http://www.shootingillustrated.com/i...eapons-system/

While the idea of being able to quickly and easily swap from one caliber to another with a minimum change of parts sounds like a great thing, I find myself questioning the actual practicality of such a system. Much interest has been expressed in the multi-caliber features of the SCAR, XCR and ACR and now I see some makers working on QD barrel set-ups for the AR.

The systems I've seen advertised tout such claims as being conceived "for specialized military and law enforcement use, where an operator might need to clear a building with a short 5.56 NATO barrel and then transition to a 6.5 Grendel for an overwatch or designated marksman role, or to the .50 Beowulf for vehicle checkpoints, close-in work against body armor-wearing opposition or any other mission where a huge, slow hunk of lead is the preferred projectile."

But, as mentioned in the article linked above, the glaring issue with this is loss of zero and POI/POA shift between dissimilar calibers. Using a 10" 5.56 for CQB--and having the optic zero'ed accordingly--will not give the shooter an optic that's useful in a 6.5 Grendel in the DM role. Even if the shooter has the ability to know his holdovers or optics settings between one caliber and the next, I have to wonder just how repeatable the POI shift is each time a certain barrel is removed and re-installed. Also, I think the idea that the individual user will have three or four barrels (along with bolts, magazines and ammo) in his backpack or whatever is silly.

With the above concerns voiced, I do see the the merits of such a system in a limited and specific role when the shooter has the chance to swap out his barrel and bolt and re-zero his weapon with the new barrel installed. But, if these systems are going to suffer from POI shift and loss of zero, even that becomes a useless feature. If I pull my 16" barrel off for transport or storage and then attach it to shoot a target at 200-300 yards, only to find that the QD barrel has a random POI shift of 3-4 MOA, my time will be spent re-zeroing rather than actually shooting.

Another benefit would be that the rifle can be stripped for a very detailed cleaning. Again, the benefits sound good on paper but I don't think I've ever really found the need to pull a barrel or gas tube off an AR so I can get every last little hint of crud out of the gas tube hole in the upper receiver or whatever.

Lastly, I guess the best and most realistic use for a multi-caliber system would be the ability to shoot more ammo at a reduced cost. Having a quick and simple system that would allow the shooter to go from 223 Rem to 5.45 or 22LR (or from 308 to 223) would probably be the best selling point for most users.

Are my concerns valid or am I missing the point of the new technology?