HW 30 Accuracy Problem

Help! I My "fun gun" has gone bonkers.

One or two of every five shots are dropping four to ten inches below the bulls-eye at 25 yds. Straight down, not to the side, never high.

Screws are tight, bore is clean, scope is not moving.

I spent yesterday working with the crony. I am getting a pretty high extreme spread 35-85 fps with 4 different pellets. However, the slower pellets are not necessarily the ones that are dropping. I can have a 571 fps on target and a 572 eight inches below.

This gun is fairly new but I have run 1000 to 1500 pellets through it, so it should be broken in.

I just ran a clean "10 Dimes Challenge" with my HW 50 so I have a hard time believing it's all me.

Has anyone had a similar problem? Any ideas?
 
Well off the top of my head I would think you have a seal problem,either breech or piston, could also be a broken spring but being so new that would'nt seem likely.

I've heard of folks performing a breech seal tissue test to see if that is where the problem lies before opening the rifle, you will have to search the net for the proceedure.

I would also try different pellets to see if u have an inconsistent batch but it sounds like you already tried that.
 
I can also be the lil ball latch on the breech . I had to send my last HW30 back to Pyramid because the barrel wouldn't latch up tight and mine was doing the Exact thing yours is ...It killed me because the gun was shooting lights out up till then


That's about the one/only flaw in this rifles design. If they used a stouter chisel-style latch the gun would be perfect.
 
As others have stated, I suspect something is interfering with the barrel locking mechanism. Try depressing the spring-loaded ball and blow some compressed air to dislodge any crud that might have gotten in there. And also make sure the notch is clean where the ball engages. If it's not locking up properly each time, a tissue test will seem to indicate a bad breech seal that may be perfectly fine in reality. First make sure the barrel is locking up properly, then move to other suspects. 

My 2 pence.

BeemanR7
 
I had the exact same problem when my 30 was new. It came with the common gauling problem from the cocking lever. I discovered that both pieces of the cocking lever were binding against the bottom of the action and the barrel would not lockup properly. The pic below shows where i had to remove material to correct this.
1532890385_12162129215b5e0d11a6dd82.55570102_HW30 cocking lever binding.jpg

 
I had the same problem with that pin pressing the mechanism to tight against the air tube,i removed the barrel and pivot assembly and took it to the grinder

And removed at least a 1/16 of an inch then found a plastic coat hanger cut a piece to fit into the lever mechanism ( had to custom fit that piece but it was easy, a little off each side then a little off the the thickness until it was a little thicker then the machanism) no more rubbing some as silk.

Shouldnt have to do that to a new gun but it is now perfect 


 
I had the same problem with that pin pressing the mechanism to tight against the air tube,i removed the barrel and pivot assembly and took it to the grinder

And removed at least a 1/16 of an inch then found a plastic coat hanger cut a piece to fit into the lever mechanism


Thanks for mentioning your using a plastic coat hanger. I will keep that in mind. I had no metal to metal contact after all my grinding so did not do the plastic insert mod.

I agree, even though this is their least expensive rifle they could do better on their QC. They DO shoot so damn good.
 
 

If you have a newer gun, did it come with the plastic insert in the cocking lever? That piece is supposed to prevent the galling the newer HW30s have. On my newer "stainless look" HW30, it felt like that piece didn't let my barrel completely lock, and I'd get the same effect: a tight pattern of 4 shots, but a fifth shot way low. I removed it and got a more positive lockup and no more odd low shots. 

If you feel some galling later, then deal with that issue by grinding away metal parts as shown above, or just shooting the gun until it smooths out.