Making the Benjamin Discovery quieter, Part 1

I don't really have a problem with how loud the Disco is, but lets face it building a silencer/moderator is just cool. I did some research and found a few Web sites that covered the basics of how a silencer works. My first attempt was simply a 3/4" OD tube with a piece of round stock turned down to fit the ID of the tube. I center drilled the round stock on the lathe to 1/4" for the pellet to pass through. Then cross drilled the round stock with a 1/2" drill bit to create chambers to give the air a place to expand and slow down before it left the end of the silencer.

It worked, not great but it did quiet down the report. It worked better on the .22 cal pumper that I tried it on than on the .177 call Disco. This prototype silencer was built while I was waiting for my replacement Disco to arrive. The only other air gun I had that was "loud" was my Experimental .22 cal pumper, so I built it for that air gun.

My next attempt at building a moderator used the "K" style baffles, the baffles ended up being more of an X than a K but the results were very good. The baffles were center drilled to 3/16" for a closer fit to the .177 cal pellet. I have talked to people who have used washers instead of "K" baffles with good results but the "K" baffles look so much cooler..... not that you can see them once they are inside the moderator but they look cooler so they have to work better. Right? I'm not going to go into great detail on building the moderator but here are some pics.

For this video the target is set up 30 feet from my bench and the camera is a couple feet from the target. I pumped up the Disco to 1800 PSI since shooting on HPA is louder than CO2. The first three shots are without the moderator, the last three are with the moderator. Quite a difference.

As you can see in the video the shots with the moderator installed hit to the right of the POA. Once the video  was done I opened up the silencer and sure enough the pellets were hitting the baffles. 3/16" is a bit of a tight fit for the pellets. I'll have to open up the holes another .010" and see how that works. Being quiet is great but if it won't hit what I'm aiming at the moderator is of no use to me.

Stay tuned for part 2.....