How do my fellow tuners make a piston seal…better?

Well I've heard of people sizing them correctly by taking a Dremel to them to fit but I haven't really heard of anyone making it smoother to shoot. What makes it smoother is crosshatching the piston chamber with valve polishing stones on a drill. I watched a YouTube video on it and did it on my Gamo hornet. The idea is to make microscopic cross hatched cuts to hold in the very light coating of moly grease. I polished my tube out with 600 and 1000 grit first. Not even sure if that helped smooth it out but the end result of doing those things was unmistakable. It was a much smoother gun when I was done. I also ground the ends of the spring flat and greased the spring with a decent amount of thick moly paste. That took the bite out of the twang. There are far more skilled men on this site than me and far more detailed articles you can look up on the subject. As far as I can tell though if the piston seal fits and works correctly I wouldn't mess with it. Anyone more knowledgeable than me can verify that or not. I could very well be mistaken. Maybe there is something I am not aware of here.... wouldn't be the first time 🤣
 
Oh another major improvement can be to buy an aftermarket delrin spring guide and or premium spring. I wouldn't go trying to get the most powerful spring out there as this will actually make the gun less smooth and more twang. To me the perfect power for a smooth springer is 12 to 15 fpe. If you need more power for hunting go ahead and get the strongest spring you need. Just understand that you will need to find the perfect hold and will never achieve that smooth quiet awesomeness you are looking for. I love heavy hitting springers btw they just are not fun plinking and target guns.
 
Oh another major improvement can be to buy an aftermarket delrin spring guide and or premium spring. I wouldn't go trying to get the most powerful spring out there as this will actually make the gun less smooth and more twang. To me the perfect power for a smooth springer is 12 to 15 fpe. If you need more power for hunting go ahead and get the strongest spring you need. Just understand that you will need to find the perfect hold and will never achieve that smooth quiet awesomeness you are looking for. I love heavy hitting springers btw they just are not fun plinking and target guns.

Thank you for taking the time to write this. Yeah I’m familiar with all of the spring guide and lathe tuning…but I’ve never considered what other people do to their piston seals (other than GPL-205 or moly). Just curious is all.
 
Seal styles generally fall within 2 distinct types. Undercut / lipped AKA Parachute and AKA Hornet types.



Those seals " PARACHUTE" that have an undercut on the compression face bordering the sealing surface that is thin and retains a sealing margin that can shape shift with tube irregularities. Those type seals "HORNET" which are sized precisely to minimal contact specs are very unyielding to shape shift, tho are by nature unchanging in there applied drag produce the best power due to low drag.



EACH has there desired application, sadly some applications don't have a choice on seal types available.



Sizing seals is for many a very precise exercise in inking out the best and most stable ES values. best done via a rotating LATHE where TIR ( total indicated run out ) can be best achieved. Compression tubes TIR also very important with HORNET type seals, less so with parachute types.



Scott S

Motorheads AG Tuning Services
 
As mentioned nothing can be done to make them smoother that I am aware of. Fitting the seal if oversize is about all that is needed. I prefer the parachute type seal, have had the best performance with these and are what comes in most factory springers. Also a lot depends on what type of rifle your working on. I did different things to different rifles, depending on how they performed. My speciality was TX200 and SR models but also did a number of HW77 and R1. In years back I often rebuilt the old 3 ball triggers in RWS rifles. Not sure what you looking for in improving seal performance.