Factors that affect us when trying to hit our target.

[North West Outpost]

I have been reading some very in depth discussions on factors that affect a bb when it is being fired. I can conclude from that that it is mind boggling. In addition, the math’s may be interesting to those able to understand it. Me I like the theories but it is a long time since I was able to understand the math’s.

As well as the math’s they will also require the gun to be completely rock solid on a bench rest in a sterile environment. That never happens on a skirmish field. Well not one I have ever been on.

So what I thought I would do is to take a step away from the math’s and put some of the other factors that I am fairly sure are not covered in there.
I will go from where someone shoulders their gun.

Gun is shouldered, but the majority of the time not shouldered properly, you see it all the time where just the lower ‘corner’ is against the shoulder so the gun is able to waggle all over the place.

When the gun is shouldered who is to say that it is vertical as you shoot. I would be very surprised if anyone checks the verticality of their gun before the pull the trigger. It is more of a reaction that comes with experience and happens without thinking about it. You have more of a chance of keeping the gun vertical if you use telescopic sights. An experienced shooter will without thinking hold the cross hairs vertical and horizontal.

Pulling the trigger, how many people pull the trigger with the first joint of their finger as the trigger fits nicely in there doesn’t it. Well let me tell you, you are inducing movements into your shot before you go any further. You should be using the pad on your finger. Try it next time and you will see the difference it makes.

Once you have pulled the trigger unless you have the gun pulled firmly into your shoulder, it will vibrate causing all sorts of inconsistencies. ROF comes into this as the faster the rof the higher the inconsistencies are likely to be.
Using a spring boltie, when you pull the trigger obviously with a lesser degree is like shooting a higher powered spring air gun. You can feel a small amount of recoil. If the gun isn’t shouldered properly and held firmly you are losing fps and allowing the gun to move inducing inaccuracies.

So we have got to pull the trigger in the best form that we are going to be able to. Once you have pulled the trigger you have to consider the follow through. If you don’t hold the gun perfectly still while the bb is doing it’s best to get out of the barrel you are moving it off target, even if the movement is slight.

I’m not going to mention other variables like temp and weather conditions.

I may have missed something but I think I covered most.

This next section is repeated endlessly but it is pertinent and keeps it all relevant.

Quality of you bb’s will play a huge part in all of this, size, constancy of size, shape and voids.

Barrels irrespective of internal diameter will benefit more from a consistent bore.

Hop rubbers choosing the right one and making sure it is fitted correctly.

Hop units will be better if they are a snug fit to the hop rubber, not just for less air leaking but to support the barrel, make sure you use the little brass stabilizing ring or something similar, it has to help.

Then of course once we have done a really nice job of hop up, rubber and barrel just put it straight back inside the gun. How many people consider the stability of the barrel inside the outer barrel, yes more people with spring snipers will, but the same is true of AEG’s. Don’t allow the open end of the barrel to move around freely. In a lot of cases this happens when people have dremmeled the front of the outer barrel to fit a longer barrel into a silencer.

Buffers.

When you look at the drawings where someone predicts the bounce of a bb as it goes down the barrel you can understand that happening. My take on that is it is like a tiddlywinks you press down on the back of one disc using another one, then as the pressure slips off the back it is propelled up in the air and forwards. That must be similar as to what happens to a bb. But obviously you have the air pressure to propel it forwards with your hop buffer to give the downward pressure.

More so in spring snipers or high powered DMR’s with a standard hop rubber using a small contact patch the ‘jump’ is going to be more pronounced than if you use a longer contact patch with less down ward force. So maybe with the longer contact patch the bb stabilizes in the barrel quicker and reduces vibration and bb rattle.

BB’s.

As above. This induced vibration within the bb can be reduced considerably by using good quality consistent bb’s. Odd shape bb’s with voids will oscillate on their journey causing inconsistencies. So flight will be reduced as energy is being used elsewhere.

I also read where it was thought that following stabilization in the barrel of the bb, it is possible the bb skips along the channel of the barrel. I’m sorry but I find that very hard to believe. The most powerful sniper I have owned and used on site was 505fps with a 0.2 no hop. With 0.4’s and a good amount of hop as soon as the bb left the barrel to reach it’s maximum distance it jumped up in a very long arc. So I can’t see it sitting just above the channel of the barrel to do that. It seems much more logical they run along the top of the barrel, than anywhere.

Where you see the drawing of the bb that shows the bb making contact with the barrel at all angles around the barrel before exiting it seems logical this may happen due to the inconsistencies with in the system and bb. If the system and bb are perfect the back spin on the bb must work the same as a gyro so it would only travel in a straight line contacting the top and bottom of the barrel.

Barrel length.

Let’s forget brands and diameter. It seems logical that the correct length of barrel coincides just following the point at which your bb stabilizes. Not something you will be able to find easily. Any longer and you are introducing inefficiencies. Any shorter would be potentially a worse situation.

To conclude.

The above are my thoughts on this subject as I have sat and thought it through this morning, not taken from any hard evidence or other people’s views or experience. Furthermore I am not expecting everyone to agree. But would like to think a good few will.

[Gaffa]

Re: Factors that affect us when trying to hit our target.

Hmm... very interesting mate! I've always tried narrowing it down but that's an excellent sum-up post!

[laurence]

Re: Factors that affect us when trying to hit our target.

What affects when a bb stabilizes? Velocity? Spin?
Thanks

[No1_sonuk]

Re: Factors that affect us when trying to hit our target.

You can't spin-stabilise a sphere all that well. A spinning sphere is better than not spinning, but nowhere near as good as a spinning long bullet.

[Caveira]

Re: Factors that affect us when trying to hit our target.

Don't forget spin-drift. People assume it only effects real world mega-long sniper shots, but it effects any shot that takes a significant time to reach the target.

For example, the latitude of GZW is roughy 50.84, so the speed of rotation there is 293m/s!

[LtPurcy]

Re: Factors that affect us when trying to hit our target.

I find it funny that no one has yet to use the ballistics of a round ball from the 1800's because that is very relevant to any argument

[ElCarl]

Re: Factors that affect us when trying to hit our target.

Don't forget spin-drift. People assume it only effects real world mega-long sniper shots, but it effects any shot that takes a significant time to reach the target.

For example, the latitude of GZW is roughy 50.84, so the speed of rotation there is 293m/s!

The Coriolis Effect? Oh god, I can see it now... A guy, standing up, with the stock out of his shoulder with a recoil AEG talking about how he's working out the amount of drift due to the Coriolis Effect there's going to be... :D

[Caveira]

Re: Factors that affect us when trying to hit our target.

I find it funny that no one has yet to use the ballistics of a round ball from the 1800's because that is very relevant to any argument

Yes and no. The lack of stabilised flight is a good comparison, but an old ball round didn't go up after firing.

Although Daniel Bernoulli published his book Hydrodynamica in 1738, the use of the back spin effect we get from a hop unit wasn't used in weapons design.

The Coriolis Effect? Oh god, I can see it now... A guy, standing up, with the stock out of his shoulder with a recoil AEG talking about how he's working out the amount of drift due to the Coriolis Effect there's going to be... :D

Finally, an airsoft app that might be worth writing!!

[LtPurcy]

Re: Factors that affect us when trying to hit our target.

Yes and no. The lack of stabilised flight is a good comparison, but an old ball round didn't go up after firing.

Although Daniel Bernoulli published his book Hydrodynamica in 1738, the use of the back spin effect we get from a hop unit wasn't used in weapons design.

A BB doesnt naturally fly up either? not without hop anyway or any factors in the barrel to cause upward lift, im aware the weight difference obviously lol

however one point i did notice was that there is a video of a VSR firing 800 or so FPS give or take an extra 50..even that struggled to hit a 200m target not because wind was blowing it left or right up or down, the BB just couldnt sustain long enough, however a round ball is capable of going quite frankly obscene distances for what it is taking away the fact they are firing from example out of a springfield muzzle loader at 60 grains of powder at 1500 fps.

[Caveira]

Re: Factors that affect us when trying to hit our target.

A BB doesnt naturally fly up either? not without hop anyway or any factors in the barrel to cause upward lift

Exactly, we use hop up and they didn't.

We get a far greater range for the given amount of energy than any real steel weapon.

however one point i did notice was that there is a video of a VSR firing 800 or so FPS give or take an extra 50..even that struggled to hit a 200m target not because wind was blowing it left or right up or down, the BB just couldnt sustain long enough, however a round ball is capable of going quite frankly obscene distances for what it is taking away the fact they are firing from example out of a springfield muzzle loader at 60 grains of powder at 1500 fps.

I've just done a quick bit of maths and come up with this.

Based on a Springfield 58, which fired a mini ball weighing 32.4g at 290m/s, it had a muzzle energy of 135.8J. For all that power, it only managed accurate fire in the low hundreds of meters (300m to a smallish target and a man and horse sized target at 600m).

A 500fps bolt action firing a 0.20g BB has a muzzle energy of 2.32J. With only 1.7% of the energy, it can achieve results in the region of 25% of that of the musket (which wasn't a smoothbore either).

[LtPurcy]

Re: Factors that affect us when trying to hit our target.

Exactly, we use hop up and they didn't.

We get a far greater range for the given amount of energy than any real steel weapon.

This is where it gets to the point of scientific equations and what not so on that basis

im out

[North West Outpost]

Re: Factors that affect us when trying to hit our target.

You know I have been assuming again.....

I have assumed the person who is taking the shot knows which way up to hold the gun and what direction to point it.

Silly me!