What kind of ammo are you using? What are you using to lube with, and how are you doing it? Have you stripped it and made sure that the recoil spring is good? Are you making sure that the mag is securely locked in place, and that the mag springs are good?

PhilR.

Remington UMC 9mm. The gun is brand new. I really dont know how to tell if the springs are good or not.

You need to pull the slide all the way back and release it fast. Just like it fired a round.
Welcome to the forum and enjoy.

First I've heard of that problem on one of those guns. Sexy gun though. Hope you figure it out

-Jeff-

Did you clean and lube it before your first range session? Have you cleaned it since? Oil it up and rack the slide a few times. Feel for any catching or grinding. Hold the slide all the way back and release. Also check your ejector and your spent casings. You may have an ejector problem especially if the casings are coming out misshaped, slowing the ejection process an causing a return delay.

Originally Posted by Baldy

You need to pull the slide all the way back and release it fast. Just like it fired a round.
Welcome to the forum and enjoy.

I'm thinking along with Baldy. Either not releasing fast enough or riding the slide a bit.

CZs are notorious for weak springs new out of the box. Contact CZ USA about your RTB failure and they will ship you a new recoil spring.

I know of folks who have replaced all springs in their CZs: recoil, mainspring, extractor, slide stop, firing pin, mag springs (usually with Wolff kits), and others who have had no problems straight from the factory.

Springs are the most common customization for CZ75Bs. Those who have replaced with Wolff kits usually suggest upgrade the recoil spring from 14#to 15-16# and upgrade the mainspring from 14# to 15#. I have shot one of these tuned guns and it handles in SA like an accurized Browning HP with a trigger job, better grips and safety. The DA trigger still feels a little heavy. According to the owner, after a spring job, these guns are bulletproof reliable. And it is one of the few DA/SA 9mm that you can carry condition one.

Originally Posted by Todd

I'm thinking along with Baldy. Either not releasing fast enough or riding the slide a bit.

I'm going to have to disagree with both. If the recoil spring isn't heavy enough, that could cause a fail to return to battery. As Submoa
said, upgrade the recoil spring. If you're not sure if that's the problem, take a look at how far spent casings are ejected from the pistol. 3 to 6 feet means its roughly correct. Less, you want a heavier spring, more, and go lighter.

Originally Posted by Patient_Zero

Its also a good idea to control the slide after a reload. I don't recommend letting it slap forward after a reload. That can cause the gun to fail to return to battery.

I fail to see the difference between letting the slide slam home after a reload and letting the slide "do it's thing" while shooting. It's the same mechanical action. When you fire, the slide goes back full speed then slams forward full speed, to strip a new round off the mag. Why do you feel is it OK when the gun is firing and not OK when reloading?

The spring makes sense to me, riding the slide does not.

Todd:
I went back and read my previous post again. I've deleted the statement in question because after trying for an entire day to figure it out, I have NO idea what the hell I was thinking about. I'll be over here in my corner wearing my pointy hat if anyone needs me.

Originally Posted by Patient_Zero

I have NO idea what the hell I was thinking about. I'll be over here in my corner wearing my pointy hat if anyone needs me.

Good, 'cause that makes two of us.

Make sure you use your own hat and not mine (it has a big "T" on it). I'm sure I'll need it eventually.

I will tell you that i have a para 45 auto and if you do not pull the slide all the way back then it will jam a shell like you are talking about. basically if the slide is all the way back it will chamber. Just keep one in the pipe when you are carrying. I always do and have never had any problems except sometimes like you say.