$6 DIY Hammer Slap Mod
I posted this as a response to a thread in a different category, thought it would best be put here too, in case anyone finds it helpful.
Ok, I finally got off my lazy butt and decided to post my “armchair engineer” solution to the terrible affliction known as “hammer slap”. Go to Lowes or Home depot or any reputable hardware store. pick up the $5 bronze sleeve bearing that has a 1″ diameter. This part is listed elsewhere in this forum as the “heavy hammer”. I found it here a long while ago, and got the idea to make it quiet. Then get a rubber grommet that fits the diameter of the bronze sleeve bearing. You will need a razor blade or sharp knife to cut off the one side of the grommet, leaving the inside lip in tact. Just cut off the one flange. Apply a good rubber based adhesive to the inside of the grommet and stick it to the end of the bronze sleeve bearing. I polished the sleeve bearing up a bit with some 220 emery cloth by attaching the sleeve bearing to a dowel rod, then chucking the dowel rod in the drill press(hillbilly lathe….). I held the emery cloth while the bearing rotated on the drill press, and polished it until all the pits were removed.
I don’t have any numbers to tell you about performance, or loss of performance. I just bought this talon ss 6 months ago, and don’t have a chronograph. It seems to work well for what I am using the ss for, so your mileage may vary. This approach also keeps your stock setup in tact, in case you want to undo this setup later.
It is easier to look at the picture, so here is a shot of my quieted heavy hammer, and one showing the rubber grommet and where to cut it……………..and there it is. no fancy mills, or lathes or laser guided o-ring grooving hootchamajigs, just good ole’ fashioned hillbilly engineering. enjoy.
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I think you have a great little invention there and very cheap indeed, and shooting a few hundred rounds is proof enough for me. Thanks for the info if I want a heavy custom hammer I know what to do.
It really isn’t any different than a more expensive oring type mod, both are rubber based. If you are looking to eliminate hammer slap, which is where 2 hard surfaces smash together, you need to remove one of the hard surfaces. Even when the 2 hard surfaces collide, there is going to be some bounce back, less than when 1 surface is rubbery, but it will still happen. If you want less noise, you have to deal with some trade-off consequences. Some bounce occurs, I’m sure, but I have never had a tank dump or “machine-gunning”. From some comments by others who have actually measured the power, fps, etc. there is also a power trade off to this mod, but it works toward the intended goal of being quieter…
I could see it causing ‘machine-gunning’, something I’ve had issues with. From as little as a slight noise to a full-on tank-dump. The breech flies forward, bounces off whatever the cocking-knob shaft hits and comes back against the valve with enough force to open it again.
walt,
the breech area cutout was chewed up when I received the gun, the cocking knob was loose and the o-rings were worn in the breech, causing it to be a bit sloppy. I don’t know what actually caused the corners to be chewed up, but it wasn’t pristine when I did this mod, the gun itself is well broken in. I am unsure if this mod would have the effect you are describing, but certainly plausible and worth watching out for if you go down this path.
Actually my question about how long you’ve had it on was to find out really, how many rounds you’ve had through the rifle this way. Your closeup of the breech showing the handle cutout shows the corners of the cutout very chewed up. Some wear is normal and on some guns more than what you have is also normal when people go around changing hammer weights and using weird custom valves. However, yours does look a bit chewed up; I was wondering if the breech was bouncing up due to the rubber grommet.
aloha,
walt
You probably could freeze that grommet then cut off one side wall and leave even a little more of the lip to attach to the hammer.
walkonking, thanks for the info. I am curious about the numbers, but not enough to buy a chrony just yet. I was thinking the extra weight may up the fps, while the rubber bounce would lower it, so not really sure where it would end up. but hey, for $6 you can get rid of that hammer slap. I seem to be of the opinion that the talon ss has plenty of power to spare, so no big deal losing a couple fps for plinking and medium duty varmint control.
Walt,
I have had this on the talon ss for about 4-5 months(3-400 rounds or so) I would guess, put it in about a week after I bought it from blkdout here. If you are getting at what kind of longevity you would get with this, I am confident it will last quite a while. I used an industrial grade rubber cement, and the lip that rides inside the sleeve bearing seems to be the key to getting it firmly attached. without that inside lip, it wouldn’t last a couple rounds.
brian
Very nice.
Just a note to those who try this. Your velocity will vary depending on the hardness of the bumper you are using. The softer the more fps you will lose.
Nice quick DIY, redeye. How long have you had this mod on your rifle?
aloha,
walt
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One thing I might add I was a machinist for 35 years and buying bushings you have to be careful, you said you bought a bronze bushing you should be ok but I have seen places that sell those bushings and call them bronze and they are what they call oillight bushings which is a bronze bushing impregnated with oil, which is not a bad thing just don’t know how long glue would hold up to these. I used to machine them down to fit in different applications and when they get warmed up oil runs out of them. I am not tyring to say that is what you have or that is what is going to happen just pointing this out. I am going to guess regular brass is going to be heavier becasue bronze is more open pored. anyway something to think about.