I recently purchased a used surefire CA556AR203. I have the FH, Shims and rockset but no instructions. Can some one enlighten me on the installation of one of these?
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Clean threads with alcohol or acetone both on the barrel, and inside the FH.
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Install one of the larger shims, a medium one, and a thin one. Screw on the FH, and see how it times up. You want the FH to be about the 1 or 1:30 position to get the right amount of torque. Sometimes you only need 2 shims but it just depends on how the tolerances are. You want to use the least amount of shims nessessary so don’t put like 5 thin ones on there when one thicker one could do the same as 3 thin ones.
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Change out the medium, and thin shim as needed. Thicker = moves the timing position counter clockwise looking at the barrel muzzle to buttstock. Thinner = moves it clockwise.
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Once you get the right shim combo so the FH is hand tight at 1 or 1:30 take the FH back off, and apply 2-3 drops of Rocksett on the barrel threads. Reinstall the FH, and tighten it so its timed correctly.
A trick I use for timing it if you have rails you can look down the rail, and align the end of the rail with the flats on the FH so they are both parallel. You should see the flat edge of the rail, and align it with the flat edge of the FH.
Use a barrel clamp if you have one, and its not a bad idea to let the Rocksett cure for a day before shooting with it.