The Eigenbarrel

[Frizzle Fry]

Florida.

Any place with high humidity... I road tripped down to GA to play with old college buddies last year. My friend and I (both having digicalipers in our kits) measured and inserting accordingly but upon arrival we found that our balls had grown (be mature ) along the trip, which also resulted in misshaping what was left upon our return. The shot fine after going from .684 to .691 but back in MA they were ovoid and averaged .688 and splattered like waterballoons in the barrel. This was all over the course of a week and they were living in regularly jostled/agitated bags.

[cockerpunk]

in the summer when we get 95 degrees and extreme humidity, we still have small bore paint.

[Loneassassin]

i have no idea where poeple are finding .685+ paint.

i often have rollouts out of my .679 python. forget underboring, just to prevent a rollout you need a barrel like this around here. underboring a huge bonus when you get the chance to do it though.

Ditto. Only in my dreams can I find paint bigger than .682, lol. This includes Marbalizer. I haven't used a barrel back larger than .682 for years. And with some of the cheaper or mid range paint, I have had rollouts in my cockers using a .679 Freak insert with TWO pieces of electrical tape in the breech end. Maybe GI Milsim is in cahoots with the paint companies to force .50 cal on us slowly over time...

Anyway, this is actually one of the reasons I'm in the market for a Mag - I'm sick of dealing with tiny paint rolling through even my smallest Freak insert. And on an open bolt marker, it doesn't really matter...

[kcombs9]

Maybe GI Milsim is in cahoots with the paint companies to force .50 cal on us slowly over time...

My thoughts exactly

[CatoRockwell]

I was going to say that humidity shouldn't have much to do with our large paint. UT is a desert, almost no humidity ever. In fact people who come here from other states often find that they get dehydrated easier and also tend to get dry and cracked skin.

[Rudz]

I've got. 4 kinds of paint in the last 2 months, evil was 684, ultra evil was rolling out of a 681, and I have marbs and premium, both at 682

So yeah, I'm thinking this barrel might help rollouts on my sniper, but I want to see it tested

[Poe]

you can easily do the same experiment at home or at the chrono station.

take the front off your 2 piece barrel, fire a few shots, then stick the front back on and take a few more shots. they will be higher in velocity.

means that this "the mm the ball hits a port the barrel is over" business is the hype. the expanding gas does continue to push the ball even after it hits both the massive overbore of a barrel front, and the porting.

Cockerpunk,

Considering barrel pressure after five inches is quite low and it's trying to evacuate in less than 1ms.. this is understandable, but just out of curiosity what additional "control bore" distance does the front add? Since the front's porting doesn't start where it contacts the insert, the front does add some additional "control bore" distance doesn't it? What's the back only control bore distance vs the back + front (measured to first port) distance?

[cdc120602]

Just thought I'd add my $0.02. I played in 10 degree weather with Polar Ice this weekend in Eastern Ohio (Battlefront). I had my .682 Freak insert installed and the paint was still rolling out! It wasn't even close! Maybe I should look into this. Maybe I should just wait till summer to play...lol On the plus side, my cheater was amazing!

[cockerpunk]

Cockerpunk,

Considering barrel pressure after five inches is quite low and it's trying to evacuate in less than 1ms.. this is understandable, but just out of curiosity what additional "control bore" distance does the front add? Since the front's porting doesn't start where it contacts the insert, the front does add some additional "control bore" distance doesn't it? What's the back only control bore distance vs the back + front (measured to first port) distance?

on the CPs the short fronts only add about a quarter of an inch before the first ports. i think that is what your referring to.

[xluben]

Lurker barrel arrived today:













More info and pictures here:

http://www.pbnation.com/showthread.php?p=64627922

[drg]

means that this "the mm the ball hits a port the barrel is over" business is the hype. the expanding gas does continue to push the ball even after it hits both the massive overbore of a barrel front, and the porting.

Not only that, but TK's results only pertained to efficiency. Sound signature is in fact a part of barrel performance, so there would be a point to porting even if it had no influence on efficiency.

[cockerpunk]

Not only that, but TK's results only pertained to efficiency. Sound signature is in fact a part of barrel performance, so there would be a point to porting even if it had no influence on efficiency.

im going to come out and say that the ONLY point to porting is sound signature.

[kwood]

so xluben
have you tried it out yet?
we are all anxious to here about how she does

[drg]

im going to come out and say that the ONLY point to porting is sound signature.

Yes porting per se, however I'm talking about how you mentioned a ported section doesn't equate to no barrel at all when it comes to propulsion.

[cockerpunk]

Yes porting per se, however I'm talking about how you mentioned a ported section doesn't equate to no barrel at all when it comes to propulsion.

right, however it is significantly worse efficiency wise compared to even an unported overbore.

[kwood]

will there be enough clearance for an automag bolt to fit inside this barrel when a shot is fired

[kcombs9]

will there be enough clearance for an automag bolt to fit inside this barrel when a shot is fired

Its not a Twist lock barrel I don't understand your question.

But if it helps my .689 insert fits over the LvlX bolt but not my .687

[xluben]

This barrel is available in 'Cocker threads only.

Quick video:

Planet Eclipse Geo
0.693" SL2 Barrel - 288.4fps
0.685" SL2 Barrel - 293.4fps
0.678" Eigenbarrel - 299.2fps

RPS Marballizer - Bore Matches 0.685" Back

Shot with Canon 7D
and 17-55 2.8 IS
Full 1080p24
ISO100, f/10, 1/50sec

Click the 360p button, and then select 1080p!
YouTube - Lurker Eigenbarrel - Geo - Bore vs Velocity - 1080p HD

[drg]

right, however it is significantly worse efficiency wise compared to even an unported overbore.

But better than no barrel there at all, you claim.

[georgeyew]

That's some pretty impressive numbers.

[jolt00]

im going to come out.

look every body CP is finally coming out of the closet!!


jk CP
-----------------------

how is everyone measuring the diameter of there paint?
if your using freak inserts I know that a lot of them are off size wise. They may say .689 or .683 or what ever and not be the size they say SP was never consistent.
so unless your using calipers who knows what size the paint is lol.
just saying

[chafnerjr]

look every body CP is finally coming out of the closet!!


jk CP
-----------------------

how is everyone measuring the diameter of there paint?
if your using freak inserts I know that a lot of them are off size wise. They may say .689 or .683 or what ever and not be the size they say SP was never consistent.
so unless your using calipers who knows what size the paint is lol.
just saying

I measure by my freak inserts... but I'm also anal enough to have measured those to spec with a calibrated digital vernier caliper. Our RPS up here (NH) runs .687-.689 it's the winter stuff that gets a bit smaller. Good thing I have a .687 Dye since I don't have an insert that size!

I'm really interested in these results.. I just can't believe that I could stuff a .685-.689 ball in a barrel like that at any decent rate of fire... and having watched the video I'd like to see the test done on a more consistent marker. While the under bore did average higher I was seeing variances of 30fps during the test and 15ish on the other barrels. Not that I'll dispute the averages there just seemed to be a lack of overall marker consistency.

Nice to see some real world testing of products rather than a bunch of arguments and conjecture.

[cockerpunk]

Not that I'll dispute the averages there just seemed to be a lack of overall marker consistency.

Nice to see some real world testing of products rather than a bunch of arguments and conjecture.

you'll note that ANY gun does this when you measure more then 5 or 6 shots. plain and simple - guns are as consistent as people think they are, yes, even nice ones.

[xluben]

I measure by my freak inserts... but I'm also anal enough to have measured those to spec with a calibrated digital vernier caliper. Our RPS up here (NH) runs .687-.689 it's the winter stuff that gets a bit smaller. Good thing I have a .687 Dye since I don't have an insert that size!

I'm really interested in these results.. I just can't believe that I could stuff a .685-.689 ball in a barrel like that at any decent rate of fire... and having watched the video I'd like to see the test done on a more consistent marker. While the under bore did average higher I was seeing variances of 30fps during the test and 15ish on the other barrels. Not that I'll dispute the averages there just seemed to be a lack of overall marker consistency.

Nice to see some real world testing of products rather than a bunch of arguments and conjecture.

I have digital calipers, but they are not calibrated in any way.

The Eigenbarrel was within 0.0005" of the advertised bore (both ends).

I agree with cockerpunk, a standard deviation of ~5 or slightly higher is fairly typical even with a high end gun. My paint was fairly consistent, so I don't think I'd be able to get it too much better than this even with high end paint.

If you do calculate the confidence interval and do a t-test or ANOVA, you will see that even with this amount of variation, and the given sample sizes, there is plenty of data to show that the difference in the velocity populations is statistically significant.

Here is a bit more data for you to ponder (includes the video I posted above as well as data from the next day, both Geo and Etek3).



I'll try to get a video of it shooting at 12BPS on ramping. Hopefully I won't see breaks at that rate of fire, or the barrel is of no use to me.

[FutureMagOwner]

I also want to point out with these measurements is the level of uncertainty with the measurements themselves. The only specs I could find on a chronograph was that measurements are nominally within 1% accuracy. That means a measurement of 300fps is within +/- 3fps. I wanted to mention this because this makes a pretty big difference when it comes to making any reasonable conclusion on any test in that regard.

[drg]

I also want to point out with these measurements is the level of uncertainty with the measurements themselves. The only specs I could find on a chronograph was that measurements are nominally within 1% accuracy. That means a measurement of 300fps is within +/- 3fps. I wanted to mention this because this makes a pretty big difference when it comes to making any reasonable conclusion on any test in that regard.

Yup and that's for optical chronos. Radar chronos are even less accurate.

[chafnerjr]

Fair enough... now to see 12bps or more through it.

[Enemy]

ok ill just come at as well....


why are thinking at an increased rate of fire your going to see more breaks??

and cp was getting at a 6" barrel with no porting will lose performance to a 14" ported barrel with 7" of control bore, but conversely an 8" un-ported will out perform the 14" or something to that extent.

[rawbutter]

Fair enough... now to see 12bps or more through it.

Did you ever get to do this? I was watching this thread, and then it just died.

Also, while you've showed at lot of data about efficiency and fps readings, you haven't said anything about the accuracy or the tendency of the barrel to break paint. I really don't care if a lower bore barrel gets slightly better efficiency (I shoot a mag, don't I, so why would I care about efficiency ), but I AM very curious about (a) how accurate the barrel is, (b) if the smaller bore causes more breaks, and (c) how well it cleans itself.

[drg]

There is fairly extensive discussion about this barrel on a couple other forums.