Comp Erosion

[Jon Merricks]

I was looking at a friends open gun and I noticed that the comp had some erosion around the holes the bullet passes through. When does this erosion cause the comp to lose it’s effectiveness? When should the comp be replaced?

[L9X25]

Jon,

I believe that wiper erosion becomes critial when you can see erosion on the final one or two wipers (depending on how many ports you have). As the first wiper erodes away the second wiper begins to show more erosion and soon the third etc... The performance gradually degrades but it is so incremental that you hardly notice that it has become less efficient until you replace it. I personally use 4 port comps and try to replace them when I notice significant erosion on the 3rd wiper.

Wil Schuemann has stated that the wiper hole diameter is not that critical but I disagree. I always strive to keep the wiper holes tight as possible. I usually start out with about a .368 wiper (assuming .38 caliber) and do not increase the size unless I notice contact with the bullets, then I will go to .375.

Leo

[TheOtherErik]

Say one starts to supsect bullet hitting the last hole of the comp. Enlarge the last one or all of them?

[BrianH]

Just enlarge the spot that is hitting, and only on that baffle. Don't cut all the way around (there's no need to) and don't cut baffles that aren't being hit.