CZ Open Build Theory

[DungFlinger]

1 hour ago, kneelingatlas said:

 

If you're not reloading don't bother with the comp, just slap an optic on a TSO and Rock n Roll!  170mm pads from Springer plus CZC spring/follower should get you 24-25 rounds in your big stick.  If you love Open you'll buy a Czechmate and reloading press in no time!

shucks I was afraid that's what it would come down to.  I thought a comp would make a big difference even if  I use factory loads.   I guess I got akot more research to do.  Thanks for your input I value what you have to say.

[Ludde]

Getting the Standard Division sight block CZ Shadow dialed in.

 

Close to perfect return to Zero.

 

Minor 124gr Frontier FP VV N320 just below 130PF.

 

16lbs mainspring, 12lbs recoil spring, 53mm total stroke.

 

 

[kneelingatlas]

Some pictures on passing the barrel through the front of the slide

 

[jmu7b6]

Just curious if anyone can help me... trying to decide will I save any money by buying a cheaper gun and upgrading, or I won't save much just buy the Czechmate.

 

For anyone that went the upgrade route and now have a gun similar to Czechmate, did you save a lot of money?

[adovlad]

dont own parrot, but i purchased sp 01 safety, tear later put in costume natch barrel, single action trigger, accu bushing, upgrade sights.... i spend more money then my recently purchased shadow 2 orange

[-JCN-]

@Ludde

@kneelingatlas

 

Thanks so much for sharing knowledge. 
 

Here’s mine: shooting 124gr 9 major from Everglades in a Czechmate to get to 0.12s splits. 
 

 

Edited October 28, 2021 by -JCN-

[regor]

Has anyone experimented with opening up/removing a baffle in the factory CM compensator? Specifically I was thinking of having the third baffle removed so it's two small chambers followed by a larger chamber, similar to the binary engineering comp. I found an older thread where @kneelingatlasmentioned opening up the first chamber but the image was dead so I don't know what was actually done.

 

 

I want to do some experimentation with my backup CM this offseason, I'm planning on sending it off to have popple holes added (thinking 2x3/16") and I'm considering asking the shop to modify the comp at the same time. 

 

Another option would be to chop the final chamber off totally and then remove the 2nd baffle to make it similar to the 2-chamber binary engineering comp, which seems to be the general trend on 9Major 2011s with popples currently. That's obviously a riskier modification but would have a nice benefit of reducing the front heaviness even more. 

 

 

 

 

 

[regor]

And as a second comment for better visibility; for those who have added popples to the Czechmate, did you add them behind the comp cone or did you mill a slot/hole in the cone too? 

[kneelingatlas]

On 10/29/2021 at 12:08 PM, regor said:

And as a second comment for better visibility; for those who have added popples to the Czechmate, did you add them behind the comp cone or did you mill a slot/hole in the cone too? 

 

I like the holes closer to the muzzle, so I drill right through the comp.

 

Chopping off the fourth port and combing the second and third would be an interesting experiment, the best effect would be the reduced muzzle weight.

 

If you're looking to change the feel, I would go with option 2, number one will likely be hard to notice.

[regor]

3 hours ago, kneelingatlas said:

 

I like the holes closer to the muzzle, so I drill right through the comp.

 

Chopping off the fourth port and combing the second and third would be an interesting experiment, the best effect would be the reduced muzzle weight.

 

If you're looking to change the feel, I would go with option 2, number one will likely be hard to notice.

Any particular reason you prefer them closer to the muzzle? I was thinking of both under the slide with the first right at the cone. My compensator has a little bit of wobble so any hole through it would need to be even more oversized compared to the hole in the barrel. 

[-JCN-]

I have a Ti comp from Sebo coming so I thought it would be a good time to experiment with side hole theory. 
 

 

This is a 5mm hole I drilled. 
 

 

The factory comp is flat but harder to predict and dot track for trigger timing. The side holes allow for a little less downforce jetting and more predictable vertical tracking and triggering. 
 

Will test 6.5mm hole next. 
 

Edited November 1, 2021 by -JCN-

[kneelingatlas]

23 hours ago, regor said:

Any particular reason you prefer them closer to the muzzle? I was thinking of both under the slide with the first right at the cone. My compensator has a little bit of wobble so any hole through it would need to be even more oversized compared to the hole in the barrel. 

 

My preference is based mostly on trial and error, I've never enjoyed the feel of guns with holes drilled further back.  Besides bleeding gas with more barrel left before the bullet exits, the down force created has less leverage over the pistol.

[-JCN-]

@kneelingatlas

 

My opinions on the subject that it is like sway bar tuning on race cars. Stiffer is better… until it’s not. 
 

Compensator tuning following Akai’s principles means you want some muzzle flip because super flat is hard to predict and time on the “first bounce.”

 

It’s also like a 2 iron or a driver in golf. Your swing speed and mechanics are going to drive what resonant frequency you want built into the system. 
 

I’m a GM in CO so I’m used to dots and dot tracking at speed. My resonant frequency for a single bounce accurate split is around 16 with a CO gun. 
 

See here:

 

For an Open gun with the stock Czechmate compensator it tracks flat until it crashes my strong thumb. So the dot doesn’t move until it jumps late. It’s hard to time but when I do, it’s a 0.12s split. 
 

That’s hard to do reliably. 
 

With the 5mm side holes in the last baffle, there’s still gas escaping the muzzle and there’s a little bit more muzzle rise earlier in the cycle. Which lets the dot come up and easier to predict. 
 

It also slows the impact by changing linear motion into angular. 
 

Splits come up to 0.14s or so. 
 

When I went to larger side holes (6.5mm), the muzzle moves earlier and it’s WAY easier to predict the nadir of the first bounce. Splits came up to 0.15-0.16 but way easier to shoot. 
 

I prefer that quite a bit over the stock compensator. 
 

But if people are settling on second, third, fourth bounces or splitting slower then they be might be better served with a different setup. 
 

Just like race car builds and golf clubs, it kind of should be tuned to individual mechanics and preferences. 

I picked bleeder ports at the end to be consistent with what Sebo and Akai do. 
 

 

There’s still a little muzzle gas left but I’m pretty happy with this setup for me. It was a lot easier and more comfortable to shoot. 
 

I’m still putting together the comparative video. 

[-JCN-]

Okay, here it is.

[regor]

6 hours ago, kneelingatlas said:

 

My preference is based mostly on trial and error, I've never enjoyed the feel of guns with holes drilled further back.  Besides bleeding gas with more barrel left before the bullet exits, the down force created has less leverage over the pistol.

How have the slides held up that you've modified for popples? Any cracking issues? I saw at least one where you milled it all the way forward without leaving a bridge a the front of the slide; do you think that's as structurally sound as milling a slot a little bit further back? 

[-JCN-]

@regor

 

Funny, a friend linked me one of your videos and I absolutely think what you’re describing with the factory comp versus your friend’s modern comp is what was going on with having too much downforce in the up ports. 
 

It’s what Akai describes here that translates into “less forgiving” and less predictable tracking. 
 

 

My Sebo titanium comps have shipped and I’m looking forward to them. But even drilling the 6.5mm side ports bled off enough downforce from the last port to allow some more muzzle up and that made a huge difference in shootability. 
 

It’ll be interesting to compare it back to back with the Sebo. I have thoughts of cutting off the last baffle completely with a grinder and moving the last side hole forward. But if the Sebo comp works awesome then it’s not worth the hassle. 

Edited November 2, 2021 by -JCN-

[kneelingatlas]

3 hours ago, -JCN- said:

@regor

 

Funny, a friend linked me one of your videos and I absolutely think what you’re describing with the factory comp versus your friend’s modern comp is what was going on with having too much downforce in the up ports. 
 

It’s what Akai describes here that translates into “less forgiving” and less predictable tracking. 
 

 

My Sebo titanium comps have shipped and I’m looking forward to them. But even drilling the 6.5mm side ports bled off enough downforce from the last port to allow some more muzzle up and that made a huge difference in shootability. 
 

It’ll be interesting to compare it back to back with the Sebo. I have thoughts of cutting off the last baffle completely with a grinder and moving the last side hole forward. But if the Sebo comp works awesome then it’s not worth the hassle. 

 

I'll be interested to hear how you like the Sebo comp

[-JCN-]

4 hours ago, kneelingatlas said:

 

I'll be interested to hear how you like the Sebo comp

Will definitely post some videos here. I really appreciate all the time and effort you have put into sharing knowledge. Without you, I wouldn’t have started with CZs. 
 

Your threads gave me the confidence to do internal work and later on to drill my first frame mount! 

Edited November 2, 2021 by -JCN-

[kneelingatlas]

Cheers @-JCN-!

[-JCN-]

 

 

[George16]

5 minutes ago, -JCN- said:

 

 

Looks nice! How long did it take to make it across the pond?

 

Looking forward to your review.

[-JCN-]

22 hours ago, George16 said:

Looks nice! How long did it take to make it across the pond?

 

Looking forward to your review.

I usually do the UPS option shipping which costs a little more but gets here faster and more reliably. Usually under a week. 
 

The one time I cheaped out and had it shipped post… the package was lost (was some extended safeties). 

Of note I confirmed with Robin Sebo that some Czechmates are a little different in machining tolerances. 

Initially when I tried installing it, the threads were perfect but the slide was too long and pulled barrel out of battery. 
 

I backed it off one full turn but this wasn’t going to be a stable solution: 

 

 

So after confirming with Robin that this was a thing with some guns, I had the option of either trimming the comp or trimming the end of the slide. 
 

I chose the slide since it was easier to grind flat and I didn’t want to compromise the integral bushing in the comp (the cone that basically acts like a barrel bushing). 
 

 

I did my best @kneelingatlas gunsmithing

 

 

[-JCN-]

Dremel grinding wheel inverted with the center in the holes on lowest speed. 
 

[Squirrel45]

HI  JCN, 

 

Would this affect the use of the stock comp now since it's been shortened? (I know you wouldn't want to switch back but just thinking, what ifs) 

 

Thanks

Squirrel

 

[regor]

7 hours ago, -JCN- said:

Dremel grinding wheel inverted with the center in the holes on lowest speed. 

 

How much material did you have to remove? Hoping I don't have to do the same with mine...