Why would bullets from a Walther P22 keyhole?

I normally teach new shooters with a Walther P22. It’s small, light, acceptably accurate and runs fine with subsonic and standard velocity ammunition.

Last weekend, all subsonic and standard velocity ammunition began keyholing quite severely. At 5ft, the spread was several inches and all bullets impacted the target sideways. At least I had no baffle strikes. High velocity ammunition works just fine, but it is much louder and less suitable for teaching.

Walther tech support wouldn’t guess as to the cause. I am baffled also. Any ideas?

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31 Responses to Why would bullets from a Walther P22 keyhole?

  1. Sigivald says:

    Does it keyhole with the can off? (Assuming the picture is current and it was being fired with the can.)

    I ask on the vague theory that some problem with the can could destabilize the bullet – and in any case it’s a variable to exclude/confirm.

    • Sigivald says:

      (Okay, a closer read suggests very strongly that the can was on.

      But still – does it reproduce the problem with the can off?)

      • Oleg Volk says:

        I do not know, don’t have a barrel bushing wrench but one is on order now. Still wouldn’t explain why high velocity bulk ammo printed a tiny group.

  2. When was the last time the barrel was cleaned to remove the fouling?

    With .22s they often build up a lube track from the lead deposits. If the lube track is getting heavy enough the standard and low velocity rounds may be going slow enough to not be stable. Another option is at the slower speed the bullet may pick up excess deposits or shed more weight throwing off the center of gravity.

    The high velocity rounds may be going fast enough and have enough pressure to not have a problem with the lube track.

    If it has been cleaned, I would do it without the can on and see what happens. If it still tumbles break out a chrono and make sure you’re getting expected velocities. It is a mysterious problem keeps us updated. I’m interested in hearing what the final root cause is.

  3. Miguel says:

    Undersize bullet? It might not be biting the grooves enough at low speed.

  4. Terry says:

    Something’s dirty is my guess. Cans can load up and create enough back-pressure to slow the action down, so I’d suspect if you chrono’d your selection of ammo, it’d all read low.

    In MT, I shot a G19 with a can that had been used for instructing earlier, and developed enough backpressure that the action wouldn’t cycle.

    Clean everything – barrel, can …

  5. Sideburns says:

    I’d eliminate causes 1 by 1 to determine the cause. I’d first remove the suppressor. Second clean everything. Third visually check for crown damage and rifling damage. Forth check for chamber damage. Fifth get a replacement barrel. Sixth replace the whole gun (or send it to a competent gunsmith if it was a higher value tool, I’d hate to spend more than the gun is worth repairing it when it can be replaced with a new tool at the same or less cost).

    Yes. Guns are tools. Just as a 15 round mag is standard capacity not high capacity in a 9mm/.40 s&w.

  6. When I bought one for Dixie, my research brought me to only use CCI Segmented HP Hypervelocity. They are 32 grain and 1640 FPS. Never had a problem.

  7. The Architect says:

    I’ll second that – dirty barrel. If you’ve run any copper jackets through it, doubly so. Sweet’s 7.62 does a killer job if it’s badly fouled.

  8. I’d say fouling is likely, made more likely by the can. You could have had a baffle strike and the can is causing the key holing. First step is to get the can off and clean both the can and the gun. If you can take the can down, do it and check each baffle. Check the crown on the barrel (very common source of key holing)

    You could spend a lot of time trying to figure out why it’s key holing, but I can almost guarantee you that once you have everything torn down, the answer will be obvious.

    Or you can send it to me and I’ll fix it for you 😉

  9. Alexander Smirnov says:

    Which ammo did you use? I am using P22 for teching too. Last time I went I had problem with loading almost each third round. I noticed bulett had to much wax. It was CCI ammo.

  10. Lanius says:

    @Architect
    Copper fouls more than lead?

    I thought it was the other way round. I guess ammo manufacturers should start making epoxy coated lead rounds, those actually clean the bore..

  11. Firehand says:

    I’m with clean the bleep out of the bore and try it. I had a Sig Trailside that was wonderfully accurate for about 75 rounds; at that point fouling built up enough it started throwing patterns instead of groups.

    In this case, what fixed it was a stuff called Microlon Gun Juice. Cleaned the bore to make sure had all traces of fouling out, then treated it as per the instructions; no problem since.

  12. David says:

    Betcha that bore’s smooth from all the lead fouling in the grooves. Loooong scrub time, Choreboy copper pads do wonders on lead. Had to be the Choreboy actual copper pads, the cheap imports are copper washed steel that can actually scratch the bore. High velocity might have been going the right speed to pick up what little rifiling is still available while the others skipped over. Not a gunsmith, nor do I play one on TV. 🙂

  13. Nikolay says:

    Стволы и глушаки иногда надо чистить.

    • Oleg Volk says:

      Кирпичом?

      • Nikolay says:

        Как это ни противно, надо снять глушак и чистить его отдельно (промывать раствором от освинцовки). Ствол – обычнам манером, но тоже промыть. Пули-то мягкие, освинцевание быстро приходит. А у дозвуковых недостаточно скорости, и их срывает с забитых нарезов.

  14. BoomSmurf says:

    Had the same problem with my Ruger Mini-14. And that one’s only used with FMJ’s. Problem did start after burning up a lot of Barnaul’s ammo (with the lacquered cases) at a high speed. Apparently the lacquer started to come off of the cases when the chamber got very hot. Subsequent rounds pushed the residu into the barrel while leaving their own in the chamber, cycle to be repeated shot after shot, building up some serious fouling. [sarcasm]Had fun removing that from the barrel and chamber [/sarcasm]

  15. Kevin says:

    Did you ever get the ultrasonic cleaner you were asking about?

  16. JD says:

    only time I saw this was with a friends .22. Barrel was so dirty you could barely get the cleaning rod through it. . . . clean clean clean I think. . ..

  17. trainer says:

    Mine keyholed with lead fouling the bore. Got the lead out (in a perfect half-cylinder) and it was fine.

  18. North says:

    I have to agree with Barron and the others. Visually inspect the inside of the barrel.

  19. Philip says:

    I know you mentioned that you used more than one velocity, but was it all the same brand of ammo?

    The first two things I’d try are trying some different ammo in those velocities.

    The second thing I’d do is clean it thoroughly.

    I’m not a gun doctor, but it occurs to me that it’s possible that the pressure from the higher velocity ammunition might be causing the bullet to expand a little more and get a better grip on the unfouled portion of the rifling, which would keep it spinning.

  20. Kristopher says:

    Clean yer barrel and can. Then inspect both carefully for damage. If you can’t remove your can in the field, fix that.

    .22 lrs are dirty. They need much more maint than other rounds.

  21. Mark A. says:

    My Ex-Father In Law had a small gunshop, I used to work for him and 90% of the problems with .22 semi-autos always came down to a thorough cleaning was required. The lower velocity rounds don’t have enough oomph to obturate the base of the bullet into the rifling. You don’t normally hear about .22’s obturating but they do slightly at standard and more so with high velocity rounds. So a thorough cleaning of the pistol and can with a furious scrubbing of the bore should get the ammo back to proper spin stabilization.

  22. Nikolay says:

    Мыть горячей водой с мыльным раствором для посуды. Можно совсем мягкой натуральной щёткой.

  23. tincankilla says:

    i’ve been looking into a P22 since i went plinking with a friend’s last month. i recently read online that you’re ONLY to use high velocity ammo. it’s a good post: http://www.spentbrass.com/pistol/walther/p22/ammo.php

  24. GreySquirrel says:

    Agree with cleaning suggestions above.

    If a through cleaning doesn’t help, check the bore for poor or shallow rifling. Had this problem before myself. Upon close inspection the bore was apparently oversized and the rifling so shallow as to not prove effective. Worth a look…

  25. Firehand says:

    Might consider picking up a Outers Foul-Out cleaner; the newer version is supposed to work a lot faster, and it’ll clean the bore down to bare steel, no trace of fouling left behind.

    Mine’s an older one, still works very well.

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