I have a CMMG all stainless conversion and it works great..what I did is I bout an unlined barreled upper using a wilson barrel and use that as my dedicated .22 upper...still though my 10/22 with BX 25 25 rd mags is the most reliable .22 I have.

The twist of your 5.56 barrels has a lot affect on the rimfire ammo. Every barrel is unique but generally the faster twist barrels like 1 in 7 twist produce larger groups and more fliers than slower twist barrels. Some posters state they've gotten decent accuracy out the 60 grain Aguila SSS ammo in faster twist barrels. In my 1 in 9 twist I get decent accuracy and good reliablity out of Federal 36 grain 550 bulk packs.

I have a 1 in 9. From the look of the pics I've seen does the part that fits in the 223 chamber stay there and the rear of the bolt move on the spring and the buffer and spring keep it in place? What about the gas tube?

Yes, the chamber adapter stays in and the bolt rides along the adapter rails. They're a lot of fun and an easy way to get into rimfire conversions and see if you like it on your AR. The design of the bolt is such that it doesn't have an issue with the gas tube.

Well not to pop your bubble BUT if you intend to be profecient with the AR in FULL caliber dress you better shoot it that way.

ignore the troll.

Using 22 lead bullets can leave a lot of lead fouling especially in the gas port which can cause cycling issues. running some 556 ammo through it or even cleaning out the gas tube/port may be needed occasionally.

I was seriously considering a 22 conversion but decided that for close to the same money i could just buy a dedicated 22 rifle.

I like accuracy. I bought a CMMG dedicated barrel, conversion kit, and assembled a dedicated upper. With Fed bulk pack ammo, I can rip a ragged hole at 25 yards, shoot about 1" at 50 yards and about 3" at 100 yards with magnified optic (2X7 scope.) Not stellar groups, but fun to plink around with. I have bolt action 22's that will shame my AR conversion with most any ammo.

I've seen guys with the converstion kit in a 223 upper and accuracy is poor at best. Good at 25, pretty bad at 50 and non-existant at 100. If you just want to blast and plink at 25 yards, have fun. If you want accuracy, invest in an upper with dedicated barrel. Of course, you can buy the conversion now, shoot short range and save up some money, and buy the upper and barrel later using the same conversion kit you already have to complete the build.

I've bought 3 of them.

They work in every AR I've tried them in. Had some magazine issues in one rifle. By coincidence (maybe) that is also the only rifle we've had leading issues in. All the ARs we've used them in have 1 turn in 9" barrels.

The one that leaded up was a chrome lined 20" HBAR clone.

The XM177 clone shoots exactly 3" low (vs. .223 ammo) at 25 meters.

My 20" HBAR clone shoots about 3" low and almost 2" to the right at 25 meters.

My son's .20" HBAR clone shot high and left at .25 meters.

Another 20" HBAR clone shoots low left at 25 meters.

My 16" carbine shoots a couple of inches low at 25 meters.

It depends on the rifle and ammo where yours will shoot vs. .223 ammo - so get out and try different brands to see what shoots best (groups) and where vs. POA.

I really enjoy shooting cheap .22 ammo through my rifle. Cheaper, still fun, don't notice recoi of an AR anyway (except that .300 Black Out that raps my nose more than the .223 or .22 rimfire).

I have an army M261conversion. I put it into a regular Bushmaster upper and shot it for about a box of shells and the accuracy fell off dramatically. The faster twist barrel was the culprit. Two to three inches in front of the chamber was leaded so heavily that the rifling could not be seen.

I put the conversion into a Colt SP-1 upper with a long rifling twist and it shot extremely well at all ranges. It has never leaded at all in the Colt upper after a lot of shooting.

The faster twist is the boogeyman with conversions is most cases I think. Find an older pencil barrel and stick it on an upper of most any kind and the conversion will work well for you.