PRF Chassis CZ455 Installation Instructions
Prior to working on any firearm insure it is empty and safe!
#1 Package Contents
#2 Preparing for install
1. Remove the bolt from your rifle
2.Rest your rifle on the scope dovetail on a flat
surface or invert in a gun vice or other fixture as shown in Image #2.
3. Use your finger to reach through the chassis mag-well and move
the magazine drag-link all the way forward.
#3 Placing the chassis on the receiver
1. Pick up the chassis from the ends.
2. Carefully lower the chassis on to the receiver keeping it parallel to
3.Using the trigger opening as a guide move it down until the trigger
is through the opening, This will allow you to move the chassis
slightly forward. Capture the rifles magazine release with the chassis
drag-link as shown in the image.
4. Move the chassis rearward to clear the recoil stop and lower the
chassis all the way to rest on the rifle action.
#4 Installing action screws with 5mm Hex Key
1. Insert 1 (M6x40mm) SHCS in the rear action screw hole and start
into the threads (do not tighten yet).
2. Insert 1 (M6x35mm) SHCS in the forward action screw hole and
start into the threads (do not tighten yet).
3. Use light pressure pushing forward on the chassis to insure the
rifled action is fully rearward against the recoil stop.
4. Lightly tighten both bolts until they are just snug.
5. Using a torque wrench moving back and forth, tighten each bolt
1/8 to 1/4 of a turn at a time until 25-30 inch pounds is reached. This
is our suggested starting point for action screw torque. You may
increase torque as you wish but exceeding 35-38 inch pounds may
damage the V-Block surface possibly resulting in poor fit and accuracy.
#5 Invert the rifle
1. Inspect that the receiver is against the rear stop as seen in image
#6 Check Function
1. Reinstall your bolt and safely check all functions of bolt and
#7 Install handguard
1. Lay the chassis on a flat table or bench on its left side. Insure the
barrel is not overhanging the edge.
2. Lay the handguard on the working surface on its left side.
3. Position the hand guard in front of the barrel and slide into
position. The working surface will keep the handguard in proper
alignment to clear the barrel and mate up with the chassis body as
in image #7
4. Using a 3/16 hex key install two 1/4-20 x 5/16 SHCS into the
bottom counter bores in the chassis. Engage the threaded inserts
in the handguard.
5. Snug up both bolts and then torque 35-40 inch pounds.
#8 Re-position the rifle for receiver extension install
1. Position the rifle as shown.
#9 Install castle nut on receiver extension (Not included with purchase)
1. Thread castle nut onto receiver extension as shown in image #9.
#10 Install receiver extension
1.Thread the tube into the chassis until it bottoms out.
2. Thread out until the tube appears to be straight up and down.
3. Using a 1/16 hex key, install (1) 6-32 x 3/16 set screw in the
alignment hole seen in image #10.
4. Slightly wiggle the tube back and forth while tightening the set
screw. You will feel the set screw contact the alignment groove flush.
This will align the tube true vertical. Tighten the set screw hand tight.
5. Use a spanner or Armorers wrench to tighten the castle nut
against the rear of the chassis and torque 15-20 foot pounds. There is
no operation in the tube such as on the AR15, it just holds the stock
#11 Installation is complete
1. Install magazine and check function. The paddle and drag link are
installed prior to shipment. There is a small swab of light gun oil
placed in the track and it is tested against spring tension for return.
2. Install any flat top AR compatible grip of your choosing. Chassis is
threaded 1/4-28. This is the same as AR15 lower receivers.
3. Install the butt stock of your choosing.
4. You are ready to sight in and enjoy your new Rigid Alloy llc CZ455
Note: Installing your rifled action in an aluminum chassis changes firing harmonics. It is common for the rifles ammunition preferences to change.