MDT XRS install with CZ 457

[u/CoolGuy1980]

Hi all,

I've encountered a frustrating issue installing my CZ 457 in an XRS chassis.

It is supposed to be "captured action screws" (won't fall out when loosened) and the supplied action screws do have what look plastic nut on top of them that would stop the screw from falling out when loosed somewhat.

BUT with them left on there is no threads left on the screws to catch in the action. With the chassis off the rifle the screws can be tightened down so hard they spin in the plastic but they just end up flush with the tops of the nuts.

If I take the white nuts off it should be long enough to catch on the action, but then the front screw just falls out and is no longer "captured" at all.

It looks like there is a slot forward of the screw that would serve the purpose of capturing the screw in a longer action rifle, but this action isn't long enough to reach there.

Is this how it is supposed to be?

1. A loose 'uncaptured' screw at the front so it falls out and 'captured' at the back because the plastic of the trigger guard doesn't let it fall out?
2. Or leave the white plastic nuts on and somehow squish them down REALLY hard to get a couple threads to catch?

Sidenote to people looking to order an XRS chassis: The rear action screw is not accessible with even the fairly long 4mm hex bit that came in my torque wrench set.

The slots are too skinny to be able to turn the bit and the body of the bit catches on the sides of the slot.

Only a long manual allen wrench has room to turn or else to be able to use the torque screwdriver you'll need to buy an even longer 4mm extended skinny hex bit (which I currently don't have)

Thanks all

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Update: Got it in place - thanks to everyone

Also tried to adjust the trigger weight with no real success, started at 2.5lbs, went up to 3.5lbs, back to 2.5. Even with the trigger weight screw backed out so far it almost falls out. Seems to be the lowest it would go with the stock spring...

Trigger pre/post pull is negligible now though.

Now I'm looking forward to getting back to the range to test it all out.

[u/barthammer]

Other comments got it, but yes those white nylon nuts are just there to keep the nuts in place during transport. The screws are not meant to be captive. They are to be removed when you install the action. I had the exact same confusion on this very chassis!

The rear screw is a pain to access, you will need to buy an longer bit. No real way around it.

Make sure you transfer over the "recoil lug" from the original stock and put it in the slot just behind the rear action screw. That will help ensure the action is sitting in the right spot for when you thread in the screws.

Happy plinking. You will like this setup a lot I think!