Hatsan AT P1 PCP air pistol: Part 2

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1

Hatsan AT P1 PCP air pistol
Hatsan AT P1 air pistol.

Today, I was all set to report the velocity of the .22-caliber Hatsan AT P1 PCP air pistol, when I discovered that there’s more I need to know about this airgun. I’d like to thank those who’ve been waiting patiently for this second report. I stalled for a long time because Hatsan uses a proprietary quick-fill probe. That means I have to undo one of my more universal fill connectors to attach their probe. Thankfully, the threads on their probe are standard 1/8″ BSPP that connect to most air hoses coming from tanks and hand pumps these days (I can still remember when that wasn’t true!), but I was working on both the Condor SS and the twist-rate report and needed a fill device for both of those. In the end, I pressed my Hill pump into service, and it proved to be a great way to fill the AT P1 pistol.

Rotary clip
The first problem I encountered was with the 10-shot rotary clip — but I want to stress that it wasn’t the pistol’s fault. It was mine. I tried loading 28.4-grain Eun Jin domes that looked like they fit the clip well, but proved to be too long and jammed the gun.

Because they were the first pellet I tried, I thought the gun might be broken until it dawned on me that the pellets were the problem. Once I changed to Crosman Premiers, the gun functioned perfectly and there were no more cocking or feeding problems.

Rotary clips are sensitive to the length of pellets. If they stick out on either side of the clip, that can cause the gun to jam, as this Hatsan did. So, when selecting pellets for a rotary clip, keep this in mind. I chose the Eun Jin pellet for the weight. I thought it would allow this powerful pistol to develop its maximum power, but I went too far.

Removable air reservoir
In Part 1, I completely neglected to mention this pistol has a removable air reservoir. I saw the degassing tool in the tool kit and knew that it could only be used on the other (hidden) end of the reservoir, but for some reason I didn’t think to mention it.

Hatsan AT P1 PCP air pistol reservoir removed
The air reservoir unscrews from the pistol. When it’s out, it can be emptied by the brass tool at the bottom.

Of course, the reason for a removable tank is so you can carry extra charged tanks in the field. Each one will give you more shots. I don’t think this is such a great feature after you learn how many shots you can get on a fill, but the choice is yours. At least Hatsan gives you the option.

Shots per fill
This will be the remainder of the report because I discovered during velocity testing that the AT P1 pistol has a very specific power curve. It’s not an inverted bathtub curve — where the velocity rises to the optimum level and remains there for a number of shots before falling back down again. Instead, the velocity rises, peaks and drops instantly. The curve looks like a peaked mountain with no flat spot at the top.

The manual says to fill to 3,000 psi and that there are 35 useful shots per fill. Several readers expressed doubts that the 50cc reservoir held enough air to give 35 powerful shots, and I agreed with them. If this was a target pistol, then 35 shots would be very possible; but at the power Hatsan claims, which is a .22-caliber pellet traveling 780 f.p.s. at the muzzle, it seems impossible to get 35 good shots on so little air. And, indeed, it isn’t.

My first fill was higher than 3,000 psi, and the velocity was depressed for many shots. When it did rise, it did so in a straight up and straight down fashion. There was no group of shots going at similar velocities. This told me I needed to control the fill very carefully.

I also noticed that the pistol fell off the power curve with about 1,800 psi remaining in the reservoir. But I didn’t stop shooting there. I stopped with about 1,500 psi remaining in the reservoir. From this test, I was able to determine that the pistol used about 62.5 psi per shot. I did that with a chronograph and with an accurate pressure gauge on the hand pump. The pressure gauge that’s built into the test pistol’s reservoir reads several hundred psi too low to be of much use.

I know how much air is in the reservoir when I start shooting because that’s what the pump’s gauge reads when I stop filling. I know how much air is in the reservoir when I stop shooting because that’s the spot on the gauge where the reservoir inlet valve is overcome by pressure during the next fill — you can see this when the gauge needle clicks at the opening of the inlet valve.

It took 1.5 pump strokes per shot, so refilling the reservoir went very quick. That’s why I believe the Hill pump is the best way to go, and the possibility of spare reservoirs isn’t worth the effort.

The shot count test
The next test I conducted began with a fill to exactly 3,000 psi on the hand pump’s pressure gauge. I used Crosman Premier pellets, exclusively for this test. I’ll give you the velocity readings and then interpret them afterward.

Shot…..Vel.
…1……..702
…2……..714
…3……..725
…4……..737
…5……..750
…6……..761
…7……..769
…8……..773
…9……..776
..10…….773
..11…….767
..12…….761
..13…….748
..14…….732
..15…….720
..16…….710
..17…….692
..18…….667
..19…….648
..20…….627

I’m not going to give you an average for this string because I don’t know which shots you want to consider as the good shots. Clearly, the pistol was slower at 3,000 psi on the hand pump gauge. And, remember, this is with the more accurate hand-pump gauge. The pistol’s built-in gauge was still showing about 2,700 psi at this point. Either way, there’s too much air pressure in the gun because the valve isn’t opening as long as it should, as evidenced by lower velocities.

Let’s say I like 761 f.p.s. for the first shot. If you agree, then the first 5 shots in this string were wasted. At 62.5 psi per shot, the gun was overfilled by 312.5 psi when it was filled to 3,000 psi. Since these gauges don’t read that accurately, let’s round that back to 300 psi overfill and say I need to stop filling the reservoir when the pressure gauge reads 2,700 psi.

If you select a different velocity as the start point of the shot string, then the beginning fill pressure will need to be adjusted accordingly. This is why I am not giving you an average velocity today. I can give average velocities, but before I do you need to know what is behind my numbers, because this pistol operates within narrow limits.

If I take the second reading of 761 f.p.s. as the ending shot in the string, there are a total of 7 good shots in the string. I think that’s probably too restrictive, and I need to expand my velocity variation allowance. If I allow a velocity variation of 74 f.p.s. between the fastest and slowest shots in the string, I can get 16 good shots on a fill and can start the fill at exactly 3,000 psi.

Do you see how I’m doing that? I’m using the chronograph numbers and accepting all shots until the pistol no longer drives Crosman Premiers out the muzzle at a velocity of greater than 700 f.p.s. My choices are arbitrary; but until I make them, I can say nothing about the shot count of this pistol

Well, maybe that’s not entirely true. Whatever I select as the acceptable velocity variation, I can say with certainty that this air pistol can never get 35 useful shots on a single fill. Where I draw the line is my choice, of course. If I want to shoot groups at 50 yards, the variation has to be tighter than if I want to hunt with the pistol out to 30 yards. Do you see how the anticipated use of the gun drives the useful number of shots you’re going to get?

Loading
When you change the clip, the gun must be cocked to pull the loading probe back out of the clip. Then, the clip’s axle must also be withdrawn to the front of the gun and held out of the way. That’s a separate brass bolt on the right side of the gun. The clips come out and go back in easily enough when these things are done.

Hatsan AT P1 PCP air pistol cocked
A lever on the left side of the gun is pulled to the rear to cock the action and advance the clip to the next pellet.

Hatsan AT P1 PCP air pistol bolt probe
Here you see the bolt probe that pushes the pellet into the barrel (brass pin in the clip recess) and the brass clip axle (the head is a brass knob) that’s been withdrawn to the front of the gun to remove the clip.

Discharge noise
This gun is LOUD! I had to wear electronic ear protectors when testing it in my office. And although my office door was closed, my wife, Edith, remarked on the loud discharge when I was finished.

In the next report, I’ll test the pistol with several good pellets and give you some of the velocity data you’re used to seeing. But when I do, you’ll know what’s behind my numbers.

44 thoughts on “Hatsan AT P1 PCP air pistol: Part 2

  1. Pete zimmerman Says:
    June 18, 2013 at 11:51 pm
    I AM alive. Not doing well but hoping for a miracle. When las I wrote I was recovering from radition treatment. That’s finished; I really do seem to have licked cancer.

    But in a possibly related development, my kidneys are failing, and I’m groggy a bit of the time and dead tired the rest. I am on transplant lists and have offers of three living kidneys from people who love me. We are praying that one is close enough a match to work.

    I have not pulled a trigger in a literal year. I do hope to try again this coming weekend.

    I posted this twice forgetting that at midnight a new blog went up. —p

    My best to all my friends here; I’ve missed you.

    Pete

    Reply



    • Pete,

      Just never give up. That’s above all. I hope you’ll find a good match for your kidney and enjoy thousands a lot of excellent shots. We all pray for you.

      duskwight






    • PeteZ! We’ve missed you too! I think a kidney will find you and you’ll be well. It’s a long road but you’ll get through. Hope you start feeling better soon!

      /Dave


    • Thanks for writing PeteZ. We were wondering about you. Thank goodness you licked the cancer. Hang in there with the kidneys. I had my own scare with kidney failure but it worked out.

      B.B., what could possibly be wrong with multiple replaceable air tanks? :-) I thought your office was your whole house. :-)

      Titus, thanks for the archery background. Isn’t 50 pounds of draw weight still 50 pounds whether your bow is long or short? How could length of bow make any difference? I’m not aware of any single battle where the recurve showed its superiority to the longbow. The longbow showed its superiority to the mounted knight very memorably in a couple battles but I’m not aware of anything comparable between the two bow types–although I know in shooting contests, the range of the recurve was clearly superior. There some documented instances of deflex/reflex modifications to the longbow in medieval manuscripts so that’s not a new thing. The Crusaders could appreciate better technology and learn from it. It sounds from your description that the recurve has all the advantages over the longbow. Can that be true? Usually, design is a matter of give and take.

      Wulfraed, you are a really brilliant character with that graph. No, it’s not what I was describing. It’s much better. It took me somewhat longer than Titus to figure it out, but I did arrive. I can share something with you. In my maps class, someone confided to me about the power of the R statistics program. But he said that such was its difficulty that it made grown adults cry! I can see that on first appearance, but it does deliver. Reading the bottom row for group size summarizes everything that B.B. said about the superiority of the number 6 power setting and of the 1:16 twist rate–and of the superiority of the shorter distance. :-) If you can get colors in there, there will be no stopping you.

      Matt61


      • Might want to glance back at the plot — I managed to get the x’s and o’s to properly map to the pellet type (o is premier, x is JSB).

        Twist vs Power, Twist vs Distance, and Power vs Distance are meaningless intersections. The rest are what would provide indications of what should be used for further investigation..

        Playing with R makes me sometimes wish I HAD taken Stat-II in college (even though that used SPSS); just so I’d have a somewhat better idea of what to use when. As it is, I’ve spent over $100 on books this year (two of which were second revisions of books I’d bought in 2011): The R Book 2nd Ed; R Graphics 2nd Ed, R Graphics Cookbook, R in a Nutshell, and also have Using R for Introductory Statistics.

        If I dig deeper into the books, I may figure out how to get R to do a two-sample comparison (Premier vs JSB might be a meaningful test if it pairs the pellets by power, but 10m vs 25yd might be viable too. Really need more data though — the raw velocities would have worked for power vs velocity, but not for group size tests).


    • Hello my name is Daniel Barker and i don’t know you but i have
      had cancer touch my family and i am truely sorry to hear of your battle
      with such a horrible and evil substance as cancer .And i just wanted to
      say that all though i don’t know you i will be praying for you and your
      family with my strongest and best prayers.


    • Pete…

      Sorry to hear that you have additional problems . I really hope that you can beat this new one too.

      twotalon



  2. B.B.

    Sorry I missed the last blog – I spent last evening deep inside FWB65 innards. Yesterday I received spare parts from Oberndorf, so that was a grease and steel time. Despite my fears the pistol is built quite simple and logical, and is easy to maintain and repair. I noticed that “small dampener” in lower part of cylinder’s front was made of that infamous “FWB plastic” that degrades with time – something between an old rubber and clay, eek.

    duskwight


    • deuskwight,

      That old synthetic material has popped up in a number of vintage airguns of very high quality. Walther used it in their LGVs and Diana used it in all their recoilless target rifles for piston seals.

      Fortunately they all learned their lesson in time and we don’t see it these days.

      Good luck,

      B.B.


  3. I would agree looks like 16 shots that will be pretty consistant towards accuracy. That’s the way I tune my pcp’s with my chrony.

    Did I miss. But is that gun tunable for fps. ?


  4. Yep, I see a compact bullpup.

    I hope you can hit something with that little thing. If it proves to be accurate within a “useful” shot string, an extra cylinder or two might not be a bad idea if you are out for a day of popping tree rats or hop alongs. Carrying a pump or a scuba in the woods would not be conducive of a good time.


  5. I usually do not comment on pistols because I have no interest in them. However….

    At this point, I find a lot of humor in this one already. Big “seven shooter” with a ten shot mag. Thirty five powerful shots…powerful enough to get past your feet maybe with shot #35. Lousy gauge. Worthless curve.

    At this point, I would not even care if those 7 good shots were accurate.

    twotalon


    • twotalon

      However I must notice that this pistol can be a good “starter kit” for custom bullpup PCPs built on a “just screw in” principle. Longer reservoir with pressure regulator, longer barrel, detachable shoulder stock and I think you can make a good hunting stuff with decent performance.

      duskwight


      • Maybe if they gave it away, but sold the kit to turn it into something worthwhile. Or just buy a Pneuma and build it into a bullpup.

        I am not much for the idea or buying the wrong thing for the purpose of turning it into the right thing. Too much work.

        twotalon



    • Kevin,

      I was thinking the same thing. Plus, the Marauder pistol is made here in the USA for those of us here that care. (not trying to disrespect those non-US citizens here. The US is having a tough time keeping its industrial base, so I try to support the effort…)

      /Dave


      • /Dave,

        Not to mention the marauder pistol is shrouded, has a better shot count, is cheaper, comes with a shoulder stock, etc. The small difference in power can be overcome.

        kevin


    • I have had a Marauder pistol for some time now and have been very disappointed in it’s accuracy. Would you please tell me which pellet(s) you use. I am very frustrated.
      G & G


      • G & G,

        I might be able to help you with your marauder pistol if it’s in .22 caliber. I’ve had some experience with that platform. My experiences MAY also translate to .177 caliber but no guarantees.

        First let me say I don’t own and have never owned a marauder pistol. The .22 cal marauder pistol I spent a lot of time with is owned by one of my shooting buddies. Eventually we got dime size groups at 30 yards but we spent some time to do it.

        Here’s my advice, based on first hand experience, in order of priority:

        1-Remove the barrel and clean it with the JB Bore Paste technique that B.B. describes on this blog. You can do a search to find the details. In short, get a brass or bronze brush (not nylon), load it with jb bore paste and run it through the barrel 20 times each way (forwards and backwards). Clean it after this step with patches. I use FP-10 to lube the patches to expedite the cleaning out of the residual jb bore paste. Ballistol works well too. Don’t use any harsh cleaners that can eat seals for a lube in this step.

        2-Re-install the barrel. If you’re shooting a .22 cal try kodiaks, barracuda match pellets in 5.53 and 5.54 head size, crosman premiers (out of a cardboard box not the walmart stuff), and beeman fts pellets.

        3-If your marauder pistol still doesn’t group order two (2) new barrels from Crosman. Think they’re $10.00 each and the shipping is the same for one or two. Clean these new barrels with the JB Bore treatment before installing them. We had a bad experience with a lothar walther barrel ordered from Jim Gaska but many have had success ordering these barrels for marauder pistols from Jim Gaska. To Jim Gaska’s credit he refunded the money for the lothar walther barrel after it was returned to him.

        4-The second barrel we received from Crosman was a peach. It shot Crosman premiers well, fts pellets well, baracuda match pellets very well and beeman kodiaks the best (not unlike the marauder pistol B.B. received for testing that shot kodiaks only). We shot jsb 15.8 gr and 18.1 gr pellets out of all the barrels and although they performed ok the heavier kodiaks did better or did best.

        Don’t give up on your marauder pistol. It’s a great platform. In my lengthy experience it’s only the barrel that is restricting you from owning one of the best pcp pistol’s for the money today and replacing the barrel (thanks to Crosman’s reasonable offerings) is inexpensive.

        Hope this helps. If it does, please post your results. Thanks.

        kevin


        • Thanks so much for the advice and info. It has occurred to me to clean the barrel but I haven’t tried it yet. Now I will as I have suspected all along this was the problem. At least I hope this solves the problem although a new barrel isn’t a big deal. I will definitely post the results of this effort. Thanks again.
          G & G


  6. To all of you,

    THANKS!

    It’s a long hard pull, and support from friends is absolutely necessary. Just as much as it is from family.

    pete


    • Having a number of serious physical ailments of my own (heart failure for one) I have an inkling of the long hard road you are traveling down. I pray that God will sustain you through these hard times as He has me.
      G & G


  7. The variation in shot velocities near the indicated 3000 psi fill point (say shots 1-12) shows one thing very clearly. Accuracy and shot to shot consistency in a PCP gun absolutely demand that there be a pressure regulator so that the pressure driving the pellet doesn’t change over a usefully long string! I always thought so, but this is a beautiful demonstration.

    pete


  8. This thing looks like a rather complicated gun to use. But it does give me an idea of what my experimental 2240 pcp gun should do if I ever get around to finishing it. I found a source for a pcp tube for it and of course the valves. I just have to get around to putting the thing together. I’m hoping for at least 10 good shots at 2000 psi before I need to refill. But realistically I’m betting on 5-8 good shots. The benefit of my 2240 experiment over this pistol is no plastic on it. I already tore all the plastic off it and replaced it with wood and stainless steel. Pricey, but I am worth it.


  9. Off-topic, but is anyone else unable to get on the PA site to order? Ordered something this morning and all was OK. Went to check on my order’s status and have been unable to log on. I am getting an error report . Been that way since this afternoon. Tried from the yellow forum header banner and the link above , and the link on the airgun arena dealers page but no joy?


    • Robert,

      Can’t help you but maybe Edith can.

      I have a way off topic that hope someone can comment about.

      Came across a custom build in 6mm ppc. Never had one. Built on a sako action with shilen bull barrel. Nice custom synthetic stock (don’t care for synthetic stocks) and a Swarovski 3-12×50 fine reticle. .238 ctc 10 shot targets at 100 yards (supposedly). He shot 10 shots of 3 different loads (30 shots total on the gun). Saw the sako case of cartridges with only two boxes touched.

      Would like this to be a competitive bench rest gun at 200 yards and a coyote gun from a blind at up to 200 yards. Am I enamored and/or dreaming? Is this smoke and mirrors?

      kevin


      • Kevin , don’t have one but have read a bit about the Sako and the 22and 6mm ppc cartridge. Sam Fadala’s book ” Ledgendary Sporting Rifles” ISBH 0-88317, Stoeger Publishing Company ,1992 , which I do have, has chapter 28 devoted to the Sako rifle and goes into some depth on this cartridge. “PPC ” stands for Pindell-Palmisano cartridge. Ferris Pindel was the gunsmith tool and die -maker , and Dr. Lou Palmisano was a vascular surgeon who collaberated to make the world’s most accurate production rifle and cartridge. Palmisano and his son won several bench rest titles with the Sako rifle chambered for this cartridge. Sako picked up on the cartridge in 1988. I would suppose it would make a fine combination for what you discribe, as well as for deer hunting.


        • Robert,

          Thank you very much.

          I envy your library.

          It’s a tiny thing compared to my 22-250 I currently use for coyotes but the difference in report is critical for me. Deer hunting is not a factor.

          Forgive me but I must ask. Any details on the bench rest matches they won?

          Thank you again.

          kevin


          • Kevin,

            Again, no details, but the 6mm PPC has won ALL the benchrest matches, since it was created! It is the dominating caliber.

            B.B.


            • B.B.,

              Very interesting. Thanks for the validation. Yes, I’m hoping that minimal wind allows me to shoot the 6mm ppc this weekend.

              kevin


          • Kevin, You’re welcome, and here is some more info… From Sam Fadala’s book that I mention above: Palmisano won the 1975 100yard Heavy Varmint Class Aggregrate with the 22PPC . Five , five shot groups totaled .265 inch center to center. In 1976 ,his son won the 200 -yard Bench Rest Shooters National Championship , with a 25 shot aggregate group of .3280 inch group . From 1981 -1985 ,116 IBS ( International Benchrest Shooters) records were broken ,every one by shooters using a PPC . By 1981, 59 of 60 competitors were using the PPCs. When in 1987 various IBS records were set , the 6PPC set them all. That same year ,several NBRSA (National Bench Rest Shooters Association) records were set also. All but one was captured by a 6 PPC . That one was by a 6 PPC with a shortened neck. I’ve also have seen articles on this cartridge and the rifles in the “Rifle “and also “Handloader ” magazines of the 1985 -95 range/era. These two cartridges essentally blew the old BR standards of the past out of the running.


            • Robert,

              Now that is very interesting. Greatly appreciated. Based on your information I’ve become very interested in this gun. Thanks.

              kevin


      • Kevin,

        Robert gave you all the info, but I’ll throw in my two cents. I hear the 6mm PPC is hands-down the most accurate cartridge in the world. From your description I know the price is high. Will he give you the chance to shoot a group before buying?

        B.B.


    • Robert from Arcade,

      I was monitoring the blog comments on my iPhone when I saw your comment.

      I’d emailed Pyramyd Air’s IT dept earlier this evening that I got an error. They couldn’t find it. When I saw your comment, I immediately forwarded it to them…and now they’ve located the problem. Thank you for posting this issue!

      You should be able to log on now and not get an error.

      Thanks!
      Edith


  10. One more reason to love the detuned models we’re getting here in Canada.
    I think the tank for the pistol is the same diameter as the one fitted on the rifles so one could just screw the rifle tank on the pistol and get a bunch more shots… I would look goofy but it would work!

    J-F


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