I have a Stoeger .22 Air rifle with an integral suppressor, or rather it did have an integral suppressor before I turned the plasticky thing off the barrel. As near as I could tell, the suppressor had virtually no effect. I plan to rebuild the integral with a design with a larger number of baffles. Has anyone had experience with successful air rifle suppressor designs? The old unit had four baffles and a lot of airspace in the reflex area, but a very constricted bleeder area between the baffles and the expansion chamber. I am considering porting the distal end of the barrel, is this madness? This is one of the "springer" type Stoegers, not one of the Gas cylinder models, so it is fairly mechanically noisy. Since I will generally be shooting out of a garden window at the rodential beasties in my garden, at a range of no more than 30 feet, I think I can live with a reduction in power, and of course, there are lots of pellet choices to tune the results. The designs that I have heard in the EU for airguns seem pretty weak, but this will be a sealed design permanently mounted to the barrel, and overall diameter and even length are essentially unlimited.Ideas?

Unfortunately a spring-piston airgun changes very little in noise output even with an enormous diameter and long suppressor. You might scrub off a perceptible amount of noise, but since most of the sound is coming off the main cylinder during piston cycling there's really not a lot to be done about most of the sound pressure at the muzzle end. Porting will only reduce velocity and potentially harm accuracy if the inside ends of the ports isn't made very smooth.

Your best bet is to fine tune power, as you seem to be suggesting in part of your question. I've found that by clipping a couple of coils off the mainspring, grinding the cut end flat, then using a couple of washers to add preload, there's only slight power loss but considerable reduction in noise. I do have a 1" x 6" K baffle can on the front of one springer, bumping out .22" 14gr pellets at 540fps, and it does make an appreciable difference, but it'll never be anywhere close to as quiet as a finely tuned and efficient PCP running at the same power level with the same suppressor mounted. Sleeving the spring with a tough plastic sheet can help a little too, if you can find something that will survive the abuse.

Thanks, I can't disagree with any of what you have said!

I haven't done the side by side comparison myself, but I'm told that the "nitro piston" gas spring guns are more quiet than steel spring piston air guns.

When Stoeger introduced the integrally suppressed pellet rifle, they only had the springer version. The Distributor swore on a stack of CHICOM manuals that this springer would be as quiet as the not-then-released Nitro-Piston version. Subsequent reports show that they may have slightly misrepresented that...I was in a hurry, and went with the Spring/air version. My bad. I guess that's why I am willing to do major surgery on a couple hundred bucks worth of noisy pellet rifle.

<< https://www.pyramydair.com/blog/2009/09 ... or-part-1/ >>

An interesting spring operated .22 air pistol from the 1930's is the Webley Senior I.

It is still fun firing inside during winter months. In the past it has served to
get the attention of feral animals when they would not remove themselves
willingly from back porch in fall.

As for quiet, it is at level of a .22 with Deadair Mask.

Historian wrote: ↑Wed Jul 10, 2019 3:13 pm << https://www.pyramydair.com/blog/2009/09 ... or-part-1/ >>

An interesting spring operated .22 air pistol from the 1930's is the Webley Senior I...

As for quiet, it is at level of a .22 with Deadair Mask.

Which would be rather loud, for a rather weak air pistol. My Webley Senior shoots an 11.9gr RWS Hobby wadcutter pellet (pretty much an average .22" diabolo pellet) at 300fps, with a freshly made Webley-spec mainspring, new beryllium-copper alloy piston ring and new leather breech seal. They can be tweaked to run a little bit hotter but not much. A truly fun plinking pistol, difficult to shoot accurately, and very beautiful to look at. But it's not that loud. Standard velocity CCI out of a Dead Air mask on a 4" barrel runs at about 114dB or so. A Senior tops out at around 110dB. Close, but not quite as loud as a nicely suppressed .22lr pistol. My spring-piston rifle shooting a heavier pellet at 540fps is not much if any louder than the Senior. In fact they're about comparable. The rifle has a 14" barrel, quieting things a bit, and a much heavier action which further damps noise.

a_canadian, thank you for pointing out my bleary-eyed mistyping in
my
"... it is at level of a .22 with Deadair Mask".
Actually should have read "... it is at a noticeably
quieter level than the .22 Deadair Mask."

I cannot blame SIRI for improper dictation here.

For redundancy parts source for Senior:
John Groenewold (847-566-2365, Central)
Webley Parts

A book that shooters might want to add into their collection:

"Webley Air Pistols: Their History and Development" Gordon Bruce
Publisher Robert Hale London ISBN/ASIN 0709066198 2001

I've appreciated the service and inventory at this place for Webley parts:
http://www.proteksupplies.co.uk/webley- ... parts.html

And a tip for anyone restoring one; the little spring inside a floppy disc, the one which closes the sliding window, is almost the same as the original linkage arm spring, just a delicate little thing. Works if you can't obtain an original.