Question. Don’t know if this has ever been questioned or not, but just curious. The 25m zero target in use by the military places a 300m silhouette on the 25m line of a range, to zero a rifle for that distance. Now say you get a microscopic group on that target, what does that mean for the real thing? Obviously the bullet holes are going to be a little smaller on the true 300m, but what about the size of the group, comparatively speaking. So let’s imagine this. Perfect world, NO wind, NO atmospheric anomalies, and you mounted two 16" M4s in rests, side by side. Now 5 shots would be fired from each, one at the 25m zero, and one at the true 300m target. What happens? (this is assuming that both rifles are initially zeroed together at the same distance before the exercise). Any takers? I know the math, just wondering if anyone else has wondered the same thing, and what you think. I think of pointless crap like this from time to time.
I think, yeah the groups will be bigger, due to the moa of the gun. But if you zero at 25 yards, it will be zeroed at 300 yards also. I guess they use 25 because then the soldier is focusing on what he can control - his point of aim. He can’t control the accuracy of the gun, so no sense trying to qualify at 300 I guess.
true, and 300m ranges can’t be found on every street corner either I guess.
Military’s been qualifying at and beyond 300 meters (Marines, 500yds, with irons) for a few years shy of a century, now, and there’s plenty of sense in doing so. Whether or not it’s truly applicable, though… Wooo, there’s not enough bandwidth to settle THAT argument.
Also, can we ever get over the idea that yds/meters are the same thing? They’re not, and while it makes no difference whatsoever on the front end of a ballistic arc, it makes a helluva difference on the back end. Plus, it’s the 21st Century, nobody worthy of note fights in yards any more. 25yds (75’) vs 25m (82’) = if you do a 25yd field-expedient zero, you will NOT get close to a 300m zero. OP said meters, so meters it is.
CAI, if I read your question right, and presume that both rifles have been zeroed @ 300 for-real meters, then you will likely see the group on the 25m target print somewhat differently. And not just because it’s a different gun. A 25m zero doesn’t really give you a 300m BZO. It ensures you are on paper @ 300m when you confirm the zero. Only a 300m zero gives you a 300m zero, once you leave the realm of whiz-bang calculators and get to pulling triggers. Virtually all the dudes here that utilize the things will say the same thing, that you never KNOW until you shoot what you graph.
So, the gun on the 25m line in your scenario will likely have the center of its group print differently than the gun shooting at the 300m target, presuming a COM hold. Close, within reason, but probably not the same. The same would be true if both guns were zeroed @ 25m, but shot at 300m targets. the one shooting at the 25m target would be POA/POI, and the group on the 300m target would be on paper, but group POI will probably be off from POA.
I doubt you meant it this way, but just to be clear, the diameter of the bullet does not shrink over distance provided it’s still intact.
I am completely confused by the larger/smaller bullet hole question, so I’m not even going to guess on that one.
I think what you’re after is the difference in the groups. Well, for one, your mean point of impact (the center of the group) won’t be in the same place going from 25 to 300 meters. It’ll be close, but not the same. Also, your group will be 12 times as big at 300 meters as it is at 25 meters. Example, a .5" group at 25 meters will become a 6" group at 300 meters (assuming a benchrested rifle, constant wind, all of that “ideal” stuff).
I think what he was saying about the size of the bullet holes is that obviously the holes on the 300m target would not be as large scale-wise.
That what is basically .25 inch holes at 25 meters would not scale up to 3 inch holes at 3oom.
Or he might have meant that. 
I thought that part sounded like somebody trying to divide by zero. I was afraid to address it, lest it destroy me.
I never liked the 300 meter zero. At 100 and 200 the point of impact was way too high. I used the Improved battle sight zero.
That’s the trend 'round these parts, too, and I wholeheartedly agree with and use it on my irons and RDS. Hell, I push it to the Marines I train for use on their BUIS, in spite of the cries of “Blasphemer! Follower of a False Prophet!” I get from many.
It bears mention, though; a good point. Molon and others have posted lots of good info regarding different zero theories on numerous occasions.
CAI, we’ve had some pretty nice cat-fights over zeros. Something for your Pointless Crap File: https://www.m4carbine.net/showthread.php?t=34671
good times, good times indeed. didn’t mean to open a can of worms, just curious. and about the size of the bullet holes, all I meant was figuratively speaking, the size of a bullet hole on a 300m silhouette set at 25m, is huge compared to the “subject/target”, that’s all.
I’ve been interested in doing the improved battle sight zero, got some free time this weekend, might have to give it a go. thanks guys, just wanted to poke some brains.