Designing a flexible rifle

[Trooper]

One of the problems with the current AR design is that it is difficult to change calibers. There have been some attempts with the Remington ACR being one of them. Another is the Lewis Machine Tools (LMT) who can change barrels easily.

http://www.lewismachine.net/

Wonder if Alexander Arms could do something similar? Or if DS Arms would do so.

[LRRPF52]

I would say the AR15 is one of the easiest designs to change the calibers on, even if just switching out barrels, let alone uppers. You would be hard-pressed to find another system that is as modular as the AR15. The Masada is basically a modernized hybrid of the AR15 and AR18, with influence from the XM8, using a Quick-Barrel Change mechanism where the wrench is attached to a nut on the barrel, and folds up under the handguard.

I have 2 tool-less Quick Barrel Change uppers, and I never use the Quick-Change feature anymore. They are my least-used AR15's, as I had horizontal stringing issues with the first one, and don't want to waste anymore quality ammo through it. For close-range blasting, it's fine, but I don't trust it at 100yds or further.

I still think LMT would do well to introduce a 6.5 Grendel Conversion for the AR15 MRP.

[Drifter]

Push two pins to change uppers, and maybe change the mag and bolt if necessary. Quite flexible as is.

[bwaites]

Templar Consulting has a quick change system as well. From those who have shot it, it sounds as if the accuracy issues have been resolved, but it is nowhere as cheap as simply having two uppers!

[Bill Alexander]

Why, what is the end function of being able to change caliber on an assault type weapon. Are you compromising the primary function to allow for a little used secondary and tertiary role.

How does the addition of complication influence weight and reliability and how far you you wish to extend the change over ability. The Lewis Tool and Machine set up is elegant but stays within a caliber family. Contrast the Colt system which presents a 12lb 5.56 carbine.

[Variable]

Why, what is the end function of being able to change caliber on an assault type weapon. Are you compromising the primary function to allow for a little used secondary and tertiary role.

How does the addition of complication influence weight and reliability and how far you you wish to extend the change over ability. The Lewis Tool and Machine set up is elegant but stays within a caliber family. Contrast the Colt system which presents a 12lb 5.56 carbine.

Hunh???

[bwaites]

Hunh???

I think he's talking about the flexible caliber Colt LE901, which when its railed up weighs north of 10 pounds. The stripped version is over 9.

[Nukes]

precision bolt rifle

Gotta love the DTA SRS system. Mark Gordon at Short Action Customs has prototyped a .223/.300 BLK conversion. I have hinted about a 6.5 Grendel conversion, but most 6.5 lovers gravitate to the 6.5 Creedmoor.

[Variable]

I think he's talking about the flexible caliber Colt LE901, which when its railed up weighs north of 10 pounds. The stripped version is over 9.

Right. 9.4# in 7.62mm--- not anywhere near 12, and less with a 5.56 upper on board. It would be wrong to blame Colt for that too. They merely developed and provided what was requested. When the .gov asks stupid questions, they'll get stupid answers. On the side though, the 901 seems to be a nice stick so far. I might keep one for me after people stop going ape for them. I've been a dyed in the wool Grendel convert since the beginning of the old board, but every once in a while I want to go crazy just for something different for a while.LOL


ETA: I just read what I wrote... Derrrr. I need to communicate more clearly. I need to add the fact that I also certainly see what Bill was saying though.

I also agree. Wanna change calibers? Push two pins and swap uppers. Done. If you need a whole 'nuther class of cartridge, then just switch weapons. I wouldn't want to freight a 901 just so I could stick a 5.56 upper on it. It's not like keeping a 5.56 lower on your 5.56 upper is that hard. All that crap will be in the vehicle anyway. I don't think anyone in there right mind would be freighting an extra upper in their pack while they were on foot.

[kegs]

Personally, I can see it being very useful to have one firearm with maximum modularity. The AR is a nice design due to the upper & lower separation but the AK is advantageous in that the stock can be folded & the action is still fully functional. Ideally, a rifle in which the stock is a robust, highly precise folder and the barrel has a threaded connection with a threaded shroud over that, with the ability to take a variety of calibers from .22LR to .50 BMG, (upper receiver also modular) would be my choice. I expect something like this is readily available for enough $$$, but its but a dream to me. Lets keep in mind that these rifles aren't only used for combat! No need to have a battery of rifles when you have one that can do it all.

[Fillar]

I don't think anyone in there right mind would be freighting an extra upper in their pack while they were on foot.

That is funny that you wrote this. My BOB has the ability for strapping on my 6.5 upper while I'm assuming I'll carry my assembled 5.56. It's akward, and I needed to shift other stuff out of the pack to ensure I can sustain a long period on foot. Hopefully, I'll never run into a situation where I have a desire to carry both.

[Trooper]

Why, what is the end function of being able to change caliber on an assault type weapon. Are you compromising the primary function to allow for a little used secondary and tertiary role.

How does the addition of complication influence weight and reliability and how far you you wish to extend the change over ability. The Lewis Tool and Machine set up is elegant but stays within a caliber family. Contrast the Colt system which presents a 12lb 5.56 carbine.

Bill,

It is easier to carry an additional barrel than a whole upper. I liked the idea of a modular system such as the XM8 or ACR. LMT has a similar system for the 7.62x51 (ie 6.5 Creedmore, 260 Rem, 7mm-08) family of cartridges. It would be nice to have a modular system for the 5.56x45, 6.5 Grendel and maybe the 300 BLK. Also would be nice to go from a 16.5" barrel to a 20".

[LRRPF52]

Bill,

It is easier to carry an additional barrel than a whole upper. I liked the idea of a modular system such as the XM8 or ACR. LMT has a similar system for the 7.62x51 (ie 6.5 Creedmore, 260 Rem, 7mm-08) family of cartridges. It would be nice to have a modular system for the 5.56x45, 6.5 Grendel and maybe the 300 BLK. Also would be nice to go from a 16.5" barrel to a 20".

In field conditions, where and when is it viable to change barrels in your upper? I think that's the important question, and what skill level do you trust to do it? From a practical military standpoint, as well as the hunter, it has no application in the real world.

Having worked with QBC systems now for many years, I see their validity only at certain levels, and operator-level isn't one of them. Accuracy and return-to-zero are significant considerations with these systems, depending on the method of barrel attachment. In a military setting, this should only be accomplished at the armorer-level, or supervised user-level maintenance.

[Drifter]

Since you would have to also carry different ammo, and possibly different mags, a bolt, and / or optics, I fail to see why a complete upper is so much more of a burden than just a barrel. And as LRRPF2 alluded to, I would have more confidence in a complete upper being dialed in than I would a barrel change.

[Variable]

Yep. When you swap barrels without uppers, you have retained the optical interface of the old barrel. To me (at least), I'd much rather have a seperate dialed in optic still unified to the new barrel. I don't want to have to risk mistakes with changing zeros.