Want an M4forgery upper to dedicate to .22LR

As the subject line sez, I am seeking an “M4” looking upper to use with a .22LR kit and BDM mags.

I want to occasionally swap out a dedicated .22LR fakey XM177 upper I have on my Oly plinker CAR for this fakey M4. (FWIW; I have an untouched 1974 SP1 to plink with when I want to make more noise and spend more ammo money…)

I do not need a high-end M4 upper by any stretch, just something that looks exactly like a street-legal LE6920 from a few feet away and goes bang with the .22 kit, and maybe occasionally with the original Oly bolt.

If anyone can recommend a cheap parts combo or a cheap pre-built upper from any source, I’d appreciate it!
Thanks!
Steve in Pittsburgh

edit: Gave you an answer, but they did a good job here as well…

https://www.m4carbine.net/showthread.php?t=19697

Pretty much anything that looks like an M4 built for 5.56 should work… Slower twists (1:12, 1:14) will work better, but for just plinking you should be fine.