Ideal Bolt Travel Times/Accelerations

[SlartyBartFast]

Thinking about the bolt cycle (open-bolt) required to fire a paintball I figure a bolt has four states:

1- Waiting for a ball to fall into the breech.
2- Travelling forward to chamber the ball.
3- Waiting for ball to leave barrel.
4- Travelling back to open breech.


Considering an open-bolt system, what is the optimum waiting time or acceleration for each stage?

1- As long as the ROF (rate of fire) will allow. 1/ROF minus time for other three stages.
2- As fast as the ball can handle. What is the maximum acceleration a PB can handle?)
3- Fixed time for ball to accelerate to end of barrel. From the Data Graph supplied by Tom Kaye, this would seem to be in the range of 4.5 to 5 ms (or am I reading the graph wrong?).
4- As insanely fast as possible.

Anybody have more concrete data/ideas?

Analysing the travel in this manner also had me thinking about the Open Bolt/Closed Bolt debate. The states are the same regardless of whether the marker is open-bolt or closed-bolt. In a closed-bolt system the sequence just runs 3-4-1-2.

I figure WARPIG has conclusively demonstrated that one is not better than the other as far as accuracy is concerned when all other variables are the same. But if you think of the bolt timing, open-bolt does show two large advantages. The bolt can stay open for as long as possible giving far more time for a ball to correctly feed. This gives highly reliable feed at low speed and (second advantage) high ROF performance is only limited by the feed system. In a closed bolt system, the bolt opening has to be timed which means either sacrificing maximum ROF for reliable ball feed or sacrificing ball feed reliability at high *AND* low ROF by timing bolt opening for high ROF performance (AND your performance is still affected by feed system performance).

So an open-bolt shows two advantages:
1- Reliable low ROF ball feed.
2- Maximum high performance ROF.

The bug in the ointment is of course Blowback. But if you could control the bolt travel precisely and hold the bolt forward for an adequate length of time, blowback would be eliminated.

The other bug (as far as some are concerned) would be the possibility of short-stroking the trigger on the Automag. Could the sear pin that connects the trigger to the sear be designed in such a way that the trigger and sear are 'disconnected' as soon as the sear is moved? The trigger would then have to be fully released to 'reconnect'. This isn't such a far fetched design problem as this is how all(?) open-bolt full-auto firearms perform when in semi-auto mode.

One thread and three issues. If discussion is lively I'll rephrase the different points and start individual threads.

Any Thoughts?

[SlartyBartFast]

I think I hear crickets.:D

Guess everyone`s busy drooling over the level 10 mod....

[Top Secret]

Whatever the Lvl 10 is, is perfect. :p

[Miscue]

Consistency of air regulation = accuracy... not much more to say on that. (What about barrels? Good fit = more consistent regulation) Closed bolt? Open bolt? LP vs HP? Anodization? Irrelevant.

As for ball breakage... bolt speed and bolt knick. Closed bolt? Open Bolt? LP vs HP? Endorsements from hot bikini models? Irrelevant.

Cockers have about 4 ft/sec bolt speed... a big reason why they're good on brittle paint. That bolt speed is ridiculously slow... it's not necessary to have it that slow and have good paint breakage results.

Level 10 has a low/ideal bolt speed... (whereas regular Mags had a pretty fast bolt) and if I remember it speeds up since the initial speed/impulse force as the bolt comes in contact with the ball is what's the issue as for ball breakage. Soft on paint, but same ridiculous ROF... and the pneumatics have been untouched... same as before. Cool eh!

[SlartyBartFast]

Miscue,

You`re right on and I agree with you concerning accuracy. My question does not concern accuracy.

The 4ft/sec bolt speed number for the cocker is interesting. That`s the kind of info I`m looking for. The problem is that`s a speed and not an acceleration. I do suppose I`ve come up with my own answer however. The maximum acceleration a bolt could reasonably put on a paintball is at least as great as the acceleration a paintball experiences due to the air pressure from firing. How is that acceleration calculated?

My question regards ROF really. My Meandering into closed vs. open is only really to show that IMO open bolt has an inherrant advantage over closed bolt for high ROF. It`s at least much better over a range of ROF whereas a closed bolt can be timed for high or low ROF and not both. Or, closed bolt at least adds the complication of adding ball feed rate calculations to determining bolt accelerations and dwell times.

LVL 10 is obviously an attempt to reach the ideal bolt acceleration curve. It would be interessting to know what the ideal is and how close the LVL10 comes to it. I suppose the next great leap in automag design would have to be the *reactive bolt*. Use the tank pressure in some manner to return the bolt to fully open.(Upcoming LVL11 you heard it here first ;) )

As far as all the other malarky you mention I`ve been arguing the same for ages. I was laughing at the rediculous claims in everyone`s favorite sales catalog APG magasine beginning in the late 80`s early nineties. I even participated in the heated debates over the ludicrous claims of ball spin made by Smart Parts when their *rifled* barrels were introduced. You`ll find me under my real name in the rec.sport.paintball archives. I had far too much time on my hands back in university.:D

[Telefragged]

Acceleration: Final Velocity - Initial Velocity / Time

[Miscue]

Whoops, didn't read carefully.

It's the initial impact... amount of energy bolt puts onto ball at time of collision that's important. Lower energy/speed = less stress on paintball. Bolt speed after impact... ie: whether bolt accelerated and picked up speed afterwards doesn't matter since the force applied during this accel. is nothing in comparison.

It's more understandable to think of things in terms of energy rather than acceleration... in this situation. (Energy is derived from acceleration)