My 7mm LR Odessy

Discussion in 'Big Stuff -- 6.5mm, 7mm, 30 Cal' started by alf, Sep 4, 2017.

  1. alf

    alf Silver $$ Contributor

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    Here's my journey to fulfill a one mile plus 7mm cartridge.......

    So I've had the hankering to put together another long range plinker of some sort, and really was planning on a 7mm of some flavor. But reality (money) set in, and I made the executive decision to stick with another 6.5-284, as I had 150 pieces of used brass, plus dies, bullets, powder, and the reamer.

    I ordered a new SPS 25-06 for the donor, tore it apart, found a Bartlein 3B 8" twist in stock, and sent it and the action off to get chambered and fitted. I picked up a used McMillan Sporter stock, sent the bolt off for fluting and tig welding, and cobbled it all together when things came home. Managed to topped it off with an extra NXS 5.5-22x50 Nightforce in Seekins rings and 30 MOA bases:

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    With minimal effort, I found a damn good load with 130 Berger VLD's at 3150, and tested them to 1200 or so yards multiple times. Also gave the 142 LRAB's a good test too. They shot decent, but couldn't hang with the Berger load in the wind.

    I even managed to break it in on a meat buck in Montana at 350.

    Hard quartering away, devastating....trashed both lungs and the top of the heart:

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  2. alf

    alf Silver $$ Contributor

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    But I still couldn't shake the 7 thought.....
    Ended up buying a S/S magnum bolt last year "just in case".

    I wanted something more than a 7 mag offered, but didn't want to go with any wildcat with their related expenses with dies and fireforming. I had read a 100 page thread on LRH about the 7x300WM that planted the seed. I knew TiminTn was a 7 freak, so I finally gave him a buzz. He had a minimum spec no turn 7x300WM reamer and a 7mm throater. Shazaam....

    I found a 8.5" twist Krieger RV contour in stock, so ordered it and had it sent directly to Tim. Ordered up 500 Berger 180 Hybrids, and another 500 183 SMK's, a couple hundred Hornady 300 WM brass, A Wilson 300WM inline bullet seater, and 300WM Redding body die, and 7Mag neck die. I seated both bullets where I wanted them, and sent them to Tim for proper throating.

    7Mag w/162 Amax vs the 7x300 w/183 SMK....

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  3. alf

    alf Silver $$ Contributor

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    Next, I decided I didn't want the Sporter stock, as I prefer the McMillan Marksman for my big barreled plinkers, so I peddled it and found a used Marksman to tied me over till the new one showed.

    The used stock was for a HV contour, so I fiddled around and filled it in with 2 part epoxy/micro baloon mix to better fit the RV contour, and bedded the action:

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    Then had to address the OD green paint. Decided on a snow camo motif:

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  4. alf

    alf Silver $$ Contributor

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    Finished product:

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  5. alf

    alf Silver $$ Contributor

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    Some bullets for comparison:

    120 BT - 140 BT - 162 Amax - 168 Berger VLD - 180 Berger Hybrid - 183 Sierra Matchking:

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  6. alf

    alf Silver $$ Contributor

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    For those that promote a 33 of some flavor for distance.....BTDT.......

    So the sole reason for this build was to have a LR toy to replace my 338/300 Ultra that I sold. I never cared for the A-5, it was a tad heavy at 15 1/2 pounds, and while fun to shoot, I didn't want to deal with the blast and concussion in lighting one off any more. I had taken it as far as 1925 yards in the past, and was hard to ignore the performance at distance. To me, it didn't make sense to unleash the beast unless you were going beyond 13-1400 yards or so. Plus I have other things more fun to shoot out to that distance w/o the "drama" and hassle setting up those targets, so down the road it went, and funded the new parts.

    Bat HR single shot action, 29" fluted Rock barrel, Hollands brake, McM A-5,
    Bat 40 MOA base, Seekins rings, 5.5-22x50 Nightforce.

    Berger or Sierra 300 grainers at 2820.

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    So the goal was to equal the 338/300 Ultra's performance, which stayed supersonic beyond 2000 yards, keep the weight to around the 12 pound mark, skip the muzzle brake, and still be able to spot my own shots, while making it more portable.

    The last requirement was I had to stay within the confines of the feed rails, as this is still a switch barrel gun with the 6.5-284 barrel, and need it to reliably feed either cartridge. That ruled out the Ultra/Nosler sized cartridges.
     
  7. alf

    alf Silver $$ Contributor

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    Another reason for the 7x300 was I had a couple left over 8 pounders of H-1000,
    that should be been perfect for the cartridge.

    Priming the new Hornady brass, I was surprised how easy some of the primers seated. After the initial firing, fifteen or so never made it to round two, and that number again after round two. I have 60 some left now, still going on their 4th & 5th firings.

    Shooting at 200 yards with the H-1000/183 Sierra SMK combo, 77 grains yielded a best group of .880" at 3147 fps.

    Best group also, at 1.1", was with the same 77 grains and the 180 Hybrids at 3175 fps.

    I went to 80 grains with both, and got the first tattoo, so felt I was OK at 77.

    I loaded up a bunch of both at 77 to test seating. All loads were .020" in the lands, and I went off in .015" increments.

    The Sierra didn't like getting off the lands at all.

    The Berger Hybrids lived up to their reputation as not being fickle in seating preference, laying in a nice 1" group .080" off the lands, leaving plenty of room in the mag box for hunting.

    So the results met what I was going for, the Sierras for play, the Bergers for fur.

    Except.......


    I didn't care for the Hornady brass, and while I got decent accuracy,
    it seemed I could never got consistent results.

    So, I sent back the other 100 pieces of Hornady brass, and ordered some Nosler.....
    world of difference. Luckily I always use my Sinclair priming tool, as the 'ol Lee Auto-Prime woulda fell to pieces trying to seat primers.

    At the same time, I had a burning desire to try some R-33. Just so happened the closest supplier had an 8 pounder in stock. After another round of testing with both bullets, I settled on 82 grains with either giving single digit ES's at 3125 fps.

    I went back the next day and bought another 8......
     
  8. centerlineseal

    centerlineseal Gold $$ Contributor

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    And just how well did the RL-33 group? I've been contemplating putting some of that in my 7mm Remmag elk gun.
     
  9. alf

    alf Silver $$ Contributor

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    Under an inch at 200 with either bullet.....
     
  10. alf

    alf Silver $$ Contributor

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    Play time....from 550 to 1000:


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    The victims.....

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    Moved back a little more to stretch it to a little over 1400 or so....

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    Aftermath:

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    Glamour shot:

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  11. loud_noise

    loud_noise

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    Very tidy...
    I'm looking for an excuse to build a wicked 7mm and that 7-300 sounds brilliant.
     
  12. Clancy

    Clancy

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    Al do you have any knowledge of 7mm LRM?

    I've never had a long action, but if I did, that would be the reason.
     
  13. alf

    alf Silver $$ Contributor

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  14. alf

    alf Silver $$ Contributor

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    More play time.....

    Filled up some more jugs with colored water:

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    Backed up a little bit and got set up:

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    Not really the best day to be out there, as it was cold with the winds huffing & puffing more than predicted. But worse yet, it had rained a little bit, which made spotting impacts sketchy at best. The bullets were just bombing out little divots. Managed one kill for my effort though.

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  15. alf

    alf Silver $$ Contributor

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    Forgot one detail.....1785 yards......
     
  16. snert

    snert Gold $$ Contributor

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    did I see a mention of a budget early on???! :);)

    I like living vicarously thru ya, cause my budget wouldn't buy 500 bergers....
     
  17. alf

    alf Silver $$ Contributor

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    Time to stretch it a bit more.....1825 yards...

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    The previous night's forecast called for light winds this AM, so I went out after supper that night to set the steel up, to take advantage of good conditions.

    Well that didn't pan out, the wind never did lay down and was still huffing as soon as I rolled out of bed. Right in my face too....oh well....

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  18. alf

    alf Silver $$ Contributor

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    So I dialed in 56 MOA and took two sighter shots in the dirt to foul the bore and get a wind reading, then moved over on the 24" square (12x24 each) steel.

    First shot was the low/left hit, next was the low impact in the dirt just below it, 3rd was the upper right hit, 4th was just a RCH left of the steel (in the shadow), and 5th was the low right hit. I'm calling it around a 24" group. Not bad consider the head on blow.

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    Looking back:
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    Set-up was at the back treeline in the gap three quarters of the way to the right by the tallest tree....
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  19. alf

    alf Silver $$ Contributor

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    New day.......1850 or so....just jugs for targets....

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  20. alf

    alf Silver $$ Contributor

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    [​IMG]


    Exit of 183 SMK.....zero expansion....

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    Tough to confirm some hits at this distance:


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