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  1. L

    7mm SAUM AR

    Minor load work update: I picked up an expanding mandrel from Cortina and reworked my brass process. Shoulder bump .0025” with full length die(no neck expander on the de-caper), & .282 neck mandrel in the mandrel die. All to brass with multiple fires. The test was 10rds, average velocity of...
  2. L

    7mm SAUM AR

    After this deer season I want to try a few other powders like H1000 and MagPro. Really want to get out to a PRS match or two and put the rifle through its paces next year
  3. L

    7mm SAUM AR

    Load development update 150 ELDMs have proven to be the sweet spot for this barrel. 62.2 grains of 7828 provides good groups and around 10fps SD. 8rds of the above load in fired ADG brass Average velocity was 2910 5rds of the above load in fresh ADG brass velocity average was 2808 Is a 100fps...
  4. L

    7mm SAUM AR

    What are the ranges shot in ELR? With the 162 load I’ve been working on it stays supersonic to 1496yds. That’s at more or less sea level and going 2770fps from an 18” barrel. So your 26” barrel should much faster. I don’t know if X-Caliber would do it but you may want to look into having the...
  5. L

    7mm SAUM AR

    Do you reload for your PRS gas guns? What is your brass prep and load development for gas guns?
  6. L

    7mm SAUM AR

    It’s honestly pretty straight forward. Some flavor of SAUM would be my suggestion, but ELR may not be the best purpose. I did some initial loads with 175s, they fit and feed but they are waaaay short of the COALs everyone is running for 180 class bullets. 2.825” will be your COAL. As far as...
  7. L

    7mm SAUM AR

    Thanks, I’ll try that.
  8. L

    7mm SAUM AR

    Update: currently in the middle of load development, the rifle is functioning very well with no major issues. I’ve got three loads I’m working with. 1) 139 Interbond w/ 64gn @ 3045fps 2) 150 ELDX w/ 62.3gn @ 2875fps 3) 162 ELDM w/ 60.9gn @ 2783fps All in ADG brass using 7828ssc. I did switch...
  9. L

    7mm SAUM AR

    about $1500 in the upper build
  10. L

    7mm SAUM AR

    Designing two inserts that convert the mag to single stack. Spring is a 6.5 Grendel 25rd spring. It holds 8rds in a ASC 20rd 308 mag and locks back on the last round. So far it feeds flawlessly, but more testing is needed to really prove the concept.
  11. L

    7mm SAUM AR

    Small update: The 150 ELDX / 62.3gn of 7828 load did very well today. Average velocity of 2857 / SD 9.4 and a nice tight group minus a first round flyer. I’ll load up 20 or so rounds and stretch it out to distance. also tried the 162s /7828, found a velocity node around 2770. I think I’ve...
  12. L

    7mm SAUM AR

    Now that I’ve got more data I’d like to get input from the site. I’ve done ladder test with the 150 ELDX over H4831SC & 7828SC and a 10 shot string with 61.5 of H4831SC. The H4831 load had an average velocity of 2809 with an SD of 10, grouping was 1”. With 7828 I was able to get a velocity node...
  13. L

    7mm SAUM AR

    “shrugs” I did lots of reading. Anyway, The rifle continues to shoot well, I worked up to a max of 62.2gns of H4831 over a 150 ELDX. Velocity was 2832. No pressure signs or swipe marks on the base. The only issue I ran into was too much gas causing deformation in the rim where the extractor...
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    7mm SAUM AR

    That’s not my target velocity, that’s just what the Hornady load manual produced. I don’t know why the Hornady max load for that powder is 4gns less that Noslers max load. It’s also an 18” barrel. I should sort it out this afternoon as I’ve got new loads worked up to 62.2gns.
  15. L

    7mm SAUM AR

    I was using Hornadys load data which is considerably lower than Noslers. My max load was 58gn with an overall length of 2.820”. Velocity at 58gns was 2617 measured at the muzzle with a magneto speed. Nosler suggested max load is 62.2gns of the same powder. I’ll be shooting the new test loads...
  16. L

    7mm SAUM AR

    My first loads were 150 ELD-X over H4831sc in ADG brass. The initial shots went well, I had the rifle speed set at six and single fed rounds over an empty mag. The gas was enough to lock the bolt back and the brass would just clear the port. Grouping was “good” for a load testing. Recoil was...
  17. L

    7mm SAUM AR

    I’ve got mine together for some initial load testing. I had to steal the handguard off my 308 as I ordered the wrong barrel nut for mine. Here is the upper parts list. Mega upper KAK bolt carrier and magnum bolt Xcaliber barrel - 18”, 1/8 twist, 14” gas system Handguard is a SLR as is the new...
  18. L

    7mm SAUM AR

    I designed it based off of some research and other magazine dimensions. The first print has some issues. The rear webbing being so thin allows the side walls to bow out. This is just the first rev.
  19. L

    7mm SAUM AR

  20. L

    7mm SAUM AR

    Something interesting I noticed tonight; the X Caliber 7SAUM barrel has a single feed ramp rather than the traditional “M4” style dual ramps. Given this I’m going to proceed with an MJF printed single stack magazine designed to fit in a “SR-25” mag well.
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