I have already have a ar-15 in 223 what's the easiest way to make it shoot also 22lr and 9mm I know for the 22lr I can just buy and upper and mag right? But for the 9mm what is easest way to do that?
Thanks

Your better off with a dedicated 9mm lower like a Cmmg and build your new 9mm gun around that. Dropping in a block and switching uppers gets old quick.

.223 and .22 is doable with just switching bolts and getting a .22 magazine. A dedicated .22 upper will in most cases be more accurate though.

That's the answer.
Dave N

for 9mm, buy an upper and mag and mag block;  or buy the Olympic Arms 9mm upper, which uses dedicated magazines that don't require a mag block.

So if I by an Olympic arms upper I don't need to by a mag block for my lower is what ur saying?

Correct.  Olympic Arms uppers use a new polymer magazine of their own design which uses the regular fullsize magazine well and does not require a block.

Thanks for the heads up anyone else do that yet?

Will that mag work with other companies 9mm uppers?

Nope.  Oly feeds from the front of the magwell, and has the feedramp into the barrel extension.

Colt-pattern conversions feed from the middle of the magwell, have the feedramp in the mag block, and have no barrel extension at all.

I'm running a 5.56, 7.62x39 & 9mm upper all with the same stock Rock River Arms lower w/single stage trigger. The 9mm upper is a Rock River 9mm upper with a ramped bolt, I ordered the complete upper with the bolt already ramped from ADCO but any 9mm upper will do as long as the bolt is ramped, that will let it work with the stock hammer of the lower. For a mag block I'm using a Hahn top loader, it just drops right in the top of the magwell with no adjustment. And I replaced my stock buffer with a RRA 5.5 oz 9mm buffer. Total cost was $500 for the complete upper + $150 Hahn magwell block + $30 buffer. Since the magwell block just lifts right out I can easily swap between uppers at the range.
The disadvantages to my setup vs a dedicated rifle are that I can only run metalform mags if I want 100% reliability, they're about $40 each. And the hahn toploader doesn't lock the bolt open on last round, although other Hahn blocks will. Any of the bottom loading magwell blocks have some adjustment up & down which will let you tweek them to run the cheaper ASC/CProducts mags but they don't quick swap like the Hahn top loader does. ProMag also has a dedicated magwell block for $50 that seems to work well with their mags. I looked at the Oly upper & mag option but couldn't find a source for just an Oly 9mm upper & mag, only found complete rifles.

I've got two lowers - one (AeroPrecison) with fixed stock and standard fixed stock buffer; and one (DPMS) with the DPMS 'Pardus' M4 type collapsible stock and RRA 9 mm buffer.  I have several 5.56 uppers and use an older (no BHO or live round extractor) CMMG .22 conversion and mags when I want to shoot .22 LR.  For 9 mm, I have an upper built from parts - Colt system pattern barrel, NDS-32 upper receiver, CMMG ramped bolt; and I have a VM-Hytech magwell adapter so I can use unmodified Uzi mags.  I also have an Olympic .45 ACP upper and mags; and an Alpha Shooting Sports 7.62X39 upper with Model 1 Sales enhanced firing pin and C-Products mags.  I switch uppers interchangably for five caliber capability on both lowers.

I have no affiliation with any of the named companies.

Best of luck whatever you decide.