CZ Open Build Theory

[dansedgli]

Thanks

[Tonyscomputery]

On 8/29/2018 at 8:17 PM, Superpipe9 said:

I would be interested in this as well

If you follow them on Facebook they have video of their testing. If it’s available depending on price I may have them fit mine this winter. But think I will probably just stay in Limited but you never know lol.

[Fo0]

Is anyone still making 170mm magazines for the 75b (welding together and cutting)?

[TerryYu]

Not that I've heard but I'll tell you that a promag 20 rounder with CZ 75 long base pad #10213 and follower kit seats 29+1 and is 173mm long so I'd bet their short basepad 10187 will fit in the gauge and be in the realm of 26 or 27+1. I've got one on order so once i get it I'll check back in with actual dimensions and capacity. 

[stefanhalvarsson]

Tanfoglio sf 170mm fits cz 75 

[kneelingatlas]

7 hours ago, TerryYu said:

Not that I've heard but I'll tell you that a promag 20 rounder with CZ 75 long base pad #10213 and follower kit seats 29+1 and is 173mm long so I'd bet their short basepad 10187 will fit in the gauge and be in the realm of 26 or 27+1. I've got one on order so once i get it I'll check back in with actual dimensions and capacity. 

 

I cut the 26 round Promags down to 170mm and get 28+1

[robert.a.brewer.]

[/url]
 
There is an angle to deal with.  Machining a comp is not as easy as it looks, the bore axis is not parallel to the frame rails, and in some pistols, the frame rails are not parallel to the top of the slide and those angles are not necessarily the same, from manufacturer to manufacturer or even from model to model from the same manufacturer.
 
For example, through a miscommunication with the machinist, the first batch of Czechmate comps I made tilt down by one degree:
 

 
For the second batch he cut the body of the comp in one step, then set up at a one degree angle to cut the cone, and bore hole.
 

 
The top edge of the 75B SA slide, however slopes down relative to the frame rails but roughly one degree, so the comp doesn't look as funny in that pairing:
 

 
(Comps from this first batch are available at heavy discount on clearance [emoji6])
 
If you look closely at some 2011 builds you can see the comp is cut with the outside edge concentric to the bore hole and when in battery the tilt down by something like a half degree, in small frame Tanfoglio compact slides, the barrel tips down by more like two degrees.
 
 

Atlas,

I'm wondering about how you lightened the grip shown in your second pic titled, open sport.jpg, I think you drilled holes straight into the backstrap.

But, please tell me how you did the front strap. Did you cut grooves, or drill holes, then shape them. I cannot really see.

[kneelingatlas]

8 hours ago, robert.a.brewer. said:

 

 

Atlas,

I'm wondering about how you lightened the grip shown in your second pic titled, open sport.jpg, I think you drilled holes straight into the backstrap.

But, please tell me how you did the front strap. Did you cut grooves, or drill holes, then shape them. I cannot really see.
 

 

 

 

My friend cut it on his mill

[robert.a.brewer.]

 

 
My friend cut it on his mill

I need more friends.[emoji846]

[TerryYu]

20 hours ago, kneelingatlas said:

 

I cut the 26 round Promags down to 170mm and get 28+1

Well the rest of us mortals don't have your fabrication skills or friends with machine shops!

[trub7dur]

Compensator comparison

 

 

[igolfat8]

On 8/22/2018 at 2:32 AM, kneelingatlas said:

few

I see no difference in muzzle rise between the two. Actually the second one appears to rise higher than the first comp. Am I missing something?

[Fo0]

On 10/3/2018 at 8:07 PM, igolfat8 said:

I see no difference in muzzle rise between the two. Actually the second one appears to rise higher than the first comp. Am I missing something?

 

I bought one as an alternative to the oem comp since I dont own a czechmate and they are sold out online for the same price.

Also - to be fair - in the video, it doesnt say what ammo is used- he could be using a load that was worked for the oem comp and the second comp needs different load

I haven't used mine yet but hope to finish the build this coming year

Edited October 6, 2018 by Fo0

[obsessiveshooter]

Since this is an open build theory, can someone explain something very basic...
If a 9mm pistol's barrel and frame can handle major PF, then why is it more complicated than throwing a comp on the threaded barrel, & finding a mount for the dot? I know open guns are finicky, but I have never truly understood why. (Especially with open Glocks.)

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[kneelingatlas]

53 minutes ago, obsessiveshooter said:

Since this is an open build theory, can someone explain something very basic...
If a 9mm pistol's barrel and frame can handle major PF, then why is it more complicated than throwing a comp on the threaded barrel, & finding a mount for the dot? I know open guns are finicky, but I have never truly understood why. (Especially with open Glocks.)

Sent from my SM-N960U using Tapatalk
 

 

Who says it's more complicated that that?

[obsessiveshooter]

I guess I just assumed that was a common understanding. Based on the cost and reliability issues I've seen with open guns. It must have more to do with the 2011 platform than the dot and comp. You know what they say about assumptions...
I guess when you add electronics and really long mags, you have more opportunities for something to go wrong.



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[kneelingatlas]

11 minutes ago, obsessiveshooter said:

I guess I just assumed that was a common understanding. Based on the cost and reliability issues I've seen with open guns. It must have more to do with the 2011 platform than the dot and comp. You know what they say about assumptions...
I guess when you add electronics and really long mags, you have more opportunities for something to go wrong.



Sent from my SM-N960U using Tapatalk
 

 

I'm still confused, what specifically are you talking about?

[obsessiveshooter]

I'm sorry, I've always understood open guns as being difficult to get running and hard to build, perhaps mistakenly. So, I took your thread as a discussion about addressing these hurdles. I was asking for a dumbed-down explanation of why open pistols are so difficult to make run reliably.

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[kneelingatlas]

50 minutes ago, obsessiveshooter said:

I'm sorry, I've always understood open guns as being difficult to get running and hard to build, perhaps mistakenly. So, I took your thread as a discussion about addressing these hurdles. I was asking for a dumbed-down explanation of why open pistols are so difficult to make run reliably.

Sent from my SM-N960U using Tapatalk

 

People make all kinds of choices when building Open guns, for all kinds of reasons including a desire to do something different, to save money, the way the gun looks, how much it weighs, with the infinite choices available, the potential hurdles are also infinite.  If you have a specific problem with an Open CZ I can probably help, but if not I don't know what to say.

 

Are you currently shooting Open? Considering Open and trying to decide on a platform?

[obsessiveshooter]

 
People make all kinds of choices when building Open guns, for all kinds of reasons including a desire to do something different, to save money, the way the gun looks, how much it weighs, with the infinite choices available, the potential hurdles are also infinite.  If you have a specific problem with an Open CZ I can probably help, but if not I don't know what to say.
 
Are you currently shooting Open? Considering Open and trying to decide on a platform?

I really don't want to hijack your thread here- I shoot limited with a TS and one day I'll probably shoot open with a CZ set up identically. I was just curious about an issue I was mistaken about. Never mind, carry on...

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[aandabooks]

10 minutes ago, obsessiveshooter said:

I really don't want to hijack your thread here- I shoot limited with a TS and one day I'll probably shoot open with a CZ set up identically. I was just curious about an issue I was mistaken about. Never mind, carry on...

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Moving a TS over to an open gun is actually fairly easy.  Keep an eye out for a SP01 upper or a 75b upper and snag it when you get a chance.  Then you'll have an upper to build off of when you get ready.  I drilled mine for a STI optic mount so I have more options.  Fitting a barrel in a CZ is really simple.  Toughest part is threading the barrel and making a comp.  Slide racker can be an issue.

 

[aandabooks]

On 9/13/2018 at 7:40 AM, kneelingatlas said:

 

 

My friend cut it on his mill

 

Did you do this to add grip or subtract weight?  Or did you get both benefits?

[TerryYu]

3 minutes ago, aandabooks said:

 

Moving a TS over to an open gun is actually fairly easy.  Keep an eye out for a SP01 upper or a 75b upper and snag it when you get a chance.  Then you'll have an upper to build off of when you get ready.  I drilled mine for a STI optic mount so I have more options.  Fitting a barrel in a CZ is really simple.  Toughest part is threading the barrel and making a comp.  Slide racker can be an issue.

 

If you have access to a 3d printer it's very easy to make your own slide racker in whatever shape you want. Mine has an upward cant to it and it's double sided (helps prop the gun up on table start). Plastic is plenty strong for the job and weighs very little, mine weighs about 5 grams, so you can build a pretty crazy looking one without compromising slide function. 

[kneelingatlas]

37 minutes ago, aandabooks said:

 

Did you do this to add grip or subtract weight?  Or did you get both benefits?

 

Primary to shed weight, but I did add some grip too.  All in all it's more trouble than it's worth, it only dropped 0.9oz. By switching from rubber grips to plastic the difference is 1.5oz.

 

For my next TS build I'll cut the dust cover as short as possible (it's more than an ounce per inch).  I'm not crazy about micro dots, but the RTS2 and mount is 2.7oz less than the horizontal Slide Ride.

[kneelingatlas]

1 hour ago, obsessiveshooter said:

I really don't want to hijack your thread here- I shoot limited with a TS and one day I'll probably shoot open with a CZ set up identically. I was just curious about an issue I was mistaken about. Never mind, carry on...

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If you want an Open gun which feels like a TS, the Czechmate will serve you nicely, it will be every bit as reliable as your TS right out of the box.  Converting your TS to an Open gun and/or switching back and forth will require some machining skills or the help of a gunsmith.