Difficulties With The IZZY

[Frank in Fairfield]

Shot Sillywet today at Concord, CA.
I shoot the pistol ranges with the peep-sighted HW35.
Did OK (for me)...62.5%

Was going to shoot the IZZY too but it was acting up.
I have no clue why.
I shot the first shot at 10m and the pellet hit about 5 “ low.
The next one fell somewhere.
The next sounded like it didn’t fire at all.
So I shot again.
Pffft.
I looked in the muzzle and could see a pellet.
So, I shot just the rifle.
At home I am ready to tear into the pistol.
First I pushed out the pellet (pellet (s) as it turned out).
Then I cocked, loaded and fired.
Fine.
Repeated the process 25 more times.
Fine.
Hmmmm.
Clueless.
I did take some photos of one of the pellets.
It is not damaged so the rifling can easily be seen.
Now, we know why the IZZY shoots so well.
With most of my air arms the rifling appears only on the skirt.
The IZZY engraves rifling on the head and the skirt...

[Frank in Fairfield]

Checked the speeds today with ten 7.0 RWS Basics.
482fps.
Sd: 9

I shot a target from 18 yards.
I guess I will adjust the sights.
I shot ten but the bunch at 3 o’clock is seven of them...
I guess it is OK...

[Duckfish]

Gremlins!

[Frank in Fairfield]

I suppose

[subscriber]

Frank,

The "stuck" pellets look like Crosmans?  Hard lead with "large" heads, and undersized skirts (expanded from the jamming and unjamming).  Even at that head diameter, there is a large gap between head ans groove diameter.

Thus, I  think the Crossmans leak too much air past the pellet, and require a higher pressure to get going, due to the hard lead and large head.  Thus there is also more air leaking at the breech seal.

My 46M is relatively new, yet I can swear the breech seal leaks a little (trying to remember what I did to make me think that).  No, I don't store it with the breech locked down.

I think your velocity with the RWS pellets is ballpark, so it might be a matter of the pellets you chose.  I have shot 10.3 grain JSBs from my IZZY, and they achieve a little over 400 FPS.  So, it is not the weight, but the friction and the ability to seal air at the pellet that matters.

I have never tried Crosman pellets in my IZZY.  An I don't really want to...

[Frank in Fairfield]

Opinions.
Everybody has one.
I was surprised there was any engraving on the head at all.
The good Dr. Beeman used to tell us the most important part of the pellet is the skirt.
The problem with the stuck pellet was not the size of the pellet.
This IZZY has shot 6-7000 CPH pellets.
The problem was I put too much oil in the chamber.
Shooting in the sun you can see it when firing.
After shooting 200 Crosmans yesterday it is fine now.

[subscriber]

The problem was I put too much oil in the chamber.

You left that part out, when you said this:

I have no clue why.

In the absence of facts, all we have are opinions.  Or in my case, speculation.  Reasonable speculation.

[Duckfish]

Nope, you are all wrong.  It's Gremlins!

[subscriber]

In all seriousness, whatever one did to a system between it last working right, and the start of malfunctioning is usually related to, if not the direct cause of the trouble.

Many a forum goer has declared, "my gun does not work anymore".  After some careful teasing, it becomes apparent that trouble started directly after some parts were changed.  However the chap experiencing the trouble does not believe his improved parts could be the problem, so he fails to mention it. 

My IZZY shoots slower after I oil the compression cylinder, despite the higher compression that one can feel while cocking it.  It seems that sneezing oil with every shot makes the air "thicker" and harder to flow.  Or the film of oil in the bore adds significant viscous drag, as the pellet travels down the barrel.  All I know is that the velocity is reduced from peak performance, until the gun stops sneezing oil. 

Dry firing the pistol with the muzzle and inch from a piece of cardboard is my test to see if there is obvious oil expulsion.  Oil expelled results in a dark patch that is easily visible, while too much oil is present in the pistol's valve body.  If it does this, I store the pistol with muzzle up at about 45 degrees for a few hours; with the grip uppermost.  The idea is to accumulate the runny oil near the open valve body exhaust port; so the bulk of it it can flow out under gravity.  Then I dry fire muzzle up a bunch of times. 

Everyone with an IZZY knows the above, or will discover it.     What I have not encountered is a pellet sticking in the barrel because of over oiling.  With mine, the velocity drops perhaps 30 FPS when there is so much oil that after a few shots, the bore still looks drippy wet.  As in, the oil forms fillet radii at the corners between lands and grooves.  This is with H&N Excite wadcutters.  The only pellets that shoot close to the rated 500 FPS out of my 46M.

This is just be my opinion, but people who post about their trouble should not be snippy when someone tries to help. 

[Frank in Fairfield]

I shot the IZZY today. More on that later.
First...we all know that we should store our multi-pump pneumatic rifles/pistols with a pump or two of air to keep pressure on the seals.
For the IZZY we know we should keep the bolt dis-engaged to keep the two bolt o-rings from flattening out (It is in the instructions, too).
But, I have never stored the IZZY (single pump pneumatic) with any air while stored.
After the above mentioned incident last month, I have begun doing, just that.
Too, I would recommend the same procedure for all pump pneumatic pistols, FWB, etc.
My results for ten shots today are as follows.

[subscriber]

I left one of my P17s charged to see if the sealing might be improved.  After a few days, I found the valve locked up.  Shooting it would make a mild pop, and the gun would not breath to take a full charge. 

My conclusion was that the valve o-ring had extruded into the valve throat.   After many attempts at dry firing and leaving the pistol uncharged, it recovered.

So, leaving any given single stroke pneumatic charged may or may not improve performance.  Probably, as always, the devil is in the details.

[Frank in Fairfield]

While I did not leave it charged for several days, after 24 hours, it was still holding air.
I inserted a pellet and sent it down range.
I didn’t check the speed but the sound was good and it hit point of aim..
The research continues.