HELP! Problem with "new" DW 22!

[Stevie]

OK, got to the range with the new 22 (6" barrel, Monson).  Cleaned it first.  Barrel looked good.
Shot a box of 50 from a bench rest.
First three shots grouped in a 1 inch circle.
Then it got crazy (see attachment)
Hits spread over 18", holes were odd shaped, as if the bullet was tumbling.  Occasional hits on center, nice round holes, then all over again.
Looked down the barrel, and there was a little streak of powder at the bottom right at the chamber end.  Couldn't tell how thick it was.
Used Remington round nose high-velocity.

I'll clean it again and try some standard velocity ammo, but is this a sign of wrong ammo choice or bad barrel or what?  Trying to figure out if I should work the problem (new barrel?) or try to get refund from seller....

Thanks for your help!!
-Steve

[wiley]

Shouldn't keyhole unless you are shaving lead. I'd check the barrel gap and barrel nut for tightness. Any chance of a picture of the forcing cone area of the barrel?
A way to see if the bullet is shaving is to fold a piece of cardboard and rest it over the top of the barrel and cylinder. There may be some cutting from propellent gases but you'd be looking for tearing as small bits of bullet material impact the cardboard.
Regards,
Wiley

[Flash]

yep, shaving lead. The bulet diameter is shaved and the gas escapes, slowing the bullet down considerably and keyholing starts then, accuracy is in the toilet.

[Stevie]

Seems to work OK with standard velocity ammo (Remington Target) instead of high velocity (Remington Thunderbolt)....time will tell.....