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Slavia · Moderator

I wanted to try introducing a choke at the muzzle of my G1 to enhance accuracy. After reading CW's instructions in another thread, I felt confident enough to try it.

http://www.airgunhome.com/agforum/viewtopic.php?t=2114&highlight=choke

I used the same concept, but modified the procedure somewhat. Instead of boring out a nut and cutting it in half (as CW suggested), I took a 2" length of steel pipe and cut a slit lengthwise about 1/8" wide. I pressed it in a vise until the I.D. of the pipe was approximately the same as the O.D. of the barrel. Then I sanded the inside to remove gouges and rough spots, and de-burred the cut edges with a Dremel.

With the pipe on the end of the barrel, I tapped it against the anvil of my shop vise with a hand maul, rotating the barrel slightly between each blow. The blows were soft - more like letting the hammer fall with gravity than hammering with muscle power.

I had pushed a pellet through the bore before beginning the procedure, and it measured 4.492 mm (my micrometer is metric). After about 40 blows I pushed another pellet through. Then 40 more blows, and another pellet. After the third set (120 blows approximately) I could feel the constriction as I pushed the pellet through, and the rifling marks engraved on the pellet skirt from obturation were more obvious than before. That's where I stopped. (The pellets in the photo go from left to right.)

The final measurement was 4.477 mm, 0.015 mm smaller (equal to 0.0006", or slightly more than half a thousandth). Truthfully, the engraving on the pellet skirt and the "feel" as I pushed the pellet through gave better feedback than the micrometer.

There was a significant decrease in group size. Go here to see sample groups and the rest of the G1 project:

http://www.airgunhome.com/agforum/viewtopic.php?t=1760&start=105