I have the same combo, in 308WIN.
The scope isn't a bushnell, it's a simmons.
Check your rings and bases for being sure they're snugged down well, then try your test again.
Alternatively, ditch the POS simmons, get something that will actually hold a zero, and start over.
I'm waiting to get mine set up until I put decent optics on it, with quality rings and bases to go with it.
Simmons scopes are good for pellet guns and 22's IMHO, but not much else.
Bushnell is a fair scope for the money.
I'm going with a Millett or a Nikon.
Have had good experiences with both, and I usually go with what I know.
Yes, they're a lot more money, but in most cases with optics, you get what you pay for.