(Help) 7 SAUM barrel specs

Jackomason

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Hey guys, my build is coming up on its "final" evolution. What I'm hoping for is a short action ELR rig. It doesn't really need to do anything else in this configuration.

Here's what I'm working with if that matters:
20211208_121137.jpg


As of now I have a 224v barrel and a 6.5 creed barrel.

What I'm wanting is a 7 SAUM. Don't really want to mess around with the Sherman's or anything. I'd like to use mags (even of the rest of the build makes no practical sense).

Where I'm lost is barrel specs and what to realistically expect.

-What do you guys like for freebore?
If 180's work in a SA can the lack of case capacity be over come with barrel length? Or should I settle for 168's?

-What barrel length is nessisary?
I'm willing to go up to 32" but I'm not sure if that's nessisary or would cause other issues.

I've got places to shoot, I'm sure I could max out what this could do. Let me know what you guys think. This is the last stop before building a 300 norma but I'd like to know if ELR tickles me first.
 

badassgunworks

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If elr tickles you ? Lol cube steak is not a good representation of red meat i would consider the purchase of a flame grilled ribeye to figure out of you like red meat... 7mm saum is not a bad cartridge. but its not a elr cartridge. Elrish perhaps. Might be good for matches like the nightforce steel challange. Even though its not really a elr match despite its name. 300 norma would be a better option. shooting long distances is like a lays potato chip you cant eat just one. And long distance is never long enough.
 
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kthomas

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If elr tickles you ? Lol cube steak is not a good representation of red meat i would consider the purchase of a flame grilled ribeye to figure out of you like red meat... 7mm saum is not a bad cartridge. but its not a elr cartridge. Elrish perhaps. Might be good for matches like the nightforce steel challange. Even though its not really a elr match despite its name. 300 norma would be a better option. shooting long distances is like a lays potato chip you cant eat just one. And long distance is never long enough.

ELR is any range where you are shooting your projectiles past transonic.

You can shoot "ELR" with a .22lr.

There's no reason why the OP can't try a 7SAUM and see if shooting past its transonic distances is fun or not, and worth a bigger cartridge.

Anyways, I don't have any experience with the 7SAUM, so can't help the OP. But I believe @Sheldon N has one if my memory is correct? @Steel head ?
 

Steel head

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    28”-30” is what I use.
    The standard 0.090 freebore is fine for a SA, if you like to run close to jam a .045 is better.
    All the bullets I use have no issues jumping.

    The regular freebore is optimal for hunting 168’s at SA mag length.

    180’s are great to 2000ish, 183, 184 and 190’s are great for a mile + but I tend to run them at single feed lengths.
    You can run them at 2.95ish.
    The 168’s are fun for short range.
    R26 and N565 are the cat’s meow in short magnums.

    I was pleasantly surprised at how well the 7mm’s do at 2 miles.
    Super efficient caliber.
    Beats the standard 338 lapua ballistics for substantially less $$$ and with really mild recoil.
     
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    Sheldon N

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    -What do you guys like for freebore?
    If 180's work in a SA can the lack of case capacity be over come with barrel length? Or should I settle for 168's?

    -What barrel length is nessisary?
    I'm willing to go up to 32" but I'm not sure if that's nessisary or would cause other issues.

    I've got places to shoot, I'm sure I could max out what this could do. Let me know what you guys think. This is the last stop before building a 300 norma but I'd like to know if ELR tickles me first.

    I have a 30" barrel with a ton of freebore, it was originally cut for F-Class single feeding with heavy bullets. I load all my rounds at mag length 2.95" OAL and jump the bullet a bunch and it still shoots good.

    RL26 is an excellent option for powder, it will still make very good speed. I've run Berger 195's at 2875fps from a 30" barrel, even with the loss of case capacity due to 2.95" OAL. 180's have also shot very well for me, I think I ran those at around 2970 fps. I have some Berger 190's but haven't tried those out yet. H1000 is another powder that would work well if you cant find RL26.

    Dug up an old video... three in a row on a bladed IPSC at 1 mile with 180's and 7SAUM at mag length.

     

    Shoots 700's

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    In the short time I have had mine, I have no issues with a standard chamber and free bore with 180's I"ve been running RL26. I went with a 28" HV barrel.
     

    Steel head

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    I have a 30" barrel with a ton of freebore, it was originally cut for F-Class single feeding with heavy bullets. I load all my rounds at mag length 2.95" OAL and jump the bullet a bunch and it still shoots good.

    RL26 is an excellent option for powder, it will still make very good speed. I've run Berger 195's at 2875fps from a 30" barrel, even with the loss of case capacity due to 2.95" OAL. 180's have also shot very well for me, I think I ran those at around 2970 fps. I have some Berger 190's but haven't tried those out yet. H1000 is another powder that would work well if you cant find RL26.

    Dug up an old video... three in a row on a bladed IPSC at 1 mile with 180's and 7SAUM at mag length.


    Lol
    Look familiar?

     

    Steel head

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    We need to fix both those targets lol
    Yea
    I’m hoping to get at them in March.

    The 850, 950 and 1120 are all down or hammered.
    I need to improve the mile target as well.

    I have a piece for 2300 I want to put up as well.

    Too many shooting them but not maintaining them!
    :(
     

    Jackomason

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    I've gotta get in your guys circles! Thanks for all the info. I've only got steel out to 1050 but it's just me shooting it haha.

    It sounds like it'd be a pretty standard barrel job so that's kinda nice. I guess that's the direction I'll start working then. Thanks for all the great info guys.

    How do the 7mm solids do when you get out there? I used the 151 Cayuga in my hunting rifle and was amazed by the numbers but they were kinda hard to spot especially by myself.
     

    calshipbuilder

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    I shot a short action 7 Saum at the NF ELR - ran 183s one year and 184s the other. Had lots of feeding issues - defiance and atlas actions, different magazines too - running at 2.95 leaves little room for error - about one in ten would hang up.

    I moved to the XM platform and feeding issues went away, plus I picked up speed from the extra capacity. If you want to stay short action, I would run 6.5saum/prc - lots of great bullets in 6.5.
     

    badassgunworks

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    ELR is any range where you are shooting your projectiles past transonic.

    You can shoot "ELR" with a .22lr.

    There's no reason why the OP can't try a 7SAUM and see if shooting past its transonic distances is fun or not, and worth a bigger cartridge.

    Anyways, I don't have any experience with the 7SAUM, so can't help the OP. But I believe @Sheldon N has one if my memory is correct? @Steel head ?
    No.... elr the sport has been defined by the sport as starting at 1500 yards and going out past 3000 plus yards. It has nothing to do with where your cartridge goes transonic your ability or what is far to you. 22 elr is a defined and organized match for 22 only.
     

    kthomas

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    No.... elr the sport has been defined by the sport as starting at 1500 yards and going out past 3000 plus yards. It has nothing to do with where your cartridge goes transonic your ability or what is far to you. 22 elr is a defined and organized match for 22 only.

    That's a very arbitrary distinction, and not one that everyone agrees with.

    If the OP wants to be competitive on the ELR circuit, then I would agree with you. But it doesn't sound like that's his intent, at least not yet anyways.
     

    Steel head

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    I shot a short action 7 Saum at the NF ELR - ran 183s one year and 184s the other. Had lots of feeding issues - defiance and atlas actions, different magazines too - running at 2.95 leaves little room for error - about one in ten would hang up.

    I moved to the XM platform and feeding issues went away, plus I picked up speed from the extra capacity. If you want to stay short action, I would run 6.5saum/prc - lots of great bullets in 6.5.
    Interesting
    Thankfully I haven’t had feeding issues
    B3A74965-A0C0-4D8C-A1CC-A2F9342528DC.png

    Interesting results in a competition setting
    For a Joe Shmoe wanting to do some ELR with a lot of bang for the buck 7 saum makes even more sense.

    I do think that if you want mag fed and ELR it’s better on a medium or long action.
     
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    Sheldon N

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    running at 2.95 leaves little room for error

    Yeah, I should clarify that I load at 2.94 or so, to leave room in the 2.95 magazine.

    I've even had mag issues when shooting heavies with 308 loaded at 2.95". Fed great in normal weather, had to shoot on a frosty morning for a match and the magazine contracted enough so that 2.95 was too long. :)
     

    Jackomason

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    That's crazy. Where do the feeding issues show up in the 7 SAUM? Is it just the shoulder angle hitting too early?

    I don't really want another 6.5, I was able to help a buddy set up his hunting rifle in 6.5 prc and wasn't really all that impressed. Now that was factory ammo but still it didn't really get me excited.

    I guess a decent start may be to take my 6.5cm out to a mile or maybe 1500 and get a feel for why I need more. Although I've wanted a 7 saum of some flavor for a long time now.
     

    calshipbuilder

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    That's crazy. Where do the feeding issues show up in the 7 SAUM? Is it just the shoulder angle hitting too early?

    I don't really want another 6.5, I was able to help a buddy set up his hunting rifle in 6.5 prc and wasn't really all that impressed. Now that was factory ammo but still it didn't really get me excited.

    I guess a decent start may be to take my 6.5cm out to a mile or maybe 1500 and get a feel for why I need more. Although I've wanted a 7 saum of some flavor for a long time now.
    One part of it is that bullets walk out of the case, especially when seated on top of compressed loads, over time and travel. If you cram in 62+ grains of H1000 or similar powder in the 7 saum case, seat a 180+ grain bullet on it, then drive across country, you will find that a significant percentage of your rounds seated to a max OAL of 2.95 now wont fit in the magazine, and the ones that do barely fit. I tried to fix this with more neck tension, but that just ended up denting bullets.

    Another part is just the general feeding issues with the short magnum cases, at 2.95 you leave very little room for error between then end of the magazine and start of the feed ramp.

    Look at what you can do with the newer 150+ grain 6.5 bullets. I really enjoy running them around 2750 in a 6.5cm in NRL hunter matches, and 6.5s have done very well in the NF ELR matches - although not quite as well at the top of the charts as the 300 Norma: https://precisionrifleblog.com/2020/08/27/best-rifle-elr-caliber-cartridge/
     

    Steel head

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    One part of it is that bullets walk out of the case, especially when seated on top of compressed loads, over time and travel. If you cram in 62+ grains of H1000 or similar powder in the 7 saum case, seat a 180+ grain bullet on it, then drive across country, you will find that a significant percentage of your rounds seated to a max OAL of 2.95 now wont fit in the magazine, and the ones that do barely fit. I tried to fix this with more neck tension, but that just ended up denting bullets.

    Another part is just the general feeding issues with the short magnum cases, at 2.95 you leave very little room for error between then end of the magazine and start of the feed ramp.

    Look at what you can do with the newer 150+ grain 6.5 bullets. I really enjoy running them around 2750 in a 6.5cm in NRL hunter matches, and 6.5s have done very well in the NF ELR matches - although not quite as well at the top of the charts as the 300 Norma: https://precisionrifleblog.com/2020/08/27/best-rifle-elr-caliber-cartridge/
    You need to dump H1000 and run N565 or R26
    No more compressed BS
     

    Steel head

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    What twist rate would you guy's recommend for 180-190's ?
    I have used a 1-8 on all my 7mm’s
    Great with Berger 180 and 190 and Sierra 183’s
    The older 180 ELD did well with it but all the newer ones had a high percentage of poofs
     

    Geno C.

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    For sure I have. And never once have I had a bullet end up long than I seated it unless it was a compressed load. If dropping your luggage is making your bullets walk out of the case mouth, you
    Might want to re-evaluate your neck tension
     

    Alpine 338

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    3 custom short action 7 SAUMs built by Jon Beanland. First one on a Remington action, the other two are Defiance Rebels. Running 180 Hybrids loaded at 2.950". (Not sure on the FB? Whatever Jon uses) No issues feeding. However, I do make sure the magazine feed lips are aligned properly.

    I use 4831SC with a velocity of 2960-fps with Norma brass. Barrels are 26" Bartlein 5R.

    One of my favorite cartridges.
     
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    calshipbuilder

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    A kinetic puller uses the mass of the projectile to remove it from the case. If you watch the above video, you can see this on a smaller scale from leaving rounds in your car while you drive around. Many f class shooters seat long and do final seating at matches to avoid this issue.
     
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    Geno C.

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    A kinetic puller uses the mass of the projectile to remove it from the case. If you watch the above video, you can see this on a smaller scale from leaving rounds in your car while you drive around. Many f class shooters seat long and do final seating at matches to avoid this issue.
    Actually, they seat long and reseat at a match to avoid any possible cold welding.
     

    Mike Casselton

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    Are some of the competitors transporting their ammo in these?

    Screenshot_20211213-070219_Chrome.jpg



    Even though the insert supports the projectile, I can see how it's weight would allow it to move outward if stored in the bullet down position.

    Screenshot_20211213-070224_Chrome.jpg


    I agree that it would have to be super light neck tension for it to happen.

    Easy fix is simply to seat long and do final seating at the match.