7 mm SHERMAN SHORTMAG vs 7 SAUM

[RH300UM]

Any estimate for pressure? Quick load?
70k plus?

+1.
3200+ fps with a 180 Berger in a case smaller than the 7 saum??
200fps over a 7saum.
I have a 6.5 SS. With 143 eld's I use 60 grains of RL26!!!!
65 grains with a bullet weighing 37 grains more.
This isn't adding up for me

 

[wilkup]

Here's the 5 pieces of brass lying down.

 

[RH300UM]

Here's the 5 pieces of brass lying down.

AND???

 

[wilkup]

The base of all 5 cases.

 

[wilkup]

AND???

Maybe one of you guys can see something I'm missing. I know the bolt lift was stiff and there were extractor marks, but I see no other signs of them being way over pressure. Primer pockets are still tight.
Help?

 

[RH300UM]

Maybe one of you guys can see something I'm missing. I know the bolt lift was stiff and there were extractor marks, but I see no other signs of them being way over pressure.
Help?

Back it off!!
You've got pressure signs. Stiff bolt! Ejector marks!

 

[kyron]

I have never seen it in person but the edges of those primers look very flat, with very sharp corners. Is that not another pressure sign?

 

[elkaholic]

As the designer of this case, I use 62 grains as a maximum useable load. I have fired 63 and thought it was a bit much. You would do well to take heed Wil, before you look like a unicorn!.......Rich

 

[wilkup]

Rest assured everyone, I will definitely be backing off.
I think 64gr is where I'll sit with my loads. Gives decent speed and good accuracy for me.

 

[TheDerkster]

What grain bullet Will?

With 195s, 59 grains is still hot. If I run up to 61, I get severe primer flow into firing pin hole. 59 grains gives little pressure sign including bolt lift except for ejector marks that may be due to a shiny chamber so there is no grip on the case.


64 grains wouldn't come close to even seating. 61 really starts to pack the powder. 59 gr provides over 2900 fps with a 195 grain eol and shoots better than I can. I'd be scared to shoot your loaks unless they are light bullets and cold weather

 

[TheDerkster]

Oh, and 2 out of 3 pieces of brass at 62 grains blew out the primer pockets. Just be careful. Want to make sure you can keep contributing to LRH!!

 

[wilkup]

I'm pushing the 180s loaded to 2.95"

 

[wilkup]

I think the load I'll end up shooting with is 64.0gr of RL26, 2.95" COAL, Berger 180gr Hybrid.
Primers are tight, cases look good and bolt lift is normal.
After all the concern, I will rethink hotrodding my loads.

 

[TheDerkster]

I think the load I'll end up shooting with is 64.0gr of RL26, 2.95" COAL, Berger 180gr Hybrid.
Primers are tight, cases look good and bolt lift is normal.
After all the concern, I will rethink hotrodding my loads.

I mean I'm all for that load if it works for you. My biggest concern instinctively without knowing you is that you don't know what actual pressure signs actally are because I have seen that happen and the poor guy got hurt over it, but luckily not bad. Just gas blowback from primer and a split case. There's also that issue of load development in the cold and not testing max loads in the summer. That never turns out good either.

So you be the judge of your loads and assuming you know what to look for every time you fire a round, I'm sure you'll be fine. I'd say elkaholic may be more inclined to persuade you away from running that far up on loads because as any designer, maker, or inventor of a product and in this case (no pun intended) an extremely efficient catridge design over a range of calibers, he's going to worry that any user could get hurt as a result of his design. I know I would be, because there is no published data for the SS due to being a non SAAMI round except for that of Rich, myself, and a few others. I'm guessing some pepole will try to use SAUM data which is a huge NO NO because the case is slightly higher capacity.