Just ordered an MDT LSS XL ...finally!

Discussion in 'Modifications' started by Mikaveli, Dec 25, 2016.

  1. Mikaveli Member

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    Ok, so I've done it the long way round (rather than just buying an MVP LC), but I wanted a longer barrel than 18.5".

    I have the varmint model - I like the rifle, and the stock looks good - but don't think it's been doing the accuracy many favours (stock isn't true to the barrel, not free floated and uses a fairly cheap plastic bedding ).

    I've been getting just over 1 MOA at 100yds - going to be nice to do the before and after comparison.

    Also, slight aside - but I'm assuming the XL still uses AR-10 mags?
  2. Keith Moderator

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    I'm assuming you are talking about a 7.62 model? If so, the chassis uses the LR308 and SR25 design magazines used in most of the 7.62/.308 chambered AR-10 clone rifles. An actual AR-10 magazine is different, though I've been told (but have not verified) that newer Armalight AR-10s are no longer using that older format.
  3. wood chucker Moderator

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    In a nut shell you have two basic patterns of AR10 magazines A and B covering three evolutions of the Armalite AR10 rifle.

    The AR10B ( second evolution) Gen 1 mags (1990's) use M14 magazine bodies with a mag catch slot cut in the side and a modified flower. AR10B Gen2 mags ((post '94) were purpose made that way and don't have the M14 tab on the spine.

    AR10A (third evolution) mags (2010's) are the same pattern as the first evolution 1960's Costa Mesa and Dutch made AR10. It's also the same pattern that DPMS, KAC, Remington, Magpull and the rest are using nowadays.

    What;s old is new I guess.
  4. Mikaveli Member

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    Ah, that answers a few questions - yes my 7.62 MVP uses an LR/SR 25 PMAG at the moment.

    I'd read that their was also an earlier M14 compatible mag, but that only the later type works with the MVP?

    Is AR-10 the wrong term to use (I've always used it to refer to any AR-type rifle in 308)? I know people misuse AK-47 to refer to rifles that are later evolutions (and often completely different calibres), so don't want to be making that kind of mistake myself.
  5. Keith Moderator

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    Technically, AR-10 is only for the Armalite rifle. The others are a LR308/SR25 format. Perhaps the most correct would be the SR (Stoner Rifle) but either of those two will work. Unlike the AR-15, the big ARs are not completely cross compatible. There is some proprietary stuff in all of them, so one has to be careful when getting new parts and pieces. My S&W M&P10 has a proprietary barrel and gas tube as an example. Like the MVPs, it's damn near impossible to find a replacement barrel for them outside of the manufacturer. One pretty much has to start from scratch and get a new BCG, barrel extension, and barrel if they can't get S&W to fix t under warranty. Everything else is pretty much cross compatible with other LR308 (DPMS/Bushmaster) and SR25 (pretty much everyone else outside of Armalite) rifles
  6. spamassassin Well-Known Member

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    Skim bed your LSS stock on the v-block and fully epoxy bed the recoil lug. Helps with the flyers. Most any 2 part epoxy will do. I like steel epoxies but not JB Weld (too brittle for me). Pam cooking spray makes a great release agent.
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  7. wood chucker Moderator

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    +1 to what Spamassain said !
    Devcon had a steel filled epoxy that was hard but not brittle, good stuff. 3M made a metal filled epoxy "Metal Set" that was good stuff too. Johnson's paste wax in the yellow can made a good release agent and I heard Rain-X was good but never tried that.

    So back to magazines for our MVP's. Mine have worked with every mag I have tried. I love that I can stuff any ol M14 or .308 AR pattern mag in them no matter what generation or evolution and they work. I think some fellas may have a had a problem with one of the mold revisions of P-Mag but mine worked.
    I do prefer M14 mags because the follower holds my bolts open on the last shot same as all the great old school bolt action battle rifles and I grew up with that.
  8. Mikaveli Member

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    So, the chassis has arrived (just waiting for my buffer / stock delivery now):

    14829608014111.jpg

    Very happy with the install. Literally dropped straight in - no mods required. Importantly, the Timney cleared the chassis (I had to modify the OEM varmint stock as the safety hit it, preventing operation). Not so here.

    14829607839310.jpg

    The mag well is great - the mag button is much easier than the varmint paddle. PMAGs lock up snugly - but also drop free. I'm very impressed with the machining in this area.

    14829608220872.jpg

    Everything aligns and centers just as it should - very happy so far. Keen to get it to the range now.
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  9. wood chucker Moderator

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  10. Mikaveli Member

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    Thanks :)

    I'm surprised Mossberg don't offer the 24" barrel and LSS XL from the factory. 18.5" on a 308 'precision rifle' always seemed like an odd choice to me - especially as the LR is lighter etc.
  11. Keith Moderator

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    I would a agree, typically a longer barrel is the preferred choice for long range shooting for a multitude of reasons.
  12. Mikaveli Member

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    Had the stock and buffer tube delivered:

    14835656026040.jpg

    Overall, the LOP is nearly identical to the OEM varmint stock - when fully extended. I know the XL is really meant for rifle tubes - but I preferred the carbine look - although I will be fitting a thicker butt pad (which will help with recoil too).

    The grip is currently a hack job (even if it's not obvious from the picture). I bought the duck bill Magpul grip, thinking I could bend it to fit - I couldn't... Oh well, K grip on the way!

    Just leaves a slightly higher riser (1/2" rather than the 1/4") and an Atlas bipod to buy.
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  13. Mikaveli Member

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    Range report:

    14844279526853.jpg

    I was a bit concerned because there's some noticeable play in the Magpul stock - so my expectations weren't too high. However my best group still improved by at least 1/4" over what I had got from the rifle before.

    14844278006521.jpg

    Basically 7/8" today (always 5 shot groups).

    Frustratingly, I had one dropped shot on this group - not the gun's fault - but still doesn't count. :(

    14844277805790.jpg

    I'm hoping by the time I've got the stock sorted and fitted a more comfortable grip there'll be more to come.
    wood chucker likes this.
  14. boostless Active Member

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    Looks good, keep shooting it. Eventually you'll get better and the barrel will "burn-in" as I've heard 8541 Tactical say it and the groups will shrink.
  15. Mikaveli Member

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    I'm pretty happy with the group sizes as is - but if they get any better, great.

    I've only tried a few brands of ammo - GGG surplus being (expectedly) the worst at about 2". S&B training came in around 1.5".

    This is all at 100m (110 yards), so the actual MOA is around 10% better than the group sizes.

    I'm not the greatest shot anyway, so just with some more regular range time, things should improve.
  16. jwb47 Active Member

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    If your stock wiggling is bothering you get the mag-pul ctr stock . It will lock down and not move at all . I have used one on a 458 socom for 9 years .
  17. Mikaveli Member

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    Thanks - that's exactly what I've ended up doing:

    14848980641313.jpg

    It also has the right grip on it now. I'd like to extend the LOP a little though - fully extended it's the same length as the OEM stock, but I'd like a bit more.

    Was thinking either an MDT recoil pad - or maybe they do a slightly longer carbine tube?
    wood chucker likes this.
  18. boostless Active Member

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  19. korn New Member

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    You helped me make my choice ;-) thk

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