That stuff looks like burned off Moly lube to me.If you use the krytox? Don't over do it! A little goes a LONG WAY! (same with moly)You really only want enuff to assist the piston going in. Nothing more.I'll double check the compression tube I have here before I ship it all.
This post got me thinking about my old Beeman dual cal. It has had all kinds of ammo sent down both barrels for over 6 years , and got extra wear and tear being my only air rifle for over 2 years. Still shoots accurate as heck but I am sure it is on its last legs. So it is sitting on my work bench awaiting a tear down and inspection.
And going back looking at your seal pictures real close?I can see the chamber is out of round.Look at the color differences near the seal lip.See how some spots are dark and others are almost clean? That is wrong!
OK. Dug the compression chamber and stuff out.This has a brand new seal and spring. I don't like the fit of the rear spring guide so I'm going down and turning a new delrin guide for it. It will fit tighter and help reduce spring twang.I'll send both with the package.This piston is not buttoned but I'll include old school buttons you can glue on if you want. You'll need to clean the piston REAL good and use NEW super Glue then sand to fit.You will NOT need to lube this assembley! It's all been done.
Any lube you use? You don't want much!That piston is slamming forwards and any build up will follow the laws of momentum.Just like a person in a car with no seat belt and the car hits a tree!Your getting bits and pieces of both off of something it shouldn't be on!Given you used a slap sander in your tube? Yep. I can see excess moly passing the round seal in a not round tube. Moly doesn't diesel much so it don't surprise me you may have missed it.It's more a smell thing with that stuff.
I don't care what Rocker says about you, Jeff. You're alright.
So everything is working better then?
Sure is fun seeing you keeping on with this tuning path!Wish I could get your freehand groupings!
My Sportsman is VERY hold sensitive. Even shooting from a bench, I have to place rests and sliding surfaces PRECISELY, and anchor the cheek in the same exact position, and hold the stock with exactly the same pressure, to get any kind of grouping.Others have FAR more shooting experience than I do, but it looks to me like you have the gun itself nicely dialed in... the rest is the hold.I'd have asked if you checked your screws, but that first picture shows two pretty close groupings. Can't imagine you'd get those with loose screws!One thing about cheek weld... I found that scope to be extremely sensitive to that! I put a piece of tape on the stock, so I could repeat consistently. I think it has something to do with exactly where the reticle is in the optical chain.