Writing about the American Rifleman review of the .380 automatics reminded me of the review I posted on a couple of forums of the CMMG .22 conversion kit for the AR. Considering the cost of ammo and the quality of the conversion kit, I think that’s worth posting here, so, here goes.
Introduction
5.56 / .223 ammo costs about 40¢ per round. .22 Long Rifle ammo costs about 4 ½¢ per round. Less than a nickel each or 8 times more? That’s our choice. But, are these conversions reliable, and is the training you get valid: is it like training with 5.56mm? With the SWAT article a few months back, and the cost of my last 5.56 order, I decided to stockpile more 5.56 for the zombie invasion and go for one of the conversion kits to get more practice.
The purpose of this review is to tell you my experience with the CMMG conversion kit.
Summary: Buy it today and be having a trouble-free blast this weekend. Be sure to buy the magazine loader, and get a spare magazine too, to practice your reloads.
Product reviewed:
CMMG (www.cmmginc.com) stainless steel .22 conversion kit with 26 rd magazine,
“ARC AR conversion .223/5.56mm to .22 LR in 30 Seconds”
Supplier: http://www.luckygunner.com/accessories/conversion-kits
Cost: $210 in stainless steel (The parkerized version costs $180)
Accessories tested and reviewed: magazine loader, AR15/M16-.22LR, by Christie’s Products, also supplied by Lucky.
Product description:
The Kit is a direct replacement for the bolt carrier group. The assembly features a blowback bolt behind an attached chamber insert that fits past the chamber lugs and into the chamber. This insert portion looks, as you might expect, like a stainless steel 5.56 case. In place of the bolt carrier key on top of the bolt, The Kit sports its own recoil spring and tube. This is not a gas-operated mechanism; The Kit fits its blowback .22 bolt and carrier mechanism into the AR receiver. From the user’s standpoint, take out one bolt carrier group and slide in another. Go from gas-operated 5.56mm to blowback .22 Long Rifle. That’s it. It’s Plug and Play, for real.
The bolt is machined steel; surrounding parts are forged and welded. Solid piece of equipment. I am impressed.
I’d like to see the feed ramp more highly polished but, then again, the weapon fired flawlessly so, what the heck? I examined the feed ramp more closely and it looks pretty good. No need to polish it further.
The Kit comes with a green rubber protector slipped over the chamber insert. The instructions don’t say, but you have to remove this, of course. KEEP IT. You will want to protect that chamber insert from damage. Keep the packaging too, as your storage.
The installation and maintenance instructions
Clear, detailed. Save them.
CMMG mentions possible break-in period needed, typically with the parkerized mechanism, but I did not experience any need for break-in with the stainless steel version. CMMG cautions that units work best with lowers using rounded hammers. They show pictures contrasting rounded hammers with the notched hammer. I checked and my M-4gery has the notched hammer, but I experienced no problems with it.
CMMG recommends high-grade, round-nosed ammo, and they specifically recommend Federal high velocity hollow points. Whatever. I used Winchester and fired away.
The magazine is interesting. First, it looks almost identical to a regular AR15 30-round mag. It’s of high-impact composite plastic, with an extension on top to feed .22 rounds. The follower, while green, is easily distinguished from the 5.56mm mag. Shooters will appreciate that the floorplate shows a distinctive cutout and green part that distinguishes this magazine floorplate from a 5.56mm mag by both sight and touch. You are not likely to mistake one for the other.
The outside dimensions are slightly less than the 5.56mm magazine. This causes the magazine to insert easily but wobble around a bit. Odd. Why not make it the same size exactly? However, I found that the magazine locks securely on insertion, stays locked when you confirm its secure seat by pulling down on it like Pat says, and it stayed secure during firing. I’d think the magazine would fit the well more tightly, but I experienced no problems at all with the magazine. I used a vertical forearm grip, so I was not holding the mag well with my support hand.
The magazine fits my Blade-Tech mag pouch if I tighten the screws on the pouch a bit.
My Mag-pul magazine pullers fit.
Note: The magazine follower operates as a last-round-fired, bolt hold-open device. This means that dropping the magazine out releases the bolt; therefore, tactical shooters will find that this does not comport with their reloading drills. That is the only distinction I found in the reload drill.
The cheap,lightweight, easy to use loader is a must. Buy it. You’re going to do a lot of shooting with your uber-plinker.
Purpose of test:
Determine expected malfunction rate, if any
Compare carbine manipulations and drills with those you would use firing 5.56mm.
Determine whether combat accuracy sufficed to make training with the CMMG kit (The Conversion) valid—Would shooting be realistic compared to firing 5.56mm?
Weapon fired: Bushmaster XM15-E2S: basically, Bushmaster’s M-4gery, chrome-lined chamber and barrel, with about 20,000 rounds fired through it, 1 in 9 twist, aluminum quad rail by Midwestern, vertical forearm grip by Tango Down, sling by Viking Tactical V-Tac.
Preparation and installation:
It was, no joke, just as easy as they say. Remove your bolt carrier group. Replace it with The Kit. That’s it, boys.
I did not figure I’d use The Kit to lie in night ambush or to fire from 400 meters in the desert sun, so I didn’t care about shine. I chose the stainless steel for durability and reliability. I swabbed the chamber and barrel with a Boresnake before firing. I lubricated The Kit amply before firing using just 3-In-One oil—nothing exotic—and made sure to wipe a film of oil onto the portion that fitted into the chamber.
Ammunition
Winchester 36-grain, rimfire, plated hollow-points, in the “333” box. Standard stuff, brass cased, plated hollow points.
Should have brought more, of course. Bought it from luckygunner.com too.
Zero
My carbine is zeroed at 50 yards / 200 yards for 5.56mm. Keeping the same zero, the .22 LR fires a few inches low at 50 yards. I expected elevation differences, of course. The purpose of 50-yard shots was to determine whether The Kit sent rounds significantly left or right. Result: no windage differences.
At closer combat distances, say under 30 yards, the elevation offset you must account for with an AR15 fired close in is well-known. I figured the same laws of physics applied with the .22 rimfire round, but it’s best to check.
I’m pleased to report that at close combat ranges (in-your-face to 50 yards) you should aim that same couple of inches high to offset line of sight versus impact. In other words, firing .22 with The Kit, aim the same as you would firing 5.56mm close in: a little over 2 inches high. Aim at the top of the skull to make that head shot.
Note: I consider this very important. The Kit does not alter your need to employ offset aiming with the AR15 fired at close ranges. The Kit supports your training in this regard.
Reliability
My chief concern was malfunctions. I’d actually welcome a few, since I didn’t buy The Kit to fire .22 at terrorists or home invasion robbers. A few malfunctions would give you the training opportunity to practice tap-rack-bang and magazine changes.
First operations were several box drills on two targets.
Second, some hammers.
Third, I did some NSRs of about 10 rounds each.
Next, I just got carried away and emptied the 26-round mag “as fast as you can pull the trigger.”
I meant to fire just 100 rounds. I was having so much fun I ate further into the box.
In 150 rounds of firing, I experienced no malfunctions. None. No malfunctions of any kind. I expected some. Nope, didn’t get any. Impressive!
Did I say I experienced no malfunctions?
Like you, I’d say 500 rounds might be a better test, but work just didn’t allow that today. Still, out of the box and 100% ignition.
Conclusion
Click http://www.luckygunner.com/acc…ies/conversion-kits, or wherever you want it from, buy it, pop it in and have a blast training for a fraction the ammo cost. Luckygunner says you’ll pay for it in 750 rounds. They ship real fast. Be sure to buy the loader. Keep the packaging and be sure to keep that rubber protector thingie for the chamber. Think rubber = protection so you knuckle-draggers don’t forget.
This thing is fun. Lots of fun.
