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Mentolio · Veteran Member

I recently took apart my Vantage NP (pronounced pain in the...you get the idea) to "lube tune" it. I thought "why not, it worked so well on my Browning Leverage!" It saddens me that this Crosman rifle I bought last May of 2013 would be so junky! The insides were a mess. To make matters worse, Crosman tells me that there is no parts diagram for the Vantage, because it's so "new." What?!? That's crazy...but they took their best guess and sent me a new piston seal at no cost...so I can't complain too much. I put it back together, and while it's smoother and seems a bit more accurate, it still isn't as fun as the Leverage. I modded the trigger, and it made it better, but then I bought my Chrony Beta. Now, I'm sad again...the numbers are just not what I expected. I'd say I did something wrong, but pre-Chrony data, I thought it actually shot a bit better after the rebuild.
I like to think I'm a realistic guy, and don't have crazy expectations, but Crosman says : "1200fps with alloy pellets." Ok, that says to me: will probably get close to 900-1000fps with lead, right? WRONG...

Test conducted on a windy (25mph gusts) and cold (36 degrees) day, with the Chrony set up about 1.5 feet from the muzzle. Tests were conducted with two pellets the gun has always seemed to like, shooting tight groups on paper. I only did two ten shot strings, as this was only intended to make sure the Chrony actually functioned.

H&N Terminator hollow point, 7.25gr .177: Low: 819.8, High: 842.2, Average:833.7, Extreme Spread: 22.36, Standard Deviation: 6.08
Ok, not exactly terrible...but shouldn't I expect faster? These are light pellets!

JSB Exact Diabolo Domed, 7.33gr .177: Low: 741.4, High:788.3, Average: 770.8, Extreme Spread: 46.94(?!?), Standard deviation: 12.24.

Now don't get me wrong, if the gun shot well, I wouldn't be very bothered by any of this data. The fact that my Browning Leverage shoots tighter groups, at almost the same velocities, slinging lead that weighs twice as much (.22 cal)...and I'm coming up well short of velocity data that others have claimed. Shouldn't that be bothersome? Has anyone here Chrony'd a similar model?

AirGunEric · Site Admin

You should be around 900fps using a 7.9gr pellet. This may be a matter of breaking it in until the piston seal mates better to the tube- output may very well come up.

That being said, over-lubing it won't help anything (not suggesting you have, but it does happen)- burnish the exterior of the piston with grease (burnish, not slather it on) and put some grease on the ends of the strut, fore and aft so it can "rotate" if need be. Lastly, lube the piston seal with silicone oil.

Mentolio · Veteran Member

Thanx AirGunEric, done, done, and done. I probably did over-lube the seal and chamber a bit, nasty habit from my days as a mechanic. I NEVER put an engine together that wasn't fairly well dripping with lube. Y'know, I can't believe I didn't consider "break in." I've got fewer than 50 (actually, a LOT fewer!) shots put through the Vantage since putting it back together. You may be right, as it breaks in, it will most likely pick up some velocity. I'll test again and post results after I throw a couple hundred more through it. Thanx again for the wisdom!

AirGunEric · Site Admin

As you mention "mechanic"- it might be something to think about- using a ball hone in the tube to create a cross-hatch and eliminate any potential other issues (burrs, bumps) might be worth the time (would also allow for faster piston seal break-in).

Mentolio · Veteran Member

Honed, just not with a ball hone. Gun is still new-ish (bought last may). I didn't mic the cylinder, but when I looked at it, it looked smooth with no obvious imperfections, other than a lack of cross-hatch (which I just assumed was a common oversight in Chinese guns, not assuming it was wear?). I ran a mandrel with red Scotch-brite pad on the end of it to put a light cross hatch into it (used it all the way to the back of the receiver, figuring a light cross hatch would help the rear of the piston stay lubed as well). I didn't want to get nuts with the cross hatch, as the piston seal is only plastic/nylon/something like that, and I wasn't sure how well it'd hold up when run across a "proper" (more aggressive cross hatch) honing job.

AirGunEric · Site Admin

The factory (and most airgun manufacturers in every/any country) do not hone their tubes- more work and they are either too lazy or don't believe it's necessary due to whatever high-quality standards they believe they have in place for tube production.

The piston seal is a harder urethane- i.e. 90D or slightly higher.

Mentolio · Veteran Member

Haven't played with this gun in a while, but recently took some new Chrony data. There are about 200 pellets through it now, and I have seen some improvement, though it's still not shooting anywhere near where I'd like. As an example I offer a comparison of the first shot string average vs. my newest, third shot string average, both with JSB Exact 7.33 domed pellets:

1st string average: 770.8fps, & about 100 shots later...3rd string Avg: 803fps

The first shot in my new string was also the highest at 835.9fps. All other shots were down hill from there. It may have been dieseling causing the first 4 above 800fps shots. The other pellets I've tried mostly improved, but by much smaller increments, typically by fewer than 10fps. I'm looking to get better than 800fps with this pellet, 900fps being my ideal number, which would get me to 13 ftlbs of muzzle energy. I'm not sure how realistic that goal is at this point. I could just keep on shooting it, and hope the velocity keeps increasing until it stops, hopefully at speed I can live with. I could also just rip the gun apart again, rebuild (again) in the hopes I did something wrong, and see what happens. If I'm very lucky, I may have over done it with the moly paste, as suggested by AirgunEric (that would be nice!).
I suppose I'll pull it apart and check the condition of the seal, unless anyone with more experience thinks that I may see a 100+fps increase in the next few hundred shots? Maybe more to follow...

EDIT: Almost forgot, in the 60 or so shots I took doing the Chrony testing, the Vantage ate it's fifth (5th!) scope. After the 60 shots, I noticed that the reticle in the Optima 3-9x32 scope I mounted had rotated about 45 degrees...sigh...

Mentolio · Veteran Member

So I tore the Vantage back down today and inspected my previous rebuild. Not too much moly paste, and the seal looked ok. So I grumbled about how lame this rifle is as I started lube and reassembly, then I noticed how easily the piston seal went back in. The edges didn't even catch on any of the cut-outs under the gun!
This "bad" seal is one that was sent to me for free by Crosman. I called to inquire about buying a new one, when I disassembled the gun initially and found all the crap and junk floating around inside. There was no (and still is no) exploded parts view for my model, so I started looking at other similar models for comparison. I called to see what Crosman thought, and the woman I spoke to said that since my gun wasn't that old, she'd figure out which seal was the right one, and stick it the mail.
Now I don't know what model this seal came from, or even if it is somehow defective, but I started looking at models like the Nitro Venom, and decided that the two models looked pretty much identical when it comes to the important stuff...so I ordered four seals for the Nitro Venom, and put one of them in today. I'll stick to "Average fps", "Extreme Spread", and Foot pounds of energy (calculated with AOA's online calculator) for comparison. I will also limit it to a few pellets for before and after:

Best readings with old piston seal:
JSB 7.33 Domed: Avg-803, ES-51.26, Ftlbs-10.5
JSB 8.44 Domed: Avg-736.8, ES-19.89, Ftlbs-10.18
H&N Barricuda 8.64 Domed: Avg-745.2, ES-18.44, Ftlbs-10.66
Crosman Ultra Magnum 10.5: Avg-654.1, ES-25.13, Ftlbs-9.98

Best readings so far (dieseling not included) with new Nitro Venom seal:
JSB 7.33 Domed: Avg-886.8, ES-26.37, Ftlbs-12.8 (+2.3!)
JSB 8.44 Domed: Avg-835, ES-24.33, Ftlbs-13.07 (+2.89!)
H&N Barricuda 8.64 Domed: Avg-832.7, ES-24.63, Ftlbs-13.31 (+2.65!)
Crosman Ultra Magnum 10.5: Avg-766, ES-7.71, Ftlbs-13.68 (+3.7!!?!!)

Somehow, the Crosman Ultra Magnum was also the most consistent pellet BY FAR!?!? It had the best extreme spread, and the third highest FPE of all the pellets I tested. I sincerely hope they are accurate, as they have proven to shoot poorly in the past from this gun. In the past this gun seemed to perform best with a pellet that "just fit," and shot poorly with "tight" pellets. Hopefully this new-found power makes that untrue. By the end of my Chrony testing, the gun had 106 shots through it. It took about 30 or so to stop dieseling and start acting like it was settling down. Accuracy tests next, WOOOT!!

MikieG · Member

When I did my rebuilds I used all factory parts with a slight coating of molly lube on the sides of the piston seal.
within a couple hundred shots I noticed the rifle lacked the oompf to unseat pellets from the breach.
When first rebuilt the rifle chronied at 850. After a tin of pellets it chronoed at 560. So I dropped 4 drops of nonflammable synthetic paintball lube thru the transfer port. A few strokes of the barrel and it noticeably was smoother. Then the chrono revealed consistent 960 ish speeds. So it shows you can definitely under lube a rebuild.

AirGunEric · Site Admin

Moly "lube" does not lubricate piston seals- if it gets to the piston seal, it will leak to the other side, into the chamber and burn off- silicone oil is the appropriate lube for piston seals in springers (which is what many paintball lubes are as well).

I do not believe anyone has ever actually established that "moly" really does do anything in a spring-type airgun environment except possibly as a temporary problem "cover up" on slightly damaged tubes. Molybdenum is a spacer- i.e. a scratch filler that 'sticks' to things- i.e. metal- quite well. Perhaps in a worn-out tube with excessive scratching where seal leakage is a problem, it might assist temporarily until it burns off- but the proper lubrication of a tube and piston with any lube is to burnish the exterior of the piston, not soak it in grease. The spring and spring guides I can't see moly having any useful effect on.

In my view, the use of moly is a remnant of when people somehow believed a "polished" tube was a good idea (it's not, for a piston seal to mate to a tube properly the tube should actually be honed, much like an engine cylinder wall) and the going theory was that the slipperier the tube, the "better" things were. An idea and theory which is really not correct.

My only point is people can save their money and avoid moly lubes. Looking at it from another point-of-view, if it was a useful/practical idea, at least one spring airgun manufacturer somewhere in the world would use it (none I have ever heard of use it)- especially on guns costing $500+ where 50 cents worth of specialized lube would hardly be a cost consideration worth speaking of.

MikieG · Member

Glad you got that off your chest! My sourses were Peter the gunsmith at Beeman, various writings of a guy they call B.B. Pelletier and the gunsmith at Pyramid.
I guess you might call these guys and educate them on the woes of moly.
As a matter of fact, I would love to read your book or maybe visit your website, or even call the airgun shop you work for to discuss the proper lubes that should and should not be used.
The point here is that no matter what lubes are used, you can go too far with sparingly. A dry cylinder in front of the seal seemed to not work well with my polished and unscratched powerplant.
Something has to be in there or a new piston seal will drag and burn.

AirGunEric · Site Admin

I'm glad they all have this view that molybdenum is a wonderful idea- maybe when they can show us their degree in mechanical engineering with a specialty in metallurgy and/or lubrication, their books and views on the subject might carry more weight.

Go ahead- find something silly like "evidence" that moly in a springer does something useful. I think you'll waste alot of time looking, but not finding.

Also, stating a view doesn't justify such a ridiculous commentary trying to make it appear as if I have no idea what I'm talking about- perhaps you should do a bit more research on things before making such comments ("let's see your website", "call the airgun shop where you work"- I'm not sure if I should be laughing or crying about the ignorance in those statements). I might also point out there are many people with high levels expertise in areas such as airguns that neither write books on airguns or run an airgun repair business, some of them right around here. At least a couple of them likely have forgotten more knowledge than some of the published "experts" will ever know (and no, this is not in reference to myself, but others around here).

You may note that nobody said not to lubricate your piston seal, I very plainly stated that the use of silicone oil, which is what most paintball lubes are, was appropriate- where were all your "experts" and their moly advice when you were shooting 560fps? Perhaps you also missed it, but you must re-lube your seal every few hundred shots with the silicone, otherwise what you describe will occur again- all that wonderful moly isn't doing a darn thing for you.

Really, I am basically daring you- go look into molybdenum lubes and what they actually do or do not do (also note, all molydenum lubes are not the same, the "base" lube is one thing, the molybdenum is added to the base- so unless you can define the quality of the base, there really is no data on its lubrication capabilities)- then you come back and educate us all on why it should be "the" lube for spring-powered airguns.

Mentolio · Veteran Member

Oops, looks like AirGunEric beat me to the post! Wink

Moly paste: something I never used alone as a lube, before airguns. I have mixed it with oil, to thicken up the oil or thin out the moly, which I may add a few drops of oil behind the piston to see if it frees-up a little (though I suspect it'll just make a mess). As mentioned above, Moly paste seems to be the favorite among several "experts" online, so I'm trying it on this gun. While I didn't use moly on the seal (I only used the silicone chamber lube on the seal itself), it did scrape a little residual moly along with it into the chamber...smelly, smokey, and loud dieseling for about 15 shots.
The point: it IS recommended by several recognized experts, though I must agree with Eric that as a lube, it seems to be a little lacking. It sticks well to metal, and doesn't sling-off and splatter like other greases can...it stays put better than most. I think it is also fairly resistant to temperature changes as well? Time will tell for sure. It might be nice if one of these experts would mention WHY they like moly paste, though to date I don't believe anyone has.
When I rebuilt my Leverage, I used a lithium based wheel bearing grease to lube up the spring and other moving parts, and that gun works great (though it does still smoke a bit, even after hundreds of shots).

AirGunEric · Site Admin

That would be the problem- all the experts with the view that moly should be used have rarely hinted at the "why". You are correct in that it clings to metal quite well, and is less prone to slinging/flinging- but its carrier- i.e. the grease (or oil) in which it is resident is. The best that can be hoped for is that the molydenum comes in contact with the metal through the lubricant/moly mix, sticks to the metal and then do what it does- fill small gaps. From a practical standpoint, if there are imperfections in an airgun tube where molybdenum would be useful, the carrier (the "lube") would then coat the metal again and deposit more moly as it is worn off.

The big question in all of this is; is there a 'defect' of some sort where molybdenum would be the "repair" however temporary? I just don't see it, gouges will ultimately rip seals or if not in contact with a seal, wear down as there is metal-metal contact, small creases or other minor defects might be aided by molybdenum, but if such small metal creases exist, honing the tube would seem to be the proper way of resolving the problem, not a "cover up" with molybdenum in a lubricant carrier.