The world of rimfire cartridges offers a fascinating blend of affordability, accuracy, and versatility, making them a favorite among target shooters, plinkers, and small game hunters. Within this realm, the .17 caliber rimfire cartridges, specifically the .17 HM2 and .17 HMR, have carved out significant niches for themselves. Choosing between these two can be a challenge, as both offer distinct advantages and cater to different shooting needs. This article aims to provide a detailed comparison of the .17 HM2 and .17 HMR, examining their history, ballistics, applications, advantages, and disadvantages, to assist readers in making an informed decision about which cartridge best suits their specific requirements.
A Look Back at History and Development
The story of the .17 caliber rimfire cartridges is a story of innovation, driven by a desire for flatter trajectories and higher velocities in the rimfire world. Understanding their origins gives us context for their capabilities.
The .17 HM2
The .17 HM2, or .17 Hornady Mach 2, emerged as a product of collaboration and adaptation. It was born from the need to provide a higher-velocity option than the ubiquitous .22 Long Rifle. The .17 HM2 cleverly repurposed the .22 Long Rifle case, necking it down to accept a tiny, incredibly fast .17 caliber bullet. This allowed manufacturers to build rifles and ammunition that could be readily produced, while offering shooters a new level of performance. The early days saw a surge of interest, as the promise of reduced wind drift and improved ballistics for small game hunting and target shooting quickly captured shooters’ attention.
The .17 HMR
The .17 HMR, or .17 Hornady Magnum Rimfire, followed a different path. Instead of adapting an existing case, this cartridge leveraged the strength of the .22 Magnum case. This foundation provided the necessary structural integrity to handle significantly higher pressures and, consequently, generate substantially higher muzzle velocities. The .17 HMR offered a substantial leap forward in terms of range and downrange energy. The cartridge proved to be a resounding success, quickly becoming a popular choice for small varmint hunting and target shooting at extended distances. This cartridge quickly became a huge hit.
Comparing the timelines, the .17 HM2 preceded the .17 HMR, but both were born from a similar goal: providing rimfire shooters with enhanced performance. However, the .17 HMR built upon and surpassed the .17 HM2’s capabilities, primarily due to its more robust case design and higher pressures.
Cartridge Design and Specifications: Understanding the Fundamentals
Delving into the physical characteristics of these cartridges reveals crucial distinctions that dictate their performance.
The .17 HM2
The .17 HM2, employing the .22 Long Rifle case, has a relatively smaller overall size. It typically utilizes bullets in the 17-grain weight range, which are known for their high sectional density. This allows them to maintain their velocity at longer distances, and can be very helpful to target shooters. The standard primer type is a rimfire primer, providing consistent ignition.
The .17 HMR
The .17 HMR, with its foundation in the .22 Magnum case, is noticeably larger and sturdier. The design allows it to handle more propellant and withstand higher pressures. .17 HMR rounds usually offer 17-grain or 20-grain bullet options, providing versatility for different shooting scenarios. As with the .17 HM2, the standard ignition system is the rimfire primer.
Visually, the difference in size is immediately apparent when comparing the two cartridges. The .17 HMR is significantly longer and wider than the .17 HM2. This difference in case size is a key factor in their differing ballistic performance.
Ballistics Performance: A Matter of Velocity, Trajectory, and Energy
The numbers tell the tale of how these cartridges behave in flight, offering insight into their strengths and weaknesses.
Velocity
When considering velocity, the .17 HM2 typically achieves a muzzle velocity in the range of around two thousand feet per second. This high velocity allows it to have a fairly flat trajectory, making it a good option for target shooters. At longer ranges, however, the velocity drops off more rapidly than that of the .17 HMR.
The .17 HMR, taking advantage of its larger case and higher pressures, boasts a significantly higher muzzle velocity, around two thousand six hundred feet per second. This higher initial velocity results in a flatter trajectory and less wind drift at longer ranges.
Trajectory
When analyzing bullet drop, the .17 HM2 will show more noticeable drop at longer distances. The .17 HMR, because of its higher velocity, exhibits a much flatter trajectory, extending the effective range for accurate shots. For instance, at one hundred yards, the .17 HM2 might experience several inches of drop, while the .17 HMR would experience considerably less.
Energy
The kinetic energy comparison paints a clear picture of terminal ballistics. While the .17 HM2 delivers a respectable amount of energy at the muzzle, the .17 HMR consistently retains more energy at various ranges. This means the .17 HMR is better able to deliver effective stopping power at greater distances. The higher energy delivered by the .17 HMR translates to improved performance against larger varmints and greater effectiveness on target.
Applications and Practical Use: Where They Shine
The best choice depends heavily on how a shooter intends to use the cartridge.
.17 HM2 Applications
The .17 HM2 is a good choice for varmint hunting, particularly against smaller targets. Its relatively flat trajectory and moderate recoil make it a favorite for prairie dogs and other smaller targets at closer ranges. The cartridge’s lighter weight and less pronounced muzzle blast also contribute to its suitability for certain hunting situations. Target shooting at ranges out to a hundred yards is another area where the .17 HM2 performs well.
.17 HMR Applications
The .17 HMR excels in situations that demand greater range and energy. This cartridge has become a favorite for hunting groundhogs, woodchucks, and similar-sized varmints. Its flatter trajectory makes it easier to hit targets at further distances, reducing the need for complex holdover calculations. The cartridge’s versatility also extends to target shooting, where it can be used effectively at ranges out to two hundred yards or beyond.
The selection of firearm platform also matters. Many rifles are chambered in .17 HM2, including bolt-action and semi-automatic models. The .17 HMR also enjoys a wide selection of rifles, also including both bolt-action and semi-automatic platforms.
Advantages and Disadvantages: Weighing the Pros and Cons
Every cartridge possesses both benefits and drawbacks that must be considered.
Advantages and Disadvantages of the .17 HM2
The .17 HM2’s greatest advantage is its lower cost. Ammunition is typically less expensive than the .17 HMR, as are the rifles that are chambered for this cartridge. This makes it an attractive option for shooters who are budget-conscious or new to the sport.
The disadvantages include a shorter effective range, with a flatter trajectory at shorter ranges and less energy. This limits its utility for longer shots and against larger game. Wind drift is also a more significant factor with the .17 HM2, making it more susceptible to the effects of wind.
Advantages and Disadvantages of the .17 HMR
The .17 HMR, the higher muzzle velocity and flatter trajectory result in a longer effective range and better performance in windy conditions. The higher energy delivered by the .17 HMR also makes it a better option for hunting larger varmints.
The primary disadvantage of the .17 HMR is the higher cost of both ammunition and rifles. The ammunition costs are often significantly higher than those of the .17 HM2, especially when comparing the cost per round.
Cost Analysis: Dollars and Sense
Understanding the financial implications of each cartridge is crucial for making an informed decision.
Ammunition Costs
A box of .17 HM2 ammunition typically falls into a price range. The cost per round is often substantially lower than the .17 HMR. This difference can be significant for shooters who engage in regular practice.
Rifle Costs
The initial cost of a .17 HM2 rifle can also be lower. The lower manufacturing cost of the ammunition, along with the availability of the .22 Long Rifle case which it is based on, contributes to the rifle’s generally more affordable price point.
Accuracy and Precision: Hitting the Mark
The accuracy of any firearm depends on a variety of factors.
Factors
Barrel quality and rifling design play a crucial role in accuracy. Consistent bullet performance, with accurate and stable bullets, is essential. High-quality ammunition is also critical; variations in bullet weight, velocity, and shape can lead to wider groups on target.
Both cartridges are generally capable of excellent accuracy, depending on the firearm, ammunition, and shooter skill. The .17 HM2, when paired with a quality rifle and consistent ammunition, can achieve impressive groupings at ranges out to one hundred yards. The .17 HMR, thanks to its higher velocity, offers even tighter groupings at extended ranges, often capable of delivering sub-minute-of-angle accuracy out to two hundred yards or even further.
Availability of Ammunition: Finding What You Need
Ammunition accessibility is an important factor for any shooter.
Ammunition for both the .17 HM2 and the .17 HMR is widely available. However, the .17 HMR might have a slight edge in terms of market share. Both cartridges can be found at most major sporting goods retailers, online ammunition vendors, and local gun stores.
Conclusion: Making the Right Choice
Ultimately, the best cartridge, whether it be the .17 HM2 or the .17 HMR, depends on the shooter’s specific needs and priorities.
The .17 HM2 provides an accessible, economical entry point to high-velocity rimfire shooting.
The .17 HMR offers the advantages of a longer effective range, flatter trajectory, and increased energy.
Consider factors like the intended use, budget, and desired range when making your choice. Both cartridges offer excellent performance within their respective spheres. Weigh the advantages and disadvantages carefully, and choose the cartridge that best matches your shooting style and goals.
