Handgun Repair Shop, Gunsmith for modern and antique handguns, rifles, and shotguns.
An announcement was made at the February 2004 SHOT Show that a new .17 caliber rimfire cartridge based on the .22 Long Rifle called the .17 Hornady Mach 2 would be available in late 2004.
The .17 Mach 2 reaches 2100 Feet Per Second from a 24 inch rifle barrel, and yields sub minute of angle groups at 100 yards. At 175 yards the .17 Mach 2 is still traveling faster than the .22 Long Rifle does at the muzzle. The muzzle energy of the .17 Mach 2's 17 grain bullet is 18% greater than a 40 grain .22 Long Rifle, and it's trajectory is flat. Zeroed in at 100 yards, the .17 M2 has only a 0.7 inch mid range rise at 50 yards, compared to the .22 LR mid range rise of 2.9 inches at 50 yards for a 100 yard zero.
In a review Shooting Times Technical Editor Dick Metcalf called the .17 Mach 2 cartridge "stunningly accurate", and said " The .17 Mach 2 is the most accurate rimfire cartridge I've ever fired". He achieved 0.44 to 0.63 inch groups at 100 yards with a 20 inch barreled Kimber 17 Classic Varmint rifle.
Unfortunately the problems that arose in converting some .22 Long Rifle firearm actions to .17 Mach 2, and the higher popularity of the .17 HMR cartridge, decreased consumer demand for the .17 Mach 2 chambering. Most of the manufacturers have dropped the .17 Mach 2 from their offerings. This really is a shame because the accuracy and light recoil of the .17 Mach 2 makes this cartridge ideal to train new shooters.
The .17 caliber barrel liners, .17 Mach 2 chamber reamers and tooling are still available. I can install the .17 caliber barrel liners and chamber them to convert your old bolt, or single shot action .22 Long Rifle firearm to shoot the .17 Hornady Mach 2 cartridge. The advantage of installing a .17 caliber liner in your favorite old .22 LR firearm is that you already have a feel for that gun and are comfortable with it. Another advantage is that the old .22 LR guns often have barrel lengths not available in the new guns.
Sorry, but most older tube fed magazine .22 Long Rifle actions will not work with the .17 Mach 2 rimfire cartridge. The .17 Mach 2 features a sharply pointed ballistic tip bullet and the straight side wall of the case is slightly shorter in length than the .22 LR. This allows the cartridges to rest at a slight angle in the magazine tube. The ballistic tip bullet will tend to jam between the case rim of the round in front of it and the wall of the magazine tube. You can't shoot it if it won't feed.
Browning had come out with a BL-17 tube fed lever action rifle. It seems that Browning re-engineered the tube magazine on the BL-17 to get the .17 Mach 2 to work in their tube magazine without jamming.
Standard fixed and removable "clip" type magazines that stack the cartridges side by side will feed the .17 Mach 2 reliably.
Semi auto pistol and rifle actions can not be converted by just installing a liner. In July of 2004, Alliant Techsystems (ATK) who own CCI/Speer issued the following warning;
... As a result of the time to peak pressure of the .17 caliber Mach 2 cartridge, modifications must also be made to the bolts of semi automatic firearms to assure proper containment of the fired case beyond this peak pressure point. Failure to do so may expose the firearm operator to serious injury.
CCI/Speer is undertaking a public awareness campaign to inform the industry and consumers of this situation. You will soon see the following notice placed in broad coverage throughout industry and consumer publications:
“Important Safety Notice On The New .17 Cal Mach 2
This exciting new rimfire cartridge will undoubtedly inspire consumers to want to modify some of their existing .22 caliber rimfire semi automatic firearms to accommodate it. To achieve the performance level that this cartridge offers and consumers have demanded, special blends of powders were used which cause semi automatic firearms to cycle faster than with existing .22 caliber rimfire ammunition. This difference requires special bolt designs to maintain a safe shooting condition. Reputable firearms manufacturers that follow specifications set forth by the Sporting Arms and Ammunition Manufacturers' Institute have designed their Mach 2 firearms with special care being given to this requirement.
Consumers desiring to modify existing semi automatic firearms with after market components are strongly cautioned that modification must be made to the bolts as well as the barrel. Modifications should only be made by competent gunsmiths properly trained in the modifications required.
In response to this, the following warning appears on each box of ammunition supplied by CCI:
"WARNING: To avoid serious injury use this ammunition only in firearms that have a barrel/chamber with standard SAAMI sporting dimensions for this Mach 2 .17 caliber cartridge AND a bolt specifically designed for this Mach 2 .17 caliber cartridge.""
The above warning needs to be expanded on. I have often received emails and seen search questions in my website logs where people want to know if the .17 Mach 2 can be fired in .22 Long Rifle or .17 HMR chambers, or the .17 HMR in .22 Magnum chambers, or the .22 Long Rifle in .22 Magnum chambers.
The answer is NO! NO! NO! Chamber ammunition ONLY in firearms that are marked the same as the ammunition! Firing any "bottle necked" cartridge, but most especially the rimfires, in a firearm that is marked for a different chambering can have disastrous results to the firearm, bystanders, and the shooter!
The chamber of the .17 HMR is so much longer and larger than the .17 Mach 2 cartridge that the .17 Mach 2 case would rupture when fired in a .17 HMR chamber, causing the bullet to enter the bore crooked and create a bore obstruction that would raise pressure to disastrous levels.
A .22 Short can be inserted into a .17 Mach 2 chamber, or a .22 Long Rifle in a .17 HMR chamber, and the bolt will close. It shouldn't need to be said, but, DO NOT EVER try to fire any .22 caliber cartridge in any .17 caliber gun!
Yes, most .22 Long Rifle firearms can shoot .22 Short, .22 Long, and .22 Long Rifle cartridges, and the firearm is marked to tell you that.
There are revolver rounds with straight sided cases that will interchange, such as the .38 Special can be fired in a .357 Magnum, .44 Special can be fired in the .44 Magnum, but not in reverse. The "Magnum" cartridges were intentionally made a bit longer to prevent them from being chambered in the shorter "Special" chambers.
This does NOT apply to firing the .22 Long Rifle in .22 Magnum chambers just because the case is straight! The .22 Magnum case is longer and has a slightly larger diameter and a slightly thicker rim, which would allow the .22 Long rifle case to expand and split open when fired in the longer and larger .22 Magnum chamber!
Work was done to develop drop in barrel kits that have a heavier replacement bolt and recoil spring to solve the problem in converting some .22 Long Rifle semi auto long guns to .17 Mach 2. Clark Custom, E. Arthur Brown Company, Shilen, and Volquartsen have had .17 Mach 2 drop in barrels/kits for the Ruger 10/22, and 77/22 rifles. Green Mountain offered 25 inch long Chrome Moly and Stainless .17 caliber barrel blanks to custom fit to other rifles that can be chambered for either the .17 Mach 2 or the .17 HMR. Prices varied according to the styles and types available from each manufacturer.
Magnum Research, Inc., makers of the Desert Eagle Pistol, introduced the Magnum Lite 10/22 17HM2 Barrel for the Ruger 10/22 rifle, but it is no longer available .
Magnum Research, Inc. also offered a 10/22 action silhouette style semi auto pistol called the PiCuda, but it is no longer available.
For those who want to know about compact holster sized semi auto pistols in .17 Mach 2 the news is not so good.
The .17 Mach 2 is not just a .22 Long Rifle necked down for .17 caliber bullets. See the safety warning above. Special blends of powders were used to achieve the high performance level this cartridge offers.
Alloy slides commonly used on .22 Long Rifle pistols can not withstand the pressures of the .17 Mach 2 cartridge, so conversions to .17 Mach 2 did not hold up in the alloy slide pistols. Alloy frame .22 Long Rifle revolvers can not be converted to withstand .17 Mach 2 pressures, even when the cylinder is made of steel.
The word through the grapevine is that Ruger had problems with the bolt stop pin breaking when they tested the conversion of their MK series pistols to .17 Mach 2.
Kimber previously had a .17 Mach 2 conversion kit for 1911 pistols listed on their rimfire pistols page, but Kimber no longer offers it. For a short period of time Kimber also listed their 1911 Rimfire Target series pistols as available in .22 LR or .17 Mach 2 on the same page. The word is that some lots of .17 Mach 2 ammo gave extraction problems in the Kimber .17 Mach 2 pistol and the .17 Mach 2 1911 conversion kits, so Kimber no longer offers them for sale.
This does not mean that it is impossible to convert any .22 LR pistol to shoot .17 Mach 2. What it does mean is that the factories have not seen enough customer demand for .17 Mach 2 pistols to invest in re-tooling and building a new pistol design for shooting the .17 Mach 2.
I have successfully built my own personal prototype .17 Mach 2 pistol by modifying a High Standard Sport King .22 LR pistol. A .17 caliber barrel blank was turned down and machined to replace the .22 LR barrel, stronger springs were installed, and a substantial amount of weight was added to the slide. Accuracy and feeding have been much better than I had expected, and only occasionally has there been an extraction problem when the chamber gets dirty enough that the barrel needs cleaning. For a backyard plinking gun I can accept an occasional failure to extract when the barrel is getting dirty enough to be past due for cleaning.
Excel Arms has a semi-auto pistol called the Accelerator MP-17 chambered in .17 HMR that can be seen at http://www.excelarms.com/acceleratorpistol.html . Excel Arms also showed a .17 Mach 2 semi-auto pistol as "Coming Soon" on their New Products page at http://www.excelarms.com/newproducts.html for a while, but is no longer listed there.
Revolvers in .17 Mach 2 and .17 HMR were available from Heritage Manufacturing Inc., North American Arms, Ruger, and Taurus. Occasionally some of the .17 Mach 2 revolvers and pistols can still be found for sale on the gun auction sites.
Conversion barrels and cylinders were available for a while to convert the Ruger Single Six to either the .17 Mach 2 or the .17 HMR. These had to be gunsmith installed to properly set the barrel to cylinder gap. There was not enough demand to keep these parts in production.
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