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Education / Training The Pump-Assist Benjamin 392 – Part 3

The Pump-Assist Benjamin 392 – Part 3

by B.B. Pelletier

Part 1
Part 2

First, some news about Blogger that’s affecting all of us. Blogger must have made a software change recently that has screwed up our postings. They now take a very long time to show up on the website, and so do your comments. Several of you have had comments refused by Blogger.

We have contacted Google and are working to correct this problem. Please be patient and know that we are aware of what’s going on.

I tried to correct the velocity for 7 pumps with the modified gun in Part 2, but Blogger kept reporting the incorrect version of the report. The correct velocity was 563, not 663.

In this third report I will tie up the loose ends of this report on the modified Benjamin 392 and do a test for accuracy.

What about the velocity?
Loose ends first. I contacted the inventor, Bob Moss, and he tells me that he tested all the guns before modification. The .22s were doing 580 with a 14.3 grain Crosman Premiers, and the .177s were doing 660 out of the box with Crosman Premier 7.9-grain pellets. The advertised speed in .177 is 800 f.p.s. I don’t have a .177 to test, but I did test my .22 with lighter pellets. Here are the results:

11.3-grain .22-caliber Skenco synthetic pellet

8 pumps………638 f.p.s.
9 pumps………670 f.p.s.
10 pumps…….682 f.p.s.

That demonstrates that the rifle can do the advertised 675 f.p.s., though not with the recommended number of pumps. I did fire the rifle following the 10 pumps and there was no air left in it, so I have a rifle that works with 10 pumps. I’m pumping this gun 10 times because I’m testing it. Neither Crosman nor Bob Moss recommends going over 8 pumps.

What happens to the warranty?
The Crosman warranty goes away with the modification, so Bob Moss gives you a written one-year money-back guaranty with your bill of sale. As I mentioned in the last report, the inside of the gun hasn’t been touched, so if it lasts longer than a year, it should be repairable by any repair station down the road. In other words, except for the easy pumping, the gun remains unchanged from a stock gun.

How much?
Bob sells this gun for $265, plus shipping. His modification ends up costing around $125 more than the base rifle. Of course, when you buy from him you get a brand-new rifle that he has modified. He is really giving a lot of value for the price. If you look at the work he has to do to mount his modification – disassembly, silver-soldering the anchor patch, reassembly, testing and refinishing the gun, plus the cost of the parts, he isn’t getting rich! On the consumer’s side, though, this is a $265 Benjamin 392. You really have to want the lighter pumping effort for it to make sense.

And accuracy?
My 392 has it in spades! It’s as good as my 1978-vintage Sheridan Blue Streak, which is very pleasing to me. I used the open sights that, once adjusted, hit right above the aim point at 10 meters.


Any time this 60-year-old man can shoot a 5-shot group like this by sighting through open sights and his bifocals, the rifle is accurate. JSB Exact 15.8-grain pellets on 6 pumps.
Turtle asked me whether or not the new 392 will replace my Blue Streak as a “go-to” airgun. That’s hard to say, because my wife has a 50 percent share in the decision. But now that I know where the rifle is sighted, I’ll probably use it from time to time.

Where do you buy it?
Pyramyd AIR doesn’t offer this modification yet. To get one, you need to go directly to the manufacturer. Bob’s website is http://airchanics.com/. Follow the instructions found there.

I may do a follow-up on this rifle down the road, just to let you know how it holds up. If I seem to forget to do that, one of you should remind me.

43 thoughts on “The Pump-Assist Benjamin 392 – Part 3”

  1. Hia BB,
    I’m thinking I might need one of these 392’s. I’m just a bit concerned over the missing velocity. Could it be he received some tuned down rifles ment for the UK. When I bought mine, I remember seeing some boxes marked with a sticker, stating that they meet UK guidelines. My dealer did not know why. Go Figure.

    My Silver Streak is shooting .20 cal. 11.8 grain HN Match at 530 FPS 3 pumps and 732 FPS at 8 pumps.

    As Always
    Thank you for the blog
    Joe G from Jersey

  2. Hia BB,
    I’m thinking I might need one of these 392’s. I’m just a bit concerned over the missing velocity. Could it be he received some tuned down rifles ment for the UK. When I bought mine, I remember seeing some boxes marked with a sticker, stating that they meet UK guidelines. My dealer did not know why. Go Figure.

    My Silver Streak is shooting .20 cal. 11.8 grain HN Match at 530 FPS 3 pumps and 732 FPS at 8 pumps.

    As Always
    Thank you for the blog
    Joe G from Jersey

  3. Hi BB.

    It would be interesting if you continue posting stuff about spanish made air rifles, like the one you reviewd, the Hammerli Storm (made by Norica).
    Spanish guns are well know for the quality tey put on the guns, the Norica Marvic Gold (sold in US market as Hammerli Razor) may be a little overpriced comparing to Gamo guns, but the Norica gun really put the Gamo one on the pocket in terms of construction quality and reliability.

    Gabriel Brazil

  4. I think there is something wrong with that benjamin, my silver streak does 635 fps with 8 pumps and 14.3 pellets (benjamin cylindrical) and a 392 of a friend is giving the same numbers with a 14.3 Crosman Premier.

    For 11.3 grain the velocity seems very low for me.

    By the way I’m about 1500 feet over the sea level

  5. It’s important to note that the 392 is a BENJAMIN and the Silver Streak is a SHERIDAN. They are different rifles, though there does seem to be a lot of commonality.

    There are possibly differences in the valves that make this happen. I didn’t think irt was so, but Bob Mosss tested many 392s and 580 was the average with Premiers.


  6. BB, I have removed the paint fron the last 1.5″ of the barrel of my late model Sheridan 5mm. There was quite a bit of resistance in that last bit. I took out the bolt and used a very thin wooden dowel to push a pellet down the barrel and you can feel the major resistance once the pellet reaces the paint.

  7. B.B.

    I have a question about the Plano non-scoped double rifle case that I received from Pyramidair. The description says that it is lockable and airline approved, but I don’t see any way to lock it. There are four clasps down the length of it that shut securely enough, but you flip them open by hand without any locking mechanism that I can see. What am I missing?

    More generally, do you have recommendations about transporting airguns when flying? Is it enough to check them through in a gun case? And should the gun case even be locked? I seem to remember a sign somewhere saying that locks on luggage will be broken. I guess that would rule out another gun case that I have with a combination lock, and it also makes me very concerned about the safety of the guns. I want to exercise my right to transport pellet guns but certainly don’t want to tangle with the TSA if I can avoid it. Thanks.


  8. I am sorry to say I did not Crony before and after. I did on my HB22 and it went up by 56fps ave. The POI alos is now on vs before it shot 1.5 in left and I could not change the windage on the rear sight without modification.

    In the old days the Racine Sheridans had no paint in barrel see my pic of Racine Blue Streak here:

    Now it is SOP to not plug the barrels before painting I guess. Here is my newer Sheridan after paint removal. Note the brass. It should show the brass and be apparant, don’t you think? Here is the pic link:


    Taking out the paint was a step forward in improving the group size. I like 5 pumps and CP’S 0.20


  9. BB, By the way I did get some improvement on my RWS 36 0.22 problem child. There is a clue in the photo.


    I do get these groups now as tipical. Note the lower left group. I usually get one flyer though runing the group. I still will proceed to acuglas bed the stock now I have major improvement.


    I can’t get the links to work directly. you need to past them in the browser and hit go. ??


  10. Matt,

    You have NO CHOICE but to lock your gun case when travelling by air. It’s federal law. Check with the airlines before taking a trip with an airgun, because there may be other requirements. I do know you have to personally stand while the TSA inspects the gun, then YOU have to lock the case in their presence.

    As for the Plano, some cases have lock hasp loops cast into the case at places other than the latches. You slip the lock through the holes and the case is locked. Use at least two locks when locking that way!


  11. B.B.

    Thanks for the info. This is certainly stuff I want to know beforehand.

    Another equipment question. I own two peep sights, one that came with my UHC Super 9 airsoft rifle and the other the Daisy Avanti precision sight that I ordered for the IZH 61. Both are distinctly dark to look through. The UHC sight–a real cheapo–is practically unusable indoors and the Daisy sight is borderline even after changing my lightbulbs to 75W. Are peep sights supposed to be like this? I ordered the Mendoza, which one Pyramidair comment complained had too big of an aperture, to see if that’s any better. Thanks.


  12. Matt,

    All lights should be off except on target and the shooting area should just be light enough to see to load safely. In matches, they often use 500 watt target lights becausse the room lights must stay on.

    You want the aperture to be as small as possible. However, with upgraded rear sights like FWB ($400+) you can install an adjustable rear aperture that can be “tuned” to the room lights. I use one, but I don’t know that it fits on the Daisy sight. Probably not.


  13. B.B.
    With my eyes, the smaller the rear aperture is, the closer I can move it toward my eye and still keep everything in focus. It also gives me a longer sighting radius.
    Small aperture, close to the eye, is that what usually works best?

  14. B.B.,

    I’m thinking about ordering a scope with a 30mm tube and a 50mm objective lens. I was looking at 1 piece mounts but I want one that is adjustable. I see B-Square has the 17130 mount but it fails to mention the height. Would this one work or are there others that would work better? I’m thinking a high mount would be appropriate. I plan on using it on several different air rifles where loading isn’t an issue. Any help would be appreciated. Thanks.


  15. B.B.

    This Bob Moss modification is neat stuff!
    You could always mount a PSI gage on each Benjamin rifle – and compare PSI to PSI. Too bad they can’t handle more pumps – you might have a “PCP Benjamin 392” if it could handle 30+ pumps. Neat article!

  16. Thank you for your enlightening report regarding Bob Moss’ modifications! I’m all pumped up, if you’ll excuse my use of the word.

    Before you wrote of Mr. Moss in August, I’d been examining the Mac1 Steroid modifications. Is there a chance you will be able to compare and contrast those two treatments?

    They both promise me easier pumping, something I find increasingly attractive as I age.

    Thanks again! I just filled out the Pyramid customer query and put in a good word for you under both names.


  17. Shawn,
    This is quite a coincidence because this afternoon I received a B-Square 17130 from Pyramyd to mount a 3-12×50 scope on my Diana 54. I’ve got it mounted but haven’t done the final adjusting and sighting in yet. The actual diameter of the objective bell on my scope is 2.44″ (62mm), and it clears the receiver by about 3/16″. With the lens cap on, there is still about 1/8″ clearance; plenty. This mount measures 4-3/4″ long, so make sure your scope has that much straight 30mm length. I think most scopes do. The 17130 also has a sturdy stop pin built in.
    Hope this helps,

  18. Pestbgone,

    Thanks for the reply. I was looking through Pyramid’s scope mounts for the 4th or 5th time and happened upon the B-Square 2 piece riser extension base. Knowing my luck, when I elevated the back of the mount, the bell would drop too low in the front. I think this little extra might help if that problem came along. I plan on switching out the scope onto other rifles so this might be useful to have around.


  19. Matt,

    I have had that same gun case for years now.
    I am lazy, so I just lock it by slipping an ordinary Master padlock around the handle, where the two halves of the case meet.
    It’s not perfect, but it makes it a PITA for someone to plunder.
    Alternatively, you could select some small padlocks with thin shackles, take a drill bit of the same diameter as their shackles, then drill through the case right behind the closed slide latches.
    Then, you could simply slide the latches to the closed position, and snap the padlock through the drilled holes to stop the slides from opening.
    That would definitely be a more secure method of doing it.
    You could use either two or four locks, but if you use only two, I recommend doing the mod/lock on the outermost two slides.

  20. FWIW, to those of you asking about having to type in the authentication code twice:
    I discovered that small quirk long ago, and I figured it out.
    That code expires after approximately five minutes.
    I know this because if I start posting soon after I open the blog comment page, I need type it in only once to post.
    If I spend time to read the whole blog (remember the 70+ replies just a couple of days ago?), I have to type it in twice.
    That’s not a bug, it’s a feature.
    It’s a small price to pay to prevent slimey automated spammers from invading this blog.
    I have no problem with that.

  21. fflincher,

    I have tested a Steroid Streak, so reporting on it isn’t difficult.

    There is really no comparison between the two modifications – one is for power while the other is for effort reduction. But it might be interesting to do the Streoid.


  22. I think the pod cast is pretty cool. Althought the blog, now indexed, is extremely detailed and helpful. Tips at pyramydair are very useful. Was expecting BB info page to say TG. Always wondered about that….I’m glad you did confirm our guesses.

    Difference between CM Pellgun oil & CM Silicone is an often asked question in a lot of AG forums. One diving instructor explained the difference and I am glad you did too.

    I’ve never tried the Beeman silver bear .177 pellets, but found some similar looking coated hollow points at a local store (Beeman 1222) made in china or germany and have helped reduce my 10M groupings with a stock CM 2100 down to 2 to 4mm and CM 1377 around 5mm both with simple 4x scope of course.

    My cm quest 800x does well with H&N baracuda match (beeman kodiak) or CM premier hollow points. Generally I can get 5 to 9mm at 10M.

    All groupings usually 3 to 5 shots c-t-c. One inch = 25.4mm.

  23. Tom,

    I’ve read that you can use a mirror to optically center a scope. Is this method as effective as using the box technique and turning the scope that you mention in your blog?


  24. Off topic a little. I got a Crosman Phantom as a gift and cant seem to get the scope to stay accurate for more than a few shots using premier in the tin pellets. Do I sell the gun, buy a new scope, or learn to shoot better? im on a budget, and like to shoot targets and possums.

  25. Remote diagnostiocs are difficult because I don’t know anything about you. Before we blame the scope, let’s explore some other things.

    The Crosman Phantom is a breakbarrel that requires a LOT of technique to shoot accurately. Holding it like a deer rifle won’t cut it.

    1. Have you cleaned the barrel with JB bore paste? If not, have you fired at least 500 shots through the gun?

    2. Do you use the artillery hold faithfully?

    3. Do you follow through?

    4. Do you have a consistent spot-weld?

    5. When you balance the rifle on the flat of your palm, it it situated just in front of the trigger guard?

    6. Is the pivot bolt tight enough that after cocking the rifle you can leave the barrel in any position and it will stay there?

    7. Is the vertical scope adjustment below the 3/4 elevation level?

    8. Have you tried other premium pellets like JSB Exacts, Beeman Field Target Specials and H&N Field & Target?

    You are using Crosman pellets, which will lead the bore after several hundred shots, so if you have fired 1,000 shots, have you cleaned the bore again with JB paste?


  26. BB
    Crosman has now posted parts diagrams on the Benjiman Sherdan and also the Remingtons.

    When looking over the parts list between my C9 phase II and the 392 phase I; they do appear to have a diffrent trigger and valve assembly.

    Could you tell if your modded rifle is a phase I or II? It looks like the trigger group and trigger guard might give the tell tale signs.

    Thank you
    JoeG from Jersey

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