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Open Gun Design Questions


JoeC

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34 minutes ago, Maximis228 said:

Hybrid barrel is a must. Biggest improvement I have seen in all the open guns ive had.

 

I' m not familiar with the concept.

 

Be very interested in what you mean - what hybrid barrel, what caliber, and what is the improvement?    :) 

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1 minute ago, Hi-Power Jack said:

 

I' m not familiar with the concept.

 

Be very interested in what you mean - what hybrid barrel, what caliber, and what is the improvement?    :) 

 

Hybrid/Island/Schuemann/Whatever you want to call it. Think the SVI team guns.

 

I run 9 Major. Its the softest and flattest gun I have ever owned.

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2 hours ago, Maximis228 said:

 

Hybrid/Island/Schuemann/Whatever you want to call it. Think the SVI team guns.

 

I run 9 Major. Its the softest and flattest gun I have ever owned.

What does this barrel do different than just say a KMM with holes in it. Is it because your take more weight off the slide because of the island. 

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Just now, Steelix said:

What does this barrel do different than just say a KMM with holes in it. Is it because your take more weight off the slide because of the island. 

 

Less reciprocating mass on the slide and more weight out front from the hybrid barrel.

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9 minutes ago, Maximis228 said:

 

Less reciprocating mass on the slide and more weight out front from the hybrid barrel.

This plus the Schuemann hybrid holes are actually nozzles instead of straight holes to increase down force.

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PT agressive steel grip.

limcat mount with thumb rest.

SV trigger to suit.

SV disconnector.

EGW hard sear.

Caspian slide.

STI long wide frame.

9 mm.

Delta Point 2.5 MOA

KKM, Scuman or Kart barrel. All good.

Edited by jnr88
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I'm having a gun built and wish I would have saw this thread before I filled out my build sheet. I never knew this about the Schumann barrels.  At least now I have that tidbit of info for when I need to replace the top end.  I love this forum! 

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14 minutes ago, Balwolley said:

I'm having a gun built and wish I would have saw this thread before I filled out my build sheet. I never knew this about the Schumann barrels.  At least now I have that tidbit of info for when I need to replace the top end.  I love this forum! 

 Its a type of barrel offered by Schumann and Infinity.

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On 8/22/2017 at 9:07 AM, Maximis228 said:

 

Hybrid/Island/Schuemann/Whatever you want to call it. Think the SVI team guns.

 

I run 9 Major. Its the softest and flattest gun I have ever owned.

1

 Are you running the factory 4 nozzles with 9 major or was it blank rib with traditional holes added by gun builder?

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Just now, andersonj55126 said:

 Are you running the factory 4 nozzles with 9 major or was it blank rib with traditional holes added by gun builder?

 

 

Blank rib with holes drilled by builder. Binary Engineering Comp.

 

20663746_10159046283820459_4290178175095938794_n.thumb.jpg.9bca6f2f8bdf6be0c4af09daae535cfc.jpg

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Those are gorgeous! What black coating is that? 

 

When I can figure out how to resize pics on my phone, I will post up pics of my current 2011 open pistol build.

 

CK frame and slide, Brazos Thundercomp SX2 barrel compensator combo , currently short chambered. Not determined 9 Major or 38Super yet...

Egw fire control and mostly EGW small parts.

 

Really thinking about a Vortex Viper red dot instead of the RTS2. Have had good luck with mine on my CO pistol.

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Blank rib with holes drilled by builder. Binary Engineering Comp.
 
20663746_10159046283820459_4290178175095938794_n.thumb.jpg.9bca6f2f8bdf6be0c4af09daae535cfc.jpg



Have you Shot your load out of a gun without holes? How much PF shift from a standard barrel to one with poppels? Just wondering if you have to crank up the load to work the extra ports.


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4 hours ago, shooterDrew said:

 

 


Have you Shot your load out of a gun without holes? How much PF shift from a standard barrel to one with poppels? Just wondering if you have to crank up the load to work the extra ports.


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Velocity varies so much from barrel to barrel, I have a Schuemann barrel with two 3/16" holes which chronos the same as a KKM barrel without any holes.  When I build a new gun, I chrono before drilling holes to see if it's a fast barrel or a slow one.  When adding holes to a particular barrel I've come to expect about a 1% drop in velocity per hole.

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My buddy just built a 5" (not 5.4) with 6 holes, and it chronos very very similarly to both his other gun with a 5.4" KKM and 3 holes and my 5.4" Schuemann with no holes. At this point I put essentially no stock in loss of velocity based on barrel length or holes, I just go out and test and adjust accordingly.

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The whole popple holes vs no holes thing is interesting.  Many different opinions.  I've heard several say "the holes tame the dot", while others say "holes don't help a bit, just burn powder".  Both can't be true. 

 

Could someone with serious experience with guns with holes vs. no holes (shooter, tinkerer, gunmaker) tell us what the difference(s) are between the two?  Impulse, dot control, etc.?  Data would be helpful if you have it, like kneelingatlas and gooldylocks gave us above. 

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teros, I have two Open Major guns.  My main gun has two 3/16" poppels and a comp.  My backup has the same comp, but no poppels.   The main gun shoots flatter than the backup by a noticeable amount.  However, as a result of the poppels it is harder on the hands, because the comp is not working as well, and it is louder.

 

Here is my philosophy.  If you can get the gun to shoot the way you want using only a comp, do it.  Felt recoil will be softer and slide action less violent.  If you cannot, add poppels.  The more and larger poppels you add, the flatter the gun will shoot, and the harder it will hit your hands.  You 'may' have to add more powder to make PF, but that's not certain.  If you want to add more powder to generate more gas to get the comp working as it did without poppels, you make the gun louder and more violent.  I once went up to 188PF trying to get the gun to shoot dead flat.  It did, but was earsplittingly loud (even double plugged), hard on the hands and extremely violent.  The bottom line is everything works hand in hand.  You trade off something here to gain something there.  Bullet weight, type and amount of powder, slide and barrel weight, recoil spring, number of poppels and comp design are all part of the equation.

 

Velocity is a crap shoot.  There is no telling until you test.  My Open load makes 172PF in the main gun with two poppels.  The backup makes 169PF with the same, identical load, and it has no poppels.  Go figure.

Edited by zzt
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