kneelingatlas

My Jericho is 2.945" in the same place:

The thread is M4x0.7, 2.5mm may be the Allen wrench size.

m4x0.7

cpa5oh, I've fired ~4K 115s over 1,470 fps throut the oldest of my barrels without any noticeable loss of accuracy. An FFL 07 can file a form with the ATF and relocate the serial number. The CM barrel is the same length as the TS so to convert a TS, you need to cut back the slide. I've never cone it, but I think the cone is sized to fit the slide without the bushing.

jdd817, the 75 SA slide needs to have the bushing removed plus opened up a bit more to fit the CM cone. The SA slide is a little shorter than the CM slide so the barrel needs a few more threads and a slight trim. The TS hammer fits the SA frame without modification, it's the notch in the slide which is narrower, you can narrow the hammer or open up the notch on the slide. Bill at highercapacity.us will weld two tubes together into a big stick; I've also cut Pro Mag 30 rounders to length, they make a 20 round that might come to 170 with the right base pad, I've never played with them. My CZ75 big sticks hold 28+1.

Henning mag well, base pads and followers. Then FO front sight and trigger work.

I tumble all my 9 major after loading

Yes I've seen it done, the current Gold Team I'd the same frame/slide as the Stock II with holes for optics and lightening cuts in the slide. A Limited 9mm is a better candidate because the frame is already drilled and tapped for optics; It's a quarter inch longer which is good or bad depending on your preference. Plus it already has a SAO trigger and a factory mag well.

These will come from CGW: "replace spring #31 with a CGW reduced power trigger return spring,#39 with a CZ sear spring, #13 with a 10-11# recoil spring, spring #34 with a CGW reduced power firing pin return spring for CZ" The short hammer springs will come from Wolff and the reduced power firing pin return spring from France is probably not worth the shipping if you have nothing else to buy, besides, you may not need it if you're not getting light strikes.

Yes, increasing the size of the first port increased the effectiveness of both my Czechmate comp and my three port Witness comps; I used the Dawson Awesome comp for a guide and cut the first port to 0.465". To do this on a stock CM you would need to cut back the barrel a little. I haven't tried it yet, but I also think the CM could benefit from two 1/8" to 3/16" holes in the barrel at 12 o'clock.

I get what you're saying, but while KC Eusebio can beat many Open shooters with a G34, I don't think KC/G34 can beat KC/Limcat Open gun. I've shot a Open G19 once which I found to be pretty quick and enjoyable to shoot at minor, but when I loaded it with my major rounds (which definetly wouldn't make major in the short G19) it was very hard in the hand and felt like it was coming apart. You may get into Open for a smaller investment going to Open Glock route, but they seem to depreciate more than 2011s, so it may actually cost you more to shoot one. For example if you build a Glock for $2,000 and after a season it's worth $1,500, it cost you $500 to shoot it for that year, but if build a 2011 for $3,000 and after a season it's worth $2,800, it only cost you $200. Actually, for guns built by famous gunsmiths who have a 6-12 month backlog, a used gun may fetch as much as a new one from a buyer who doesn't want to wait.

This 75 SA based gun was my lightest with a plastic dovetail mounted optic and an aluminum comp: With all the comps I've tried and the big C-More lenses I'm used to using I'm a little spoiled so this one didn't make the cut.

This picture reminds me of something which needs to be considered is the fact that when the slide cycles the barrel moves back relative to the frame, so your comp will hit the frame without clearance, which is one of the two reasons I like the short dust cover frames for Open over the SP01, the other being the added weight. Static weight may help fight muzzle flip, but in Open you're using the comp to fight muzzle flip, so the rail just makes it heavier; that being said there are plenty of good Open shooters shooting 50+ ounce guns plenty fast, but I prefer a lighter gun.

So if you want to screw a comp onto the end of your barrel you need a barrel long enough to stick out the front of the slide. The first thing you need to know is that in the US the barrel lengths advertised don't match reality; don't take my word for it, check with a ruler for yourself. The full sized guns like the 75B and the SP01 have 4.5" barrels and the TS/CM have 5.1" barrels, the nice thing about this is that you can put a TS barrel in an SP01/Shadow slide and it will stick out 0.6" which is plenty to thread and attach a comp. For the slides which use the skinnier barrel, CZ makes and sells a 6" barrel, the downside of a 6" barrel in a 4.5" slide is that you most likely need to cut the barrel to length which adds an additional step and specialized skills. The nice thing about the skinny barrel is that you can thread it 1/2"x28 and use any number of off the shelf comps (although the slide profile won't match like the Witness comps do). This is by far the cheapest/easiest way to compensate your CZ. Here's a picture of one dcloudy777 did using a Lone Wolf Glock comp:

The hardest part about a CZ Open build is the comp, unfortunately for aspiring CZ Open shooters all the comp design development is being done for 2011s. 2011s use either "bull barrel" comps threaded 0.685"x40 or cone comps designed for use with busing barrels threaded 0.575"x40. Here's the scoop on CZ barrel sizes: The 75B, 75B SA, and the P01 (there may be others I'm unaware of) utilize a barrel with an OD of 12.75mm (0.502") for 9mm, but a barrel with an OD of 14mm (0.551") for .40. The SP01, Shadow, Champion, Tactical Sports and Czechmate all use the same OD barrel for 9mm and .40 (14mm); the factory thread for the Czechmate and Champion is M14x1. On the Tanfoglio side, the small frame pistols use 14mm barrels and the large frame pistols use 15mm barrels. The factory thread for small frame is M14x0.75 and the M15x0.75 for large frame. There are some factory comps floating around for small frame Witnesses (http://www.gunpartscorp.com/Manufacturers/EuropeanAmericanArmory-33215/AutoPistols-36073/WitnessFullSize-34951.htm?page=4) and CZ USA seems to be stocking Czechmate comps regularly now. I have my own taps/dies and thread my own barrels, but it seems to me there are very few gunsmiths who cut metric threads. I ended up with a few comps from the Springfield custom shop which were threaded 0.540"x40 and since that was a proprietary thread I welded up the hole, re drilled it and tapped it with a M14x0.75 thread to match my barrels; that's an option, but not a very easy one I've also made thread adapters from M14x0.75 to 0.685x40 which work really well.

What I hear you saying is that a Glock with a comp shooting major is not any flatter than a Glock shooting minor without one right? Assuming that's true they have the advantage of Major scoring, unlimited trigger mods, but the dot and the capacity are the biggest advantages in Open.

We just aren't a forum sponsor...yet. I should make it clear I'm not a professional gunsmith and I don't like to do commissioned work. If I ever complete any of my projects to my satisfaction I might be interested to sell some projects to make way for new ones, but I have none for sale at the moment

Every so often I get a message about CZ Open guns and since they've been comming more frequently in the past month I decided to start this thread, hopefully it will become a great resource for anyone interested in coming to the Dark Side, CZ style Disclaimer: Open is not for everyone, it's loud, fast and EXPENSIVE! I want to emphasize this because I hate to see people get in over thier heads financially and there are pleny of other divisions in which you can be compeditive and have lots of fun with less initial investment and less expensive components. It seems like a lot of people want to build a custom Open CZ as a cheaper alternative to the Czechmate (CZs factory Open offering), but unless you are very handy and are excited about the adventure, you will almost certainly be better off with the Czechmate. With that out of the way, let's talk about Open CZs! When I first got into USPSA I shot a range rental Tactical Sport in 40 and fell in love First and foremost I loved the trigger; when I was young I shot 25M Rapid Fire Pistol with a Walther OSP 2000 which had a trigger pull weight of 47g (that's 0.1 lbs for you English folk!) so I'm a real trigger snob as you may have gathered from my DA tuning thread: CZ Tuning 101 with Professor Atlas. I had seen other shooter shooting Open and knew that's where I really wanted to be, but I wasn't yet reloading, the Czechmate had a prece tag nearly three times as much, and lastly I was scared of being a noob stepping up to the line with a $3,000 race gun on my hip and making a fool of myself. So I bought a Tactical Sport and promply began turning it into an Open gun It wasn't long before I gained access to a reloading press and started experimenting different loads and comps: I ended up with a modified three port Tanfoglio comp and a chopped dust cover: As you can see I got it shooting pretty flat: but it was very heavy, 52oz without a mag! By comparison the Czechmate is 49.3oz with the same optic which is pretty heafty as well, so I embarked on a new project: a 75 SA based Open gun This "Baby Czechmate" weighs 42.5oz and swings around much easier. As you can see I modified the last port of the Czechmate comp, but the biggest gains were made by opening up the first port: This is all I have time to write now, but I'll get to the more on the process of building a CZ Open gun later

It definitely sounds like your gun would benefit from a supermodel diet! I would start with an aluminum guide rod, it could probably stand to lose an ounce or two out of the slide, then if you want to keep going you might chop the dust cover and switch to a Ti comp.

That's awesome big boy!

I've built a few CZ Open guns and and been asked quite a few questions about building them, so I'm going to start a thread called "so you want to build a CZ Open gun?" Stay tuned...

"The factory ammo I've been shooting is 1.155" so the barrels can handle that OAL." I recommend sending this idea down the memory hole. I have some 147s I can load to 1.140", others touch the rifling at 1.070"; the best case gauge is the barrel of the pistol through which you plan to shoot the ammo.

What do you have in mind?

Had fun shooting this hot little number yesterday

Matt Cheely is stocking Czechmate mounts again: https://www.ccgunworks.com/store/shop/cz-horizontal-c-more-mount/ Three M4 holes drilled and tapped in the left side of the frame and bolt it on. I can give direction on where the holes go.