Of AR15s and Adaptors

kBob · Jul 3, 2019

So right off the bat let me say I do not want to hear "Forget those things and buy a dedicated upper or entire dedicated .22 rifle!" I am aware of those options and chose to have a BCG replacing .22LR adaptor (mine happens to be and Olympic Arms that uses M261 style magazines)

I have heard the "I think" and "well it seems like" and the "every body knows"
lines about

1. "only use copper clad type ammo"
2. ".22 ammo will so lead your bore that you will have no accuracy when switching back to .223"
3. ".22 ammo will lead up your gas tube so bad it will effect .223 reliability"
4. "just shoot a round or two of .223 full powered jacket ammo for every X number of .22LR"

Now I am not looking for opinions (I have heard a lot and shared as many myself) but has anyone or some agency ACTUALLY published data to support any of these issues?

I have always wondered how firing a round or two off .223 is supposed to clear leading and powder residue from the gas tube and where such fouling goes when one does that. The gas key on the BCG is even more restricted and fires into the carrier itself and onto the bolt and then out the two vents in the bolt carrier one sees in the cut out for the rifles ejection port cover. I suppose it might be easier to clean lead off and out of the bolt carrier, bolt. and upper receiver than the gas tube.

-kBob

cougar1717 · Jul 3, 2019

I would think that it would be the 22LR bullet lube (not necessarily shearing lead/copper from the bullet) that is the problem with cycling. The bullet lube probably gets built up at the gas port since the 22LR doesn't use the gas port to cycle. If the gas port/tube is actually blocked with sheared pieces of lead or copper, firing a 223 through the rifle won't fix the problem (like you are thinking). At that point, a person would be either mechanically removing the metal or replacing the gas tube. If it is lube that clogging the gas port/tube, then I could see how firing a 223 every so often would have enough pressure and ignition to incinerate the excess lube. In that case, it isn't that much different from dropping a few drops of CLP down the gas tube to coat whatever is left in the gas tube and incinerate it on the next firing.

It is hard to know if the hearsay problems are true. I doubt any manufacturer would publish the weak points of their products. Maybe there is someone independent out there that isn't paid to promote the product. I'm kind of surprised that "breaks firing pins" isn't on the list, though.

kBob · Jul 5, 2019

Cougar,

Thanks for your thoughts. I am very familiar with clogged gas tubes as near the end of their service lifes M16A1s could be notorious for such. This was caused by a lot of blank firing and for most of their lives having no decent way to clean them. Just be fore the A2s begain replacing them in units the Army did two things. First they allowed unit armorers to replace the gas tubes and made them available with a new pin. Second they issued these Very long white pipe cleaners to clean the gas tubes with.

My unit armorer just before these things became available was appalled when I ripped the metal spiral ring from a paper notebook half asses straightened it out and screwed it into the gas tube of a rifle that was failing to eject then jerked it out several times. A bunch of near white hard crud came out, almost like lime deposits in a water pipe. The rifle and most other so afflicted ones cycled fine after this treatment.

I think it interesting that no one has leapt aboard with an actual study as this indicates that it may well be that NO ONE has done one.

One might think for example the USAF might have done such a study as they used the M231 equipped gaggle of various AR15s they used for many years as training and even initial instruction

Oh I was also puzzled by your firing pin comment. Which firing pin do you mean? The actual AR fifing pin is removed along with the rest of the Bolt Carrier Group and the firing pin of the conversion unit strikes the edge of the conversion unit chamber just like most .22 Semi autos other than the 10/22.
-kBob

CapnMac · Jul 5, 2019

My experience with adapters, and their magazines, is less than salubrious.
This is likely due to how adapters are built to a tolerance to fit as many possible rifles as possible. So, that's not a specifically tight tolerance. That is what it is. The magazines also have sub-ideal tolerances. Which does not combine for a smooth-running combination.

I've never hear the shoot xx rounds of this or that, or if I did, I paid it no mind. Military practice for weapons cleaning is of little guidance, too, as many military practices are about keeping people busy rather than a useful guide to care. For a lot of troopies, it's just another tool, of no particular importance, just one more thing to PCMS, and ont a cherished thing which exists as a trade of precious labor and time to own personally.

If I'm keen to run .22lr through an AR, I've carved out precious time to go be at the range. I've no sergeant to complain to about failures to feed, not cycling correctly or the like. There's the potential I'm paying for range time on the clock, too. So, stoppages and issues are cutting into my recreation time (and dollars). In that circumstance, I'd rather have an upper with a well-fitting BCG, and a lower designed for the magazines used. But, that's me, and my experiences. That, and if I've broken out a brick, I'm probably more inclined to shoot 100 rounds than 10, so a drop-in conversion kit is not really aimed (NPI) at me.

OrangeCat · Jul 5, 2019

I wonder if one of those fancy gas blocks you can shut off for the .300 bo would alleviate some of the issue.

Of course if you are going that far to avoid issues like that I would suppose that a dedicated upper would be an attractive option.

MistWolf · Jul 5, 2019

I have shots several thousand rounds of 22 rimfire through my AR using a 22 adapter. I've never had any problems with the gas tube clogging, but at the end of the shooting session, I always ran a few rounds of 5.56 through the rifle.

We now have a dedicated upper. We no longer use the adapter for much shooting because the adapter leads up quickly and the groups go from a couple of inches at fifty yards to three or four feet. Cleaning out the lead helps, but it's not long before the groups open up again.

bfoosh006 · Jul 7, 2019

Bear in mind.. 22LR ammo has changed as well over the years. Now a days the bullet is "harder" lead.
When the first adapter's came out, I bought a Colt brand adapter.. I installed it in my Colt 20" HBAR with its fancy new twist of 1n7....
The 22LR ammo I was firing, would spin themselves apart about 12ft from the muzzle.
I mean you could stand to the side and watch the 40gr soft lead bullet disintegrate into a cloud of dust.

The sharp new rifling, and to fast a twist rate combined with 22LR ammo that was never intended to fired in a firearm with such a fast twist... was fatal to the bullet.

Surely, I couldn't have been the only one that had this happen.... or many of the other tricky experiences, and all this was well before the internet...so many of the quirky tales listed are handed down.. like this.

And for those of you not familiar with bullets self destructing here is a jacketed bullet that is experiencing difficulties...( From the internet )

Of AR15s and Adaptors

kBob

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cougar1717

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kBob

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CapnMac

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OrangeCat

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MistWolf

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bfoosh006

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