ACOG Sniping in CoD4

I've been on the receiving end of my fair share of high caliber rounds courtesy of ACOG snipers in the last few weeks. More than my share actually - several other people's too it seems. Not really that fair at all. Anyway, watching the kill cam and seeing the seeming impossibility of shots at both long range and close quarters, I decided to have a go. So last night in a private pistol match while waiting for the rest of our party to get ready for a spot of domination, I kindly asked my friend TOM if he wouldn't mind awfully standing still for a while and letting me kill him. Repeatedly. Since he loves me, I was able to get some practice in at different range and was surprised at how well my M40A3 held up with an ACOG scope attached.

I must say that I did have Stopping Power selected as my second perk which is perhaps the reason for the amazing performance of my ACOG rifle - as is the case when I use the M40A3 with its ordinary scope, I did not need to aim for headshots as a hit to the main bulk of the body did the trick and got me one-shot kills. It seemed to me though that the ACOG rifle might even have been more powerful than the version with the regular scope as even shots to the lower body were providing me with one-shot kills. I'm not sure whether this is really the case as I may have been forgetting that the bullet travels to the top of the red triangle. Perhaps the reason that my ACOG M40A3 seems so powerful is that, due to its much faster aiming speed, I am now able to hit fast-moving enemies full on rather than clipping them in non-critical areas as is often the case with a regular rifle.