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View Full Version : LMT MWS in .308, .260, or 6.5CM?



RD62
12-18-11, 22:23
I started a thread below about my desire to purchase a .308 AR type precision oriented rifle in the coming months.

I have pretty much made up my mind on the LMT MWS for several reasons. In my research of different makes/models I came across some discussion of the .260 Rem and 6.5CM and their ballistic advantages over .308WIN. With the pending release of barrels for the MWS in these cartridges I am now considering one of these chamberings instead of the .308.

I did want to ask a couple of questions in regards to these rounds as I am not very familiar with them and have not seen much discussion on them on this forum.

I understand that ballistically the .260 and 6.5CM are very similar if not near identical. I also understand that the 6.5CM was intended to have a readily available supply of factory ammo at affordable prices. But my searching has seemed to show the opposite to be true, that the .260 has more offerings, so maybe I am missing something. So which of these has the most readily available factory ammo? I am not a reloader and will not be starting anytime soon (space does not allow).

I also understand that both the .260 and 6.5CM use the same projectiles. Do either of these have any advantage over the other in terms of terminal performance (I would think not) or do they give up anything in that regard to the larger caliber .308? I understand they are flatter shooting and buck the wind better, but are they as effective on target?

I will mainly be using this rifle for hunting (mainly whitetail) and target shooting at moderate range with an occasional foray into 600+ yardage (potentially out to 1k), and there is a slight possibility of its usage in an occasional competition (if I can find one and the schedule will allow).

Thank you.

Cameron
12-19-11, 01:09
That is the second time I have seen someone posting about the 6.5CM.

You mean the 6.5MM don't you? The 6.5mm Grendel.

Cameron

FromMyColdDeadHand
12-19-11, 01:52
That is the second time I have seen someone posting about the 6.5CM.

You mean the 6.5MM don't you? The 6.5mm Grendel.

Cameron

Don't you own a 2.559inch bore gun? ;)

CreedMoor not CentiMeter you limey want-to-be, sheep molesteting, marmite eating, queen and metric system defender! :D

I think the CM took off since there wasn't redialy available good .260 Brass. Creedmoor produces match ammo in CM that is pretty cheap, about $1 last time I looked and they put the recipe on the box so you can replicate it.

I think there are now good sources of 260Rem brass, but I don't know if anyone is doing an FGMM in 260 yet that could help to close the gap. There is a thread in the bolt gun area about someone making a 6.5CM gun.

I went 308 for my LMT. The idea of the 260 bullets is interesting, but I think the 308ARs are really at their best 1MOA guns. 260/6.5 loads really shine past 600 yards or so and allow realistic shots out to 1200m- things I'm not likely to do with my 308AR. Yes they are better than the 308 in bucking the wind, but with a 308AR, I'll call splash and adjust fire and move onto hits, lots of bullets in a 20rnd mag- for rifle and 3-gun comps where I'd be using a 308AR. I don't think it is wrong to have an AR in 260/6.5, but I think you really need a 1/2 inch 1/4 bolt gun to really be able to use its advantage over 308.

I know there are people here that say their OBR, KAC of MWS or POF can shoot 1/2 minute. Yeah, maybe under benchrest type conditions. I think the 308ARs are just unergonomic enough, and they have so much stuff moving around that getting consistent pressures and out put on the gun is hard to do to make them true 1/2 MOA guns. Just my opinion.

A 308AR lets you run 'cheap' :( mil-surp ammo and match grade stuff in the same gun, and there is a lot of 308 out there. 260/6.5, there is not blaster ammo, it is then a dedicated, long range capable rig. I'm not against the 260/6.5, I'll probably get my next bolt gun in 6.5CM- and let the round really shine from a nice AI MKIII.

Just my thought (no snickering) about how I decided to set up my MWS.

d90king
12-19-11, 08:37
I would start with a .308 barreled MWS and then simply add additional barrels in the caliber of your choice as they become available. I am starting to see some accuracy reports on the regular 16"CL barreled MWS that have blown away my expectations.

That said, much of that is the trigger puller but it is showing the possible accuracy that once I get squared away in learning to shoot precision that I might be able to achieve out of my MWS.

I am still not seeing a lot of commercially available ammo in either 6.5 or .260 but word is that is changing as I type this. Once I see ammo become more readily available at prices that don't make me poor I will be adding an additional caliber to the MWS setup.

Good luck in whatever direction you go.

hombre
12-19-11, 22:03
The 6.5 CM and .260 REM are more dependent on barrel length than the 308. I'd expect you'd see quite a bit of velocity drop off in the typical 16 and 18 inch barrel lengths folks are favoring in 308's. I'm sure they'd have less wind drift at distance, than a 308, with the same barrel length, but you'd also have less barrel life and wouldn't really be coming close to the potential of the cartridge for long range with a shorter barrel. That is one of the great things about the 308, its efficient. Not saying its a bad idea I've thought of it myself.

m1ajunkie
12-19-11, 22:44
I think hombre is on the right track. I have been looking into a new caliber for my mws to reach out a little better than my current 16" .308.

The 6.5's and .260's are a great round if you have the velocity to make them worthwhile. I am not sure if a 20" gas gun is going to get enough velocity to be a worthwhile upgrade. Either of these calibers is going to require me to get some new reloading components which makes is a large investment.

I am thinking a 20" .308 barrel might be a good choice as a supplement to the 16" barrel if you are looking for a little more range. The one I had shot very well, but I am back at 16" to make a handier package when my suppressor arrives.

RD62
12-21-11, 19:53
d90king makes a lot of sense, and after seeing the accuracy Trident is getting out of his new 16" CL .308 MWS in the AR General Discussion forum, I believe I will initially pick up the standard MWS with the 16" CL .308 barrel.

I'll wait and see what results others are having with the .260 and 6.5CM barrels once they have been out for a while. I am still liking the concept of these rounds, and will be closely watching the factory ammo offerings.

Now to decide what make/model of optic would best suit the MWS....

ALCOAR
12-21-11, 22:27
Sounds like a really great plan to me, and ultimately I think most MWS owners will always want to own the 16" CL barrel given it's versatility. All the other barrels options are really specialized like the .260rem and 6.5cm models.

I believe in time my 16" CL barrel will be sent to Marvin Pitts to be cut down to 13.5" and dimpled. My end game here is ultimately 2 different MWSs....

1. MWS LR...with two barrel options, a 20" 5R SS 6.5cm, and a 16" 5R SST .308.

2. MWS SBR...dedicated 13.5" CL .308

Cameron
12-22-11, 00:44
I believe in time my 16" CL barrel will be sent to Marvin Pitts to be cut down to 13.5" and dimpled. My end game here is ultimately 2 different MWSs....

1. MWS LR...with two barrel options, a 20" 5R SS 6.5cm, and a 16" 5R SST .308.

2. MWS SBR...dedicated 13.5" CL .308

WTF??? You stealing my ideas?!?!?

ALCOAR
12-22-11, 01:51
Negative ghost rider, I already ask your subconscious and was granted permission to proceed full speed ahead:p

When it comes to matters of ARs, I'd like to think we are extremely like minded.

Spooky130
12-22-11, 20:59
Trident has posted links to Zak Smith's comparison of all the 6.5 cartridges that are hot in the long range game world right now.

I'm still trying to decide on the .260 Rem or 6.5 CM now. I lean towards the .260 because it is the round that essentially spawned all the others trying to duplicate it. I want to see what twist LMT releases before going in that direction. I reload so I can very easily get into the .260 game as Lapua has started to produce .260 brass.

I'm still tossing around the 6.5 CM though... I like the idea that Hornady prints the load recipe right on the box and that match grade ammo is relatively inexpensive at about $25/20. Reloading should be easy but I would have cheap, accurate ammo available for the times I can't reload...

I will likely wait and see how the LMT barrels are performing. I think it might be good to see how either round holds up to use in the MWS platform as well.

rundm
12-31-11, 16:04
While not quite exactly about the 6.5 creedmore, I read George at GAP is doing a 6mm based on the 6.5 creedmore if I am not mistaken. If I read the article right, he has said that the round is optimized in a gas gun and that all you need to do is run the brass through a sizing die that hornady is making for him. There are a couple of ammo companies that are producing rounds for sale also. There is much more info on The Hide about it. You could easily get one of the custom barrels out there and send it off to get machined to fit the MWS no problem.

d90king
12-31-11, 19:23
Trident has posted links to Zak Smith's comparison of all the 6.5 cartridges that are hot in the long range game world right now.

I'm still trying to decide on the .260 Rem or 6.5 CM now. I lean towards the .260 because it is the round that essentially spawned all the others trying to duplicate it. I want to see what twist LMT releases before going in that direction. I reload so I can very easily get into the .260 game as Lapua has started to produce .260 brass.

I'm still tossing around the 6.5 CM though... I like the idea that Hornady prints the load recipe right on the box and that match grade ammo is relatively inexpensive at about $25/20. Reloading should be easy but I would have cheap, accurate ammo available for the times I can't reload...

I will likely wait and see how the LMT barrels are performing. I think it might be good to see how either round holds up to use in the MWS platform as well.

That's what I did on the whole rifle and I think it's a good practice to have on any new products on the market...

I know the initial specs for LMT's barrels were as follows- .260 barrel was 1/9 SS - 1/9 .243 SS - 1/9 6.5 C SS - 1/10 .338 Fed - 1/10 7mm-08 SS

Hope that helps. I will probably be joining you on the .260, it seems like a hell of a round. The 338 Fed is also interesting but since I'm not hunting with it not sure I have a use for it.

Spooky130
01-01-12, 14:04
That's what I did on the whole rifle and I think it's a good practice to have on any new products on the market...

I know the initial specs for LMT's barrels were as follows- .260 barrel was 1/9 SS - 1/9 .243 SS - 1/9 6.5 C SS - 1/10 .338 Fed - 1/10 7mm-08 SS

Hope that helps. I will probably be joining you on the .260, it seems like a hell of a round. The 338 Fed is also interesting but since I'm not hunting with it not sure I have a use for it.

Here's the picture SMG Lee took at SHOT last year... .300 BLK is 1/8...

http://photos.imageevent.com/smglee/ss11/huge/P1050155.jpg

It will also be important to see what velocities LMT is able to achieve with a 16" / 18" / 20" barrel with the 6.5mm rounds. Who knows if they will be worth the extra effort if they can't achieve decent velocities.