I am kind of paranoid about using the ceiner kit in my 5.56 upper do to all the issues I read about lead fouling of the gas tube.

I hate to spend the money for a dedicated upper since I already spent the money on the kit. I bought the CCI Mini mags since I heard they are the cleanest 22s you can get.

I know firing some 5.56 after the 22s cleans out the gas tube, but I do most of my shooting at the indoor range where you cannot use 5.56.

Just shoot the thing.  Use copper plate .22s.  The .mil used conversion kits.  You can too.

Quoted: Just shoot the thing.  Use copper plate .22s.  The .mil used conversion kits.  You can too.

+1

I have shot thousands of rounds of Federal Bulk Pack ammo and haven't had any problems at all!

Don't worry about it.  Have fun shooting it.  And when you can give it a good cleaning then blast some .223/5.56 out of it.  Surely you have somewhere to shoot .223/5.56?

Quoted: Quoted: Just shoot the thing.  Use copper plate .22s.  The .mil used conversion kits.  You can too. +1 I have shot thousands of rounds of Federal Bulk Pack ammo and haven't had any problems at all! Don't worry about it.  Have fun shooting it.  And when you can give it a good cleaning then blast some .223/5.56 out of it.  Surely you have somewhere to shoot .223/5.56?

The only outdoor range is an hours ride away and I only get there a few times a year :(

Shoot it then fire a few .223/5.56 rounds to clear everything out. I did this for a long time without any issues. The biggest complaint is that the rimfire stuff is dirtier and more of a pain to clean. It does foul a lot quicker than full power loads and may cause some reliability issues after about 500 rounds of rimfire, or at least that is what mine did.

I bought a spare gas tube and cut it off and installed it upside down to block off the gas hole when shooting rimfire. This kept the gun a whole lot cleaner and would easily make it to 1K of rimfire before I started getting the same reliability issues I did at 500 before. Now I just leave the conversion in along with the flipped gas tube because most of the shooting I do now is rimfire. I normally shoot 500 or so rounds 3-5 times a week.

Dolomite

If you never clean your rifle, worry. Otherwise shoot it. I have no issues from 22's.
Many Thousands of rounds later. Federal Bulk 22's Only.
SO-13

Quoted: I am kind of paranoid about using the ceiner kit in my 5.56 upper do to all the issues I read about lead fouling of the gas tube. I hate to spend the money for a dedicated upper since I already spent the money on the kit. I bought the CCI Mini mags since I heard they are the cleanest 22s you can get. I know firing some 5.56 after the 22s cleans out the gas tube, but I do most of my shooting at the indoor range where you cannot use 5.56.

I'd say 99% of the "lead fouling from firing .22s in an AR" scary talk comes from back when both the Army and Air Force depended on .22 conversions for a lot of rifle training.  Those rifles had the crap shot out of them with .22s, and in the case of the Air Force, not enough cleaning and maintenance.  Sure, you'll get crap from those lead bullets, especially non-plated bullets, building up in the gas tube.  But there won't be much of it, and it will just be "deposited" there, not scraped on like bullets leading a barrel.  Just stick to plated bullets and fire a magazine worth of .223 every now and then, and your gas tube won't have any problems.