looking to build an AR, but I don't feel like buying all the tools and putting the lower together.  Was planning on buying a complete lower with a buffer tube but no stock(have a fixed magpul moe stock) and then purchase a completed 16" upper later on down the road and put it together.  will there be any issues with this?  

mainly concerned with the 4473 form and what the lower would be classified as.    don't ever plan on making this a pistol or one of those sbr "other firearms"

No problem at all doing this. 
 

The complete lower will be transferred as a rifle. 

I believe a complete lower without a stock is an "other" since it is not a rifle unless it has an upper and a stock nor is it a pistol because it does not have an upper on it. I don't believe it makes any difference if the lower has the buffer on it or not when you get it. 

1 minute ago, SJG said:

I believe a complete lower without a stock is an "other" since it is not a rifle unless it has an upper and a stock nor is it a pistol because it does not have an upper on it. I don't believe it makes any difference if the lower has the buffer on it or not when you get it. 

this was my big concern.  if it gets listed as an other will i still be able to buy that 16" upper and use it or will there be issues? 

I seem to remember having that conversation with my FFL and he told me that a complete lower would be transferred as a rifle..although he may have presumed it included a stock. 
 

Or maybe I mis-remembered...could be that too. 

13 minutes ago, Rick said:

this was my big concern.  if it gets listed as an other will i still be able to buy that 16" upper and use it or will there be issues? 

If you buy an incomplete lower it’s an” other” you turn it into a rifle or “ other”. But definitely not a pistola in this state 

I actually recently completed my first lower, and besides and armorers wrench (which you can get cheap) and a 15 minute YouTube video..I didn't need anything "special". It's extremely intimidating when you haven't done it before. After completing my first one I could confidently do it again without the video. There's a couple tricky parts and a detent and spring may fly across the room, but besides that it's pretty straight forward. Don't let it scare ya. 

Also to add, always have an easily lost or broken parts kit or two around. Ya know in case....they're like $6 each...

so basically never put anything but a rifle buttstock and keep a 16in or longer barrel and it's good?  there shouldn't be any issues releasing the lower to me without a buttstock attached, right?

1 hour ago, InFamous said:

I actually recently completed my first lower, and besides and armorers wrench (which you can get cheap) and a 15 minute YouTube video..I didn't need anything "special". It's extremely intimidating when you haven't done it before. After completing my first one I could confidently do it again without the video. There's a couple tricky parts and a detent and spring may fly across the room, but besides that it's pretty straight forward. Don't let it scare ya. 

Also to add, always have an easily lost or broken parts kit or two around. Ya know in case....they're like $6 each...

Hear that @Bighungry618

2 hours ago, InFamous said:

I actually recently completed my first lower, and besides and armorers wrench (which you can get cheap) and a 15 minute YouTube video..I didn't need anything "special". It's extremely intimidating when you haven't done it before. After completing my first one I could confidently do it again without the video. There's a couple tricky parts and a detent and spring may fly across the room, but besides that it's pretty straight forward. Don't let it scare ya. 

Also to add, always have an easily lost or broken parts kit or two around. Ya know in case....they're like $6 each...

^^^^^  This.^^^^^^.  I build my first AR last year, can’t wait to do the next one. 

Just now, Tony13 said:

^^^^^  This.^^^^^^.  I build my first AR last year, can’t wait to do the next one. 

My first AR I actually had my wife's cousin build. I purchased all the parts but he put it together. He's a Marine sniper and a gunsmith. This next build I built an "other" and did the lower myself. A couple frustrating moments but it made me just want to build another one!