Anybody use a rear-entry action wrench?

Probably not what you want for removing stubborn factory-installed tubes, but for swapping barrels on the go it seems like it might make things a little easier? This spring I had to have the chamber in a barrel tweaked just a smidge, and when it was reinstalled the 'smith clamped the barrel in a Davidson vise he had bolted to a divider in the bed of his truck (serious varmint hunter) and stuck in a rear-entry wrench with a square-drive head for a torque wrench... clickety-click done. Seemed pretty slick compared to my usual farting around with taking the scope and stock off and clamping the barrel (as the Midway action wrench above requires removing the scope rail, another step that I'd rather avoid) and then remembering that I forgot to snake the barrel nut wrench over the barrel before I clamped it, so unclamping and starting over...

Just wondering how good of a grip I could get with a modified barrel nut wrench - modified to clear a scope tube