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Hard to close bolt on new CZ457 MTR

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2.5K views 26 replies 19 participants last post by  dogtrialerguy  
#1 ·
I just picked up the rifle yesterday brand new. Just cycling the bolt empty chamber it doesn't feel bad at all. But closing bolt on a round it's very hard. No matter what brand of ammo i.e-Eley, SK CCI, all the same. After 50 plus rounds no change. After talking to some folks I'm going on the assumption it's probably a head space issue. I've ordered a set of barrel shims for the CZ to see if this will fix the issue first. If all else fails I send it back to CZ.
 
#4 ·
The bullet is 'Engraving' on the initial rifling. I'd be concerned if I DIDN'T have a bit of resistance. I'd get a second opinion by an EXPERIENCED 22LR Competition shooter who can determine if the resistance is 'excessive' for a Match Chamber. And 50-ish rounds is not much of a break-in, either. Have you Dis-assembled your Bolt yet ? On some rifles the 'manufacturing "grease" is quite thick and I've seen it become very 'stiff' from sitting on a shelf for a while (like xx-months) since assembly - it may have been built 6+ months ago. I'd add bolt shims as a 'last resort' after looking into other possibilities.
 
#5 ·
I bought a new CZ-457 MTR a month ago. Even without chambering a cartridge I found the bolt stiffer to manipulate than I liked so the first thing I ordered was a replacement bolt knob... one of the large steel replacements. It helped a lot. As others have said, the MTR has a match chamber and should close hard on a cartridge due to the rifling engraving the bullet's drive band.

Other things I did prior to firing the first shot included:

1. Remove the barreled action, loosen the barrel grub screws and tighten them to 35 inch-pounds (ip).
2. Re-install the barreled action and torque the action screws to 20 IP rear and 18 ip front.
3. Remove all three sling swivel studs so the stock would ride the bags
4. Order a new Jard 3 - 6 oz trigger which has now been installed.
5. Order three 10 round mags

Below are some of the groups I've shot with cheap ammo while testing for accuracy.

Image
 
#10 ·
I bought a new CZ-457 MTR a month ago. Even without chambering a cartridge I found the bolt stiffer to manipulate than I liked so the first thing I ordered was a replacement bolt knob... one of the large steel replacements. It helped a lot. As others have said, the MTR has a match chamber and should close hard on a cartridge due to the rifling engraving the bullet's drive band.

Other things I did prior to firing the first shot included:

1. Remove the barreled action, loosen the barrel grub screws and tighten them to 35 inch-pounds (ip).
2. Re-install the barreled action and torque the action screws to 20 IP rear and 18 ip front.
3. Remove all three sling swivel studs so the stock would ride the bags
4. Order a new Jard 3 - 6 oz trigger which has now been installed.
5. Order three 10 round mags

Below are some of the groups I've shot with cheap ammo while testing for accuracy.

View attachment 544440
2,3 & 4 I've done except 2 I set at 25 both. My JARD trigger is set at 2.5ozs. 5 I didn't need to because I already have several with my other 457. I was going to try #1 today to see if that helps some but I getting a set of barrel shims being sent today if they're needed.
 
#9 ·
A buddy at the range loved my @1 so much he ordered one too. He got the 24" barrel that I really wanted but could not find. He mentioned the same thing because compared to mine his is very stiff to close on any ammo. I had to explain that mine has maybe 3000 rnd through it now and it also started stiff but got steadily smoother. I showed him the back of the bolt handle on mine where it has worn to a mirror polish and I keep it greased. He hasnt even got a wear mark in the blueing yet. Just start ammo testing and by the time you find the brand and lot# you like it will be smooth as butter.
 
#12 ·
After reading all this I took my brand new, never been fired, CZ 457 MTR out into the backyard and chambered a live round. The bolt closes no more difficultly than on my 50 year old Remington 581. I realize this proves little but before I started installing barrel shims on a one month old rifle I'd send it back to CZ for inspection. I realize this isn't like sending your toaster back to Cuisinart but it's nearly a $1,000 rifle that you may own for many years. Besides it's winter and you may not even use the rifle for another few months.
 
#13 ·
I tried several different things with the rifle today.
1- I broke the bolt down & cleaned it. That didn't change anything. Bolt was not caked up with any grease or any other matter.
2- I loosened the 2 grub screws holding the barrel. Barrel was installed very tight. Broke it loose & reset it. Then I cycled a round. It was not near as hard to close the bolt. Also the match chamber is pretty tight. It really imprinted the bullet. Will try some more test firing today.
 
#20 ·
I tried several different things with the rifle today.
1- I broke the bolt down & cleaned it. That didn't change anything. Bolt was not caked up with any grease or any other matter.
2- I loosened the 2 grub screws holding the barrel. Barrel was installed very tight. Broke it loose & reset it. Then I cycled a round. It was not near as hard to close the bolt. Also the match chamber is pretty tight. It really imprinted the bullet. Will try some more test firing today.
If it’s not excessive I wouldn’t worry about it with the match chamber
 
#15 ·
When I got my MTR I was disappointed with the bolt as it didn't slide very smooth compared to some of my other rifles. This won't affect how hard the bolt closes but it will make the bolt slide back & forth smoother. Remove the bolt & look at the surface where the serial # is then slide your finger across it & you'll notice the material around the numbers is raised slightly. If you don't already have any fine flat stones get one & rub it back & forth across the numbers there isn't any excess material above the flat area. The number is deep enough so it'll still be very legible. I think the stone I used was a 400 grit but it might have been finer. When I did this to the bolt on my MTR I also took the bolt apart & used my Dremel with a felt polishing tip & some Mother's mag wheel polishing compound & polished the bolt. This really made bolt work a lot smoother
 
#16 ·
A problem I immediately noticed was that the bolt handle/knob are short and small which severely limits the leverage, especially when opening the bolt. That made the bolt operation seem more difficult than it should be. I ordered a new bolt knob - The Executive - from DIP for $25. The improvement in leverage was significant and made bolt operation much easier.

To remove the factory knob, I wrapped a piece of thick leather around the knob and then clamped vice-grips on it. It came off without marking it in any way. I cleaned the threads and used Loc-Tight to secure the new knob.
 
#22 ·
I got a Varmint then an MTR and, just recently, another MTR. The Varmint is pretty standard - solid but not stiff lock-up on chambering and does not engrave rifling. The first MTR is noticeably stiffer on lockup and does engrave the rifling but still allows an unfired round to extract - it's also maybe slightly more accurate than the Varmint. The most recent MTR is definitely harder to close on a round and engraves the rifling deeper than the first MTR and doesn't extract an unfired round. It seems to be the most accurate of the 3, though not by much and I've only shot it a little so far.
The match chambers are definitely tighter/shorter and I'd be disappointed if there wasn't some difference in the way it chambers and holds a round. The MTR is made for bench/target shooting where ease/speed of loading is completely unimportant - not like a hunting gun where offhand shooting is normal and smooth and easy chambering and extraction/ejection is a plus.
 
#25 ·
Is this when dry fried or with a round chambered?
Some movement when dry fired can be expected if not excessive. The bolt and trigger mating might not be meshing quite right which could be the cause and the release of the striker spring tension will cause a bit of jump.
if it does it with a round chambered you might have a tad too much headspace