After you have loose fitted the rail and barrel clamp assembly to ensure there are no fitment issues. You can begin to cut the stock for barrel clamp clearance. First place the weapon with loose fit rail assembly in the trigger side of the stock. To get an idea of were the mounting point is going to align. Mark the ribs that are going to be trimmed. (See Figure C.) Locate the rib A and rib B (DO NOT TRIM Rib A or B.) Locate ribs 1, 2, and 3. Then Trim ribs 1, 2, and 3 1.05" forward from the face of rib A and .175 deep on rib 1 and straight across ribs 2 and 3. Make sure ribs A and B are flush. (See Figure C1 & C2) Repeat cuts on other half of stock. Now the weapon with rail assembly should fit your stock. If it doesn't fit identify where the stock is interfering and trim to fit accordingly.
Once you have trimmed the stock to fit the weapon rail assembly. Place the weapon loose fit rail assembly in the stock then slide the rail clamps back to rib A. The barrel clamp should be flat against ribs A and B, so the lower mounting hole is aligned. When the barrel clamp fits flat then you can tighten the four allen screws around the barrel just enough to hold barrel clamps secure so the rail can be aligned in the sight pocket. Leaving the top two allen screws loose. Make sure the rail sits flat against the sight pocket before you tighten the two upper allen screws. Now tighten the two upper allen screws to hold rail in position to align the old site pivot hole with the rail. That's where you will need a 5/32 or 11/64th center punch. (See Figure D.) To center punch the rail for drilling and tapping: Remove the rail and drill straight through on your center punch mark with a #29 drill bit. Then tap with a 8-32 bullet tap. Next put the rail back on loose fit all fasteners starting from the bottom of the barrel clamp working up then back, tightening all fasteners. Make sure to use lock tight for final assembly. The gas tube may need clearancing by placing in a vise and squeezing the heat sheld together. Place back into stock and reassemble. Once the two halves of the stock are fastened together take the 10-24 allen screw, lock tight and install to the forward mounting point. The forward mounting hole in the stock may need opening or shifting. And for rifles, we highly recommend using a regitity plate for greater stability.
Do a loose assembly onto the stripped down weapon looking for fitment interference. Some minor sanding or filing may be required. [The barrel clamps have very tight tolerance. For the best clamping surface area, heat sink contact. Keeping optics zeroed for accuracy. You may notice a small gap when you loose fit clamps around the barrel. This gap will close up when tightening screws for final installation. On 223. and 7.62 x 39 16" barrel, there is a step down on the barrel that may vary as much as 1/8" of an inch. (See Figure B) If the step down is too far forward, it will cause misalignment to the lower mounting point. If you find this to be the case, then contact us and we will remedy the problem with no shipping charges or fees. We welcome any feedback and adjustment to make a better product.]
ATTENTION: IF YOU HAVE PURCHASED THE OPTIC RIFLE RAIL FOR YOUR KUSHNAPUP IN 223/7.62X39/5.45 OR 308. THE BARREL CLAMPS FOR 223/7.62X39/5.45 WILL ONLY WORK ON 16" BARRELS WITH A STEP DOWN ( NOT 20" BARRELS ). (20" BARRELS DO NOT HAVE A STEP DOWN SO YOU MUST USE THE 308 RAIL FOR LONG BARREL 223/7.62X39 TO FIT).
After you've successfully fitted your 16" barrels 223 or 7.62 x 39 or 16" to 20" barrel 308 into your Kushna stock, making sure it functions properly in all modes, safe and fire, have fired the weapon, and cycled through at least 100 rounds without malfunction you then can take it back apart for fitment of the Jordan Tactical Optical Rail. Make sure all the parts are present.
You should have:
1 Picatinny Rail
1 Barrel clamp assembly
6 8-32x1 1/8 socket allen screws
2 8-32x3/8 taper head allen screws
1 10-24x3/8 socket cap allen screws
You will need:
1 8-32 bullet tap
1 #29 drill bit
1 Center punch 5/32 or 11/64
1 Allen wrench for 8-32
1 Allen wrench for 10-24
You
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First make sure your weapon is unloaded and made safe to work on. NEVER DO ANY MAINTENANCE OR MODIFICATIONS ON A LOADED GUN. That also means no magazine installed with the bolt open exposing the chamber to make sure there are no bullets in the chamber ensuring no accidental discharge possible. After you've taken all the necessary safety precautions to make the weapon safe, you can now begin installation of JTI Optic Rail System.
You must remove the factory sights by pushing down and back to slide sights out of the lock position to make room for your new optic rail. Then pull the spring out with needle nose pliers. (See Figure A)