Help on CZ Scorpion EVO accuracy

[badger]

Hello everyone, newbie here.

I bought a CZ Scorpion EVO 3 S1 pistol a few month ago. It runs great until a couple of weeks ago I cleaned the gun for the first time. It had very tight group at 10 yards before, but now the POI can be one inch below the POA or 16 inches below the POA.

I only moved the charging handle to the right side and added a tailhook mod 1 to it, and I always shoot Sellier & Bellot 9mm 115gr FMJ (SB9A). I cleaned it again last night, and went to the range today. I got similar bad results even when I rested it on the table with the mag.

When I was cleaning it last night,  I noticed the ejector is a little loose, and there is a tiny gap (1/8 inch?) between the lower and the upper. Is there anything I can do myself to fix it or should I send it back to CZ?

Thanks for your help,

[Asylum9]

Check your 1/2x28  thread protector under the flash hider. It's probably loose.

[kdog78]

Concur!!!   Just cleaning it will not move anything that would move you POI like that. Also are you using irons or a red dot?  THey may be a little loose and cause the POI shift.

[ndmiller]

Check the sights as well, a loose front or rear rocking could cause issues with group size. 

[OpusXJ]

The gap between receivers is normal.

The ejector should move freely, it moves when the bolt rides over it.

[badger]

Check your 1/2x28  thread protector under the flash hider. It's probably loose.

You are right. The thread protector inside the compensator (part #1 in the assembly drawing) is loose. How could I tight it up? Is there any way to take it out of the compensator?

[badger]

Concur!!!   Just cleaning it will not move anything that would move you POI like that. Also are you using irons or a red dot?  THey may be a little loose and cause the POI shift.

I am using irons. The thread protector inside the barrel nut is loose.

[badger]

I don't want to be captain obvious here, but since you mentioned that you added a tailhook, could the POI shift be caused from a different cheekweld?

Or a bad optic?

I also suggest making sure that all of the receiver bolts are tight.  Especially the ones up front because they are the ones that capture the barrel in place.  Don't torque the crap out of them, just make sure they're finger tight at least.

And if you do have one of those stupid thread protectors that has already been mentioned, be sure to check it.  I've seen a lot of people have that same problem.  Take it off the gun.

When I was cleaning it last night,  I noticed the ejector is a little loose, and there is a tiny gap (1/8 inch?) between the lower and the upper

I don't know what to make of this.

It is the thread protector in the compensator. What else should I put on there if I take them off?

[GearFondler]

Check your 1/2x28  thread protector under the flash hider. It's probably loose.

You are right. The thread protector inside the compensator (part #1 in the assembly drawing) is loose. How could I tight it up? Is there any way to take it out of the compensator?

You simply unscrew the flash hider to take it off... Then unscrew the 1/2x28 thread protector and leave it off... Then reattach the flash hider.

[badger]

Check your 1/2x28  thread protector under the flash hider. It's probably loose.

You are right. The thread protector inside the compensator (part #1 in the assembly drawing) is loose. How could I tight it up? Is there any way to take it out of the compensator?

You simply unscrew the flash hider to take it off... Then unscrew the 1/2x28 thread protector and leave it off... Then reattach the flash hider.

My problem is that the thread protector is already off. So when I unscrew the flash hider off, the thread protector will come off and stay inside the flash hider. I read in another thread that it can be forced out using a punch. I am just wondering if there is any safer method to avoid damage to the flash hider's thread.

[jmstallard]

I am just wondering if there is any safer method to avoid damage to the flash hider's thread.

Reverse pliers should allow you to pull the the thread protector out. You can improvise one if you don't own one.

[Destructo6]

I am just wondering if there is any safer method to avoid damage to the flash hider's thread.

When the flash hider is in place, it will also protect the 1/2x28 threads. It won't keep them clean, but they won't get banged up, either.

Just be careful when you take the FH off to clean.

My thread protector has been sitting in a parts bin since about the third time I shot the gun and each time that thread protector was barely hanging on.

[badger]

I am just wondering if there is any safer method to avoid damage to the flash hider's thread.

Reverse pliers should allow you to pull the the thread protector out. You can improvise one if you don't own one.

Sorry for the late reply, I was out of country. Thanks for the tip. I will try it later.