El Gamo 68-XP .22 caliber: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

El Gamo XP-68
The El Gamo XP-68.

Part 1

A history of airguns

This report covers:

  • Preparing to shoot
  • Petroleum oil or silicone?
  • Velocity determines which oil you need
  • Velocity
  • Deep-seating
  • JSB Exact RS
  • H&N Baracuda Match 5.51mm head
  • RWS Meisterkugeln
  • Trigger pull
  • Cocking effort
  • Evaluation so far

I said I would return to this report after I repaired the plastic clamshell halves of the buttstock. That job is now finished. I was able to epoxy the pieces of the broken post that receives the stock screw together and, although it wasn’t completely straight, it was straight enough for me to drill a new pilot hole for the wood screw that holds the two halves together. The butt is now complete, so today I will test the velocity.

Preparing to shoot

In preparation to shoot I oiled the piston seal with a lot of silicone chamber oil and let the rifle stand on its butt for a day. If it has a leather piston seal, and I am almost certain it does, the oil will be absorbed and make the leather pliable again. That should give the highest velocity.

Petroleum oil or silicone?

Before I get to the velocity test, I have some words about oiling the piston seals of older air rifles. First, the age of the airgun usually determines whether the piston seal is leather or synthetic — but not always. I would say that most spring-piston guns from the 1950s and earlier have leather seals, but one exception to that is the Hakim military trainer that Anschütz built for the Egyptians in 1954/55. Anschütz was also making the same action into a sporting rifle for sale in Germany at the time, and I have to believe that one used the same black synthetic parachute seal that was in the military trainer. It’s too expensive and confusing to do otherwise.

Why do I tell you this? Because leather piston seals need more oil to keep them pliant. Synthetic seals will operate on far less oil, because they always hold their shape. If you know you have a leather seal, you know it needs a lot of oil. But which type — petroleum or synthetic?

Velocity determines which oil you need

It isn’t the seal material, it’s the velocity the rifle generates that determines the type of oil that should be used. That’s because when the velocity gets up over a certain level, the heat generated by the compression is very high. You want an oil that will not burn easily, so there is no explosion.

The velocity thresholds are caliber-specific. Once the velocity of a .177 spring-piston rifle gets up over 800 f.p.s. it’s time to oil the seal with silicone regardless of what it is made of. But usually it would be synthetic, because that level of velocity only came about in the late 1970s, when synthetic seals came into popular use. For .22 caliber the threshold is around 700 f.p.s., and so on. Nothing is exact or precise, these are just general guidelines.

Given that information, it is a sure bet this El Gamo can use petroleum-based oil on the piston seal with no worries. Not that silicone won’t work, because it works fine. But it costs more and isn’t really needed.

To generalize, spring piston airguns made in the 1950s and earlier are lubricated with petroleum-based oil. Those made after that time may use silicone, unless you know for certain that the velocity is very low. Then petroleum oil works best, because it is cheapest. This air rifle I am testing is low velocity for sure, so petroleum oil will work. I used silicone, however, because the applicator needle was easier to get inside the air transfer port.

Velocity

Now let’s see what the velocity is. I will start with a lightweight lead pellet that is widely used to determine the velocity of airguns, because it often shoots the fastest. Of the practical lead pellets you might use — the .22-caliber RWS Hobby is one of the best. In .22 caliber Hobbys weigh 11.9 grains, nominally.

Hobbys averaged 454 f.p.s. from the rifle, which tells me the powerplant is in fine condition and doesn’t require attention. Shooting is smooth and crisp, without much vibration. The spread ranged from a low of 447 f.p.s. to a high of 461 f.p.s., which is a total of 14 f.p.s. That’s pretty good for an older spring-piston gun and a leather seal.

Deep-seating

I did try deep-seating the pellets with a pellet seater, but it didn’t seem to make any difference. So I seated most of them flush with the breech.

JSB Exact RS

Next to be tested was the JSB Exact dome. At 13.43 grains these are a little heavier than Hobbys, so we expect they will go slower, but not that much. They averaged 437 f.p.s. in the 68-XP and ranged from a low of 433 f.p.s. to a high of 443 f.p.s. That’s just 10 f.p.s., which is very consistent. And I must observe that the powerplant was the calmest with this pellet. This will be one to try for accuracy.

H&N Baracuda Match 5.51mm head

Next I tried the H&N Baracuda Match with a 5.51mm head. The first shot was loud and the gun vibrated a lot. When I saw that the velocity was only 170 f.p.s. I resolved to try one more shot and if it wasn’t better, to give up. Shot two went out at 192 f.p.s. and I was finished. This pellet is just too heavy for this powerplant.

RWS Meisterkugeln

The last pellet I tried was the RWS Meisterkugeln wadcutter. At 14 grains it’s about the heaviest pellet I think I will try, though it might be fun to try a Superdome in the accuracy test. I got a bimodal (two differing averages) distribution with this pellet, depending on how it was loaded. Seated flush the Meisterkugeln averaged 370 f.p.s. with a low of 362 f.p.s. and a high of 377 f.p.s. Seated deep this pellet averaged 400 f.p.s., with a low of 394 f.p.s. and a high of 408 f.p.s.

I noticed when I seated the Meisters there was a lot of resistance entering the bore. If I test this pellet for accuracy it needs to be seated deep.

Trigger pull

The 68-XP has a heavy two-stage trigger pull. It breaks at 7 lbs. 7 oz. at present. The shape of the pistol grip enables me to pull it without affecting the hold on target, so it won’t affect accuracy, but I may try to lighten it a bit. We learned from the other 68-XP that the trigger does respond to adjusting.

Cocking effort

This rifle cocks with just 13 lbs. of effort. That makes it one of the lightest-cocking air rifles I have ever tested! There is an anti-beartrap mechanism that prevents the gun from firing, once cocked, until the breech is closed, so you have to fire it when you cock it. The detent is light enough to not need the muzzle to be slapped to open the barrel, which is quite pleasant.

Evaluation so far

This surprise buy in a pawn shop is turning out to be a very nice air rifle. Now that the butt is fixed and I know the power is where it needs to be, all that remains is to see how accurate it is.

42 thoughts on “El Gamo 68-XP .22 caliber: Part 2


  1. BB,

    Going off topic here.

    I was just looking at the new Kral N-07 with walnut stock over at PA. That is a nice looking sproinger, even if it does have glowy thingy sights. Maybe you can get them to send you one in .22 to test?


  2. B.B.,

    Great news on the stock fix. I am drawn to the looks of this thing. Nice lines with some curves thrown in for good measure. The receiver finish is intriguing. Does that finish have a name? Is it a type of paint or does the metal itself have a texture? I have been trying to think on what else I have seen that finish and the only thing that rings a bell is office related wares such as an old type writer, paper punches, etc.

    Good Day all,…. Chris


    • Chris,

      That is a crinkle paint finish. It is the exact same finish you are thinking of. It was a popular, durable finish of the time. I think you can actually still get that type of paint. It sprays on smooth and wrinkles up as it cures.

      By the way, my mobile air unit is on the roll. 😉



      • RR,

        That is what I thought, but was not sure. I have some experience with powder coat and you can get a home set up that will do a fine job for not much. Cure is done in a home oven, (that can NOT be used for food cooking again). Works great as long as the parts will fit in the oven. That stuff is tuff is all get-out too. They have crinkle, vein, hammered and about anything else you can think of.


        • Chris,

          Yeah, the wife would not stand for that. I used to rebuild old Mossberg target scopes. I used an epoxy based paint that took about 7 days to fully cure. It was some tough stuff. They have another version that you cured in the oven, but I did not think much of that idea. I figured it would mess up the taste of the corn bread.


  3. BB

    I am intrigued by the velocity gained when the Meisterkugeln pellets were deep seated. This has me wondering if I should be using a seater or ball point pen instead of a finger to press tight fitting pellets flush.

    Decksniper


  4. Pingback: El Gamo 68-XP .22 caliber: Part 2 | Airguns: Air Rifles and Pistols



    • Riki,

      This rifle wasn’t made by Gamo. It was made by El Gamo. That was the company before some marketing guru got ahold of it and went crazy with the velocity, thinking that was the way to success.

      El Gamo air rifles were quality items, made when things like smoothness and accuracy ruled the day. I have no idea whether a PBA pellet would work in it on not, because I would never try one.

      B.B.



    • Steven,

      Silicone usually isn’t a good lubricant, so don’t use it for friction reduction. I know that seems to fly in the face of the hardware store silicone sprays that are for door hinges, but they are not the true silicone we are talking about here.

      As far as piston seals go, silicone is good for just about all applications. I say “just about” because there may be one that isn’t good — I just don’t know about it.

      B.B.

      B.B.


      • Good point. I would never use silicone for metal to metal other than in an HPA pump or fitting. Even there I have been looking into doing a tear down and switching over to Krytox GL205 or another more modern non-detonating lubricant.

        I was only asking about piston seals.

        Thanks!


  5. Not my style of rifle but still it’s an interesting design. If it is decently accurate, the low cocking force would make it a nice plinker.

    BB, do you know if the sear engages at the front of the piston or is there a “bull-pup” linkage to the rear of the piston?

    Cheers,
    Hank



      • B.B.,

        The trigger looks so far forward that I was curious… guessing that it is a typical rear latching system with some sort of linkage. If you ever disassemble the rifle enough it would be interesting to see a picture of the innards.

        Years ago I replaced the leather piston seal on a friends’ BB pistol. The one-piece trigger latched directly to a collar on the piston head. It was a “folded sheet metal” design that cocked by pulling a knob on the back of the receiver. The trigger location relative to the spring chamber looks similar to the 68-XP so I thought it might latch up the same way.

        Hank


  6. BB

    This won’t be far off topic as there are several comments on the stock…after reading your review of the bamboo stocked x25 from a while back, and in keeping with RR’s RWS34 suggestion (way over my budget for a try this and see gun), I settled on a Mike Mellick tuned Xisico XS25SFB model. Ordinarily this is an unsighted prospect, but I am a die hard sight user so MM agreed to drop a standard XS25 barrel and action into the bamboo frame at no extra cost.

    So I ended up with a sub-150 dollar rifle that looks good, shoots good (when my hold is right – still working on that), and has been setup by someone with far more tuning experience than me. The advice I received here steered me away from a big box store “deal” into what appears to be a much better investment for my hard earned dollars.

    Thanks guys,

    Steve



      • BB

        …exactly what I wanted for starting out the journey…I can see where this may become a lengthy sojourn into what someone else called the “dark side.” I had the day off and put in an extended (for me) shooting session for the new rifle and the pistol collection…had forgotten how scary accurate some of these guns ca be, but this “sproinger” is in a whole ‘nother world in that regard..most fun and best shooting I’ve had in a long time!

        Steve


  7. Forgot to add that I did order a P17 from Pyramid to replace the one I traded for my 1377 years ago – may share that story another time. This order was largely placed on positive reviews read here, so thanks again all.

    Steve


  8. FWIW, besides wrinkle finish spray paint there’s other finishes like crinkle and my favorite, hammered finish. These can be good options to the usual gloss/satin/flat finishes.


  9. The numbers say that this rifle cocks one pound lighter even than my IZH 61 which is quite something. But it won’t be so enjoyable since this rifle is single shot. On the subject of repair, I’ve also found that it is not worth my while to send my Crosman 1077 in for repair. So that will go into the trash, and I’m going to order my third copy of this gun.

    Matt61


  10. Thanks for the comment on Kral Springers. Something new in town and was looking at them. I looked over on the euro forums. I noticed a reference to Gamo on the blog here. I found out with my reading on the euro that they are built on the B19 platform. That safety dropped down in front of the trigger must indicate the OLD Gamo trigger. I want no more of them. Sure would have liked one of those Walnut stocks but not with that trigger.


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