What kind of problems could a 22 conversion kit cause for my barrel?

[Skyline_12]

I love the idea of one of these 22 conversion kits for to able to enjoy my AR and practice without much expense. So far I've found ones by like CMMG, 2A Armament, and WMD.

Concerns I have:
1. Would using 22 ammo cause excessive lead buildup in the rifling that would degrade performance and lifespan of the barrel? Or force me to use frequent corrosive cleaning practices that would reduce the lifespan and performance of my barrel? Are there some kinds of 22 ammo that are free of this danger?
2. Would the twist rate on my 1:8 14.5 inch Faxon barrel make accuracy so bad that it wouldn't be very useful as a plinker or training aid beyond close range? If so, I wonder if it's even worth getting, unless I were to get a dedicated barrel for it.
3. I've seen some claim that the problem with these conversion kits is that firing 22 continues to put erosion wear on the gas system of the AR, even if the barrel isn't being worn out by the 22 LR. Although I suppose a gas tube is easily replaced, I would be more concerned about it eroding the barrel's gas port or or something and lowering the lifespan and performance of the barrel. My barrel is nitrite so I wonder if the lower pressure of a 22 LR might not do much damage.

The main thing is: I could easily imagine myself sending two thousand .22 through my AR15 for every 100 5.56 rounds - So I just don't want to end up getting to the end of the lifespan of my nice barrel and realize most of that wear came from .22LR, so I never got to use the barrel for the 5.56 I intended it for. In that case it would probably make more sense to get a dedicated 22 barrel that would also have superior accuracy.

However, if there's absolutely no downside to the health of my 5.56 barrel by sending thousands upon thousands of 22LR through it then I would rather have just a 22 bolt conversion. That allows me to practice with everything else on the gun being the same in terms of weight and balance, saves cost, and makes it more convenient to carry out the gear to switch between calibers in the field.

[jsbhike]

Not sure what corrosive cleaning you mean? I use Ballistol which dissolves lead, copper, and carbon.
.not as fast as cleaners dedicated to each type, but not bad.

I really don't think the .22 down the barrel is going to cause excessive wear (any use causes some wear of course) since it is less than half the pressure and heat. I do tend to think with .22 more gunk ends up in the receiver that does need to get cleaned out regularly.

In my opinion, trigger pull and sight picture are really the only things that fully carry over when using the adapter. Worthwhile, but not 1:1.

Only other thing I can maybe think of is it a 5.56 chamber? I have a barrel I suspect was .223 that was a snug fit with a Ceiner Atchisson unit.

[SteveS]

22lrs won't cause wear. Why not buy a dedicated upper. I have had a CMMG for 11 years and haven't shot a center fire AR since. Last fall I sent the upper back to CMMG for a rebuild.life time warranty and the upper runs better than it ever had.

[austinN4]

I bought a CMMG conversion bolt before the dedicated uppers came out. It works great as long as I keep it clean. It hates the gummy Remington Goldens but loves Federal bulk pack. I like the conversion bolt because everything else about the upper (barrel length and weight, rail, sights, etc.) I use it on stays exactly the same.

[mig1nc]

I had one for years, worked great, but was very ammo picky. It only liked long hot Velocity loads.

My only concern was crap in the gas tube. But just fire a few rounds of 556 before you are done for the day and it should blow out all the crap.

Sent from my Pixel 2 using Tapatalk

[austinN4]

My only concern was crap in the gas tube. But just fire a few rounds of 556 before you are done for the day and it should blow out all the crap.

Exactly what I do.

[10MMGary]

My only concern was crap in the gas tube. But just fire a few rounds of 556 before you are done for the day and it should blow out all the crap.

For this reason and because I could, I went with a complete dedicated Tactical Solutions
22-LR upper, flat top with F marked pinned front sight base. It does have much smaller hand guards. After maybe 8-10 years with CCI minimags it has always been relatively quiet, fun & reliable.(FWIW I only use black dog mags)

[Skyline_12]

Not sure what corrosive cleaning you mean? I use Ballistol which dissolves lead, copper, and carbon.
.not as fast as cleaners dedicated to each type, but not bad.

I've been reading some gunsmithing books and I believe I recall them recommending you not overuse lead cleaning solvents because they will wear out the barrel over time, degrading performance and reducing it's lifespan. Although I could be remembering that wrong.

Also, if the fouling in the gun were to necessitate the use of brass brushes more frequently, or steel brushes and scraps in the chamber more, I wonder if that would also reduce the lifespan or performance of the parts.

I really don't think the .22 down the barrel is going to cause excessive wear (any use causes some wear of course) since it is less than half the pressure and heat. I do tend to think with .22 more gunk ends up in the receiver that does need to get cleaned out regularly.

I suspect I'd probably be more concerned about excessive lead buildup from the 22 ammo used more than the wear on the surface of the barrel or rifling itself, and the effect that lead could have on the rifling.

Only other thing I can maybe think of is it a 5.56 chamber?

I am using a 5.56 chamber in my AR. Would that be an issue?

I have a barrel I suspect was .223 that was a snug fit with a Ceiner Atchisson unit.

I am glad you mentioned that because that is a conversion kit I had not heard of yet. It looks like it could be a good one, and is cheaper than other options.

[Skyline_12]

22lrs won't cause wear. Why not buy a dedicated upper.

A few reasons why it wouldn't be my preferred method:
1. Cost. The cost of the unit is doubled to get a barrel with the bolt, and then I've got to buy a new upper receiver and handguard for it which adds even more cost.
2. Training value. By keeping more of the parts the same, only swapping out the bolt and magazine, I don't mess as much with the weight and balance of the weapon so it's value as a training aid is increased. Dedicated barrels weigh less and are balanced differently. Also, I wouldn't want to have to buy a second $300+ carbon fiber hand guard to go with the upper, so if I went with a cheap handguard that would further alter the ergonomics.
3. Ease of switching and less weight/bulk to carry. If I want to hike out somewhere and plink targets with both calibers I don't need to tote around two complete uppers or hassle trying to switch handguards out in the field.

Those are all significant advantages, but if the accuracy is horrendous out of a 1:8 barrel or it would degrade the performance of my barrel excessively for whatever reason then I would reconsider wanting to get a drop in 22 bolt.
Without accuracy it's value as a training aid is still there but likely diminished somewhat in what I can do with it.
Without accuracy it probably won't be as fun to just use as a plinker. I might find myself turning to my dedicated 22 rifle for plinking fun. Wanting to have fun using the AR platform to plink 22 is half the reason for getting it.
Although I would still probably consider it to have enough value to get it despite poor accuracy as long as it doesn't compromise the performance of my barrel when it comes time to use 5.56.

[militarymoron]

For those who use conversion kits (not dedicated .22 LR uppers), how close is the .22 LR point of impact to .223 POI/optic zero?