Shoulder angle, why?

[Changeling]

From what I read it seems most of the guys that run Dashers run a 40 deg shoulder angle, why?

Is it just for the increased case capacity, or other things?

 

[Terry]

It was the original design.

 

[Erik Cortina]

From what I read it seems most of the guys that run Dashers run a 40 deg shoulder angle, why?

Is it just for the increased case capacity, or other things?

A Dasher without a 40° shoulder is not a Dasher.

The reason for 40° shoulders is to minimize case growth.

 

[Phil]

A Dasher without a 40° shoulder is not a Dasher.

It`s a BRX.....

 

[Erik Cortina]

A Dasher without a 40° shoulder is not a Dasher.

It`s a BRX.....

True, but only if it has a 30° shoulder, otherwise it can be any number of other wildcats.

 

[Judd]

Because they shoot...that is why ;D

Seriously, all the guys above me answered your question I just had to be a smart donkey and couldn't resist.

 

[johara1]

Judd, No sense rubbing it in…….. 8)……. jim

 

[Judd]

Judd, No sense rubbing it in…….. 8)……. jim

;D

 

[Changeling]

I'm well aware of how Mr. Ackley felt about the 40 deg shoulder, it's not exactly what one would call a secret.
Personally I believe in the 40 deg angle for the very reasons Ackley stated plus I believe it burns the slower powders better and displaces recoil in all directions better therefore reducing recoil ! It might be a small amount, but it's there!

I expected some experienced answers concerning shoulder angles, instead of parroting.

However if you guys love it so well why do you shoot the rest of the so called accuracy cartridges with a 30 degree shoulder and call it a "Proven shoulder angle", like the 22 PPC, 22 BR, 6mm PPC, 6mm BR, just to name a few !

But when it comes to the Dasher, well, that's different .

As far as rubbing it in, meaning ME, maybe you should stop and think some! Unbelievable.

 

[dmoran]

I expected some experienced answers concerning shoulder angles, instead of parroting.

You asked a question...... and I gave an answer and some input

And I wrote of Parker's verdict to the 40-degree shoulder, but I guess that was "old news" to you (which makes me wonder why you even asked).
I also wrote of the combustion gas effects of the convergence angle, but guess that must not have fit into your desires either.

Since you found my reply parroting, and not befitting your expectations, I removed it for you.
And since you seem to have all the answers before you even ask a question, I will refrain from replying to you in the future.

A parrot

 

[Judd]

WOW...someone is strug a little tight.

Lighten up Changeling. I subscribe to the "there are no dumb questions" train of thought but your question didn't really make a whole lot of sense. There is no other shoulder angle for a dasher...every dasher out there has the 40 degree shoulder angle.

They shoot...look what holds the records for longer range stuff...it isn't any of those cartridges you mentioned. People shoot them because it goes back to the old adage "When in Rome you do as the Romans do". If you shoot that stuff you either attempt to compete and shoot a dasher or you shoot something else and be there for fun.

I would argue that any of the 6br improves can and will win and the dasher holds the records because they win the numbers game. But it's nothing I can prove. The dasher is easy to load for, easy to fireform and flat easy to get to shoot. Plus it holds 32-34 grains of powder depending on your freebore so it's fairly cheap to shoot to boot.

Good luck, I hope you get your answer but the bottom line is you either stay on porch or get off and run with the big dogs (fwiw...I ain't a big dog but just a pup trying to learn what the big dogs will teach me).

 

[dkhunt14]

All Dashers have a 40 degree angle and I believe they did that to get slightly more capacity. The Dasher does better at 1000 because it is slightly faster then the others like The BRDX an BRX. I believe that gives a slight edge. Also I believe the capacity is right for the 105 class of bullets. Matt

 

[CatShooter]

[...] and displaces recoil in all directions better therefore reducing recoil ! It might be a small amount, but it's there!

Sorry, but recoil is not affected by the case shape or shoulder angle. You cannot "displace" recoil in all dirrections.

Recoil is the sum of the weight of the ejecta times the mean adjusted velocities, divided by the weight of the rifle.

... there is nothing else involved.

 

[Keith Glasscock]

I think the concept was reduced bolt thrust. Of course, that is also a function of body taper...

But what do I know? I just drive it.

 

[johara1]

I would say the reason for the 40 degree shoulder was to gain case capacity but retain 1 caliber neck length, The BRX with a 30 degree shoulder lost a lot of neck length. Seating depth is more critical with the BRX than the Dasher in relation to where the heel of the boat tail is in the neck……. jim

 

[JRS]

I'm well aware of how Mr. Ackley felt about the 40 deg shoulder, it's not exactly what one would call a secret.
Personally I believe in the 40 deg angle for the very reasons Ackley stated plus I believe it burns the slower powders better and displaces recoil in all directions better therefore reducing recoil ! It might be a small amount, but it's there!

I expected some experienced answers concerning shoulder angles, instead of parroting.

However if you guys love it so well why do you shoot the rest of the so called accuracy cartridges with a 30 degree shoulder and call it a "Proven shoulder angle", like the 22 PPC, 22 BR, 6mm PPC, 6mm BR, just to name a few !

But when it comes to the Dasher, well, that's different .

As far as rubbing it in, meaning ME, maybe you should stop and think some! Unbelievable.

Take a look at the Beggs design (220/6MM Beggs) on the 220 Russian case. It retains the factory shoulder angle, but with a .060 radius at the neck and shoulder junction which eliminates case growth. The factory neck/shoulder junction is a .125 radius. So yes, the 40 degree angle primarily allows for more case capacity.

 

[savagedasher]

Bet PO Ackley had something to do with it. Larry

 

[lpreddick]

then there is the concept of "turbulence point". some don't believe in it and some do. a 40 degree shoulder focuses the TP in the neck of the case at the bullets base and supposedly gets the bullet going smoother than if the TP is outside the neck... i don't know about this but ???

 

[CatShooter]

then there is the concept of "turbulence point". some don't believe in it and some do. a 40 degree shoulder focuses the TP in the neck of the case at the bullets base and supposedly gets the bullet going smoother than if the TP is outside the neck... i don't know about this but ???

If it were true, you would see a radical improvement in accuracy with 40° cases, to the point that they would dominate all accuracy competitions...

... which they don't!

 

[R.Morehouse]

40 shoulder is a bit easier on the throat.... .....no?