hey guys im wanting a 22LR AR, i already have a complete AR15 so would it be better to buy a m&p15-22 or can i use my AR 556 lower and build or buy a 22LR upper. how does all this work? does the 22LR mags fit like the 556 so it will fit the magwell.

Its never a bad idea to have another, real, AR lower that can take any milspec upper.  So If I was you, id buy a real lower like a CMMG and then get a dedicated 22lr upper.  And yes, the 22lr magazines go right in a standard lower.  The 15-22 is good too, and its mags are awesome, but Id only get that if I already had the other.  Me, i have a couple dedicated 22lr rifle builds, and then 10/22's.  Id get a 15-22 right now, just to have, if the mags werent going for $60 apiece.......that makes it difficult to buy the needed 15 to 20 mags that any platform should have.  They make a mag well insert that allows you to use the S&W 15-22 mags in your dedicated 22lr upper.

thank you, another question if you buy the lower and later on down the road i want switch it back too a 556 i can right? and is it gonna cost about the same price as the M&P 15-22 or more going this route?

You will generally spend more on an upper/lower combo but you will have a lower that will continue to accept standard AR uppers.

A .22 LR AR style rifle like an M&P 15-22 cannot and will not ever do  that.

I run a Spike's ST-22 on a Spike's lower that I built.
My lower is complete with buffer and spring as I wish for it to be instantly swappable back to .223.

I have about a dozen mags for it but that's in consideration for wear, tear and breakage.
I do not intend to take my .22 upper into combat and have not planned on a full load out of mags for war.

nice i am looking at mybe going with the spikes complete upper or a CMMG. then gonna build a decent lower. i also looked at some of the tactical solutions and there really nice. so the plan is either spikes, cmmg, or tact sol.

I would go CMMG or Taccom upper myself. You can run either on your present Lower till you can make its own Lower. The SW upper or lower can never be used with anything else, both SW upper and lower need each other to work. Not the case with the CMMG,Taccom or TacSol..     Stuff is just really hard to find right now though, so you may have to have some patience..

Yes a dedicated upper is going to be more, but well worth the extra cost in my opinion..

There is a guy on here that sells Spikes/CMMG SS tube kits. You get a .22LR Spikes M4 profile barrel, a CMMG stainless steel bolt carrier group and a CMMG forward assist adapter. All for $300. I this route due to wanting to use my own upper receiver, and free float handguard. If you purchase a complete CMMG upper, you are stuck selling the "gas block" and hand guard assembly if you want to set it up with a free float front end. SS bolt carrier groups are preferable to phosphate coated when used in a .22 because they run so dirty. The SS BCGs are also very hard to find right now.

Here is mine for reference:

great info im geting here guys thanks. i could do 300 for that kit i just really would like a complete upper so i can just swap out until i get my lower built.that way i dont put too much pounding on my only AR. another question is what are the best mags you can get im talking like p mags in 556 but something thats gonna feed good and just good quality stuff.

People love S&W 25 round mags b/c they are durable and easy to load. Plus, it is easy to get reliable bolt hold open functionality by installing this into your lower.

The Black Dog Machine mags are also pretty popular but I have had issues with the Gen 1/2 versions b/c the feed lips crack due to the bolt slamming on them after the last round. The X-Form BDM mags I have don't appear to have the cracking issues. Still, it is more troublesome to get BHO to work with them as you have to do things like swap out the BHO spring on your lower or exchange the BHO assembly for an aftermarket part specifically designed to actuate the bolt hold open (and now you don't have a fully mil-spec AR lower any longer).

With the S&W mags and the BHO insert I linked you to, Your .22LR will perform just like your .223. when it comes to mag changes. Also, should you want to mount a 5.56 upper on it, all you have to do is pull the BHO adapter out of the bottom of the mag well.

Get the complete M4 upper or the Ultra Lite from TACCOM.
Dave N

what about this....
http://www.armslist.com/posts/880013/louisiana-gun-parts-for-sale--nib-chiappa-ar-15-m4--22lr-complete-upper--ffl-ready-to-ship-

Chaippas are lesser quality (from the extensive research I did before purchasing CMMG components and building my own). I would go CMMG if you are looking for a complete upper. Be patient, everyone and their mother wants one right now.

yeah i know its like 556 uppers and ammo its all hard too find i never thought the 22 ammo would get like that. whichever i can find first at decent price between the spikes tactical solutions and CMMG is what im gonna go with. if they wanna throw in a few extra mags that be even better on deal.

You're welcome...

http://www.ar15.com/forums/t_7_150/1159555_WTS__NIB_CMMG_complete_22_LR_upper.html

I understand these are hard to come by right now, but that price seems a little excessive (not horrible, but I guess it depends how badly you want one).  From CMMG direct, that would be $465 shipped.  I would keep an eye on the EE and Gunbroker, some decent deals lately.

Buy a CMMG or TACCOM.  

MAHA

I have 2 CMMG dedicated .22lr uppers and they are awesome and they run great.
I'm glad i have these instead of the M&P 15/22 because i can still buy the XForm mags for  $15.

EDIT; I had a Chiappa and it was WAY LOW QUALITY. The bcg had flaking chrome plating after a couple hundred rounds and the barrel nut came loose 2 times.
All the parts appear to be pot aluminum or pot metal. Very poor finish on the parts. I do not reccomend.

I have a Taccom 4" and a Tactical Solutions 16". Both run well and shoot where you point them. I would buy either again.

Be aware that it seems all dedicated 22 uppers take a few hundred rounds to break-in (become relaible) and some polishing on the bcg never hurts.

If you have a SBR, the 4" is an absolute hoot. Mine runs multiple brands of 22 LR great and is super fun with a 5" muzzle brake or a can.

I have not made any modifications to my lowers in any way to run these uppers but I do use the Taccom plug and a "filled-in" CMMG charging handle.