6.5 SS (Sherman Shortmag) Q@A

[LRJunkie]

Real data! No need to believe that Sherman dude.

Ya that Sherman dude is out there for sure !!! Not sure I would believe anything he says.... LMAO....
Best cartridges I have ever shot to date hands down...

 

[Korhil78]

Shout out to all the Sherman haters!

7mm Sherman Max w/155 Gr Edge TLR at 598 yards.

6.5mm Sherman w/140 Gr Berger at 590 yards (10 year old son)

6.5 Sherman w/140 Gr Berger at 490 yards (9 year old son)

6.5 Sherman w140 gr Berger at 670 yards

 

[elkaholic]

Dang, I might be Hating you! I don't get to hunt anymore
Thanks for the great pics. Big congrats to you and the boys.

 

[Korhil78]

Haha thanks. It's just one boy. Got a cow at 9 and then this year at 10 years old.

 

[elkaholic]

Haha thanks. It's just one boy. Got a cow at 9 and then this year at 10 years old.

Gotcha...Youre teaching him well. I cherish the early days of elk hunting with my son!
At that time, we were smackin em with a 6.5 Ackley before the Sherman evolved

 

[adamjp]

Real data! No need to believe that Sherman dude.

No surprises there at all, either for the cartridge or the elkaholic. This is real data on velocity and barrel life, not pressure needed to deliver velocity from case. You keep dodging the question so I am left with an assumption that you are making a living as an amateur wildcatter.

The performance is pretty much the same as that claimed for a 6.5 SAUM which is consistent with the very similar case capacities. A little more pressure for the smaller case and you get the same velocities, but more pressure = less barrel life. Reading on 6.5 SAUM from GA Precision suggests velocities and barrel life pretty much lineball in similar use.

This is starting to sound like the 7SS thread.

Not bothered to look that one up, but I am not surprised.

FWIW I'm not a Sherman Short Mag hater, just trying to determine if it is all wishful thinking or hard numbers. Until there is proof by way of a pressure trace, I'm going to stick with wishful thinking and assertive marketing.

I doubt I am alone in those thoughts.

 

[dirtytough]

Not bothered to look that one up, but I am not surprised.

FWIW I'm not a Sherman Short Mag hater, just trying to determine if it is all wishful thinking or hard numbers. Until there is proof by way of a pressure trace, I'm going to stick with wishful thinking and assertive marketing.

I doubt I am alone in those thoughts.

Someone posted almost the same thing you are about the 7ss. One of the smiths that has built a few 7ss and 7 saum, said even though they have the same capacity you can't push the saum as fast. And also since there is no known loads pressure wise for wildcats you can't use a pressure trace on them.

That's going off of memory so if you are interested it's around the mid teens page wise in the 7ss thread I believe.

Also an interesting thread is the 338ss thread. Where they talk about different powders no one would of thought would work. Which work in the 338ss but don't in the regular 338 Sherman. Close to same capacity but certain powders work in one but not the other. Not much different besides case shape.

Curious how 60 grains of powder in a shortmag would ignite versus the exact same 60 grains of powder in say a super long/skinny case? I doubt you would get the exact same performance.

Anyway it's interesting.

Someone that has both a 6.5 saum and 6.5 ss should do some testing for all of us.

 

[elkaholic]

No surprises there at all, either for the cartridge or the elkaholic. This is real data on velocity and barrel life, not pressure needed to deliver velocity from case. You keep dodging the question so I am left with an assumption that you are making a living as an amateur wildcatter.

The performance is pretty much the same as that claimed for a 6.5 SAUM which is consistent with the very similar case capacities. A little more pressure for the smaller case and you get the same velocities, but more pressure = less barrel life. Reading on 6.5 SAUM from GA Precision suggests velocities and barrel life pretty much lineball in similar use.


Not bothered to look that one up, but I am not surprised.

FWIW I'm not a Sherman Short Mag hater, just trying to determine if it is all wishful thinking or hard numbers. Until there is proof by way of a pressure trace, I'm going to stick with wishful thinking and assertive marketing.

I doubt I am alone in those thoughts.

I get tired of the same questions over and over and over is all. Proven by MANY shooters so just research the threads.
NO PRESSURE DATA AT THIS TIME!!!!!!!!

 

[H59]

I wouldn't usually chime in on such an off topic comment but I am. Adamjp truly seems as if you cannot accept any attempt at answering your questions with real world factual data. Nothing has been up to your standards and for some reason you have always attacked the designer of the cartridge but not the cartridge performance . The many variations of the Sherman Wildcats whether ss or sst variants in several different calibers have impressed hundreds of shooters from their performance and will continue to do so in the future. If the data provided from so many owners of the many cartridges isn't up to your own standards perhaps you should do some research and testing that is and grace us with your professional & impressive abilities and show us why the "amateur wildcatter " is all smoke and mirrors, which is what seems to be at the root of your issues with the questions and answers. I for one believe that the proof is in the pudding so to speak and do not need cup testing to show me what I already see and know from loading and shooting the cartridge and inspecting the fired brass...among other things.

 

[rockwallraider]

had elmer spin me up a 6.5ss for my blaser. looking really good so far. seems to love 57 grains of rl 23 at 3018 with the 147 eldm. did not see an ejector mark until 59.5 but seems to like 57 so we will go test it out to some distances

 

[adamjp]

...Adamjp truly seems as if you cannot accept any attempt at answering your questions with real world factual data. Nothing has been up to your standards and for some reason you have always attacked the designer of the cartridge but not the cartridge performance...

I asked a simple question and the creator could have simply said, what he ended up saying - "No pressure data at this time." Instead of this simple sentence, he chose to dodge, weave, respond with marketing passages, and rely upon velocity data and observed barrel life posted by others. None of this answered my question.


As previously said, I'm not anti-Sherman Mags.

Like some here, I have 30+ years of reloading, including wildcatting in my history. Unlike some I also have professional education in aligned fields and am always interested when a person claims superior velocity performance from a capacity smaller than an accepted, pressure checked reference.
Some things I do believe in:
- Short fat cases provide for a more consistent burn profile (measured as a pressure trace) than long thin cases.
- Sharper shoulders do appear to improve throat life,
- longer necks also appear to improve throat life,
- so a design with these features will give a longer throat life than a short necked less sharp cartridge design (6.5-284 is a classic example).
- Some powders do burn cooler than others at similar pressures.
- Some barrels are faster than others for no obvious reason.
- Some powders sacrifice outright performance for greater temperature stability.
- Pressure and heat erode barrels more than any other variable.
- Throat design has a significant effect on pressure curve and accuracy.

What I know is that Pressure is essential to velocity, the greater the area under the pressure curve, the more force is exerted on the piston (bullet in this instance). If maximum pressure is a set amount (say 64k PSI), then to deliver more velocity at that maximum pressure it is essential to 'flatten the curve' so that more pressure exists either side of the peak. This gives a larger area under the curve and is why propellants with retardation coatings (aka slower powders) are useful because they slow the rise in pressure and maintain pressure longer past the peak during their longer combustion time. Trouble is, to keep the burn going at the higher pressure post peak, you also need more fuel (aka powder). More powder means more capacity in the cartridge case.

The key thing to all of this is that it does not matter what shape the pressure vessel is (aka cartridge case) as pressure is exerted equally on all walls of the vessel which is a closed system. Sharp shoulders, minimum tapers, belts, rebated rims, long necks, etc. have no bearing on the pressure exerted. The only thing which does have an influence is a shorter powder column, and that is good for getting more propellant alight in a shorter space of time (less progression of ignition). This shorter ignition time gives more consistency to the resulting pressure curve which improves accuracy.

No, wildcats don't have pressure limits as they are not SAAMI or CIP certified. That does not mean they don't have a reasonable upper pressure threshold which is dictated by the brass, the action and the barrel construction.

To summarise, when all else is equal, to deliver equivalent or more velocity from a smaller capacity case you must be running more pressure. I remain interested in what those pressure traces actually are in cartridge designs which optimise what they can.

 

[Luckyshot7]

Hoping to revive the thread with a question about the 6.5 SS. Relevant to anyone who is chambering it since the release of 6.5SS head stamped brass and the Hornady 6.5 SS bushing dies.

Rich,
I just received the aforementioned brass and dies from your site (THANKS!), so now I am in the position of needing to size-down the 7mm necks. I have never neck turned nor necked-down a caliber before, and I have it from several sources that stepping it down with bushings is ok, yet others say conventional dies only for better concentricity etc. I have pored over as many "necking-down" threads as I could and am still unsure. Lacking a conventional sizing die for a magnum 6.5mm with 40deg shoulders (that I know of) I think stepping down with bushings is my best/only option. I'm doing wildcats on a budget (which is only possible through Rich's efforts) and ordering a custom die for this is probably out of the question.

Can I get away with necking this down with bushings-only from the 6.5SS hornady die? Brass's neck OD is 0.312 , ID 0.284. My plan was to order the following bushings: 0.304, 0.296, then finish with a 0.291.

Do you require and/or suggest neck turning these? I've read in previous posts that the necks are already properly sized for this brass to allow for the thickness increase during necking-down. Does that check out?

Maybe that is not your first choice! I hope to hear your top recommendations as well, but again, I'm in a place where I'm willing to suffer through less-than-perfect brass before spending a few hundred more dollars on neck-turning equipment and/or more custom dies. Thanks


Question is of course open to the floor as well.

FWIW my build is going to be a 24" Mullerworks #4 contour on a Bighorn Origin SA; hoping to send 156's at 3000

 

[Coyote Shadow Tracker]

Interesting thread for sure.
I am a 6.5mm person and looking at this information got me thinking. I have an extra Bartlein 5R - 6.5mm gain Twist 8.75 to 7.82 #4 contour 27" (could cut down). Might work really well chambering it to a 6.5 SS for a hunting rig.

 

[parshal]

Use your bushing die without turning necks. You'll be fine. I necked mine down in two steps but I don't know how necessary that is.