FP are equal; give me speed of a light pellet; give me a heavier slower pellet?

[Vintage Streak]

I gather from the photo you posted that the pellet on the far left  has a lower bc . I came to that conclusion because of the skirt deformation. You would have losses because of the imperfect seal and increased drag but I Don't know what medium it was fired into I assume water. So if that deformation happened in the barrel that pellet has to have a lower bc. Is this the response you were looking for?

[rsterne]

Luke, pointed pellets for airguns typically have a conical nose, a straight taper that ends in a sharp corner at the back of the head.... It is that corner that causes additional drag compared to a round nose pellet.... I have never seen a conventional airgun pellet with a Spitzer nose like a rifle bullet.... although some of the very powerful PCPs do use bullets now.... and they have much less drag than any pellet....

Joe, the 2 pellets on the left were fired into a bucket loosely stuffed with grocery bags.... They stretch to stop the pellet and recover it with no damage.... The skirt of the pellet is expanded into the rifling by the air pressure behind it, and increases the seal, as it is designed to do.... There is no way of knowing whether the BC of the 2 pellets on the right is better or worse, because they were never fired.... The point of that photo is to show you how much the shape of the pellets changes on firing.... and the exact shape when it leaves the muzzle will depend on the air pressure and the diameter of the barrel.... That is the reason that the same pellet, fired from different guns, can have a different BC....

Bob

[Vintage Streak]

There are MANY variables that go into the BC, the weight is not the answer unless you are comparing pellets of the same caliber.... In different calibers you need to use the Sectional Density, which is the "weight per unit area".... The SD is also one of the two main criteria affecting penetration in a soft target, the other being velocity....

The BC has two main factors, the SD and the shape, expressed as the Form Factor.... They are related by.... BC = SD / FF …. so even if two pellets have the same SD, they can have a different BC because they have different shapes.... To make things even more complicated, the BC of a pellet is not a constant, it depends on the velocity.... and Check out this photo....


Vintage Streak replies
So the pellet on the far left is not deformed in an irregular way but essentially looks the same as the one next to it is that it. The picture to me it seems that it has a shape not conducive to sealing. Is it just shadows that make it appear to be deformed?

[Killo Coonadillo]

Thanks for that explanation Bob, it makes sense, that the shoulder will cause drag.

[Bryan Heimann]

All things considered, I do typically go for the heavier accurate pellet.  Heavier pellets penetrate better, that is my reasoning.  As for flat trajectory, i use open sights on all my airguns.  I am not confident past 25 meters with them, not because the gun won't group but because of my sight picture with open sights.  When you properly  focus on the front post, the target is too blurry and it gets worse as the range increases.  When I just line my sights up and focus on the target, the groups open up, so that decreases my effective range.  I have 20/15 vision and perfect color vision, so there is that.

If you are pushing more than 600 feet per second at the muzzle, you should have plenty of useful trajectory for a 25 meter shot.