Multi-Caliber AR's--Necessity or Useless Boondoggle?

[Alaskapopo]

the 223 penetrates further in wall the tests i have seen. the 9mm has the perfect terminal velocity for the 15 yrds needed for any entry I have seen. I havent seen the wall penetration tests on a 6.8, but may have a little more penetration than we would want. Also may become cost prohibitive for training. But with a common lower set up for each persons shooting style and instead of issuing me an ar15, mp5, a rem pss in 308, and grabbing a 12g at the station, I could have just seperate modular uppers and magazines with ammo.

i want a 6.8 though personally

There are several sources on this if you do a search you will find them. There have been tests done on 9mm, 45 acp, 357 mag, 12 gauge buck shot and slugs as well as 5.56 FMJ and soft point ammo in simulated walls and the 5.56 is the least penetrative. Its a fast fragile bullet that breaks up quickly and comes to a stop very fast. Its safer from and over penetration standpoint although many still assume since its a rifle it penetrates more. The 9mm also sucks if you meet well armed foes using body armor which is getting more and more common these days with active shooters.
http://how-i-did-it.org/drywall/results.html
Pat

[jasonusvi]

The thread is off topic. The LMT MRP was introduced in 2004 and is used by plenty of LEO who are able to fit their own rifles because they are quality guns first (and almost never for barrel change based on posts I have seen from LEO owners). As monolithic platforms they actually have fewer parts and a superior rigidity. Unlike the HK piston, the LMT piston option uses standard non proprietary bolts.

The 308 MWS version went though competitive trials, won the British contract, and has been serving hard duty in Afghanistan for over a year. As I understand it, it won because it was accurate and reliable and barrel change ability was a less important bonus.

I obviously value and use the barrel change capability. They are solid value from the start and cant be beat in the game to field the most options at the lowest cost (and weight). That flexibility will not matter at all for some. I am a civilian with limited experience but I did run my 12" piston in an EAG carbine class without a hick up. That is in addition to having put over 1k rounds though the gun each time between cleanings over 4 times now. I have also done a bunch of research on these rifles.

The LMT Monolithics have the reputation for being heavy. True, but often not an equivalent comparison given the heavier standard barrel profile. Just yank it and send it for a profile or dimples.

While not for everyone, I think it is a fantastic (and proven) option for many. LMT should be releasing their 300BLK factory drop in barrel groups imminently.

[Tokarev]

Todd Tuttle from PWS explains their new QD barrel system

http://www.youtube.com/watch?v=mPVtG...layer_embedded

[Tokarev]

Here's a recent post on the firearm blog about a quick change barrel that Ruger was/is working on.

This does raise the question about such a system on a firearm like the M27. Could Ruger have been working on an entry for military markets?

http://www.thefirearmblog.com/blog/2...tomatic-rifle/

[blasternank]

I think there's a place for them. It's a nice concept.

[BAC]

Two extreme polling options with no middle ground...

I like and value the capability of using multiple calibers from the same weapon, provided all calibers can be used dependably. It's practicality has no bearing in my view on this. I just like having options to experiment with.

The only trouble I have with multi-caliber solutions is where to draw the line. How much headroom should the system allow? If we're planning for the hotter rounds, how much are we willing to compromise in terms of weight and reinforcement of parts? Rezeroing is to me a nonissue; I don't see many people swapping calibers in the middle of a fight or when they wouldn't be able to rezero. An optic that held zeros for different calibers would be cool though.


-B