DFL Moderator Caliber Sizing

They are already up sized for you, but I highly suggest looking into a STO Falx, they actually work, are light and cheaper than a Donny.

I have stated this before, but I will repeat this fact again. Most commercial moderators have bores much larger than optimum for good noise attenuation. You do not have to take my word on this, just measure them up yourself. I have found that optimum clearance between the exit diameter of the munition and the moderator bore should be about .020" or .5 mm. Anything tighter than that does not make an appreciable difference. I suspect the reason that commercial moderator bores are much larger is clipping. In order to not cause clipping requires that the moderator must mount square and exactly inline to the barrel bore and it is unfortunate that many will not because the moderator mounts to shrouds which may not be perfectly inline to the barrel. In which case clipping occurs along with customer complaints. This condition is easy to detect with an alignment rod which exactly matches the exit diameter of the barrel. Once placed into the barrel through the mounted moderator the rod should be exactly centered in the exit diameter of the moderator. This is a simple and fast test which should be done every time a mod is mounter to the gun. It takes very little to skew the mount out of alignment. More unfortunately, no one sells these test rods, you have to make your own.

had the Yoko on my .25 screw on it was a .30 and clipped sold it. I/A 1350 caliber correct almost 1/2 the weight.

The proper hole for your caliber will yield the best results. So the question is, how much faith do you have in the quality machining on your airgun. A gun that’s machined dead nuts, you can shoot a .22 pellet through a .24 hole no problem. My .22 Impact is shooting through a .235 hole and my .25 Impact is shooting through a .268 hole. High powered sluggers and only 4” mods. Silent. Good machining.