AR-15 build 22 dasher / 22BR

[Varmiter71]

So how long is a 22 GT with 75-88 grain bullets compared to a factory loaded 22-250
And does anyone know who would make a barrel for an ar-15 in either the dasher or gt

 

[Varmiter71]

Here is a 22BR loaded with an 88 grain eldm in a UMAR mag