High Speed Video Ball Dropping Into Breach

[Paintballer86]

That is so sweet tom

[nerobro]

now, the question is.. usingthe same math ;-) how fast does a mag fire... Again the skeptic in me comes out. I'm quite sure I've seen a cocker do more than 10bps, gravity fed.

A ball can start feeding when the breach is half open. at elast at that point the bolt pulls away from teh ball and it can begin falling. Same for when the breach is closed, as soon as the ball is halfway in, the breach can begin closing.

To be reasonable it takes 14ms before the ball can BEGIN to feed... and I'm not sure how long the ball takes to fall a little more than halfway into the breach.

[Mr. Grumble]

[manike]

Nice idea Mr Grumble but in reality you cannot start feeding the ball in that soon or closing the bolt so soon on a half fed ball. It's because of the actual shape of a sphere it's very limiting in terms of how far in it needs to be fed before you can start closing on it...

I calculated it out years ago but to be honest can't remember my figures for how soon you could close the bolt without having a serious risk of chopping the ball... It made only a very small difference.

I'll let some pictures speak for themselves...

Here you can see a ball at when it starts to fall and a ball half way into the breech. I think we can definitely say with a ball half way in this would be the worst point possible for the bolt to start coming forwards.


Here you can see a ball 3/4 of the way in. You can see even now if the bolt starts moving it is very likely to pinch/chop the ball.


You can see when a ball is fully chambered that the closest point to the front of the breech is not actually very far, this is due to the shape of a sphere.


Below you can see that with the ball almost fed all the way in the bolt is still only able to come forwards 3mm without starting to pinch and chop the ball...


Here you can see it from the front and see just how likely that ball is to be chopped.


Here you can how the second ball in a stack can drop slightly into the breech and then git hit by the bolt. This is likely the cause of more broken paint than you would think as the bolt flies forwards and cracks the second ball. This is also appearing as a problem with the Halo as it sometimes forces a second ball slightly into the breech and thus it gets broken by the bolt firing the prior ball. This is an issue due to large bore breeches and bad ball detents.


Another view of that second ball getting smacked as the first is fired.


In all of my testing of vert I've found that the feed rates do actually tie in remarkably well with the theoretical rates that the maths shows us, giving that the ball has to be fully chambered before the bolt comes forwards. The only differences tending to be when blowback and bobble reduces how well it can feed.

I don't have the same testing facilities as AGD but I have done quite a bit of research into this stuff Some things I said about bolt speed back in '97 are just starting to be proven true.

manike

[Mr. Grumble]

First, thanx for the reply.

Now, in reguards to

in reality you cannot start feeding the ball in that soon

You have no choice but to feed the ball that soon. Gravity begins to work on the ball as soon as the bolt breaks contact with it (at the half-way point). The paintball will not hit the bolt as it drops, it can't. The bolt will be clear of the breach in 11ms, the ball will not be back in contact with the bolt until it is half-way in the breach and this takes 42ms (Gravity says so). The bolt moves clear of the breach too fast for the ball to catch up to it in the short time we are talking about. For the paintball to maintain contact with the bolt it would have to already be moving at a constant velosity or it would have to accelerate at a rate that would put it half-way in the breach in 11ms. This would mean it is accelerating faster then gravity.

Next

you cannot start . . . closing the bolt so soon on a half fed ball

I will concede that point. The ball will only clear the edge between the feed tube and breach if it is fully in the breach by the time the bolt is half-way through the return cycle. The return takes 28ms, half-way would be 14ms. For the paintball to fully drop it takes 59ms. I should start to close the breach 14ms short of that (or 45ms) and not the 42ms I had first thought.

This now gives us:
open the bolt 1/2 (11ms) + drop the paint a little past .34" (45ms) + close the bolt (28ms) = 84ms (or .084s).

Which drops the rate of fire to 11.9 (or 11 balls in a given second).

12 balls = chop

Mr. G

[nerobro]

Er... 11.9bps does not equal 11 balls per seccond. :-) it means 11.9 balls are shot per seccond. your following statement.. 12bps = chop is probally correct in this situation. If the timeing period is 1 secconds, then yes, you will only see 11 balls.

Given it's 2 secconds, you'll see 23 balls... By the time you're 5-6 secconds down the line, your assumption of 11 balls is more and more incorrect. Then again as we get into doubble digit rates of fire the decimals become less signifigant.