Reamer/throat for 7SAUM with 180 Hybrids

[ormandj]

I want to chamber a barrel I have for a long-action build I’m doing with 7 SAUM, to primarily shoot 180 Hybrids. Unfortunately, I don’t have any 7 SAUM brass (ADG won’t be producing another batch for some time) and don’t have any 180 Hybrids (haven’t been able to find them in months). This is my first 7mm, so I only have a few 175 Hunters I was able to find on the classifieds.

What reamer specifications are people using for 7SAUM builds with long-action magazines, who are running 180 hybrids? I want to check against my calculations to ensure I get the right JGS reamer machined before chambering. I’m sure they’d help out too, I just figured I’d ask here first.

Is anybody doing any modifications to improve the case, as well, or just leaving it stock dimensions?

 

[gme]

my reamer has .220 freebore, works well with the 180H (LTC Aaron Grimm won the 2021 Wimbleton Cup with one of our rifles)

 

[ormandj]

my reamer has .220 freebore, works well with the 180H (LTC Aaron Grimm won the 2021 Wimbleton Cup with one of our rifles)

Is your rifle a long action or just single feeding? What’s the COAL with the 180HTs if you don’t mind? Thank you!

 

[gme]

Aarons is a long action single shot, I have a repeater built on a long action as well, dont have the exact COAL here but they feed and easily fit in a AI .338 (non CIP 3.65") magazine with lots of room to spare

 

[ormandj]

I was actually hoping for a longer COAL to improve feeding, hah. Sometimes short rounds in LA magazines don’t feed so hot. I will be using full-length magazines so have up to 3.750” COAL capability.

 

[WSnyder]

I was actually hoping for a longer COAL to improve feeding, hah. Sometimes short rounds in LA magazines don’t feed so hot. I will be using full-length magazines so have up to 3.750” COAL capability.

Didn't have any issues with the RSAUM case (6.5 GAP, 7 RSAUM) feeding from long actions whether they were from boxes or AICS type mags. Tested and checked quite a few combinations on several different brand actions with several styles of bottom metal and they all worked with no modifications. That was with both 180HYB seated for use in short action and 180HYB seated long, didn't matter.

 

[ormandj]

Didn't have any issues with the RSAUM case (6.5 GAP, 7 RSAUM) feeding from long actions whether they were from boxes or AICS type mags. Tested and checked quite a few combinations on several different brand actions with several styles of bottom metal and they all worked with no modifications. That was with both 180HYB seated for use in short action and 180HYB seated long, didn't matter.

Thank you. I've heard .200 and .220 FB thrown around, so just trying to figure out where I want to land with this barrel, at this point. Sounds like I'll be GTG on feeding, I really appreciate the feedback!

 

[davidjoe]

That brass problem isn’t showing signs of going away. I personally believe that just 3-5 active F-Class competitors could comfortably buy all of ADG’s limited annual saum output, and they are the only ones making any, maybe once or twice a year.

If you chamber for that round without already having any brass in your inventory, you will be competing with maybe 100-200 guys globally who are heavily match-invested in the round and very agitated, search the sites daily, some of whom have become prepared to buy a whole shipment from multiple vendors if permitted.

Free bore specs for a saum with 180’s is a little like planning the diet for a daughter’s pet panda birthday present in that any fresh bamboo will work, but getting the bear isn’t at all easy. To answer though, my floating pilot standard spec reamer is my smith’s preference to the solid standard reamer and neither need further throating for up to 195’s.

 

[ormandj]

I picked up some new ADG 7 SAUM over the last week, so that'll hold me over until backorders get filled or I can find other sources. I do hope some other players get into the 7SAUM brass game, though, that is a bit concerning. It's a shame it isn't more popular; too bad it was a Remington cartridge, they had a knack for screwing up product launches. I'm a little befuddled that Peterson and/or Lapua haven't picked it up yet, since it seems to be growing in popularity, but brass isn't keeping up.

 

[davidjoe]

I picked up some new ADG 7 SAUM over the last week, so that'll hold me over until backorders get filled or I can find other sources. I do hope some other players get into the 7SAUM brass game, though, that is a bit concerning. It's a shame it isn't more popular; too bad it was a Remington cartridge, they had a knack for screwing up product launches. I'm a little befuddled that Peterson and/or Lapua haven't picked it up yet, since it seems to be growing in popularity, but brass isn't keeping up.

I think it’s only popular now for long range competition use, that’s not a lot of people but some of them have 5,000 pieces of usable brass or more in their cartridge choices. It was originally billed as suitable for light weight hunting rifles with their short actions and barrels, and its moderate magnum recoil. I don’t know why they won’t make it, either.

 

[Willow]

I picked up some new ADG 7 SAUM over the last week, so that'll hold me over until backorders get filled or I can find other sources. I do hope some other players get into the 7SAUM brass game, though, that is a bit concerning. It's a shame it isn't more popular; too bad it was a Remington cartridge, they had a knack for screwing up product launches. I'm a little befuddled that Peterson and/or Lapua haven't picked it up yet, since it seems to be growing in popularity, but brass isn't keeping up.

Norma have got 7SAUM brass on the way this year...

 

[Chris Roland]

I picked up some new ADG 7 SAUM over the last week, so that'll hold me over until backorders get filled or I can find other sources. I do hope some other players get into the 7SAUM brass game, though, that is a bit concerning. It's a shame it isn't more popular; too bad it was a Remington cartridge, they had a knack for screwing up product launches. I'm a little befuddled that Peterson and/or Lapua haven't picked it up yet, since it seems to be growing in popularity, but brass isn't keeping up

I think it’s only popular now for long range competition use, that’s not a lot of people but some of them have 5,000 pieces of usable brass or more in their cartridge choices. It was originally billed as suitable for light weight hunting rifles with their short actions and barrels, and its moderate magnum recoil. I don’t know why they won’t make it, either.

care to share where some more 7 saum

I picked up some new ADG 7 SAUM over the last week, so that'll hold me over until backorders get filled or I can find other sources. I do hope some other players get into the 7SAUM brass game, though, that is a bit concerning. It's a shame it isn't more popular; too bad it was a Remington cartridge, they had a knack for screwing up product launches. I'm a little befuddled that Peterson and/or Lapua haven't picked it up yet, since it seems to be growing in popularity, but brass isn't keeping up.

Care to share if there anymore 7saum Adg brass is?

 

[ormandj]

Care to share if there anymore 7saum Adg brass is?

I've got some I'll trade for some Peterson 280AI brass. Otherwise, you'll just have to hunt the forums, that's how I found what I did.

 

[Chris Roland]

I don’t have any 280ai brass. How’s the adg brass hold up?

 

[kev77]

.220-230 is best for the 180s

 

[Wile E. Coyote]

Great thread here! From other sources, not necessarily wrong, I was leaning towards 0.180"as a good freebore in a chamber for 7 SAUM long action purposes. Guess I'll be alright if I can have the chamber freebored for anywhere from 0.180" to 0.220". I have a 7mm blank sitting with my gunsmith, but because they're so backed up, I've had time to do some more research on how to build it. I already have a 7 SUAM in a short action and love it, even with seating 180s deep.

Another question with regards to the 7 SAUM in a long action: if you were to put on a barrel with a SAAMI spec chamber (0.090" freebore?), would you then be limited to seating 180 class bullets deep into the casings (i.e. boat tail/bearing junction well below the neck / shoulder junction)? Seems like the chamber dimensions should dictate here. Also, does anyone happen to know if a Mausingfield M7 open top long action (or short action for that matter) will work with DBM bottom metals? ARC's website says they're designed for BDLs, but I'd like to run AICS magazines as suggested above. Thanks!

 

[Bad Mojo]

If you chamber for that round without already having any brass in your inventory, you will be competing with maybe 100-200 guys globally who are heavily match-invested in the round and very agitated, search the sites daily, some of whom have become prepared to buy a whole shipment from multiple vendors if permitted.

This applies directly to me. I've been ordering/collecting parts and peripherals (action, powder, primers, shell holder, etc) and I've also ordered 200 cases of 7SAUM from Bertram. Allegedly those cases will be in around June. I'm not easily spooked, but the way you put it, it makes sense. I haven't ordered my barrel yet, so I'm considering just having them make it a 284Win. Lapua 284 brass is available right now. Other than all the powder I've just accumulated, I'd only need to call to get my bolt changed to a standard bolt-face. Shoot, I even have 2000 Fed 210M primers for it vs the 300 magnum primers I've scrounged.

Should I wait for the Bertram brass and keep working on the SAUM?

 

[Bad Mojo]

It's a shame it isn't more popular; too bad it was a Remington cartridge, they had a knack for screwing up product launches. I'm a little befuddled that Peterson and/or Lapua haven't picked it up yet, since it seems to be growing in popularity, but brass isn't keeping up.

Sometimes I wonder what 7SAUM would be like if Remington put half as much marketing in, with even just a tenth of the success that Hornady did with any of the "caliber that shall not be named." What if Rem gave it a cool name that really resonated with shooters? I bet we could find brass.

 

[davidjoe]

This applies directly to me. I've been ordering/collecting parts and peripherals (action, powder, primers, shell holder, etc) and I've also ordered 200 cases of 7SAUM from Bertram. Allegedly those cases will be in around June. I'm not easily spooked, but the way you put it, it makes sense. I haven't ordered my barrel yet, so I'm considering just having them make it a 284Win. Lapua 284 brass is available right now. Other than all the powder I've just accumulated, I'd only need to call to get my bolt changed to a standard bolt-face. Shoot, I even have 2000 Fed 210M primers for it vs the 300 magnum primers I've scrounged.

Should I wait for the Bertram brass and keep working on the SAUM?

That probably depends on how much SAUM brass you may need and how often you’d being willing to wait for it.

For me, I may have to wait on custom barrels or stocks, but at least I know that the order will be filled and no one is going to buy my order out from under me. I’m on saum brass waiting lists but there is actually no assurance enough will be made to fill demand.

With nothing already committed as a sunk cost to the saum, I’d pick the .284 option in today’s market. When I started with Saum, bulk Norma brass was only a little more expensive that Lapua 6.5-.284, and straight .284 Lapua wasn’t made.

A very good wind reader and loader won’t gain much from a saum. The very top wind callers and scorers may be replacing components faster than any extra points accrue, or even determine the gun isn’t as readily small-group-shooting as a .284 is.

Merely good wind readers, when it all comes together, do tend to believe they score higher with a magnum, otherwise they’d just shoot their .284’s at all matches. I don’t think many guys use magnum primers in matches, btw, as they really seem to move the ideal powder choice, whatever a person deems that to be, up to the next faster burning option.

 

[ormandj]

For what it's worth, I've decided to pass on the 7SAUM and am just building a 280AI instead. I had SAUM brass which I had no problem selling, but it was apparent that it was nothing but a struggle with this cartridge, from medium action issues (medium vs. XM) and stock fitment to magazines to you name it.