I know I lag but too busy lately.
My Crosman; what happens is the spring bows out to the side which you can see w/ the stock off and/or clearly hear in the clink clink clink when cocking an unmodded gun. Far worse is when fired the spring is violently twanging around and reaching out much further than that. Plus the springs have a rough surface to make matters worse, so picture a rough coil reaching out onto the edge of the liner and pulling it down and in with that rough grippy surface. This is why flared (bigger) is better than just beveled, and of course plastic would survive attacks like that better than alum. I also sand the spring, not that I really need to but why not, but maybe it'll make the diff in someones borderline setup.
Ace; I disagree with it not helping at distance. I can easily tell a when a springer is fired in my hood, and I can tell if it's a coil or gas b/c the coil sound is obvious (to me) and is not drowned out by the other noises. Btw the lots here are ~50yds, and my parallax adj on my scope agrees so it's at least close to 50. I can hear five houses down easily, probably ten + if it's a quiet day. I can even hear the guys three houses down when I'm inside the house. Per my work my hearing is so bad I may lose my job, so if I can hear it then a woman w/ bionic hearing can.
The muzzle blast is hard to est but imo the coil spring is louder than the muzzle. Here's why I think so: When Stoeger made their new X20S I bought one to check out their new super suppressor. I compared it to a new Benj Titan which had no suppressor but Crosman claimed the gas spring was 70% quieter. Both guns unmodded btw. With the guns side by side I'd fire them and they were pretty much equally loud. This is subjective but side by side is a pretty fair test. The only issue is the noises were different so I fired them many times to better est. At the very least the coil spring noise is significant and worth the effort if noise is an issue. Noise is an issue for me, hence buying that gun just see if its suppressor was worth anything. Having do that test and many others to get max quiet, I can assure you this liner makes a huge diff. Unfortunately my neighbors can still easily hear my quietest springer, which is why I now have an Mrod I modded to have no muzzle blast
just the hammer and its spring. Damn springs. I buttoned the hammer and next is a little liner