Model 727 = early M4?

[MT2008]

Originally Posted by Excalibur

So none of the early colt carbines had burst?

http://en.wikipedia.org/wiki/AR-15_variants

This chart says that the models 733A, 734A, and 735 (all of which were 11.5-inch barrel models) had burst.

Also, I think there may be a typo in this chart, because I'm pretty sure I remember reading that the Model 725B also fired burst. I'll have find my copy of the book that this chart comes from to be sure.