Gun trading

Several years ago I assembled an AR 15 in 7.62X39. It has been somewhat disappointing. Magazines that were available were mostly five and ten rounders. The few thirties on the market were abominations of an AK mag coupled to part of an AR mag. They often jammed. A further down side was ammunition. I'm not condemning the 7.62x39 here, the round itself is a good combat cartridge. The readily available stuff is mostly Russian Chinese or Romanian manufacture. Most of it is steel cased. It does not feed well in the AR platform. In order to get consistent performance, I had to switch to Winchester or Remington ammo, a huge price jump.
Today I got a great deal. I traded my 7.62 upper for a 5.56 flat top with M-4 style barrel. For those of you who do not know, the M-4 is the version with the odd reductions in the barrel diameter. This is done so that an M-203 grenade launcher can be fitted to the heavy barrel configuration.
We had storms roll in this evening, so the trip to the range is postponed until Saturday. Also need to decide on what type of glass to affix. I'm getting older, my vision is getting weaker. I didn't start using a scope for deer until two years ago. I can still maintain minute of angle at 100 yards, but its straining my eyes to make it.
This upper is a Smith & Wesson. I expect I will be playing musical uppers again and will mount it on my S&W lower. right now it is sitting on an LMT lower.
Decisions decisions.