[brycelarson]

https://docs.google....ZkE&usp=sharing

rifled. barrels. are. awesome. with. first. strikes.

75' Tib 9.1. Stock 9", Lapco 9", Tib rifled 9", Lapco 16", Tib 16" rifled, Hammerhead 14" rifled.

This post has been edited by brycelarson: 15 March 2013 - 10:47 AM

[UV Halo]

First and Kickass Work!!!

[andrewthewookie]

Holy crap. Time to get me a rifled barrel.

[UV Halo]

First, I'm very surprised that the Hammerhead performed so well.

Bryce, do you think there was a statistical difference between the LAPCO short and long rifled, or is that in the noise?

I'm statistics illiterate, how do I interpret the CI?

Can you confirm if the hammerhead has significantly less fouling than the LAPCO (A silicone squeegie should aid this)? If so, this makes the Hammerhead a clear winner here.

[cockerpunk]

this makes sense given our testing vs a paintball, where at 50 feet paintballs were not that much worse then first strikes, but at 100+ there was a huge difference. this points to the accuracy errors in first-strikes being early in there flight.

it seems pre-spinning them really does help.

[brycelarson]

I didn't shoot enough rounds from each to determine if the fouling is different. I will say that the hammerhead chronoed almost 100 fps faster than the LAPCO 16" rifled. So while accuracy seems close - the hammerhead kills in efficiency. Additionally the hammerhead was much quieter. This may be just due to the gun being set much lower or it may be part of the barrel design.

Confidence interval tells you based on the sample size what the actual range might be. In other words - we're confident that the data is inside that range.

[UV Halo]

cockerpunk, on 14 March 2013 - 08:08 PM, said:

this makes sense given our testing vs a paintball, where at 50 feet paintballs were not that much worse then first strikes, but at 100+ there was a huge difference. this points to the accuracy errors in first-strikes being early in there flight.

it seems pre-spinning them really does help.

I agree and I must point out- when you look at your 100' and 150' data FS rounds appear to deviate in a closely linear manner so, these rounds should most likely remain just as accurate downrange (scaling spread for distance).

I've had a couple ideas why the pre-spinning helps (not in any order):

1. Atmospheric turbulence or cross currents prior to gyro stabilization.
2. Centrifugal effects on the fill while it is in the barrel axis could cause it to spread itself evenly (in a resting state, the fill separates and, in some rounds there are air bubbles) around the equator and stabilizing before it exits the fill.

When myself and Tymcneer (over on MCB) do our dual chrono test, we'll know if pre-spinning effects the ballistic coefficient (which could translate into a range difference).

This post has been edited by UV Halo: 14 March 2013 - 08:19 PM

[andrewthewookie]

What's the rifling like on the Hammerhead? Does it match the FS round"s direction/angle at all?

[brycelarson]

Here's what a vector of 8.5 v 2.5 looks like:

http://www.youtube.c...d&v=rzWtS0YgGV8

First set - 16" Lapco smooth bore - 16 shots. Second set - 16" Lapco rifled - 24 shots.

This post has been edited by brycelarson: 15 March 2013 - 10:50 AM

[tymcneer]

So, it seems one of the ideas that had been kicking around has proven to be effective. Thank you PunkWorks for taking care of the tedious experimental stuff. I *REALLY* like the data in simple to understand format. It makes my life so much easier

Next, we need to cover whether the prespinning changes the ballistic coefficient.

Finally, we need to check out the final pieces to the puzzle to determine if there are ways to shoot even further, without exceeding the 300 FPS limit.

Ty

Brass Monkey Customs

[cockerpunk]

tymcneer, on 14 March 2013 - 10:54 PM, said:

So, it seems one of the ideas that had been kicking around has proven to be effective. Thank you PunkWorks for taking care of the tedious experimental stuff. I *REALLY* like the data in simple to understand format. It makes my life so much easier

Next, we need to cover whether the prespinning changes the ballistic coefficient.

Finally, we need to check out the final pieces to the puzzle to determine if there are ways to shoot even further, without exceeding the 300 FPS limit.

Ty

Brass Monkey Customs

thanks for the support ... kicking around any good ideas?

[tymcneer]

Always... I might even share, once I have them from just a guess and golly and into a more reasonable form.

Did you do the high speed video of a FSR in a glass tube, being suspended via the moving air? If so, conduct that test again, but introduce a small smoke trail to see where we are having low pressure issues. This will prove very insightful.

Ty

[Troy]

Excuse me while I collect my bottom jaw off the floor... I had no idea that a rifled barrel could impart a significant spin to the round before exiting.

Is there any chance we can get some high speed video of the round coming out of the barrel in both a smooth and rifled bore barrel to confirm this effect, and eliminate some other factors that could be at play that we might not of thought of yet?

[UV Halo]

Troy, on 15 March 2013 - 11:33 AM, said:

Excuse me while I collect my bottom jaw off the floor... I had no idea that a rifled barrel could impart a significant spin to the round before exiting.

Is there any chance we can get some high speed video of the round coming out of the barrel in both a smooth and rifled bore barrel to confirm this effect, and eliminate some other factors that could be at play that we might not of thought of yet?

I can't reveal my source or share the video but, I've seen HSV that shows the LAPCO/Tiberius rifled barrel imparts a spin greater than what the punkworks smoothbore HSV showed. I pushed for this test just to see if it made a difference and yeah, I was surprised it made that much of a difference.

[brycelarson]

UV Halo, on 15 March 2013 - 12:04 PM, said:

I can't reveal my source or share the video but, I've seen HSV that shows the LAPCO/Tiberius rifled barrel imparts a spin greater than what the punkworks smoothbore HSV showed. I pushed FUNDED this test just to see if it made a difference and yeah, I was surprised it made that much of a difference.

fixed it for you.

[UV Halo]

brycelarson, on 15 March 2013 - 12:51 PM, said:

UV Halo, on 15 March 2013 - 12:04 PM, said:

I can't reveal my source or share the video but, I've seen HSV that shows the LAPCO/Tiberius rifled barrel imparts a spin greater than what the punkworks smoothbore HSV showed. I pushed FUNDED this test just to see if it made a difference and yeah, I was surprised it made that much of a difference.

fixed it for you.

I'm sure you guys put some of your own funds and time into this so, I won't say I funded the entirety I like to consider this a punkworks operation, after all, I used? to be an adjunct? (I just noticed the 'who is punkworks' thread is gone).

[Troy]

UV Halo, on 15 March 2013 - 01:21 PM, said:

brycelarson, on 15 March 2013 - 12:51 PM, said:

UV Halo, on 15 March 2013 - 12:04 PM, said:

I can't reveal my source or share the video but, I've seen HSV that shows the LAPCO/Tiberius rifled barrel imparts a spin greater than what the punkworks smoothbore HSV showed. I pushed FUNDED this test just to see if it made a difference and yeah, I was surprised it made that much of a difference.

fixed it for you.

I'm sure you guys put some of your own funds and time into this so, I won't say I funded the entirety I like to consider this a punkworks operation, after all, I used? to be an adjunct? (I just noticed the 'who is punkworks' thread is gone).

Alright... but I still want to see that video!

Knowing that it's "out there" just not public is not nice.

[cockerpunk]

Troy, on 15 March 2013 - 03:05 PM, said:

UV Halo, on 15 March 2013 - 01:21 PM, said:

brycelarson, on 15 March 2013 - 12:51 PM, said:

UV Halo, on 15 March 2013 - 12:04 PM, said:

I can't reveal my source or share the video but, I've seen HSV that shows the LAPCO/Tiberius rifled barrel imparts a spin greater than what the punkworks smoothbore HSV showed. I pushed FUNDED this test just to see if it made a difference and yeah, I was surprised it made that much of a difference.

fixed it for you.

I'm sure you guys put some of your own funds and time into this so, I won't say I funded the entirety I like to consider this a punkworks operation, after all, I used? to be an adjunct? (I just noticed the 'who is punkworks' thread is gone).

Alright... but I still want to see that video!

Knowing that it's "out there" just not public is not nice.

if we had shot it, we'd show it to you.

[brycelarson]

cockerpunk, on 15 March 2013 - 03:12 PM, said:

If we had shot it, we'd show it to you.

yup, we're open source. Unless it's useless data we publish everything.

[Danny D]

Was the discrepancy in fps related to bore size? or was it a unique feature of the hammerhead barrel?

Did you get an FPS increase with the larger bore smoothbore barrels compared to the lapco rifled barrels?