Paintball

[Clearush]

If you want to do this test right I would think you need at least 4 bolts, two single bore barrels, and a barrel kit.
1- stock bolt
1- venturi bolt (unmoded) (not necessary but if your gonna do this might as well see what effect it has)
2- undershot bolts preferably of different manufacture such as a cooper-t and alamocitypaintball

1-small bore barrel for tight paint to barrel match (lapco would be a good choice)
1-large bore barrel for over boring (bigshot lapco would probably be good)
2-barrel kits that can be switched from tight to overbored. A freak and otp kit would be good, freak gives a longer control bore while a otp give a short control bore to see if there is any difference between the control bore lengths.

1-case of very fresh paint something good and consistent marbs might be preferred as it is still similar to paint that was being shot in the 90's

First the case of paint will be need to sorted by size to limit variance due to paint size, and should be stored in a dry cool to limit temperature effect.

Second when testing a barrel it should be tested at least twice once at 260 fpd, as this is supposed the tuned velocity for the cooper-t undershot bolt and then again at 280fps for what would be normal field velocity.

Also a 20 shot set should be tested between barrel swaps to see what velocity changes are cause just by the barrel before adjusting springs and reg pressure. Notation on neccessary spring and pressure adjustments would be nice just for interest sake.

And the ball fall needs to marked a measured.



Why didn't you just ask for pictures of a copper-t and then mill a bolt out of delrin to have a real undershot bolt or just bought an alamocitypaintball.com undershot bolt so you had a real undershot bolt not a plugged up venturi, along with only testing one barrel and that barrel only being a kit type barrel and a cf one at that. It seems the experiment was set up purposefully to fail. Your supposed to eliminate variables not ignore them, ignoring variables such as bolt design and barrel design instantly invalidates any data with out full and complete testing to compare it with.

[pump]

Originally Posted by brycelarson

this is a little annoying - the whole purpose of CP and me spending time and money testing this stuff isn't to "falsify" anything. It's to do what hasn't been done in public - to apply some sort of modestly rigorous testing to claims made in the paintball world.

We make a hypothesis, run some test and then either throw out the hypothesis or suggest that it might be true. I won't speak for CP - he's more than capable, but I have no agenda. Trust me, if I saw any sort of improvement in the back spin bolt testing we did I would start using one.

I'm certainly not making a claim then trying to find data to meet that claim. I find it a little insulting that you would set out to prove us wrong - simply because our tests didn't meet your expectations.

Falsifiable
a. 1. Capable of being falsified, counterfeited, or corrupted.
2. able to be proven false, and therefore testable; as, most religious beliefs are not falsifiable, and are therefor outside the scope of experimental science.
Falsifiable - definition of Falsifiable by the Free Online Dictionary, Thesaurus and Encyclopedia.

im referring to the Testability of your procedures

[brycelarson]

we have all the kits and barrels you suggest - as well as all of the bolts you listed - or will when the loaner cooper T shows up.

We shot it through a matching control bore and an over-bored back and saw no difference between the bolt with %100 of the air flow below the mid-line and the bolt with even flow across the entire bolt face.

if the backspin had an effect - wouldn't something have changed at some point? we saw exactly matching trajectory with all combinations. If we would have seen corkscrewing, extended range, lessened range or anything else weird we would certainly have investigated further - but at 100' there was no change.

Let's say that our bolt was only %20 as effective as a commercial backspin bolt - we would have seen some change - even an increase in 8" of height at 100' would have been noticeable - but we didn't observe any change.

[brycelarson]

Originally Posted by pump

im referring to the Testability of your procedures

I don't understand - did you watch the videos?

you said:

Originally Posted by pump

no you need to tell us your testing procedures

Psi springing barrel bore ball bore

so we can test those variables as well, so we can properly falsify your clams using the same procedures

feel free to "falsify" our claims - here's what we did:

we set a shooting chrony on a bench 100 feet from a fence with alternating horizontal 8" slats and 12" openings. I built a triangle tipped barrel rest - where the tip of the barrel would rest. Each shot was fired while leveling the barrel of the gun with the barrel tip on the rest. I would call level, CP would shoot then I would read the velocity.

We tried the following combinations:

over-bored CCM kit with backspin bolt
control bore matching paint with backspin bolt
over-bored CCM kit with standard venturi bolt
control bore matching paint with venturi bolt

by noting velocity and where on the fence the balls struck we could easily compare the bolts - and we found no difference. 260 would hit the bottom slat, 270 was in the gap above that, 280 was on the middle slat regardless of bolt

there was no discernible change - the only thing that effected point of impact was velocity. As I posted earlier - even if our backspin bolt only was %20 as effective as a commercial one - it should have been noticeable at 100'.

[pump]

Originally Posted by brycelarson

but we didn't observe any change.

did you see any change with the cooper t bolt?

no?
well then you cannot comment on it then

[brycelarson]

Originally Posted by pump

did you see any change with the cooper t bolt?

no?
well then you cannot comment on it then

how much further does the cooper T shoot than a standard bolt?

[c6quad]

just resting the tip of the barrel and not the back of the gun leaves room for error regardless of using a level. the gun should really be locked down on a stable platform for an accurate test.

[drg]

I would like to direct your attention to a few things HP DID say that are being ignored:

The barrel he achieved results with was CUSTOM overbored, more than a standard barrel kit (based on the fact that barrels back then started out at what would be the large end of barrel kits today).

The barrel OVERALL LENGTH was a significant variable. I think you cannot consider a barrel with a back AND front the same thing as a barrel with just the back for the purposes of something like this, where we are looking for off-axis displacement.

I also think you are treating the difference in port location between a plugged up venturi bolt and true undershot bolt a bit flippantly. That's not mere hundred thousandths or even thousandths. That's a very large relative difference in location.

[pump]

Originally Posted by brycelarson

how much further does the cooper T shoot than a standard bolt?

well dont you know? you tested one right?

[brycelarson]

Originally Posted by pump

well dont you know? you tested one right?

ok, what was the claim when it was marketed?

See, here's the problem, this thread has turned backwards - we never made a positive claim - the manufacturers of backspin bolts claimed that they improved range.

If it's true that the only way to achieve this success was to use a 1" over-bored barrel - did the bolt actually work? How many people have you seen at the field playing with a barrel that short that was custom bored? I've never seen one.

The person / company who makes a claim that a product does something.

We will test a cooper bolt when it arrives. we'll use the CCM back (less than 2" long, and in multiple sizes - that should make a very good simulation of the short custom bored barrel). Once we've done that - will that meet the skepticism shown on this thread? Probably not, people like to believe things that they've paid for.

Pump, are you saying that nothing can be extrapolated from data? Every item has to be tested in order to make a claim about it?