The Tortoise and the Hare, Pt.1

I've been thinking about what to write about next for the past several days. I haven't had the opportunity to shoot really since my summer semester JUST ended. I had the typical closing out and finals of any semester's end and my blog has taken a back burner to all of that. I decided a few moments ago that this next post and possibly the next few posts, would be about general airgun information.

Today I am going to discuss a concept that every seasoned airgunner understands, but those new to the game might not. The subject of the day is velocity. Many manufactures claim high velocity numbers to sell rifles and in some cases their claims are true, but what are these extra fps getting you? The truth is not much of anything positive. Most people see the velocity on the side of the box 750fps, 950fps, 1100fps, 1250fps, 1400fps and think that is the most important factor. Don't worry, we all went through that phase. The truth is anything past the speed of sound is detrimental to accuracy. I know what your thinking, what? Ummm... no... my rifle bullets go past the speed of sound all the time and they're just Jim Dandy thank you! Heres the difference. Your rifle bullets are probably in the 80+ grain weight region, the higher the grains the more stable they will be (thats not cold hard fact, its quite a bit more complex than that but I'm trying to make this simple). The most accurate 22lr bullets are all subsonic for this very reason. Now when you consider that your pellets are most likely in the 7.8 grain range the impact of velocity on accuracy begins to be a bit more understandable (Im not saying there aren't fast accurate bullets, the 204 Ruger, the 223 Remington, the 338 Lapua, the 416 Barret, believe me I know, and like I said this is a complex issue Im just trying to simplify things).

So we know that the pellets get less accurate when they travel to fast but why? Well there are a few reasons, 1. a pellet that moves too fast for its twist rate will spiral, 2. pellets have a hollow skirt this makes them prone to tumble, 3. breaking the sound barrier will cause a wobble in any projectile.

1. A pellet will spiral... well duh! Thats why the barrel is rifled Iosua! Yes, you are exactly right! Heres the catch, instead of spiraling like a well thrown football the pellet will spin like a corkscrew. If Im not making any sense then try this link (http://www.youtube.com/watch?v=8z8aFP2TVyA&feature=c4-overview-vl&list=PL0BD22BD1C9B93F4C). Thats Edgun's channel, he has some excellent videos and I highly recommend watching them. The problems with pellet accuracy are pretty obvious when you watch the video so I won't waste any time covering them here.

2. Pellet skirts do what huh? 3. Sound barriers wobble? Im going to list these two together because they go hand in hand. The crack of a rifle is the round breaking the sound barrier, if you've ever seen a jet break the sound barrier you know that there is a rather dramatic reaction from the air around the jet, well... the same thing happens with a pellet or bullet on a much much smaller scale. This causes a brief wobble effect on the pellet. Its very sudden and over instantly but the damage has been done. This is when the skirt comes in to play. There is a giant cup at the back of your pellet. It is what allows the air from the rifle to push the pellet down the barrel. The skirts design is quite important as it influences the airflow behind the pellet. If you have a pellet that wobbles violently enough (worst in lighter pellets) the stream of air (think of a comet's tail) will wobble with the pellet making the problem worse. If the problem is bad enough it will cause the pellet to tumble and will destroy accuracy.

Stay tuned for Pt. 2!
As always, stay safe and keep it classy!