The .17HMR is pretty much limited to 17 grain and 20 grain bullets, while the .22WMR has current factory loads in 30 grain, 40 grain and 50 grain loads in several bullet types.
Which is the better rifle caliber for plinking and varmint hunting.? I guess it depends on what you use your varmint rig for. Neither of these calibers and respective loads is a viable choice for shots beyond 200 yards. For heavier varmints such as coyotes, eastern woodchucks etc. under 100 yards, or a bit beyond the .22 WMR beats the .17HMR for both coyotes and woodchucks. If your targets are crows, ground squirrels, prairie dogs etc. then on fairly calm non-windy days, you will be able to make longer shots on these critters with the .17HMR.
The .17 HMR is faster and extremely accurate, however there are also very accurate .22WMR rifles out there. I won't make this post about NEED as any certified gun nut knows that he would have to get rid of 2/3 of the guns he owns if it were all about NEED. I have always been fascinated by anything that fires a projectile, going all the way back to rubber bands and paper wads shooting plastic enemy soldiers in a sandbox when I was just a tyke. Now that I am retired, NEED and the cost of new toys does factor into any purchases I make.
That being said here is the LINK to Chuck's article and a comparison of the .22WMR firing 30 and 40 grain bullets, with the .17HMR firing 17 grain and 20 grain bullets.
Dan
http://www.chuckhawks.com/compared_17HMR_22WMR.htm
EXCERPTS on comparison tables:
| The .22 Winchester Magnum Rimfire (WMR), often referred to simply as the ".22 Magnum," has been the most powerful rimfire cartridge on the market since it was introduced back in 1959. And, in terms of muzzle energy, it still is. But there is a new leader in rimfire velocity, the .17 Hornady Magnum Rimfire (HMR). These two cartridges are based on the same case but use radically different bullets. Both were originally designed for use in rifles, and were quickly adapted to pistols. The single-action "convertible" revolver, supplied with two cylinders (.22 LR and .22 WMR or .17 M2 and .17 HMR), lets handgunners shoot two cartridges from the same pistol. This comparison is a natural, as both cartridges are chambered in the same types of firearms and are used for small game hunting and short to medium range varmint shooting. For use in revolvers, the .22 WMR is probably the more versatile cartridge, as its heavier bullet hits harder at normal handgun ranges. But in the longer barrel of a rifle, the issue is in doubt. Which is the king of the rimfire rifle cartridges?  The new bullet weighed 40 grains, the same as the .22 LR bullet, but it was a true jacketed bullet, available in jacketed hollow point (JHP) and full metal jacket (FMJ) forms. .22 WMR bullets are generally of flat point or round nose shape, although Remington offers a Pointed Soft Point bullet. The original catalog muzzle velocity (MV) from a rifle barrel was 2000 fps, or 1550 fps from a pistol barrel. RWS still advertises a 40 grain bullet at a MV of 2020 fps and ME of 360 ft. lbs. The major U.S. manufacturers have since reduced the catalog velocity of the 40 grain bullet to 1910 fps (rifle) and 1480 fps (pistol). CCI, Federal, Remington, and Winchester all load ammunition with 40 grain bullets to this standard. Over the years, practically every manufacturer who loads rimfire ammunition has adopted the .22 WMR and different loads have been introduced. In the U.S., CCI, Federal, Remington, RWS, Winchester, and probably others offer .22 WMR ammunition. The original 40 grain bullet weight is still the most popular. But we now have higher velocity loads using lighter bullets, such as the CCI Maxi-Mag +V and Federal V-Shok offerings that advertise a 30 grain Speer TNT-HP bullet at a MV of 2200 fps from a rifle barrel. ATK CORP owns Federal, CCI, and Speer. In addition to their 40 grain JHP and PSP bullets, Remington loads a 33 grain V-Max boat-tail bullet at a MV of 2000 fps. And Winchester now offers a 34 grain JHP at a MV of 2120 fps. And there are also .22 WMRShok load that uses a 50 grain bullet at a MV of 1652 fps, and the Winchester 45 grain DynaPoint bullet at a MV of 1550 fps. These are rifle velocities.  The .17 HMR is based on the .22 WMR case necked down to accept .172" bullets. It is a bottleneck rimfire case about 1.060" long. The rim diameter remains .291". The chamber pressure and cartridge overall length are exactly the same as the .22 WMR, so any firearm that can be chambered for that cartridge can also be chambered for the .17 HMR. The success of the .17 HMR has been so overwhelming that most of them have been. The original Hornady load drove a specially designed 17 grain V-Max bullet at a MV of 2550 fps and ME of 245 ft. lbs. This is a polymer-tipped, spire point, boat-tail bullet design. It is primarily a varmint bullet, designed to fragment in small animals and disintegrate if it hits a hard surface. In 2004 Hornady introduced a less destructive 20 grain XTP bullet at a MV of 2375 fps. This bullet is advertised as a controlled expansion, deeper penetrating bullet for small game and predator hunting. Remington Premier brand .17 HMR ammunition also uses the Hornady V-Max bullet, with a gold plastic tip replacing Hornady's signature red plastic tip. Like the original Hornady load, the MV of the Remington Premier load is 2550 fps. And Federal loads the Hornady V-Max bullet, also at a MV of 2550 fps. CCI and Federal introduced .17 HMR ammunition loaded with a 17 grain Speer TNT varmint bullet. This is a JHP spitzer bullet. Federal V-Shok ammunition claims a MV of 2550 fps, while the CCI version advertises a MV of 2500-2525 fps. In 2005, CCI announced a heavier 20 grain GamePoint controlled expansion bullet at a MV of 2375 fps. Hornady's .17 HMR ammunition is loaded with great precision. It is intended to deliver 1 MOA or better groups at 100 yards. The other brands seem to have followed Hornady's lead in this matter. All of the .17 HMR ammunition that I have tested has proven to be very accurate. The comparison We will compare the .17 HMR and .22 WMR in terms of velocity, energy, trajectory, sectional density, bullet frontal area, killing power, and accuracy. But first we have to decide what loads to compare. One of the "hottest" current .22 WMR loads is the Federal Premium V-Shok using a 30 grain Speer TNT-JHP bullet (load #P765). And, of course, the "standard" .22 WMR load uses a JHP or FMJ bullet at a MV of 1910 fps and is available from most manufacturers. In .17 HMR, the 17 grain Hornady V-Max bullet is loaded to identical ballistics in the Federal, Hornady and Remington brands. These remain the fastest, flattest shooting .17 HMR loads. Heavier bullets with better SD have appeared, the Hornady 20 grain XTP bullet being perhaps the best known of these. So those are the four loads I propose to compare, 17 and 20 grain bullets in .17 HMR and 30 and 40 grain bullets in .22 WMR. Since rimfire cases are not reloadable, there is no reloading data. In some instances this seriously limits the ballistic and bullet information available, as we shall see. The figures that follow were taken from the Federal, Hornady, and Remington ammunition catalogs. Velocity Here are the velocity numbers in feet-per-second at the muzzle, 50 yards, 100 yards, 150 yards (when available), and 200 yards (when available):
Energy Velocity is an important factor in calculating kinetic energy, but so is bullet weight. We have already seen that the .17 HMR is by far the faster cartridge, but the .22 WMR shoots a far heavier bullet. Energy is important because it powers bullet expansion and penetration, and is a major factor in killing power. Here is the energy of our comparison loads, in foot-pounds at the muzzle, 50 yards, 100 yards, 150 yards (when available), and 200 yards (when available):
What we can conclude from this is that the 40 grain .22 WMR load is the most powerful cartridge out to at least 100 yards, and beyond that adequate data is lacking. I would guess that the 40 grain .22 WMR bullet retains its energy advantage out to at least its maximum point blank range of about 125 yards. Note that the energy of the 30 grain .22 bullet falls behind the 40 grain .22 bullet by 50 yards, and behind both .17 HMR loads by 100 yards. Also note that there is no practical difference in energy between the 17 and 20 grain .17 HMR bullets at any range. Trajectory High velocity has a big effect on trajectory, as does the ballistic coefficient of the bullet. Since the .17 HMR has the advantage in both areas, we can expect it to be the flatter shooting cartridge, and it is. Here are some factory figures based on a 100 yard zero and a line of sight 1.5" over bore (a scoped rifle):
Another way to zero a rifle is to take advantage of its maximum point blank range (MPBR). In the case of a small game and varmint bullet, I like to limit the maximum rise of the bullet above the line of sight to 1.5" to avoid shooting over small targets. The distance at which the bullet falls 1.5" below the line of sight then becomes the MPBR. Here is some MPBR trajectory data for the top load in each caliber based on a bullet BC of .123 for.17 HMR and .100 for the .22 WMR:
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