Bug Buster Killer

[Feinwerk]

@rbeckey ,
So it groups ok with iron sights attached to barrel, but not with a proven good scope and mount.
I wonder if it could be the scope rail insert in your cylinder. From the picture you posted in a different thread, I was reminded that the scope rail for the RWS 34 appears to be a separate insert, and that the dovetail is not machined directly into the receiver tube.

Have a close look at how the rail insert is attached (I don't have mine handy right now to look at). If it's screwed down, check those screws. If riveted or welded, look for signs of a crack somewhere that might be allowing unwanted movement.

GL,
Feinwerk

 

[OldSpook]

Loose rail. Good work guys! That specific problem beat me up pretty hard on my D34 too

 

[rbeckey]

@rbeckey ,
So it groups ok with iron sights attached to barrel, but not with a proven good scope and mount.
I wonder if it could be the scope rail insert in your cylinder. From the picture you posted in a different thread, I was reminded that the scope rail for the RWS 34 appears to be a separate insert, and that the dovetail is not machined directly into the receiver tube.

Have a close look at how the rail insert is attached (I don't have mine handy right now to look at). If it's screwed down, check those screws. If riveted or welded, look for signs of a crack somewhere that might be allowing unwanted movement.

View attachment 280304

GL,
Feinwerk

The mounts did not appear to shift when yanked hard. The screws are locked down. There is no sign on the surrounding metal that the rail is shifting.

 

[Moog]

rbeckey, did you check the screws with a screw driver? The reason I ask is because I've had mounts that felt tight when I pulled on them but was still able to tighten down the screws. The scope rail may feel tight but can still move under recoil if the screws are not turned all the way down.
Best of luck to you in solving the problem.

 

[OldSpook]

Don't strip them.

 

[rbeckey]

The screws are secure.

 

[rbeckey]

To finish this thread as I hate when things are left hanging, I got a ARH GRT.MK2 rebuild kit and piston seal and using a homemade spring compressor I rebuilt the rifle. There is now a notable difference in both the sound and feel of the compression stroke and discharge of the rifle.

The Hawke scope and a + 26 mount are now returning groups that are what anyone would expect.

I can only theorize that whatever was going on with the old power plant somehow did not effect the sight picture with iron sights as much as with an optic. I admit that seems unlikely but I really can’t imagine what else it could be. This was all confirmed with another shooter so simple user error is less likely.

In closing thanks to all for input. I must say that decades of experience with powder burners meant little for solving this issue. At least I had decent tools and a work area.