7 mm SHERMAN SHORTMAG vs 7 SAUM

[elkaholic]

Pic next to dads 6.5 saum with a 143gr eld X at 2.970 roughly. First shot with 59.6gr of RL26 is getting me near target velocity already. Though moving to 59.8gr I've got an elector imprint. Should i have waited and fireformed a second time?

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You shouldnt be getting ejector marks with that charge? I have guys with 22" barrels running 2950' without marks.
I dont know if you have a tight barrel, but velocity isnt there either?
It could be the eldm because I cant remember what people got with them? I know the Bergers will definitely run faster. maybe Jacob (wiscgunner) can che in. He shoots the eldm's

 

[elkaholic]

Pic next to dads 6.5 saum with a 143gr eld X at 2.970 roughly. First shot with 59.6gr of RL26 is getting me near target velocity already. Though moving to 59.8gr I've got an elector imprint. Should i have waited and fireformed a second time?

View attachment 165203 View attachment 165204 View attachment 165205

You shouldnt be getting ejector marks with that charge? I have guys with 22" barrels running 2950' without marks.
I dont know if you have a tight barrel, but velocity isnt there either?
It could be the eldm because I cant remember what people got with them? I know the Bergers will definitely run faster. maybe Jacob (wiscgunner) can chime in. He shoots the eldm's

 

[5RWill]

I think the eld m is a lot of the culprit. I let the gun cool and shot the rest of 60gr with no issues. The fact of the matter is the eld m is long as hell and has a ton of bearing surface so I'm not really surprised. Given that I'm already at 2900 and it should speed up at least a little at some point I'm pretty satisfied. It's also hammering out of the gate. I've got 60.2 in there and am hunting right now since i chronod, wanna see if I'll still get pressure signs with it once it's completely cool.

This was 60.2gr of RL26 and it's 70F here also. If the next shot is sticky or has that large of an ejector print on it I'll be pulling them and just run with 59.6gr. For the time being. No doubt the hybrid would give me probably 30-50fps more per charge but i just have a hard time straying from a G7 of .401 and a G1 of .796 lol that's nearing 750gr amax BC out of a 50 bmg.

 

[elkaholic]

hmmmm no doubt about ejector mark but the primer is not very flat at all for a mark like that? Almost looks like head space, I think you said those were formed? How far did you bump the shoulder?

 

[5RWill]

hmmmm no doubt about ejector mark but the primer is not very flat at all for a mark like that? Almost looks like head space, I think you said those were formed? How far did you bump the shoulder?

I didn't i thought you told me to leave the shoulder alone for another firing. They are formed. Could've just falsely remembered that. 59.8gr is hammering though and right at 2900 i think i'm going to run that for the week or so i have left. It's hard to want to mess with a thing for this load considering how it's shooting. (2892avg 10.1-SD)

 

[Seandradamus]

I've been shooting the eldm since the get go myself .. Proof 24" 8T my node is at 2960 and shoots consistently in the 3s
G7 works out to .390 for me. How many rounds do you have through that tube?
My OAL is 2.870 so it's down in the case quite a bit , that's 15 thou off .. The hybrids sit about 100 thou longer at 15 off

 

[WiscGunner]

I settled on 60.1gr of H1000, 180 ELD-M, FGMM210M @2843fps out of a 26" Proof.

I went up to 62.8gr without pressure signs but was crunching @61.6gr
COAL 2.945 (.02 off)
This is a great load for me with a single digit ES.

 

[5RWill]

I've been shooting the eldm since the get go myself .. Proof 24" 8T my node is at 2960 and shoots consistently in the 3s
G7 works out to .390 for me. How many rounds do you have through that tube?
My OAL is 2.870 so it's down in the case quite a bit , that's 15 thou off .. The hybrids sit about 100 thou longer at 15 off

As of today 116rds. Could be possible that i'm slightly into the lands but the way i found the lands was disassembling the bolt and loading a dummy round incrementally until the bolt fell with no positive extraction. Then went 10 thou off that which is almost always my go to for a given load as far as seating depth is concerned. 2960 would be perfect but i'm not unhappy with 2900. I'll load the rest with 59.8gr and run with it until the spring.

 

[Rhovee]

I run them at 2900 in a 24" 7 saum that's throated for them. .235 fB. That's with H1000.

 

[Hawkeye Pierce]

So I have read and reread this thread a couple times. I found it so interesting because it was the exact struggle of what to choose. I started with wanting a 7mm wsm for the efficient 7mm bullets as well as there abundance for reloading. This came after getting to check out my buddies 300 wsm out in Wyoming on a Pronghorn hunt, very impressive. Then came the research and found 7 wsm brass was hard to find. On one day I stumbled across the 7 saum, more efficient and almost as fast, i like it. With more availability of brass and less powder cost big thumbs up. The problem is i have a trued Remington SA, but really wanted a Devient Hunter XM action to take advantage of the longer bullet seating. Unfortunately with being on a fixed income due to military disability and having 3 kids, a beautiful 1400 action in out of the question at the moment. All of a sudden while stalking around on the forums I find this seemingly miracle round of the 7 SS. Even more efficient, yet clearly better performance, the angels were singing. The only problem is I have already been building a .260 Terminator parts box to send out to Shawn at Defensive Edge. My world seemed to come crashing down around me.

All that to say I think it will have to be a penny pinching build on I have a no clue of an action, use a Hells Canyon summit contour carbon fiber wrapped barrel. The barrel is a Benchmark Barrel sent to Mike at Hells canyon to get wrapped. Its 23.5 inches threaded, and 2.8 lbs. But 8.2 inches at the muzzle. Most likely a carbon fiber stock from Manners or Stocky stocks. Unknown Glass, would love a Vortex AMG, I really like that company's customer service. Either a Timney or a TriggerTech straight trigger. Using my Silencer Co Omega.

What do guys think? The purpose would be to hunt long, and shoot steel even farther.

 

[ruby76]

As of today 116rds. Could be possible that i'm slightly into the lands but the way i found the lands was disassembling the bolt and loading a dummy round incrementally until the bolt fell with no positive extraction. Then went 10 thou off that which is almost always my go to for a given load as far as seating depth is concerned. 2960 would be perfect but i'm not unhappy with 2900. I'll load the rest with 59.8gr and run with it until the spring.

A few things I ran into when trying to figure out pressure signs in my 338ss was:

1. bullet into the lands, corrected by measuring with a Hornady comparator and overall length gauge,
2. Incorrect shoulder bump, measured accurately once I switched to a .420 bump gauge

3. Too fast of powder, my rifle pressured out with a fairly low charge of varget, H4350 is lower pressure

4. Federal 215m primers vs federal 210m, pressure went down with the 210's

My next step is to add some throating as I have room in the mag still, especially if I start loading Bullets other than berger.

 

[kyron]

@Hawkeye Pierce

The quality of the barrel matters much more than the action. If you are on a tight budget, check these out.

http://northlandshooterssupply.com/actions/remington/

 

[Hawkeye Pierce]

@Hawkeye Pierce

The quality of the barrel matters much more than the action. If you are on a tight budget, check these out.

http://northlandshooterssupply.com/actions/remington/

Thanks for the suggestion will do

 

[5RWill]

A few things I ran into when trying to figure out pressure signs in my 338ss was:

1. bullet into the lands, corrected by measuring with a Hornady comparator and overall length gauge,
2. Incorrect shoulder bump, measured accurately once I switched to a .420 bump gauge

3. Too fast of powder, my rifle pressured out with a fairly low charge of varget, H4350 is lower pressure

4. Federal 215m primers vs federal 210m, pressure went down with the 210's

My next step is to add some throating as I have room in the mag still, especially if I start loading Bullets other than berger.

I'll try different primers and bump the shoulders and see how it goes. I guess i need to send an extra piece of brass to Copper Creek for the OAL gauge but i feel pretty confident in the way i did it.