Tune in a Tube for Springers?

[subscriber]

I'll start another thread when I start the experiment.

Link to Ron's new thread:  https://www.gatewaytoairguns.org/GTA/index.php?topic=192358.msg156229068#msg156229068

[nced]

Wow, Ron

Thanks for taking this on.  Removing Krytox and replacing that with cheap grease seems "backwards".  If you do this, you will be able to tell us if there are indeed dragons, and if so, how large they are.

If you primary goal is to quell spring twang (rather than test sticky grease), then adding a plastic heat shrink tube over the spring guide might be an alternative to try.  Or better yet, turning a custom guide from one piece of material.

What sells grease as a de-twanger is that you don't have to strip the airgun (unless you already have Krytox).  Or, that you don't have the means to make a tight fitting spring guide.

An objective study into the effect of grease on thermal velocity stability and vertical stringing will be very useful to this forum.  We don't have a lot of real data about this.   I believe that Ed (nced) has tried several springer lubes before settling on Krytox.  He has quantified pellet drop changes as a function of temperature with regular grease at 55 yards, with at least one of his HW95s, shooting FT.  Perhaps Ed might weigh in...

"grease on thermal velocity stability and vertical stringing"
When I first tested Krytox GPL205 several years ago one of my first tests was to see if temperature changes affected velocity of my Krytox lubed and oring sealed .177 R9. A few years prior when I used "spring tar", molly paste and a factory R9 piston seal I experienced a 1" at only 20 yards poi shift from early morning when I did the sight-in during snow flurries and about 3/4 way through the match when the temp rose to the mid 50s. The match was during the early season in Virginia when the early spring temps are variable. Assuming that the poi shift was due to lube viscosity changes I stripped the spring of all "tar" and the receiver of all molly paste, then relubed sparingly with only molly paste. This did help some but I theorized the old style HW parachute seal combined with the molly paste was changing durometer affecting the poi. At that time I experimented with turning an aluminum oring seal holder to replace the factory piston seal and the oring sealed piston cap greatly reduced the poi shifting. Matter of fact, with the oring sealed piston cap the R9 only required a couple "warm up shots" to stabilize the poi instead of the previous arrangement that required about a dozen warm-up shots to stabilize the poi. This was a great benefit when squirrel hunting with my brother and I still use a home turned and fitted oring sealed piston cap but switched from molly paste to Krytox years ago.

When I first moved to NC I tested the Krytox lube by leaving the R9 in my unheated sun room over night when the temp dropped to the 20s, then directly taking the gun to the chrony and measured the velocity. The next day the R9 was left indoors at about 70 degrees and again the velocity was measured. I don't remember the velocity but I do remember being surprised that the velocity during the 20 degree average temp was 10 fps higher than the 70 degree temp. That was enough to convince me that non-dieseling  Krytos was useful for my R9. Later I bought a .177 HW95 on sale from AOA for $299+shipping and noticed that it had the newer design HW thick parachute edge piston seal and found that the newer design seal performed almost as well as mu oring sealed piston cap giving up only 10fps velocity when lubed with Krytox. I still use the piston caps in my R9 and HW95 because I like a "non-eroding/cracking" seal face compressing air through the transfer port..........



Here is my very first oring sealed piston cap after a roughly 1500 shor testing to determine if there was any "impact damage" on the face. Nope, only combustion products from the diesel prone molly paste I used at that time........


Anywhoo........the "air density" changes with the temperature can affect the trajectory of the pellet so I'm convinced that velocity at the muzzle has more bearing on trajectory that shooting longer distances in different temps.