Group size with out suppressor installed?
Single shot or magazine fed??
10 shot group fired in 1 minute or 10 minutes???
Lots of possibilities w/ a gas/piston gun!
Don't know what your setup was, whether you shot off a rest/bag or freehand. But vertical stringing usually indicates something may have come loose (sights-changed) OR the rifle is "jumping" up when fired which accounts for a vertical stringing. Check and make sure you stock is staying down and not moving up and down. That would be my first place to look.
Alex

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