Jump to content

Trajectory of .22


Recommended Posts


hi mate if you go on the hawke website and download the hawke chairgunpro which i sfree it will show you exactley what you need to know and you can look throught the different pellets etc and see what the ballistics are like and have a play with differetn fps etc then even see were abouts you should be aiming etc withthe mill dots and tells you how much ftlbs at what range you will be getting let me know how ya get on mate

kev

Link to post

Even with a sub 12 a .22 has the potential to travel hundreds of yards before air resistance, gravity and loss of velocity take their toll on the pellet and it comes to a stop.

 

How far it will travel before it begins its fall will; as said; be dictated by weight, speed, shape and most importantly the Zero of the combination (scope and gun).

 

Over a normal range ie 30 yards (using my S200 and AA Field's in .22) shown in the 1st image, will hit the 1 inch kill zone as it goes from 5.9 yards to 13.5 yards then the pellet leaves the kill zone and continues to climb until it reaches 19.5 yards. The pellet then begins its decent and at 25.8 yards it reaches the kill zone again and leaves the kill zone again at 33 yards. The Kill Zone is indicated by the purple/pink area of the graph, its also called the PBR (Point Blank Range)

 

post-18667-125977869122_thumb.jpg

 

Using the same set up but in .177 cal can be seen on this graph, as you can see the .177 follows a flatter trajectory and therefore never leaves the kill zone, effectively increasing the PBR from 8.5 yards out to almost 40 yards.

 

post-18667-125977872727_thumb.jpg

 

Hope this helps

 

Phantom

Link to post

Lord i understand your question mate but cant see where its going.

 

If you are asking to see about hold over etc it depends on the power or the rifle, the pellet weight and the range that you zero at.

 

 

For a lot of shooters that use .22 calibre the hold over is never a problem as they zero say at 30 yards and dont try and shoot beyond that range.

 

Hold under is maybe 1 inch at say 20 metres and in most cases that is the wobble of a average shooter who shoots from time to time.

 

If you want to know what a 16 grain pellet will do at 11.5 FP at 55 metres then id say that you need to aim at the top of the bunnies ears when they are raised so say 3.5 to 4 inches of hold over. x10 mag 4.5 mil dots on my Tasco with hight mounts.

 

Zini

Link to post

OMG views that defy all conventional physics & the laws of gravity!

When a pellet leaves the barrel it falls. It doesn't rise it falls & continues to fall that's gravity for ya.

A scope is pointing down at an angle, but the center of the scope is above the center of the barrel. So within the first few yards of the pellets flight path, the scope is looking above the path of the pellet.To compensate for this you have to aim over.

By about 10 yds or so the site line of the scope (which is still pointing down at a shallow angle) & the path of the pellet bisect to give your secondary zero.

Beyond this (up to say 30 yds) you need fractional holdunder because the pellet is still above the line of the scope.

However the pellet continues to drop, as friction with the air & gravity take their toll, till at 30 yds the two bisect & you have your primary zero.

After 30 yds you're into holdover again to compensate for the pellet drop beyond that.

I can understand why someone might think a pellet may rise (initally) due to the need to compensate with holdover, closer than the secondary zero.

However, gravity is a constant & the pellet falls from the second it leaves the barrel to the second it runs out of steam & hits the dirt!

Approx figures based on a sub 12 fpe .22

Edited by SteveieP
Link to post

I'd have to disagree with part (just a little part!) of what you say there Stevie and no I'm not looking for an argument ;)

 

When looking through your scope, to get a correct sight picture the scope must be level.

Therefore the barrel is on a slight incline and as the pellet leaves the barrel it is following the incline of the barrel; therefore it is clearly rising, until the speed of the pellet (if you want to get into physics this is called its escape velocity and has nothing to do with its escape from the barrel) slows enough to allow gravity to bring it back down.

Yes gravity acts on the pellet from the second it leaves the barrel (as you correctly say gravity is constant, so technically gravity is acting on the pellet before, during and after its time in the gun).

 

Its using this that allows you to have a primary zero (at what ever distance you set) and its secondary zero (much closer to you) which is why the gun is only pinpoint accurate at two points in the trajectory of the pellet.

 

Phantom

Link to post

Phantom

You're largely right & in most matters we are agreed.

However...LOL

Whilst the scope, when fixed to the receiver may be level, that's not the end of it.

If the scope is looking parallel to the trajectory of the pellet, the line of sight & the path of the pellet will never bisect & you won't get a zero.

Inside a scope is a doohickey called an erector tube. That's the thing that moves when you adjust for windage & elevation turrets. That's the bit that's looking down at a shallow angle & includes the reticle.

Here we go matey, a link to a pic' of an erector tube.

http://www.premierreticles.com/PDF%20Files/2009-HowToFFP-SFP.pdf

That's the science bit over with then...& knowing this stuff doesn't make you a better shot. LOL

Link to post

Steveie,

 

I think that you need to get out more mate and shoot some more vermin :tongue2:

 

God knows what you have just said in Chinese but it sounded technical. Probably too technical as it sort of lost its point.

 

We all know and understand what Phantom was saying, he is respected highly on this site as a regular and people only need to look at his posts (806 of them) to see that he fills game bags and knows how to shoot straight.

 

So regardless of (this or that) he knows where to aim, either high or low to nail vermin.

 

Here is an easy guide to what I think Steveie was trying to say.

 

I used to teach ballistics for many years in the military so know a little about it. The basics are explained in this attached word file.

 

Some points to note though before looking at the diagram

 

1. The scope is always parallel to the barrel on the mounts but the reticule isn’t and normally looks down on a air rifle.

 

2. By adjusting a reticule down on a scope you are actually raising the barrel up millimetres.

 

3. Gravity always pulls down on the underside of the pellet causing it to fall down to earth. The pellet never rises above the height of the barrel when it was fired. What it does rise above is the scope line of site due to the barrel being slightly raised.

 

Zini

Rifle and scope easy guide.doc

Edited by zini
Link to post

Steveie,

 

I think that you need to get out more mate and shoot some more vermin :tongue2:

 

God knows what you have just said in Chinese but it sounded technical. Probably too technical as it sort of lost its point.

 

We all know and understand what Phantom was saying, he is respected highly on this site as a regular and people only need to look at his posts (806 of them) to see that he fills game bags and knows how to shoot straight.

 

So regardless of (this or that) he knows where to aim, either high or low to nail vermin.

 

Here is an easy guide to what I think Steveie was trying to say.

 

I used to teach ballistics for many years in the military so know a little about it. The basics are explained in this attached word file.

 

Some points to note though before looking at the diagram

 

1. The scope is always parallel to the barrel on the mounts but the reticule isn’t and normally looks down on a air rifle.

 

2. By adjusting a reticule down on a scope you are actually raising the barrel up millimetres.

 

3. Gravity always pulls down on the underside of the pellet causing it to fall down to earth. The pellet never rises above the height of the barrel when it was fired. What it does rise above is the scope line of site due to the barrel being slightly raised.

 

Zini

Aint that what I said? LOL

Not trying to teach granny to suck eggs, just explain the simple physics that causes the need for hold under/over.

Someone might learn something from it & then go on to apply it in the field.

To those new to the sport, I may not be obvious how or why there is a primary & secondary zero.

However, as you point out, there's no substitute for practice & experience & after 35 years of airgunning I think I'm finally starting to get the hang of it.

Link to post

:clapper: Well done Steveie,

 

Yes that is what you were saying pal, but in a confusing and too technical way for most newbies, thats why i explained it at a lower level.

 

35 years of shooting you must be pretty good then.

 

I look forward to some of your threads pal and photos.

 

Best wishes for the future

 

Zini

Edited by zini
Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...