[CrazyLittle]

Yeah, so you might as well objectively measure and quantify what you can, and then keep subjectivity separate while also noted.

In the end the most useful information is going to be the comparison between standardized test results. That's why Mike efficiency tests don't explicitly test peak efficiency but do give a good baseline of comparison across other test results.

[brycelarson]

CrazyLittle, on 11 August 2011 - 02:49 PM, said:

Yeah, so you might as well objectively measure and quantify what you can, and then keep subjectivity separate while also noted.

exactly. My thoughts on this are that we run two parallel tests using the same data.

I want to collect a library of guns for reference as well as just cause it'll be cool to have. While we're doing that my thought was that we record perception of the quality of the kick of the gun along side the graphs. That way we can later group guns that were perceived to shoot smoothly and see if we can determine what aspect of the guns' movement gave that impression.

The basic test that I proposed to Gordo last time we talked was to round up a big pile o guns at the field. We just set up in the chrono station and get a line of shooters. We have say 5 shooters and 10 guns. Each shooter shoots each gun and rates it on a smoothness scale - say 1 being least smooth and 10 being most kicky. We record graphs like those above for each gun. We can then take the mean perceived rating and see if there are any patterns. As long as we're consistent with how we post the test we should be able to continue to add data any time we feel like setting up at the field.

[Spitlebug]

I think in the end, this will be of little consequence to how I actually use or shop for markers. It is good science, but not what I would call practical.

[brycelarson]

Spitlebug, on 11 August 2011 - 05:48 PM, said:

I think in the end, this will be of little consequence to how I actually use or shop for markers. It is good science, but not what I would call practical.

sure - that's fair. I'm in the same boat. I could really not give two shits about how much a gun kicks - BUT, it's obvious from the number of topics about kick on this forum that it matters to some people. I think a more practical application is for testing aftermarket parts. There are plenty that claim to reduce kick - we can now check them.

[Spitlebug]

Yes, I appreciate honesty in advertising.

How would you do that? Baseline with stock equipment, install aftermarket part and re-test?

[brycelarson]

Spitlebug, on 11 August 2011 - 06:11 PM, said:

Yes, I appreciate honesty in advertising.

How would you do that? Baseline with stock equipment, install aftermarket part and re-test?

sounds about right to me.

[Phenomx]

I get no to minor kick when using invert mini stock barrel until i install a freak with a very small bore, kick increased by a lot

[Troy]

Phenomx, on 12 August 2011 - 10:26 AM, said:

I get no to minor kick when using invert mini stock barrel until i install a freak with a very small bore, kick increased by a lot

I'm VERY interested to know how much kick increases with various bores when the marker is chronoed at a similar speed (like 280 fps)...

[rntlee]

brycelarson, on 11 August 2011 - 06:03 PM, said:

... I could really not give two shits about how much a gun kicks - BUT, it's obvious from the number of topics about kick on this forum that it matters to some people. I think a more practical application is for testing aftermarket parts. There are plenty that claim to reduce kick - we can now check them.

Any chance you guys could check out whether or not lighter hammers reduce kick in Tippmanns? I bought a Dark Horizon Titanium bolt for mine a few years back, but didn't think there's was much difference in kick. I think the increased cycle speed of the lighter bolt offsets any gains from the reduction in mass.

This post has been edited by rntlee: 13 August 2011 - 05:27 PM

[brycelarson]

rntlee, on 13 August 2011 - 05:26 PM, said:

brycelarson, on 11 August 2011 - 06:03 PM, said:

... I could really not give two shits about how much a gun kicks - BUT, it's obvious from the number of topics about kick on this forum that it matters to some people. I think a more practical application is for testing aftermarket parts. There are plenty that claim to reduce kick - we can now check them.

Any chance you guys could check out whether or not lighter hammers reduce kick in Tippmanns? I bought a Dark Horizon Titanium bolt for mine a few years back, but didn't think there's was much difference in kick. I think the increased cycle speed of the lighter bolt offsets any gains from the reduction in mass.

I've got a borrowed 98 here - but no A5 to test parts in.

[rntlee]

If you've got a 98, my Dark Horizon titanium hammer will fit it (60% the weight of the stock hammer)...but it's no longer sold and it's not quite as light as the Techt hammers being sold today. If you'd like to try it, I can send it down to you.

[cockerpunk]

i'd love to try it out.

[Lotus]

I really wish you guys had this rig suspended in mid-air or something. The point of an accelerometer is to measure acceleration, which is the result of the net force on an object. With Cockerpunk holding the marker, he's applying additional forces on the marker and therefore skewing the data that we really want, which is the acceleration caused solely by the marker cycling/firing. If it were to be suspended, I believe it would yield better results. Granted using accelerometers this way, we would have to measure the mass of the entire setup and multiply the resultant acceleration by the mass to yield the true numbers we wanted, but I think that's a relatively easy step.

[Snipez4664]

we already have repeatable data that approximates game conditions - the physical setup of the rig really can't be much better, and we're already past it

[rntlee]

cockerpunk, on 14 August 2011 - 03:33 PM, said:

i'd love to try it out.

Ok, shoot me an address and I'll drop it in the mail, bro.

[brycelarson]

Lotus, on 14 August 2011 - 04:35 PM, said:

I really wish you guys had this rig suspended in mid-air or something. The point of an accelerometer is to measure acceleration, which is the result of the net force on an object. With Cockerpunk holding the marker, he's applying additional forces on the marker and therefore skewing the data that we really want, which is the acceleration caused solely by the marker cycling/firing. If it were to be suspended, I believe it would yield better results. Granted using accelerometers this way, we would have to measure the mass of the entire setup and multiply the resultant acceleration by the mass to yield the true numbers we wanted, but I think that's a relatively easy step.

As snipez said - at this point we're happy with the rig. By taking multiple samples with multiple applications of the rig and showing that they produce nearly identical results we've shown that the shooter isn't introducing problems.

Lee - PM inbound. you can send the stuff to me - I've got the gun and the test rig at my place.

This post has been edited by brycelarson: 15 August 2011 - 07:43 AM

[Spitlebug]

Troy, on 12 August 2011 - 11:54 AM, said:

Phenomx, on 12 August 2011 - 10:26 AM, said:

I get no to minor kick when using invert mini stock barrel until i install a freak with a very small bore, kick increased by a lot

I'm VERY interested to know how much kick increases with various bores when the marker is chronoed at a similar speed (like 280 fps)...

Stands to reason if you get a large FPS jump going from overbore to underbore that the kick would be greater. Perhaps on order of a few joules.

[Snipez4664]

Not with normalized velocity - the internals should be able to shift more softly to produce the same fps with an underbore

[Spitlebug]

Define "normalized velocity".

If by normalized you mean under bore shooting @ 300 FPS and overbore shooting @ 300 FPS, then your example passes muster.

[Troy]

Snipez4664, on 15 August 2011 - 02:30 PM, said:

Not with normalized velocity - the internals should be able to shift more softly to produce the same fps with an underbore

I was thinking less about the internal movement, and more about the gas exhaust (and probably along the lines of what Spittle is thinking). If speed is normalized, then the underbore should kick more despite the fact that you are ultimately using less gas (and therefore less energy) because the pressure released from the barrel will be more discrete than that of an overbore situation.

It definitely could be true that internals can shift more softly and it may even mask the barrel exhaust effect I described above.

If we shot both a spoolie and put it up against a Tippmann, for example, (which has a HUGE hammer) we could possibly see opposite results between under and overbores.

EDIT: I rethought this out, and it's probably less about gas exhaust and more about acceleration... therefore, the under bore could kick more, because the ball is accelerated faster... not because the gas released will be more discrete.

This post has been edited by Troy: 15 August 2011 - 03:33 PM