I have been giving thought to getting a Ciener .22 rimfire conversion kit to use with my 20" Bushmaster. I thought it might be more enjoyable for my kids and additional fun for myself. Are there any issues with using lead vs. copper jacketed ammo? My own thoughts are that the reduced velocity of the rimfire round would minimize the barrel fouling. Does anyone have any experience using these kits? And can you start out at the range shooting .22 rimfire and reconfigure to standard 5.56mm ammo without cleaning the barrel?

You should have no problems with the conversion if you use copper plated ammo. Stay away from plain lead, they gum up the gas system. You can shoot regular .223 after using the kit without prior cleaning. I typically fire .223 after several hundred 22 LR rounds to clean the gas tube. 22LR ammo is dirty and will leave filth in your upper and lower recievers that will need to be washed out occasionally with brake cleaner if you're a clean freak like myself.

I've shot enough rimfire that the upper would not chamber a .223 round when the conversion was removed (after cleaning) Took some a good bit of work with a chamber brush up in the throat to get the gook out.

Not trying to steal the thread nor be a smartass but really want to know.

Why, do you want a .22 conversion?  Seems to me a 10/22 cost less and shoots the cheap stuff and seems to me that even the copper clad, which is really a plate, would still be dirty compared to FMJ .223.

Just my $0.02, but how about a DPMS dedicated 22LR upper?  No gas system or other cares.  Cleans up with brake cleaner and a brush.  Only drawback is no pre-ban mags and it barrel heavy.

A dedicated 22LR upper would be cool. The 10/22 is a distant 2nd to a converted AR, IMHO.

So you can train cheaper or shoot indoors where rifle calibers arent allowed, while using the exact same weapon you will be using with rifle caliber rounds.

Same stock, sights, controls etc....

The Ciener (or other .22LR kit) provides better training than a 1022 if the goal is to develop skills with the M16/AR15.  The 1022 has vastly different characteristics.  Great little rifle, but you don't get any AR15 specific skills.

I'm not sure the accuracy of these from the very common 1/9 twist barrels.  1/7 is too tight, the reason the Army stopped using this type; the fast rifling tends to reduce the lead bullets to blobs of lead which aren't too accurate.  Works great with 1/12 twist.

The rifle will have to be rezeroed for .22LR and again for 5.56mm, but if you record your sight settings you can put the sights back where they belong without a trip to the range.

-- Chuck

1.  A 10/22 does not feel or handle like an AR15
2.  It's a cheap alternative if you really like to shoot your AR15/M16
3.  A 10/22 can't mount all the accessories and gear you may have on your AR15/M16
4.  If you are like me, after you buy your M-16, you can't afford a select fire 10/22 on top of that, and let me tell you - shooting .22lr from your M-16 is cheap and suh-weeet!

Bottom line?  A 10/22 is not your AR15/M16/M4gery.  After investing in all the accessories, optics, and such, which one would you like to get more use out of?

5.  No one admires my 10/22 (don't have a fancy shmancy target version), but they all like my AR15's/M16. YMMV

I have the Colt conversion kit.  In my 1/7 or my 1/9 accuracy is pretty poor.  The best I get is 1 1/2" at 25 yds.  Typical is 3-4-5" groups at the same distance.  They do lead the barrel and foul the chamber something fierce too.  

The barrel should be cleaned before shooting 223/5.56 ammunition to keep the pressures down.

Best thing to do is to have a dedicated upper just for .22 LR.  That way you do not have to worry about the gas port getting lead in it.  You can build an upper yourself out of inexpensive parts you can pick up on the boards.  A big reason for my using the .22 conversion kit is because I have a dedicated upper with a suppressor on it.  I can shoot full auto in my backyard without having the police called on me (I live on 4 acres).  If I tried to fire a suppressed .223 in my backyard, I would definitely get the police called on me.  So, with the .22 conversion, I can shoot full auto in my backyard and even shoot in the garage with a .22 bullet trap.  I have also hunted coyote and other varmints with the .22 full auto conversion kit.  That is really a blast!  Full auto .223 would not be practical with the consideration of the distance .223 rounds will travel.

Charles Tatum
Alamo Professional Arms

I have a .22 conversion, for that very reason, but TomJefferson has a point.  Depending on how important the "it's an AR" factor is, you might better off with a 10/22 (or some other .22 rifle).  They'll be more accurate than the kit in a .223 barrel, and likely lighter and/or shorter and easier for the kids to handle.

If you do go with a conversion kit, I wouldn't shoot .223s after .22s without cleaning good first.  Even without the possibility of lead in the barrel raising pressures, the dirt that the gas port blows back into the upper makes it sound like it has sand it when you drop the bolt back in.

Also see [url=http://www.ar15.com/forums/topic.html?b=3&f=15&t=145537&w=myTopicPop]this thread[/url].