Slug Hp

[MohamedGamal79]

Hi everyone, Does the depth of the slug hp affect the accuracy?

 

[N2 Shooter]

It's complicated!

The most accurate slug I shoot, happens to have the deepest hollow point of all the slugs I shoot.

I think the accuracy has something to do with the slug length compared to my other slugs which are kinda stubby in comparison.

 

[Airgun-hobbyist]

I'm of the opinion that these deep hollow point slugs fly so well out of a lot of airgun barrels because the design puts the center of mass to the outside of the spinning projectile. This spinning heavy outer shell and hollow inside has less desire to tumble or find a wabble, and transitions over apogee well. All for good long range accuracy. If this hollow design was made in a rebated boat tail it would dominate long range like a football thrown to the long wide receiver.

 

[Ballisticboy]

The depth of the hollow in the nose coupled with the presence of any hollow in the tail will affect the position of the centre of gravity which in turn will affect the aerodynamic moments, possibly in a positive way for accuracy. The volume of the hollows, both front and back, will also affect the moments of inertia, but not in necessarily in a good way for accuracy. Hollow projectiles have been tried in the past and found to be far too gyroscopically stable, making them inaccurate and horrendously sensitive to side winds.

As with any projectile design which uses spin for stabilization, it is a matter of balancing the aerodynamic and inertial moments for the optimum gyroscopic stability factor for group sizes.

 

[MohamedGamal79]

It's complicated!

The most accurate slug I shoot, happens to have the deepest hollow point of all the slugs I shoot.

I think the accuracy has something to do with the slug length compared to my other slugs which are kinda stubby in comparison.

View attachment 432714

Thanks buddy, agree with u, I have my own slug.
I have made different hp depth start from 1.5 mm to 4.1 mm for 25 gr 0.218, and I found that the most accurate was 4.1 mm deep hp

 

[MohamedGamal79]

I'm of the opinion that these deep hollow point slugs fly so well out of a lot of airgun barrels because the design puts the center of mass to the outside of the spinning projectile. This spinning heavy outer shell and hollow inside has less desire to tumble or find a wabble, and transitions over apogee well. All for good long range accuracy. If this hollow design was made in a rebated boat tail it would dominate long range like a football thrown to the long wide receiver.

Agree
But, how I can figure out the center of gravity for my slug?
Are they any ways to know?

 

[MohamedGamal79]

The depth of the hollow in the nose coupled with the presence of any hollow in the tail will affect the position of the centre of gravity which in turn will affect the aerodynamic moments, possibly in a positive way for accuracy. The volume of the hollows, both front and back, will also affect the moments of inertia, but not in necessarily in a good way for accuracy. Hollow projectiles have been tried in the past and found to be far too gyroscopically stable, making them inaccurate and horrendously sensitive to side winds.

As with any projectile design which uses spin for stabilization, it is a matter of balancing the aerodynamic and inertial moments for the optimum gyroscopic stability factor for group sizes.

Thanks for your information

 

[Alrod224]

Fix hybrids are always a go to