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Education / Training Gamo CF-X gas spring! – Part 3

Gamo CF-X gas spring! – Part 3

by B.B. Pelletier

Part 1
Part 2

Let’s look at the accuracy of the .22 caliber Gamo CF-X with Air Venturi Ram Air gas spring installed. You’ll remember that I commented about the soft aluminum scope rail that Gamo now mounts on its rifles. It cannot take the recoil, and you’ll gouge the soft aluminum if you anchor a scope mount with a steel pin. So, I removed the rail and mounted the scope rings directly to the steel receiver.


The aluminum scope rail on the CF-X came off.

Three Allen screws hold the rail to the gun, but the large screw at the back of the rail is actually a steel stop pin screw that fits into the rifle’s steel receiver. It has to come out also, and the plastic end cap must come off the rifle, so the action has to be separated from the stock.


The plastic end cap comes off, and the scope rail slides off the back.


With the aluminum rail off, the Gamo steel receiver has a nice hole for a scope stop pin.

Once the aluminum rail is off the gun, there’s a hole for a scope stop pin in perfect position for any scope mounts you use. The aluminum rail used this hole already, so it’s clearly intended for that purpose.

I mounted a Leapers 30mm 3-12x mini SWAT scope that is so short that it cleared the rotary breech by several inches. If you have a short neck this scope may not have enough eye relief, and you’ll want a standard-length scope. Once the receiver was free of the aluminum scope rail, mounting took less than a minute, because the scope was already in rings from other tests.

Sight-in was a breeze because it took exactly one shot. The pellet was in perfect alignment and only required more elevation to hit the point of aim. I shot .22-caliber Crosman Premiers that did well in the velocity testing, but I’ve also had good reports from many satisfied customers. I did try 15.8-grain JSB Exacts, as well, but they didn’t group as tight as the Premiers.

This rifle demanded that I relax completely to group well. I tried several locations for my off hand but the best was just behind the cocking slot in the forearm. There, the rifle was balanced perfectly and shot its best.


At 21 yards outdoors, the CF-X grouped like this. Five premiers in 0.176″.

So, what have we learned with this test? First, that the Gamo CF-X is probably best-suited to .177 caliber instead of .22. Diana 48/52 rifles had a problem when they bumped the caliber up to .25 caliber, too. The rifles didn’t shoot as hard in .25 as they did in .22. Maybe we’ve run into that here.

Second, we discovered that the aluminum scope rail cannot stand up to a steel recoil stop pin. Remove it and mount the scope rings directly to the rifle and everything will be fine.

Finally, we learned that the CF-X is a good shooter in .22 caliber, just as it is in .177. Forgetting the lower-than-expected power, the rifle is dead-calm and quite accurate, as you can see.

This was our third look at rifles with Air Venturi gas springs, and I like them more each time we check one out. I’ll be going through the Gamo, Crosman and Remington guns this year and checking out several others with the Air Venturi gas spring. It’s a great way to get a fine, smooth tune.

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.

32 thoughts on “Gamo CF-X gas spring! – Part 3”

  1. BB,

    Now that you have tested the CFX and the Whisper with the gas spring, which one is the quietest?

    Also, are the gas springs identical in each of these air guns? I am trying to determine which is the best value.


  2. will the air venturi gas sring fit the winchester 1000b (its sold here in the philippines as the hatsan model 70)?

    i’ve put more than a thousand rounds through this rifle but still it refuses to group even at 10 meters! i’ve been using a local 11.6gr pellet that’s considered the straightest-shooting pellet by the CO2 and PCP shooters here (we don’t have any locally-made springers here that’s why i got this hatsan). do i need to find another pellet or does my rifle need more break-in shots? thanks for your help BB!

    abel in manila

  3. Abel,

    You need to try other pellets. I’m guessing your Hatsan is a .177, based on the pellet weight you mentioned. That is way too heavy for a spring rifle. You want something in the 8-grain region. Crosman’s Premier hollowpoint would be pretty good, I would think.

    I don’t think the Air Venturi spring will fit your rifle, but I’m not sure about that. But your accuracy problem can’t be solved by a gas spring.

    At 1,000 shots you should be through the break-in period. The rifle should be ready to perform at its best.


  4. B.B.

    A couple questions. If Crosman Premiers lead the bore, is it possible to clean the bore by shooting other pellets?

    Secondly, I’m curious about the offhand shooting position with the right elbow at right angles to the ground instead of pointing down (for right-handers). When I was shooting smallbore competition in high school, I was experimenting with this position when the coach smacked my arm down. Man, was a jerk and shouldn’t have been allowed around kids or anyone else. On a more positive note, the arm-down position does seem consistent with the principle of supporting the rifle on bone and using minimum muscle effort. I like that idea very much!

    On the other hand, I’ve noticed that U.S. army manuals all depict the arm up position, and I figure they know something about shooting. I’ll admit that when I try this position, it feels pretty good for reasons I can’t really explain. What’s to know about all this? Thanks.


  5. Matt61,

    Some people teach because it’s their job. They cling to “the rules” because they don’t know the subject.

    Arm out straight is a classic stance for offhand shooting. There was a push to eliminate it in the 1950s because some people felt it caused a pendulum effect.

    Remember, if Dick Fosbury hadn’t experimented with styles we’d never have the Fosbury flop and the high jump would still be topped out at 7 feet.

    Once leading begins in a bore, you cannot “shoot it out.”


  6. BB,

    I have a quick question for you about round ball ammo. I’ve tracked back through several of your old posts on the subject but I’m still not certain if they are safe to use in my R1.

    I thought it might be fun to try round balls in my gun just to see what they can do, but not at the risk of my rifle.

    Also, if they fit snugly in the barrel, do they get grooves in them like pellets do, and wouldn’t that effect their aerodynamics (like scuffing a baseball)? As always, thanks!

  7. Kodiak,

    Round balls will work fine in an R1. They are engraved by the rifling, which causes them to spin just like a pellet. Since a sphere is easier to stabilize than a long object, they need very little to stabilize them and can be quite accurate at short range (to 30 yards or so).


  8. Sumo: After over a week, the wind finally layed down today. Shot several 50 yrd. groups w/ my Diana 54 w/ RWS 3-9×44 scope. (22 cal. w/ 14.3 CP.) Best c.t.c. 3/4″!!,Worst, 1&1/2″. Average was about 1″. Needless to say “I” am VERY happy! when I set scope at (indicated) 50 yrds. groups only moved up maybe 1/4″ this time w/ a little less verticle stringing. Windage did not seem to change. (Im working real hard on a more consistant spotweld). Im shure you were right about my eye being off axis. (it makes PERFECT sense to me now) Thanks so much to you & others for the recent input on this A.O. thing! Im still “testing” differant A.O. settings,, but must admit my 30 yrd. “set it & forget it” still works for me. Moving back to 20 yrds. & even 25 yrds. Im ONE HOLE accuracy!! (dead center bull!) 30 yrds. little high,40, back on!! Now, if I could just get off that bench rest, & stop looking for a tree to lean on!!LOL. Sighned,admited, bench rest& chrony “junkie” Tim.

  9. B.B.,

    One last question about the UTG 4×40 scope we talked a bit about. I bought a second one to mount on my .30-06. Will the scope mounts/rings be suitable for the rifle as long as they fit the rifle’s dovetail? Are airgun-specific rings inferior to those meant for a centerfire rifle? My .30-06 is a Remington model 700 if that helps any. Thanks, and no more questions about firearms, I promise!

    – Felipe

  10. Hi BB,
    I was wondering if you might consider a post for a DIY Air Venturi gas spring installation.? I own a factory spring CFX, and I think a lot of Gamo owners would love to learn how to do their own conversion. In the mean time I will keep studying up on your spring gun tuning posts.
    GasSpring Wannabe

  11. Does the gas spring installation actually require any major modification of the gamos, other than removal of the factory mainspring/spring guide and replacement with the gas spring? I would rather do the conversion myself than have to ship my whisper to pyramidair.

  12. Phil,

    This is the third time you’ve asked this question and this will be the third and final time I am answering it.

    No, the front sight is integral with the muzzle brake, which also holds the underlever in position, so there is no easy way to remove the front sight.

    Yes, the rear sight is helt on by one easily-removed screw.

    But why take the sights off? They don’t get in the way of using a scope.


  13. Hey BB,
    Sorry, about the repeat questions about the sights. I tried posting that question twice on the other regular CFX review (as I am sure you must have seen). But neither my question nor your responses ever showed up for me. I tried refreshing the window, and even checking back on later days. I just assumed the post never went through properly. This was the first time when I saw, my question actually post. So again, my apologies for the repeats, and many thanks for your help.

  14. Phil,

    Your questions and my answers are there.

    Go to the CF-X test


    and scroll to the bottom of the report. You will see there are 320 comments, but Blogger only shows the first 200 comments. If you scroll to the bottom and click on Post A Comment, you will have a choice of which comments you want to see. Click on the Newest comments and you’ll see both of yours near the bottom.


  15. I greatly appreciate your articles, well written and informative, thanks!
    After a story last January on Gamo CF-X with a gas spring, someone asked if you would consider a post on a DIY on this gun. Although I have read most of your posts, I haven’t seen this one, did you ever write it?
    I am interested in upgrading my CF-X but as I live in Australia its not practical to send the rifle to Pyramid for installation.
    Thanks, Pete

  16. Pete,

    I know that I have not done a report on taking a CF-X apart. But I have taken other airguns apart for this blog.,

    I don’t have a CF-X, so it’s probably not going to happen here, but don’t be discouraged. I am moving your concerns to the current blog, where others can see them and perhaps help out.


  17. i cant deside between a cfx and a whisper, does a break barrel rifle's barrel start to bend after reapeatedly cocking the gun over and over again if you use the same break barrel rifle for a long time?

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