I share the concerns of Ken and Coldstreamer, but have a slightly different take. I think that we used 25mm and 40mm extremely effectively and could use something like the XM25 effectively, as well (though I see no pressing need for it and we could certainly make do without it).

In OIF III, my unit fought against a hodge-podge of various insurgent/terrorist factions that came and went in our AO. Lacking intelligence to do much more than fight them when they exposed themselves, that was about all that we did. In all of the firefights that we had over a year-long deployment (more than I can count), we had zero KIAs and all wounds were RTD. Nonetheless, the people in the city would complain that we "weren't fighting back." As they saw it, a few insurgents would dump multiple magazines of 7.62 at us, throw a few grenades, fire a few RPGs - all indiscriminately - and we would only return well-aimed fire. To the Iraqi citiizens, this looked like we were weak, because we were not firing nearly as many rounds, we were being cautious, and anything that got blown up was a result of enemy munitions. Even though we were killing the attackers and suffering no losses in the process and no collateral damage or civilian casualties, we somehow looked weak in the eyes of the folks in the neighborhood (didn't make sense then and still makes no sense). Explaining to them our rationale (avoiding civilian casualties) only earned us eye-rolls and disgust.

So here is how we fixed that perception problem. We started making copious use of 40mm. 40mm was actually far preferable to 7.62mm because it did not ricochet (in prior months, we accidentally hit some civilians with ricochets). On occasions when an OP spotted an IED emplacer and could have shot him with one round to the chest, we fired 40mm. We set up a free fire zone in which we told no civilians to travel. When we got attacked from that location, we peppered the place with so much 40mm, 25mm, and even hellfires, that rumors began to spread that we had surrounded and killed Zarquawi (when, in fact, we were simply making quick work of a few random combatants). In the first month of this new tact, we fired more AT-4s than in the prior six months combined. It actually caught the attention of the BDE S-4 who noticed an enormous amount of class V being pushed our way - he feared that we were stockpiling it or carelessly discarding ammo once it got dirty.

The result of these actions? We experienced no greater tactical success against the jerk-offs whom we were fighting against, but the populace had a far more favorable opinion of our efforts. Now, instead of more gunfire coming from the enemy, they saw more coming from us. It was reassuring to them and they actually thanked us for "finally" fighting back.

Now, this more liberal application of high explosives could have backfired, for the reasons cited by Ken and Coldstreamer. Had we used poor judgment as to when to fire 40mm instead of 5.56mm, or if the guys squeezing the trigger were poorly trained and misplaced their rounds, then our results would have been significantly worse. So the issue isn't the weapon system's risk for collateral damage. The issue is how well the guys who use it are trained. If they know their profession, then figuring out how to leverage the capability of yet another weapon should be no problem. A well-trained Soldier who understands the capability of a new weapon system will have no problem thinking through the repercussions of firing through a wall when he is uncertain what is behind it and his leaders should have no problem balancing the risks of doing that. So, long post short, I am not concerned about the issues cited with using the weapon. I am concerned with whether our Soldiers are properly trained and know the capabilities of the weapon. If they are properly trained, then they will not be misusing this weapon and causing collateral damage.