Wildcat question

[birdiemc]

I have no background at all in wildcatting, really dont even want to go down that road of creating my own, but curious about shoulders. Lots of catridges made better by going to 40degree shoulder, so why not keep flattening it out more and go to a 45 or 50 degree?
I haven't researched this at all, so maybe somebody did already... but what would be the impact of such a should bump?

 

[Tank308]

I have no background at all in wildcatting, really dont even want to go down that road of creating my own, but curious about shoulders. Lots of catridges made better by going to 40degree shoulder, so why not keep flattening it out more and go to a 45 or 50 degree?
I haven't researched this at all, so maybe somebody did already... but what would be the impact of such a should bump?

Feeding problems would be the first that come to mind.

 

[WeiserBucks]

Another issue with steep shoulders is that they're easily crushed by the die during sizing.

 

[elkaholic]

Shoulder angle changes the burning characteristics of powder, and many believe has an affect on burn time and gas flow into the throat affecting erosion, either in a negative or positive way, depending on the angle.
It is generally believed that sharper shoulders increase efficiency, me included. It is also believed that somewhere from 40-45 degree is best and beyond that, could be detrimental because of too much flow disruption?
Much is speculation but there is real evidence that design matters and shows up in cartridges like the Dasher and others. Even though there is some disagreement as to why certain things work, there is less argument that it does work.
My take is "go with what works"!

 

[adam32]

42° is the best, followed closely by a double radius.

 

[YZ-80]

Wouldn't a more acute shoulder angle also contribute to case stretching?

 

[elkaholic]

Wouldn't a more acute shoulder angle also contribute to case stretching?

for sure!

 

[birdiemc]

Shoulder angle changes the burning characteristics of powder, and many believe has an affect on burn time and gas flow into the throat affecting erosion, either in a negative or positive way, depending on the angle.
It is generally believed that sharper shoulders increase efficiency, me included. It is also believed that somewhere from 40-45 degree is best and beyond that, could be detrimental because of too much flow disruption?
Much is speculation but there is real evidence that design matters and shows up in cartridges like the Dasher and others. Even though there is some disagreement as to why certain things work, there is less argument that it does work.
My take is "go with what works"!

This question came to mind while reading through the first 15 pages of the 7ss vs 7wsaum thread. I'm thinking that might have to be my next build.

 

[elkaholic]

This question came to mind while reading through the first 15 pages of the 7ss vs 7wsaum thread. I'm thinking that might have to be my next build.

Let me know if I can help
shermanwildcatcartridges.com

 

[birdiemc]

Thanks Rich. I'll be hitting you up soon enough.

 

[Brush4646]

After much research Palmasono and Pindell came up with the most accurate cartridge in the world. The PPC with a thirty degree shoulder. Art Mashburn had a long line of wildcats all with 30degree. I think that is the optimal degree for accuracy and feeding. Just my thoughts.

 

[CatShooter]

42° is the best, followed closely by a double radius.

Actually, by extensive military tests, 41.73826° is best.

 

[elkaholic]

http://www.saubier.com/forum/showthread.php?t=5273

Here is an interesting read for anyone who is actually interested in learning.
Its pretty lengthy but talks a lot about case design; specifically how length, shoulder, neck, taper, etc. work together.

 

[chetraguse]

Let me know if I can help
shermanwildcatcartridges.com

Rich,
So even though you have your own adg brass all your cartridges still have to be fire formed??