Need advice on popple holes

[zombywoof]

I have an STI DVC-O I want to add popple holes to. It is a 9 major. I want two holes. I need to know how big the holes should be and how far apart.

 

My machinist says he CNC's the holes in a tornado shape with the muzzle side going straight up and the back side a 10 degree slope.  

 

Any help will be appreciated

[aandabooks]

I do them either 5/32" or 3/16" and space them .375" with a 10 degree forward angle.

[jim vaughan]

Facing backwards is a total disaster in terms of depositing muck on your dot lens.

Rather have the hole cut perpendicular to the barrel and then the cone should be angled slightly forward.

[zzt]

I'd angle them straight up.  Had all three- forward, neutral and back.  I have the 3/16" poppels in two guns and three 5/32" popples in the backup.  No difference.  All of them are strait up.  Just space them equally in the opening.

[CHA-LEE]

How do you know you “Need” popple holes in the barrel vs using different powders with more or less gas?

[zombywoof]

13 hours ago, CHA-LEE said:

How do you know you “Need” popple holes in the barrel vs using different powders with more or less gas?

OK I want popple holes. I have two barrels and want to experiment.

[zzt]

1 hour ago, zombywoof said:

OK I want popple holes. I have two barrels and want to experiment.

 

I can tell you what to expect.  Adding two 3/16" poppels will do the following with your existing major load.  They will definitely make the gun shoot flatter.  They will reduce your PF by 3 to 5 points, depending on the powder used.  The gun will hit your hand harder, because the poppels will rob gas from the comp.  Less gas hitting the comp baffles means less recoil reduction.  It will also be louder, especially when you get back to your original PF.

 

You can regain PF by adding more powder.  That still may not get you to your previous 'softness' level.  Add more or go to a slower powder.

[zombywoof]

4 hours ago, zzt said:

 

I can tell you what to expect.  Adding two 3/16" poppels will do the following with your existing major load.  They will definitely make the gun shoot flatter.  They will reduce your PF by 3 to 5 points, depending on the powder used.  The gun will hit your hand harder, because the poppels will rob gas from the comp.  Less gas hitting the comp baffles means less recoil reduction.  It will also be louder, especially when you get back to your original PF.

 

You can regain PF by adding more powder.  That still may not get you to your previous 'softness' level.  Add more or go to a slower powder.

Thank you for that.

 

I'm using A7 now. It is very soft in the hand so I can take more of a hit.

 

It's just a tad bouncy. Sure I could grip harder. I've never had holes and want to try them.

 

Thanks again for all that have replied.

[CHA-LEE]

Do slow motion video from the side while shooting to know exactly what gun movements are happening and more importantly, when. Your desire to minimize the “bouncy” movement of the gun likely has more to do with how fast the slide is moving and how abruptly the slide is snapping forward. Tuning those two elements have nothing to do with comp or popple ports. Keep in mind that the gas driving the comp/popple ports is vented & done before the slide even starts to move rearward. After the gas is gone its all about controling the mass of the slide slamming back and forth.

 

Not gripping the gun like a sissy will also help mitigate the “Bouncy”

[Endall]

  My only gun with “ports” is louder and shoots softer. Have an identical gun and slides are interchangeable. Angles back. 
  No dot, but can feel the warm gases on face. No deposits on glasses yet.
 The soft recoil is nice. If I was running 500 rounds per session this would make big difference.