Homemade De-resonator/Dampener Improves My Slug Groups

[AirgunBill]

Recently I posted about my FX Impact .25 slugs groups going south and decided to clean the barrel. I also did a different o-ring/ liner arrangement to maybe support the liner better. Since when you buy a liner they don't come with o-rings I try to find whatever ones on hand that seem to fit. At this point I still can't find out what the various correct sizes to use. After installing the liner I could not get my accuracy back, with groups going around 2" to 3" at fifty yards which is no good. The velocity spread on my 26.8 grain Nielsen slugs I was shooting was very tight but I guess the liner harmonics were bad. Then I was thinking about the times when I was using my FX Radar and at times the groups would tighten up although drop in elevation which is to be expected. The thought was to make a weighted sleeve to fit over the moderator to adjust and change the harmonic. The company LimbSaver has been making a rubber donut to install on firearm barrels to change the harmonics. Well I did some testing today and the results were very good. If the results hold up I might of found an easier way to fine tune for slug accuracy after you do a good initial rifle tune. Bill

https://www.youtube.com/watch?v=iz3IJJG0_ms&feature=youtu.be&ab_channel=GunPowder%26AirPower

 

[Kgphotos]

That’s a very interesting approach. I look forward to seeing more of your testing.

 

[Hoople]

Quite a bit of experimentation was done with oil filled dampeners on GTA while back. Invented by Knife, called MAD. Showed promise. 

 

[Lewis]

Harmonics can make all the difference. Eliminating unwanted resonance is acknowledged as key in everything from engine design to audiophile stereos. No reson airguns should be any less affected.

Lots to think about. Weight, placement, span,density, number, material, barrel rigidity...

I have long wondered why all the airgun barrels are so thin. Most bull barrels in powder guns have nothing to do with cartridge pressure. Look at rimfire benchrest. Lots of barrels over an inch in diameter to shoot subsonic 40 grain slugs.