Intermittent underpowered problem = bad pellets? SOLVED

[ihasagun]

I've noticed a problem that once in a while my IZH 46M makes a lower pitched sound when firing and the pellet seems to come out underpowered, striking feet low or even plopping out onto the floor. I thought I might be occasionally loading the pellets improperly or cocking the pistol improperly, but I did a lot of testing and could not duplicate the problem predictably with cocking behavior, and I still saw the problem occur when I knew I at least didn't load the pellet backwards. So I'm wondering if my pellets could be to blame? I'm using Crosman premier 7.9 grain hollow points I bought at the local Walmart. But then, I don't ever have this problem using the same pellets in my Triumph.

SOLVED: Turned out to be a missing breach seal.

[TenMetrePeter]

more likely not getting a full charge due to an occasional glitch or a leak. Try this - does this happen if you wait 2 minutes between cock and fire?

[v76]

Might be that Crosman pellets are not very uniform in diameter. I stopped using them even for plinking.

Could also be that you need to lubricate all the seals, especially the piston seal and the breech seal.

[Rover]

Feet low? It sure ain't the pellets.

[Houngan]

Counterpoint: It's the pellets. I had the exact same experience with the exact same brand in a 46. They aren't uniform and they're already a bit small. I switched to Gamo match which have an excellent fit, and have never seen the problem again. Except, of course, when I accidentally used a Gamo tin that was full of random pellets, and then it started right back up again. Get the Gamo, you won't be disappointed.

[TenMetrePeter]

no way can it be the pellets. I could shoot a matchstick and it wouldnt plop on the floor or affect the sound. There is a distinct lack of pffft in that gun..

[Chia]

My money's on a seal problem. Have you ever had one get stuck in the barrel and just not exit?

[kevinweiho]

Have you been oiling the seals and storing the pistol with the breech lever unlatched? Check the two breech seals to see if they’re in good condition. Is the closing stroke of the cocking lever consistent or has it gotten easier to compress the air? It's not a pellet problem, I concur that it’s a seal problem.

[ihasagun]

My money's on a seal problem. Have you ever had one get stuck in the barrel and just not exit?

Yes. Then I recocked the pistol and it fired the same pellet just fine. I also tried cocking it and waiting a few minutes before firing it but that had no effect. I inspected the impact points on the wall where it hit low, and it's not actually feet. More like 6 inches to a foot. And I supposed the sense that it's sometimes plopping out on the floor could be from ricochet. I just started using the IZH again recently after storing it for about 3 years with the breach closed. I have not oiled the seals since storing it. I'm not sure where my pelgun oil is, nor my game match pellets I also stored somewhere. So I just bought these crossman pellets at Walmart for now.

[kevinweiho]

I just started using the IZH again recently after storing it for about 3 years with the breach closed. I have not oiled the seals since storing it.

The breech lever should always be unlatched when the pistol is not in use or stored for a long period of time. If the breech seals are completely flat and not protruding a little bit, that’s the cause for the loss of power, and you’ll need to replace them. Also oil the piston seal with two or three drops of pell gun oil and work the cocking lever back and forth to spread the oil in the air cylinder.

[ihasagun]

I just started using the IZH again recently after storing it for about 3 years with the breach closed. I have not oiled the seals since storing it.

The breech lever should always be unlatched when the pistol is not in use or stored for a long period of time. If the breech seals are completely flat and not protruding a little bit, that’s the cause for the loss of power, and you’ll need to replace them. Also oil the piston seal with two or three drops of pell gun oil and work the cocking lever back and forth to spread the oil in the air cylinder.

The breach seal on top is flat. The one facing front is completely missing.

Anyone know where I can get some breach seals for the IZH in the US? NVM, I just ordered some from Pyramid.

Thanks!

[Rover]

Ace Hardware?

[mikeyj]

The obvious test is to get a tin of RWS hobbys and try them. You should really be using a nwadcutter in the gun regardless.

I sincerely doubt it's the pellets. I used 7.9gr premiers in Field Target competition for several years, and they were super consistent. Unless they're loose in the breech of the gun I'd look elsewhere.

Does the gun feel different when you cock it when you get a weak shot? I'd guess you have a leaky valve in there.

[ihasagun]

I found a set of seals in the box the IZH originally came in and installed the lower breech seal. Before, I couldn't even get 10 on the paper, much less a decent group, but I just shot my best ever group of 10. Too bad it was centered high in the 5 ring. :-)

[Houngan]

Huh, now I'm trying to remember if I ever changed my seals. I'm almost sure I didn't.

[nglitz]

Ace Hardware?

Those seals are not typical O-rings. I wish they were, but they are a trapezoidal cross section. The wider bottom face fits into an undercut in the breech itself. Fire the pistol with the breech unlatched and the seals will launch themselves across the range into the dark, dusty corners.

$10/pair for Izzy seals vs. 10 cents each for O-rings at Ace or $5/bag of 100 at any industrial supply house.