The .17HMR is a scorching-fast rimfire round. A 10-shot string of the Hornady load using 17-grain V-Max bullets fired through a chronograph produced an average velocity of 2,621 fps. A 10-shot string of the CCI load using 20-grain Gamepoint bullets produced an average velocity of 2,447 fps. The smaller .17M2 is not as fast, of course, but still an improvement over the older .22-rimfire rounds. A 10-shot string of the CCI load using 17-grain V-Max bullets produced an average velocity of 2,018 fps. Tests were made using typical hunting rifles fired from the shoulder on a bench rest: the .17HMR from a CZ Varmint with a Bushnell Elite 3200 3x-9x scope, and the .17M2 from a Savage Mark II with a Bushnell Banner 3x-9x scope. The chronograph was a Shooting Chrony Gamma Master.

Since the newer .17M2 is about 600 fps slower, it begs the question of why is it necessary. For pure velocity and trajectory enthusiasts, there is no reason. But to the seasoned squirrel hunter, it makes all of the sense in the world. Comparing the trajectory of both .17 rimfires and the common .22 rimfires, the .17M2 is plenty flat enough within practical squirrel hunting distances. Trajectory tracking tests were made with rifles zeroed at 50 yards. Three-shot groups were fired at distances of 25 yards, 50 yards, 75 yards and 100 yards. Measurements were made from the centers of the three-shot groups.

Test groups for the .17HMR using Hornady loads with 17-grain V-Max bullets were so close together that it was difficult measuring the distances between them. The 25-yard group was -0.8 inch, the 75-yard group -0.1 inch, and the 100-yard group -0.4 inch. Total center-to-center spread was less than inch, making no sighting compensation necessary at the head of a squirrel.

Testing for the .17M2 used CCI loads with the same 17-grain V-Max bullets. At 25 yards the group was 0.6 inch, at 75 yards -0.4 inch and at 100 yards -1.1 inches -- still inside the head of a squirrel.

For comparison, in the same test using Federal High Velocity .22LR ammunition, the 25-yard group was +0.4 inch high, the 75-yard group was -1.2 inches and the 100-yard group was -6.9 inches.

A Winchester .22WM load with 40-grain bullets has a trajectory slightly inferior to the .17M2; -0.5 inch at 25 yards, -0.2 inch at 75 yards and -1.6 inches at 100 yards. That zero distance of 50 yards was used just for equal comparison. For actual hunting purposes, either of the .17 rimfires could be zeroed at greater distances to improve performance.

A second and more important reason for choosing the .17M2 over the .17HMR or .22WM for squirrel hunting is that the light crack of the .17M2 is hardly noticed by squirrels. While inexperienced squirrel hunters might debate velocity, seasoned squirrel hunters are much more concerned over noise levels. This is much more important than the distance advantage of the .17HMR, although it too is seemingly quieter than even the .22LR, a result of the smaller bore diameter.

Loud noises such as those made by any shotgun or even a .22WM will send squirrels into hiding where they will typically stay for anywhere from about 15 minutes to more than a half-hour. If it happens late in a feeding period they might not come out for hours. The louder the noise, the wider the area that is affected. You can keep moving to get out of an affected area, but if you are hunting a small woodlot or if squirrels are congregated in a particular feeding area, this can be a big problem.

MAKING A CHOICE
All things considered, the .17M2 is probably the ideal cartridge for serious squirrel hunting. It is not uncommon to take several squirrels in succession out of a single tree -- or beneath a tree -- without scaring them. Between a 12-gauge shotgun using high-velocity loads of No. 4 or No. 5 shot and a .17M2 rifle, a squirrel hunter is on the cutting edge of efficiency. Choosing between these is either a matter of what is legal where you hunt, hunting conditions or personal preferences. But remember, responsible sportsmen and sportswomen do not use these advances as excuses for stretching the range too far. Even using high-velocity shotshell loads, the maximum range for shooting squirrels is only about 35 yards to 40 yards. Hunting with a .17 rimfire rifle, the maximum range -- depending on the accuracy of your rifle and marksmanship -- can be out to at least 85 yards.

Enjoy your time afield.