
Nocks by Throat Size
These are organized by type. Unknown sizes are omitted.
Pin nocks
Press fit nocks
Glue on nocks
Over nocks
Throat measurement
When it comes to string fit, the most important part of the nock is the throat size. Many manufacturers list this size in their packaging or marketing materials. These sizes are far from what we were actually measuring in some cases. So all the measurements listed above are throat measurements as measured with a set of pin gauges in thousandth of an inch increments.
If there are any nocks listed above without a measurement that means we don't have a sample to measure. If you have such a nock and want to send it along to expand the collection that would be greatly appreciated!