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Open Gun Design Questions


JoeC

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On 9/1/2017 at 11:05 AM, zzt said:

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.

 

This forum needs a "like post" button.  Great info.

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I can tell you holes work better than just a comp I have 5 -9major barrels all the same brand and all the same comp for the same open gun. No holes , 3 holes , 5 holes , 7 holes and three slots like magna porting !  The 7 hole barrel is super flat and loud and hits a little harder in the hand but no waiting on the dot to return from the top of the scope . But it's all a system that works for me and keeps the R.O. from crowding me. Also I own 14 different compensators that are being produced currently and I found what the right comp for my system. 

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Slower powder and lighter bullets are the prescription for all your woes if you think your gun with holes kicks hard (in my experience). Got a bunch of holes, and it's violent? Go slower. I have shot up to AA9 in a 9 major. At that point it kinda just feels like minor ammo. Sounds like a grenade going off though.

Sent from my SM-G930V using Tapatalk

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  • 2 weeks later...
On ‎8‎/‎31‎/‎2017 at 9:34 AM, Broncman said:

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.

 

 

I am building essentially the same gun.

 

CK frame

CK slide (I'll mill it down to about 11oz)

CK steel grip

Trubor 9mm with Thundercomp 2 (and a 2nd 38SC barrel, coned Millenium comp on Kart/Baer I had laying around)

EGW trigger group

Predator 90-degree C-more mount

 

 

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  • 4 weeks later...
3 hours ago, colt1911 said:

what modern comps are you guys using on 9major?

 

I'm a big fan of Eric's comp:

IMG_20160603_160810.thumb.jpg.4e4bc1e68601882b71159d9711f97c43.jpg

 

The only downside being the weight, although there is a lot of steel there, so on my most recent build I flattened off the bottom and cut the front at an angle to follow the port, which got it down to 3.1oz, plus I have a little more in mind (tri-top, 1/2" ball end slot on the bottom and some scallops in the sides).

Edited by kneelingatlas
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Another along the lines my current open gun. 6" barrel/slide, wide long frame, Scheumann tribrid barrel with 3 poppel holes & 3 port comp. swings amazingly fast, heavy enough in the front but not as long as a regular comp gun and amazingly accurate. Leupold Deltapoint at the rear so no smoke on the lens and makes a good slide racker. *thumb rest [generic]* to go fast

IMG_6269.JPG.429b10c6035f6df58cacedf10a285c83.JPG

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3 hours ago, gmantwo said:

Another along the lines my current open gun. 6" barrel/slide, wide long frame, Scheumann tribrid barrel with 3 poppel holes & 3 port comp. swings amazingly fast, heavy enough in the front but not as long as a regular comp gun and amazingly accurate. Leupold Deltapoint at the rear so no smoke on the lens and makes a good slide racker. *thumb rest [generic]* to go fast

IMG_6269.JPG.429b10c6035f6df58cacedf10a285c83.JPG

That gun is intense. 

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On September 1, 2017 at 11:15 AM, teros135 said:

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. 

I just watched a video that Shay Akai did on this topic exactly. The points he made, confirmed my understanding of the concepts. 

Comp/muzzle break= for counteracting recoil (an extremely efficient comp would prevent the slide from even unlocking)

Holes= for counteracting muzzle flip. This comes at the expense of gas to work the comp, so typically harsher feel in the hand.  Barrel length plays a factor in this due to the length of the lever acting.  Taking it to the extreme would actually push the muzzle down when you fire a shot. 

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honestly its the shooter, not gun, a heavier gun, does more than gas and holes.

 

I have the old gigantic IMM barrels, I got 2/3mm barrels, I got 4 hole short and large etc.

The most calm gun are full length, stainless steel comp guns, with heavy .920 frame and steel grip. 

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8 hours ago, RileyLV said:

 

 

Are there awards for color?

 

Black & Silver guns are so yesterday! When we built this gun it was for my 10 y.o. Son. He wanted a red, white & blue gun, so this is what we decided on. Sadly he doesn't shoot any more, on to other things. After 2 Bianchi's, 4 Masters & several area matches, I had hopes he would stay in it. 

IMG_1677.thumb.PNG.1ff32cbff57ac3168f3d066e5f87a83d.PNG

IMG_4248.JPG.ad1cdadae7922f8e609658e8c908b96b.JPG

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3 hours ago, gmantwo said:

 

Black & Silver guns are so yesterday! When we built this gun it was for my 10 y.o. Son. He wanted a red, white & blue gun, so this is what we decided on. Sadly he doesn't shoot any more, on to other things. After 2 Bianchi's, 4 Masters & several area matches, I had hopes he would stay in it. 

 

Sad when they have so much promise then drop out!

 

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9 hours ago, RileyLV said:

 

Sad when they have so much promise then drop out!

 

See it a lot though. Once kids reach the age of awareness, i.e driving and dating, shooting falls off their radar pretty quick. 

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38 minutes ago, Sarge said:

See it a lot though. Once kids reach the age of awareness, i.e driving and dating, shooting falls off their radar pretty quick. 

 

As a former child prodigy, I assure you the lessons learned from competing at a high level will serve them well in all facets of life.  From 10-15 I shot Olympic rapid fire pistol, filled a shoe box with metals, earned a spot on the Olympic development team, traveled internationally, then with the closure of my local range, stopped abruptly.

 

The lessons I learned about mental conditioning and self awareness have been a huge asset from wrestling to running my own business and being a parent.

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On 10/30/2017 at 11:04 PM, redfisher said:

I really like the configuration of the shorter slide (mid-length) TI comp and and 6 holes on my LSI build. Gun balances great and shoots very flat.

LSI Open 3.JPG

 

For mid length builds like these, I assume that it's a 5" slide that's been cut back, but what barrel length do you go for? 

 

And is it cone or bull?

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