LMT .308 Modular Weapon System 18" Match Grade Barrel with 1:11 Twist

[Defiant1]

I am getting into long range shooting and preparing to attend a civilian long range rifle training school. In preparation, I am building a 1,000 meter system on an AR platform. I am fully aware of the limitations of semi-auto vs bolt action, but prefer the semi-auto so I went with the LMT .308 Modular Weapon System, 18" Match Grade Barrel with 1:11 Twist and 2 stage trigger. Unfortunately, while the 308 with the 1:11 twist by consensus seems to meet my 1,000 meter objective, I am getting some negative feedback about the 18" barrel compromising accuracy because of an unacceptable drop after 500 yards. The preferred length being 24" minimum. I can replace the barrel if I could find one, which is a big if! My plan is to go with a Nightforce "Beast" optic (3x25).

YOUR CANDID THOUGHTS ON MY WEAPON SYSTEM WILL BE APPRECIATED. I AM HOPEFUL CONSENSUS WILL BE THAT THE PLATFORM IS SALVAGEABLE WITHOUT A NEW BARREL FOR 1,000 METERS. THOUGHTS??????

 

[ncbmx64]

Here is a YouTube video of a guy shooting with a 16" cl don't see why a 18" ss wouldn't work just as well or better. LMT MWS 16" CL @ 994yds.....steel/jugs of water - YouTube

 

[ptrlcop]

"Shooting" at 1000 yds is a pretty broad goal...if you are looking to shoot 1/2 moa at 1k this prolly ain't the rifle, but torso sized targets will be doable.

 

[Shooter0311]

Like ptrl stated, with good ammo, optic, shooter, 18 will do you fine on a man sized target. (Steel) My 18 inch SS (Before I sold the 18 SS to stick with 16.) barrel was supersonic to 1100. I would definitely stick with 175 or more past 600 but that's just my .02...

The LMT 2 stage is pretty decent but my first swap when $$ allows would be to a geissele trigger.

 

[Alpine 338]

With 18" you're loosing free velocity over a 20", and that can degrade accuracy to a small degree at longer ranges since your BC drops as velocity drops, and the wind will push your bullet more.

I also went with the SS 18" on my MWS, but my limitation is the stock factory trigger as the both the rifle and shooter could do better with a better trigger.

 

[Thebelly]

I agree that the requirements and expectations of the distance and target combination need to be better defined. The good thing is that the MWS has many options available. The only thing that will change is your barrel and your zero on your optic.

 

[Shooter0311]

I have done lots of superchrono, master chrony and acoustic chrono work with 16ss barrel and 18ss barrel.... From 18 to 16, you lose a mere 20 fps per inch. Just an FYI.

 

[Defiant1]

Lmt mws .308

"Shooting" at 1000 yds is a pretty broad goal...if you are looking to shoot 1/2 moa at 1k this prolly ain't the rifle, but torso sized targets will be doable.

Thank you! 4" MOA...what is your opinion on maximum range? Can the system group that tight at 600 meters?????

 

[BCP]

18" semi 308 is not primo for 1000 yards but you'll do okay. You won't be the only new guy there with an AR platform believe me.

If you really want to get into long range shooting I'd think about a bolt rifle with at least 22-24" of barrel.

Scopes I'd be hesitant to dump a bunch of money on whatever is latest and greatest. I MHO pick something that has been out and has been proven in comps. Bushnell HDMR, Vortex Razor HD, Nightforce 3-15 models for example all show up on the used market here pretty regularly and are proven. People know about them, use them, like them, shoot good scores with them.

 

[RG in Idaho]

I've had my 16" CL MWS barrel to 1k numerous times. No issues. I've been shooting between 2600' and 5200' elev. That being said, I did pick up a 20" for the added velocity. My 20" runs 175 FGMM at 2650fps.

 

[elfster1234]

I think a friend and myself found an area to shoot well over 1k and we are checking it out in the next week or so. What is nice is the new site is not that far away from where I live. I should have some really detailed results on paper @ 1000plus yards with my 20" CL LMT MWS. At least that is what i'm hoping for.

I've had my 16" CL MWS barrel to 1k numerous times. No issues. I've been shooting between 2600' and 5200' elev. That being said, I did pick up a 20" for the added velocity. My 20" runs 175 FGMM at 2650fps.

 

[RG in Idaho]

I've had my 16" CL MWS barrel to 1k numerous times. No issues. I've been shooting between 2600' and 5200' elev. That being said, I did pick up a 20" for the added velocity. My 20" runs 175 FGMM at 2650fps.

Didn't have all of my data on the laptop when I made the above post. My 16" CL runs 2505 fps with the same lot of 175 FGMM.

 

[Deepwoods]

I've shot both my 20" SS and my 16" CL to 1000 once. I'm getting 2605 fps with 175 SMK (and 7.62 FGMM runs about the same) out of the longer barrel. An instructor found one my SMKs from the 16"--it had destabilized, tumbled, hit the plate and bent (but was still in one piece).

On another outing, I got a nice ~ 1 MOA group (5 shot) at 600 yards a few months back. With some practice, I believe I can do better, and that the rifle will deliver. At 100 yards, I'm getting pretty consistent .5-.75 moa. So again, I believe the rifle is capable.

A friend of mine has the same [exact] setup and he is getting similar results. A few months back, I ran into a shooter with the 18" SS. His average for the 175 SMKs was 2594 fps. There may be other factor, but his barrel wasn't loosing much to mine...

Others here likely have more long-range experience than I do, but I agree with the consensus here that you should be OK.

I have a NF 3-15 with the MOAR reticle, and I find it to be an excellent setup, if a bit heavy. However, I have a vortex on a different rifle, and if I was being more budget conscious, I'd seriously consider the Vortex Viper PST 4-16. (It looks like you have a larger budget for optics, but its worth noting).

 

[redhooker]

I have a 20" CL 1:10 bbl and switched to the 16" CL 1:10 twist. The 20" was getting just shy of 2600fps average velocity with 118lr. The 16" is getting 2530 with the 118, as well as 46.2 of varget under the same pill. This speed is chrono'ed and confirmed at distance, which means I am going subsonic just shy of 1000 yards with the 16". I was surprised that I lost less than 70fps (about 17fps per inch) with a 4 inch reduction, but the 16" groups better than the 20" at 100.

I could probably find a node close to 2600 safely as I have no pressure signs at 42.6, and pretty good brass life. That would keep it supersonic to around 1100 yards with more energy than a .45 at PBR. If I load for smallest groups at 100 yards, I load 40.5 gr of varget to a speed of about 2400fps and she can shoot sub-moa "all day long " average. The hotter load shoots right at moa knocking a 10 inch plate at 850 with authority.

I would say you can build a dependable 1000 yard system with any bbl on the MWS, the main limitation being the BC of the bullet. I see absolutely NO accuracy loss from switching to a 16 from a 20, in fact the 16 seems to be more "forgiving" to me than the 20 when it comes to shooting mechanics.

 

[RG in Idaho]

Old pic from my first outing with the 16" CL MWS.

1K yards, 20" horizontal plate, about 2550' elev.

175smk, 45gr varget, Win brass, BR2

 

[George Mac]

A buddy of mine used his new mag-chronometer on some of my rifles/loads to confirm its accuracy to known speeds. We then used it on my LMT MWS 18" SS.

175SMK, 1x fired FGMM brass, 43.0 Varget, Fed 210M primers. This gave us an average MV of 2522. Using the Litz calculations on the Shooter ballistic solver says it drops to 1130 fps at 975 yards at 2000' DA.
12.2 Mils to 1K
3.0 Mils wind for a 10mph at 9 O'clock.

I can put more powder in the case but so far this load shoots the most accurately out of my rifle so I haven't pushed it further.

 

[redhooker]

A buddy of mine used his new mag-chronometer on some of my rifles/loads to confirm its accuracy to known speeds. We then used it on my LMT MWS 18" SS.

175SMK, 1x fired FGMM brass, 43.0 Varget, Fed 210M primers. This gave us an average MV of 2522. Using the Litz calculations on the Shooter ballistic solver says it drops to 1130 fps at 975 yards at 2000' DA.
12.2 Mils to 1K
3.0 Mils wind for a 10mph at 9 O'clock.

I can put more powder in the case but so far this load shoots the most accurately out of my rifle so I haven't pushed it further.

This sounds close, I have been unable to get to 1k but my ballistics ae app is tuned dead nuts on my load (g7 model) out to 850 and I need 12.6 to get to 1k @ 2000DA running 2530, so I think you may be running a bit faster than the chrono is saying, perhaps closer to 2565?

 

[George Mac]

Pleases forgive my poor articulation. I did not mean to state that have shot the LMT out to 1K.
I shoot out to 1K quite often in the course of fire of the monthly matches out here but I have always used either a 20" 308 bolt gun or my 24" 6.5 Creedmoor bolt gun. I've only shot the LMT out to 200 yards on the sniper deck and have not brought it out to the matches. The above stated dope at 1K was from the Shooter ballistic solver based on the mag-chrono speeds and the Litz data.

 

[problemchild]

Took the 18" SS to 650 in the wind. Even had the wife making hits and she has never fired the gun before. I was shooting at a 12x17 plate. Wind gusting 25mph from 20:00 direction. I only had a 3.5x acog at the time and it was darned easy to hit.