Hello, Im new to the forums and also fairly new to shooting in general. Im looking to buy an AR-15 as my first rifle. I've done a lot of research online and have bounced back and forth between different ideas for what I should buy. I have decided that because I'm new to the shooting world I want to get a AR that shoots 22lr mainly because the ammo is cheaper and I'll be able to spend more time actually shooting. I planned on building my own gun with the help of my neighbor who has a pretty extensive knowledge about guns and the AR platform, and then adding a 22 conversion kit. However now Im looking at the M4LE22-A because it has a barrel designed for the 22lr as well as the Quebec-A. Both the cmmg 22s are about 650-700 bucks which seems to be cheaper than if I built the gun on my own. My question is if I get more into shooting and decide I want to swap out the upper to a 5.56 can I do this? What parts would I need? Just a new upper or would i need anything else? Also what exactly is the difference between the Quebec and the M4LE22? I know that the Quebec doesn't have a forward assist but it is an option so I could get that but what else is different? here is a link to the gun I'm talking about: M4LE22-A 16 inch Rifle with Magpul Rear Sight, www.cmmginc.comCMMG Inc. AR15 Rifles, Parts and Accessories. .22 LR Dedicated AR-15 Rifles, Dedicated AR 15 9mm Rifles and Uppers, Tactical Bacon also there is this one again not really sure of the difference:QUEBEC-A .22 Evolution 16 inch Rifle w/Low Profile FSB, www.cmmginc.comCMMG Inc. AR15 Rifles, Parts and Accessories. .22 LR Dedicated AR-15 Rifles, Dedicated AR 15 9mm Rifles and Uppers, Tactical Bacon Also if this gun can be converted later with the 5.56 upper am I on the right track or should I be looking at something else? Another brand? Thanks in advance for your help/opinions!