7SAUM Build - Thread #1 Bullet Selection

[Bad Mojo]

It's been 8 years since I got on this forum to ask about a build. It's time again and I'm in the process of a new build for a cartridge I have been interested in for at least a decade. This is me getting off the fence. Before I began this post, I searched 4 pages of 7SAUM-related threads to avoid duplicating age-old questions. The bullets I will mention were not included in 95% of the threads as the threads pre-date them.

I'll post in 2 threads since I have a couple types of questions and I don't want to cross-contaminate with several types of questions at once. I'll stick to bullets and barrel lengths for this post.

I ordered a Defiance Ruckus Tactical XM (med. length), XLR chassis ordered and in route. This is a fun gun for my entertainment only. I have no proclivities to compete.

I contacted Short Action Customs for a barrel and ended up getting a quote for assembling everything with my supplied parts. After a bit of conversation about profiles, brakes, etc, I asked for a quote. The quote spec'd 28" Bartlein 5R, 7.7" twist and chambered for Berger 184s. I haven't agreed to the specs of the quote yet. This is where I'd like your experience:

• Does the 7SAUM have enough ass to push a 184
  • any big trade-offs spec'd for 184 w/ 7.7" twist
• Any reason to spec for 180's instead/slower twist (8?)
• If I chamber it for 184s, will it shoot 168-175s ok
• Not Berger-specific: How do the Nosler RDF 185's fair/could I shoot Bergers and RDFs interchangably without issue?
  • Barnes Matchburners 171
  • Other bullets I'm not thinking of ...

He quoted 28" but I was thinking 26". If I go with a 26", are the heavies dependent on the extra 2 inches? Primary concern is buidling for 184s and limiting to only those. A consideration or no big deal?

 

[whatwind?]

7.7 too fast, think they said 8.7 twist….are you at sea level?

 

[Fyrchief]

My 7 SAUM has a 26" Bartlein 8.7 twist barrel and shoots 168 Sierra Match Kings into one hole at 150 yds. I think you'll be fine with that twist up though the 184s.

 

[PRECISIONWELDING01]

I shoot the 180 hybrids with a 9 twist with no problems . I think the 8.5 twist would be as much as I would go

 

[rhovee]

Exactly what others have said. I have a 7 Saum hunting rifle that shoots smaller than my bench gun at 600 some days. 8.7 twist Bartlein 180 hybrids

 

[TZaun]

I shot 184s through a couple of barrels for F-Class. Both were 8.5-twist 28.5” Kriegers and .230” freebore. H4350 gave the best accuracy around 2875 fps. H4831SC could get them up to 2970 fps.

 

[Bad Mojo]

7.7 too fast, think they said 8.7 twist….are you at sea level?

850'

 

[Bad Mojo]

I thought that was too fast - it definitely says 1:7.7". Maybe he fat-fingered the keyboard. I got the quote while I was doing some long-term traveling for work and read it on my phone. I didn't realize in all that haste that my 6BR has an 8 twist. 7.7 just has to be a typo.

Any thoughts on the RDF bullets?

 

[rardoin]

A 9 twist will stabilize a 184 hybrid at 18ft ASL running at 2790fps...no problems....and I'm not the only one who can attest to this. An 8.25tw stabilizes 190 A-tip telephone poles at 2740fps and slower all the way out to 1000yds at near sea level. I would not suffer more torque than necessary to shoot the 184's.

 

[whatwind?]

Get two barrels, one 1:8.75 4 groove . 276 bore with .220 fb and one 8.45 .276 bore 5r rifling with .260 fb and that will cover winter and summer shooting and you can test to see which you like…….none of this matters under 600 yards

or go play with the Berger stability calculator adjusting for temp and elevations you plan to shoot in knowing they used to say 1.4 is good enough and now say 1.5 is needed

 

[Delfuego]

Short Action / Long Action / Single Feed and magazine length plays a lot into bullet choice for 7 SAUM. Also need to know what you expect for speed and at what distance you are shooting. The +180 are long and might not magazine feed. The 168's are great but not gonna make it to 2k yards very easy. 180 hybrids kinda do it all. you can get them going pretty fast and they do well at distances past 1500y. The also fit nicely in WSM magazines. SAUM doesn't have the powder to get +190 going super fast, but is you don't need the speed who cares (you're back to magazine & throat). Just running a long action can allow you to shoot them seated further out and make a big difference. I ran short action 180's @ +2950 1:9 twist for ELR matches with great results.

My 2 cents, if you have short action magazine, 168 to 180. If long action or single feed, get it throated longer and run 180-185gr.7 SAUM is not nice on throats and you will be jumping in no time.