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Low-Cost Ammo for Carbine Training

Time has traditionally been a firearms instructor’s biggest enemy. Recently, this has been superseded by a short supply of ammo and the resulting high cost. As a result, some police departments’ training programs have been severely aggravated by the current state of affairs.

One of the most costly aspects of police training is ammunition expenditure, especially when drilling SWAT personnel or patrol officers on various tactical events. Among the most critical skill sets is how to properly enter, search and clear a structure where offenders are committing violent acts.

Officers are taught to place two rounds into a threat, or in the case of a reactive target, until it is no longer a threat and “disappears” from one’s front sight. Automatic fire, which is questionable for most police responses, will really drain your resources. But even in semi-automatic mode, a prodigious amount of ammunition can be expended.

As a result of these realities, quality training must be emphasized over quantity. However, in reaction to these imposed restraints, some departments have now restricted their officers to no more than two rounds per target engagement. Others have erroneously returned to annual-only qualification sessions or to the absolute minimum their state will allow. So, what does a motivated training officer do to help ameliorate the situation?

Incorporate additional dry firing into training, as much can be achieved with this practice. Still, officers expect to bust caps and see their skills verified by paper and steel. So, augment some of the training with sub-caliber devices or .22-caliber rifle conversion kits. This will stretch the supply of ammunition.

Reliable Rimfire Kit

One of the most reliable and simple conversions for the AR-15 platform that I have seen was sent to me by Brownells. Featured in its voluminous catalog of gun goodies is an Atchison-style 5.6x15 MM R kit manufactured by CMMG Inc. based in Fayette, MO. Complementing high-capacity magazines have been developed by Black Dog Machine LLC in Middleton, ID. The standard rifle twist for a .22 rimfire is 1:16 inches, but I planned on using the kit in a Blackwater edition of the Bushmaster Arms XM-15 E2S with a 14.5-inch long, 1:9-inch twist barrel.

The rifle conversion was remarkably easy. Simply remove the 5.56x45 mm bolt carrier group and slip the conversion kit into place. The blowback Brownells / CMMG kit consists of a carrier that contains the recoil spring, bolt, extractor and firing pin, as well as a feed ramp and chamber insert consisting of a hollow 5.56x45 mm “shell casing” that acts as the forcing cone for the .22 as it leaps across a short gap and into the rifling.

The converter weighs 12 ounces, which is only 2 ounces less than a typical carbon steel AR-15 bolt carrier. Make sure the receiving rifle’s chamber is clean or the hollow case that surrounds the round may not fully chamber when breaking the device in. The construction is of steel that appears to be Parkerized.

Dirty Bullets

Cleaning and lubrication of the bolt should occur after 100 rounds, with attention focused on the feed ramp, bolt face, extractor and hollow shell casing. The receiving rifle’s chamber must also be scrubbed clean of carbon and lead buildup. The .22-caliber bullet has lubrication or copper coating on it, and with its primer and propellant it is traditionally considered a “dirty” round. To maintain optimum accuracy, the bore should be serviced in the usual manner.

Big Sticks

The 27-round Black Dog magazines provided were the newest addition to Brownells’ conversion kit equation. They are full-dimension-sized, 30-round M16 magazines that require no adapters and are made of tough, impact-resistant, injection-molded polycarbonate. Made of the same material, the extended anti-tilt follower also acts as a bolt stop when the last round is expended.

A constant tension spring ensures uniform feeding in either semi- or full-automatic modes. Hex screws can be removed to separate magazine halves for easy internal cleaning. They come in clear for tracking ammunition expenditure and smoke or black for a lower visual profile. A 10-round magazine is available in smoke only. Smoke is also transparent enough to permit a visual inventory of remaining rounds.

Sub-Caliber Devices Performance

The 5.56x45mm round produces little recoil in the Stoner design, but it is almost unnerving at first to experience zero recoil in a 9-pound rifle with muzzle report, depending on the load being fired, ranging from supersonic to muted subsonic. Remington’s Low Noise at 737 fps produced a “whoosh” rather than a distinctive “crack,” and the “clack” from the hammer’s drop actually exceeded the sound of the round’s muzzle report.

For a moment, I thought I had a suppressor hanging off the end of the rifle’s barrel. Bullet drop at 150 feet for this round was 7 inches. All .22-caliber rounds fired were stabilized nicely by the tighter tube, and with my original 5.56, 100-yard dope on the EOTech 512, every two punched out of the Bushmaster printed slightly low but centered at 50 yards. The tightest group of .50 inches was achieved with the CCI Small Game Bullet at 1,146 fps.

The highest velocity of 1,570 fps was obtained with a CCI Stinger round that zipped into a 2.23-inch group at 50 yards. Factory-advertised velocity is 1,640 fps from an unspecified barrel length. Some of the rounds selected for this T&E demonstrated inconsistencies that reflected poor quality control. While undetectable during CQB training and perhaps hunting, more careful selection of ammunition should be involved when your intent might be for antipersonnel use. These discrepancies are so noted below in the extreme spread between rounds of the same make and lot of ammunition.

Interestingly, large spreads in velocity did not necessarily manifest themselves on paper, and some of the rounds with the biggest gaps were quite accurate. However, for my training purposes, sub-caliber accuracy was more than adequate. With almost no recoil, accurate combat shots could be delivered out to 50 yards as fast as I could manipulate the rifle’s trigger.

A 1,000-round case of U.S.A. commercial 5.56x45 mm FMJ will run you about $800, if you can get it. On the other hand, a 525-round box of Remington Golden .22 Long Rifle HP retails for $20. The cost savings are starkly evident, and after a few months of student training with the conversion kits, they would certainly have paid for themselves.

Robert Taubert is a retired FBI Special Operations agent and president of the Center for Security Studies and Applications. He can be reached at

Published in Tactical Response, Sep/Oct 2009

Rating : Not Yet Rated

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