7mm LRM

Discussion in 'Reloading' started by Iron Worker, Sep 25, 2013.

  1. Iron Worker

    Iron Worker Well-Known Member

    Messages:
    1,747
    Joined:
    Apr 3, 2004
    What is a 7MM LRM ? The difference between it and a 7mm WSM ?
     

  2. IdahoCTD

    IdahoCTD Well-Known Member

    Messages:
    1,497
    Joined:
    Oct 22, 2008
    7-375 Ruger with the shoulder pushed back and steepened to lengthen the neck. Pretty close to a 7-300wm for performance.
     

  3. 429421Cowboy

    429421Cowboy Well-Known Member

    Messages:
    105
    Joined:
    Sep 18, 2012

    I had heard similar performance, at lower pressures was the big thing.
     
  4. Iron Worker

    Iron Worker Well-Known Member

    Messages:
    1,747
    Joined:
    Apr 3, 2004
    Lower pressure ? How can you drive a bullet faster with lower pressure ?
     
  5. IdahoCTD

    IdahoCTD Well-Known Member

    Messages:
    1,497
    Joined:
    Oct 22, 2008
    Larger case capacity equals faster with less pressure. I don't really think the pressure they are operating at is that much (if any) less than most run the 7-300wm at.
     
  6. TrophyHunter_colorado

    TrophyHunter_colorado Well-Known Member

    Messages:
    581
    Joined:
    Feb 2, 2009
    does the 375 have a belt? I thought that was another benefit for some people.
     
  7. bkondeff

    bkondeff Well-Known Member

    Messages:
    345
    Joined:
    Feb 2, 2008
    There's a fair amount of info on the cartridge on here. It's a staple for the Gunwerks guys, and you can buy brass and dies from them.

    I don't own one, but the standard expectation I believe is 3050fps on 73.0 gr of H1000 for Berger 180's out of a 25.5-26.0" barrel. I believe that is a little better than your average 7-300WSM.

    You will see quotes from the Gunwerks guys, that it is very similar to the 6.5-284 dimensionally, and it benefits from the same case capacity to bullet diameter benefits, therefore providing improved efficiency.

    I bought worked over 700 in 7STW planning to re-barrel to the LRM, but found it shoots 168Bergers at 3120 extremely well and with a LOT less felt recoil than I expected, so the plan is still on hold. I will say that while Gunwerks markets the brass, the limited accessibility of brass would be a concern, it is even a problem on my SAAMI STW.
     
  8. IdahoCTD

    IdahoCTD Well-Known Member

    Messages:
    1,497
    Joined:
    Oct 22, 2008
    I was referring to the 7-300 Win Mag not a 7-300wsm. 3050fps is pretty easy for a 7-300wm in a 26" barrel. The loads are even pretty much the same between the two. Why limit yourself to their brass when you can do a 7-300wm and use readily available brass from many different sources including Lapua (if you can find it) and RWS (which is as tough as it gets). You can also use a 300wm bushing die to size your cases to make life easier. My 7-300wm has a 27" Schneider barrel and get's 3160fps with 162 Amax's using 73grs of H-1000 in RWS cases which are slower and have less capacity than other brands but last forever.
     
  9. AZShooter

    AZShooter Well-Known Member

    Messages:
    2,071
    Joined:
    Dec 12, 2005
    I built two 7mm/375s recently, not the 7mm LRM. Reason is brass availability. I have always seen 375 Ruger brass on the shelves when there is nothing else. I had the dies necessary to make this wildcat. Only thing I needed was the reamer which I buy regardless of build. Life is too short to use reamer that isn't spec'd out.

    I would agree that the 7mm-300 win mag would be easy to make IF the brass was available.
     
  10. bkondeff

    bkondeff Well-Known Member

    Messages:
    345
    Joined:
    Feb 2, 2008
    Not sure on the advantage over a 7STW?
     
  11. trueblue

    trueblue Well-Known Member

    Messages:
    2,123
    Joined:
    Feb 18, 2008
    Not really any advantage over the 7STW, other than doing the same thing in a shorter coal.
    The 7 Rogue is I believe the best case capacity for the 180's in a 7 mm package.
     
  12. AZShooter

    AZShooter Well-Known Member

    Messages:
    2,071
    Joined:
    Dec 12, 2005
    Just read about the 7mm Rogue.

    7mm Rogue » R Bros Rifles

    It would appear to be pretty much the same as the 7mm/300 win with "some measurement relationships with todays “accuracy” cartridges" quote copied from article.

    IMO the 7mm Mashburn/ 7mm-300 win mag 7 LRM and 7mm/375 Ruger are pretty much the same. Variations will be in the throating based on who requests the reamer specifications. Pick one and run with it with indistinguishable performance.
     
  13. IdahoCTD

    IdahoCTD Well-Known Member

    Messages:
    1,497
    Joined:
    Oct 22, 2008
    300wm brass is available. I just bought 150 rounds of Nosler brass last week. Shooters Pro Shop had about 30 boxes of seconds. The good thing about it is the caliber is popular enough you'll see it for sale typically within a week if you watch for it.

    You are right in that 375 Ruger is on the shelves a lot. The down side is having to buy several sets of dies to neck it from 375 to 7mm. One pass through my 7-300wm die turns 300wm into 7-300wm.

    If your limited to standard magazine lengths the 7-300wm doesn't give up much to a 7STW. Seated long a STW is 100+fps faster.
     
  14. bkondeff

    bkondeff Well-Known Member

    Messages:
    345
    Joined:
    Feb 2, 2008
    anyone know the case capacity of the7-300?