You're right about the barrel length/size, but it is an M1A1~A2 bore evacuator on it.

You're also right about the DAZ one. Just opened it up to look (you've really got me interested here). I haven't looked at it in a long time, but now I remember why I never used it. I'm going to have to retract my statement from above about it being 'pretty darn accurate'. The guntube is way too long and the bore evacuator is...incorrect...I'll leave it at that. The whole top of the turret has size/scale issues, as well.

The hull IS pretty good, though. I like how both modelers got the track types correct, too. The M1 and M1A1 both had the T-156 style track, which the gunpoint one has. The M1A1 and M1A2 both had the T-158 style track, which the DAZ one has. (The M1A1 had both and we transitioned from T-156 to T-158 in about '92 or so.)