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Education / Training BB’s Christmas gift: Part 3

BB’s Christmas gift: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

Sheridan Supergrade right
Like all Supergrades, my new rifle is graceful and attractive.

Part 1
Part 2

A history of airguns

This report covers:

  • Wise council
  • A special technique for old multi-pumps
  • Is it holding?
  • Test one
  • How is the pump lever?
  • Test 2 — stability
  • Conclusion

Today I’m recovering from the cataract surgery, but I wrote this on Wednesday, so I was still functional. What I thought I would do is try a little experiment that could work. If it does, I will have found a new technique for restoring an old Sheridan Supergrade. Read Part 2 to learn why this multi-pump is so different from all the others.

Wise council

Before I begin, following Part 2 of this report I heard from airgunsmith Tony McDaniel of TMac’s Airgun Service in North Carolina. Tony is the guy who hosts the North Carolina Airgun Show each year (it’s on Oct. 20 & 21, 2017), and the registration form plus show info is on his website.

Tony told me he has worked on a couple Supergrades in the past and one thing he has noticed is the pump arm sometimes comes up after pumping if the inlet valve has a small leak. That would lett compressed air flow back to in front of the pump head, no matter what the head clearance is.

In Part 2 I said it was the pump piston head clearance was causing the pump handle to rise after the first few pumps, and it can be that, but if the inlet valve leaks you will get the same result. One way to test it is to fire a pellet immediately after 5 pumps and then pump the gun 5 more times and wait 10 minutes to fire again. Some velocity is lost through the dissipation of heat from compression, but my testing has shown that that velocity loss is small — perhaps less than 20 f.p.s. If you have a larger loss the inlet valve may be leaking.

One additional thing. Sometimes the inlet valve may leak down to a certain pressure and then seal completely again. The loss of velocity will then be consistent from test to test. Figuring out which it is — the pump head clearance or a leaky inlet valve — can be tricky, but if what I’m showing you today works you may not need to worry about it.

A special technique for old multi-pumps

A reader suggested I try this. He said since I was having such success with Automatic Transmission Sealant repairing leaky CO2 guns, I should try it on the Supergrade. I have tested this stuff over many years and it does not turn o-rings to mush like some people fear, so I believe the risk to the rifle is very small. Therefore, what is there to loose? So, at the beginning of this week (three days ago) I put about 20 drops of ATF sealant into the Supergrade pump tube, ahead of the pump head, and worked it through the valve by pumping and shooting the rifle several times. Then I let the rifle sit with 2 pumps of air in it until today. This will either work or it won’t, but if it does, there are a lot of Supergrades in the same shape as mine that can use it!

Is it holding?

The first test is to find out if the rifle still holds those two pumps I stored it with three days ago. And the answer is, yes, it was still holding. There’s no way to determine if it held all the air that was pumped into it, so this is not a conclusive test. The rifle also held air before I added the ATF sealant, so this also isn’t confirmation of anything. It just makes me feel better. The next test will be far more telling.

Test one

I will run the same first velocity test that I did in Part 2 and compare the numbers. That is testing the velocity with differing numbers of pump strokes, up to the maximum of 8 pumps. This test is performed with 14.3-grain .20-caliber Crosman Premier pellets that are no longer available.

Pump…….Vel. before……Vel. today
5……………..383/353……   .475

I would call this test a positive result! The velocity increased with almost every shot and with each shot I could see excess ATF sealant blowing out the muzzle. So I know all the seals are coated with it.

I tested the rifle by cocking and firing a second time after 6 through 8 pumps and there was no air remaining in the reservoir. So the exhaust valve is performing as it should.

Shots 6 and 7 are a small puzzle. Considering the velocity of shot number 5, shot 6 shouldn’t be as fast as it is and shots 6 and 7 should not be the same velocity, but I’ll take it.

How is the pump lever?

Now I wondered how the pump lever was doing after each pump. Was it still climbing up when I opened it, or was it sitting relatively low and stable? If it sits low and stable, the former problem of it climbing was more than likely a leak at the inlet valve, as Tony described. If it still climbs as it did before, the pump head probably needs some adjustment.

It still climbs. Starting after the third pump stroke, the handle climbs just a little more each time it is opened. I therefore think the problem is with the adjustment of the pump head and not with a leaky inlet valve. At least now I know.

Test 2 — stability

This is where I learn how stable the rifle is. I’ll shoot 5 shots on 4 pumps each with the same Premier pellets.

Four pumps


The velocity dropped in this test with 4 pumps from what was seen in the first test, but I’ll tell you why I think that is. Notice how the velocity climbs with every shot in this test? I think the pump head is warming up as I pump. The rifle had sat dormant for 15 minutes since the previous test. In other words, it does best with use.

I also continued to see ATF stabilizer being blown out with each shot. I think the seals inside both valves are well saturated with it and that they will continue to be conditioned for some time to come.


I had planned to have this old girl resealed, but after this test I don’t believe that is necessary. However, this is just two tests on one day. My plan now is to proceed on to the accuracy test, once my eye has been fixed.

Do you see why owning a chronograph is so important? Today’s report backs up yesterday’s report.

I think I will retest the velocity again, just before I shoot the rifle for accuracy. That will determine whether the “fix” is holding. If it is I think Sheridan Supergrade owners everywhere have a new trick to put in in their toolkits!

author avatar
Tom Gaylord (B.B. Pelletier)
Tom Gaylord, also known as B.B. Pelletier, provides expert insights to airgunners all over the world on behalf of Pyramyd AIR. He has earned the title The Godfather of Airguns™ for his contributions to the industry, spending many years with AirForce Airguns and starting magazines dedicated to the sport such as Airgun Illustrated.

60 thoughts on “BB’s Christmas gift: Part 3”

  1. Everyone,

    I’m sitting here at 3:35 in the morning, wondering why no one has commented yet. This post went live on time this morning. This discovery is a big deal!

    The good news is, my eye continues to improve by the hour. It is coming and going, but there are times when it is nearly back to where it was. I see the doctor who performed the surgery this morning and I’m going to give her an autographed copy of my book, “BB Guns Remembered” as a small thanks for what she did.


    • RR,

      There we go! I knew you were out there.

      Yes, the old girl seems to be happy again. I will continue to monitor her health as the report advances, but if this treatment really works, it is a major discovery. Think of all the Supergrades out there that can use it!


      • BB,

        This is my normal time to greet the day. If I am not sleeping as soundly as usual, I drop by earlier.

        Maybe one of these days I will end up with a pumper. When I bought my first air rifle at the Roanoke Show, I teetered back and forth between a 397, a 392 and a Gamo CFX. The CFX won. Now years later and many hand pump strokes feeding a Talon SS, an Edge, a Rogue and an HM1000X, I am not so sure I am anxious to add a pumper to the “collection”. We’ll see.

  2. B.B.,

    🙂 I am here and would have commented a half hour ago. I was trying to find a picture of the pump head adjustment,…. which I swore I recently had seen. Will you be doing an adjustment prior to the next testing?

    Those are some very impressive improvements! Now we know. The chrony was invaluable. While it only stands to make common sense,…. (saving the data) and conditions/test parameters is key to future chrony/gun testing. I have several notebooks with targets and chrony data for all of my air guns.

    Nice job! Glad to hear the eye is doing good also. Can’t wait to hear how things are a couple of weeks from now. Your reporting on the eye condition is good info. for something that we all may/will face in the future.

    Good Day all,…… Chris

  3. B.B.,

    I asked about the archive section at the bottom the other day and wondered what had happened to the old (back to 2005) articles. Well,…. they are still there! Right there! Now, instead of having them all displayed,… now you just to mouse over them and scroll. Just an FYI for the other reader’s.

    You answered but I do not recall you saying that. Perhaps an addition to the script prompting readers to use scroll?


  4. Glad to hear the eye is doing great. That surgery really does work well.

    Question: Does The History Of Airguns section cover the back blog issues going back to 2005? I had also wondered about not seeing them under the Archives.

  5. B.B.,

    Read the article as soon as it was posted which is just after lunch for me in my timezone. Refrained from posting as that I thought you would be resting.

    Clear illustration regarding the utility of a chronograph especially the before and after. Considering the amount of ATF sealant you put (about 3ml which I guesstimate from 20 drops per ml) how long/ how many shots will it take to stabilize the old girl?

    You did mention that having diagnosed it was the pump head clearance that had to be adjusted you were wary of marring the gun. Considering it would not be your daily shooter I would not bother with the adjustment. It is enough for me that it is back in shooting condition.


    • Siraniko,

      How long is a question I won’t know without a lot more experience. I would guess this is a semi-permanent fix, or at least that is my hope.

      My reasoning about fixing the pump head clearance is exactly what you explained. This rifle is just too valuable to risk damaging.


  6. Hi B.B.,

    Been AFB (away from blog) a few days and didn’t realize your surgery was so imminent. Glad it went well, thoughts and prayers your way for a quick and full recovery. Take care.

  7. B.B,
    Thank GOD for your successful operation. Prayers answered. I have to get my right eye done later this year. No wonder I was missing all those shots.lol!
    Don’t rush it we will all be here for you.
    Thanks for all the good work to promote the sport.
    Live long and prosper.


  8. B.B.
    If possible, as the Supergrade saga continues, could you slip the occasional compare and contrast of it to the currently available 392/397?
    There is just something enticing about these beautiful pumpers, and the 392/397 is probably as close to the supergrade as many of us will ever get.

    • Belgrath04,

      Well right now I will say that the current 392/397 is equivalent to the Supergrade in both power and accuracy. They are driven by their retail prices today, but a day will come when they are no longer available, and then the prices will rise.

      What I’m saying is get one if you want one, because they will hold their value.


  9. Great stuff, B.B.! If my old C-model Sheridan gets tired, I will try using ATF sealant before going for a reseal. I’m glad it all worked out for you; you’ve got a beautiful rifle there. Keep up the good work! =)

  10. B.B.,

    I have a Crosman 2200 Magnum that has issues with the pump handle flying open on 10 pumps. I thought it was because the projection on the pump arm that is tasked with holding it closed has worn away, to some degree. My solution was to screw a small sheet metal screw into the end of the handle so that the spring loaded ball in the receiver would bear against it. (I was not concerned with how my mod would be viewed by a future collector/buyer as, obviously, you have to be) It worked, but it didn’t even occur to me that there shouldn’t really even be any air present to push it open in the first place, until I read today’s blog. Do you think a head space or inlet valve leak could be my problem? (Is the 2200 design similar enough to your Supergrade?)

      • BB,

        Thanks for the quick response, but shouldn’t you be resting your eye? You are correct, again, there is no adjustment so I’ll just live with my “screwy” repair unless you think letting a shrunken head alone will damage the gun further. (just read that back,wasn’t trying to be funny) Also, if I wanted to replace the head (“I ain’t afraid ah no disassembed air gun! ” ) is a replacement available?

  11. As a Side Bar, everyone should read Hard Air Magazine’s comparison of Gas Piston versus Spring air rifle report. i could not agree more with their opinion..
    PZ1 ( aka:Pete ) in Old Town Orcutt., California

    • PZ1,(aka:Pete)

      I just signed up for Hard Air Mag a few days ago and got a confirmation email but no mag. Do they email those or do I go to a web sight ? Thanks, in advance.

      • Halfstep,

        I think that just signs you up for their email list, plus it gives them a count on who is following their postings, which they can then show to advertisers and sponsors.

        Stephen Archer and the gang do a great job of bringing us news points, articles and reviews of what is going on in the world of airgunning. I usually check HAM at least once a day for updates.

    • Pete,

      My meager experience coincides with that of Stephen Archer. I think the main issue is the manufacturers are using the most powerful gas springs they can. If they toned it down a bit, they might work quite well. To the best of my meager mental capacities I can only recall BB singing the praises of only one gas sproinger.


      I can see me getting the Luxus.

      Every once in a while someone will bring out a gas spring that can be adjusted. Unfortunately the powerhungrymaxvelocityfreaks get their hands on them and pump them up to the point that they ruin them and the manufacturers have to take that option away because of warranty and liability costs. That has happened to Theoben and others. I would love to have a top shelf gas sproinger I could tune.

      • . Thank you, RR, your response tops it off.. I have never used a gas piston air rifle one reason the cocking cycle had no appeal for me.. Another was B.B. and his blogs and people such as you, RR that have vastly more experience than this old 88 year old has..in air guns.
        Best regards, my favorite air gun brand is WH…The TX200 is just too heavy to even consider.

        • Pete,

          That is something I have considered with the TX. Although the TX is absolutely gorgeous, especially in walnut, and shoots like a dream, it is right heavy for carrying around. I myself am seriously considering an HW95. I can get one new for $315. At that price I can probably afford to have a real nice stock made for it should I decide to dress it up a bit.

          • If you can buy a New in the Box HW95 at $315, grab it for sure ! I love HW and I believe a HW 50 would be my choice because of lighter weight and lighter cocking effort. Any HW is an heirloom like Patek watches…..

  12. First things first……WOW that is really great about the eye surgery outcome.I’m right there with you on the gratefulness post-surgery.When the vascular surgeon saved my leg…..I too felt the need to give a gift to express that.I gave mine a Case XX carbon fiber Trapper that I had sharpened and polished to a ridiculous level!! I figured if ever a guy could appreciate an insane edge it would be a surgeon.:)
    Too funny that you gave an eye surgeon a BB gun book.I hope the work you put into it is realized.I remember how long you have been working on it.
    Phenominal that you are getting a good result with the ATF conditioner on (of all things MSP) a Supergrade! I was really irked at the reaction on other forums last time when you offered this up as a potential cure for some leaking Co2 airguns.It was as if you claimed Cheeze Whiz cures cancer! What the HECK is SOOOO controversial about using seal conditioner on seals???? LOL Anyway……keep on the mend.We all need you my friend. FB

  13. I am going off subject with this one, but I cannot help myself.

    Woohoo! I’ve got air! My Air Venturi air compressor will be here Tuesday! I am really going to be able to feed that big bore air hog now! I’ll be able to save my hand pumping for my Edge!

  14. B.B.,

    Ya-hoo! I’m grateful that your surgery has gone well, and am looking forward to all you will do with your repaired vision!
    We’ve been busy evaluating the new Air Venturi HPA tank for CO2 guns, as well as the Umarex Throttle. Will report some results and impressions soon, hopefully next week. Will probably have some questions, too.


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