7 mm SHERMAN SHORTMAG vs 7 SAUM

[Phil Rizzo]

My mag length held me to 2.840 coal, max.
But, my 2nd load at 61grs printed tight with an ES of 4.!
Only about 2860fps but I have room to go up.

 

[TejasRider]

Trying to line up cerakote to finally get my 7SS assembled and out to the range in the next month or so. In the meantime, I'm starting to get my reloading parts together. Assuming ADG brass, any recommendations on bushing size? I understand most typically start with a loaded round for getting a bushing size but I'm in a bit of chicken and the egg spot at the moment.

 

[haisardao]

Trying to line up cerakote to finally get my 7SS assembled and out to the range in the next month or so. In the meantime, I'm starting to get my reloading parts together. Assuming ADG brass, any recommendations on bushing size? I understand most typically start with a loaded round for getting a bushing size but I'm in a bit of chicken and the egg spot at the moment.

I just got my 7 SS a couple of weeks back, and Sherman head stamped from Rich, I used 309 bushing, worked like a charm. The .310 was a bit to loose x my taste. My loaded round was .311 with 162 ELD-M

 

[TejasRider]

I just got my 7 SS a couple of weeks back, and Sherman head stamped from Rich, I used 309 bushing, worked like a charm. The .310 was a bit to loose x my taste. My loaded round was .311 with 162 ELD-M

Thanks for the quick reply! I had a .309 and .308 in my cart.

 

[jsmitt6]

I used a .308 for the 169 HH I shot out of my 7ss.

 

[OG-danimal]

Hey all,
I want to convert my 6.5 prc Proof MTR to a 7ss. What's the best way to do this? Thanks for your help!

 

[RH300UM]

Hey all,
I want to convert my 6.5 prc Proof MTR to a 7ss. What's the best way to do this? Thanks for your help!

You would probably be better if you started your own thread asking this question.

 

[UCzO___]

Are all of the SS cases the same except for the neck diameter? I know 7mm and 338 are, but not sure if 300 is the same.

 

[Phil Rizzo]

I think on the Sherman website it says all that brass comes as 7mm and gets necked up/down by the purchaser

 

[UCzO___]

I think on the Sherman website it says all that brass comes as 7mm and gets necked up/down by the purchaser

It does say that, but it doesn't give any dimensions for the rest of the cartridge. When I built 7SS, Rich didnt have any 7 brass in stock but told me I could use 338SS, which is why I made the statement I did. I am thinking of building a 300SS and want to know if I can simply neck up my 338 brass from .284 to .308.

 

[jburns42]

I am in the process of getting a 7SS together, thanks to the gunsmithing talents of a certain forum member from Dillon Mt. I hope to be slinging lead in the next couple of weeks at which time I should have some real world data. In the mean time, I wanted to introduce the cartridge and what I am trying to accomplish. First of all, it is simply a necked up version of the 6.5 SS which has proven to be a very good performer.
Here are a few comparisons between the 7 saum and the SS and what I feel are improvements over the saum. The SS is .075" shorter oal. It is .095" shorter at the neck shoulder junction which determines where proper bullet seating depth starts. It has a .020" longer neck than the saum. It has a 40 degree shoulder and less body taper keeping case stretching to a minimum. The shorter powder burning column is more efficient. A 168 Berger seated to the base of the neck will have a coal of 2.870" to the lands so the round will cycle through much shorter magazines without loosing case capacity. The case capacity is right at 72 grains, but the USEABLE capacity is likely slightly more than the saum unless the saum is single loaded with a longer than normal throat, therefore; coupled with the shorter burn column, I expect velocity to be slightly higher than the saum. We will see I expect to be able to exceed 3100 with the 168's and 3000 with the 180's. Questions, comments, or flag throwing are welcome.........Rich

Hi, Rich I was trying to find the cartridge dimensions so I could play around on GRT. I've heard great things about the 7SS round and want it to be my next build. How would I find these dimensions?

 

[elkaholic]

Hi, Rich I was trying to find the cartridge dimensions so I could play around on GRT. I've heard great things about the 7SS round and want it to be my next build. How would I find these dimensions?

pm me on my cell 208 755-6723

 

[TejasRider]

Thought I'd share some pics of my finished Iron Man 7SS rifle. It seems I still have some more speed available but I have settled on a 63.3 gr load of MagPro behind a 180 ELD-M for now. It's giving me 2830 fps but expect to gain a little speed as the barrel breaks in. First 50 shots were to get velocity data and look for pressure signs at a local 100 yard range. Loaded up 50 more and took the rifle out to 1040 yards a few weeks ago. Without confirming 100 yard zero or getting fresh chrono data, I just dialed based on my ballistic calculator and was off by about 2 mils left and maybe 2.5 mils low. By the 3rd shot, I hit steel and the next 2 were within about 7" of the first.

A few other guys got some time behind the trigger including someone that didn't do much long range shooting and he connected on his first shot. Everyone commented on how easy it was to manage the recoil and get back on target.

Love this rifle!

 

[CA48]

If Iron Man shot long range thats what his rifle would look like.
Very Nice!