Does ones scope have the ability to dial out parallax?
No it sure doesn’t. Can that be a factor at 300 yards?
Next time out, prop up ones firearm on a stable platform, look through the scope, and move ones head side to side/up and down and check out just how much his cross hair intersection appears to move at a variety of ranges from near to the extreme horizon. Make sure ones firearm is absolutely stable during those gyrations. That perceived movement is "parallax." At some given range there will be none. Likely near and far, it will be present.
If ones technique is such that his eye is perfectly aligned with his scope's central axis for every round fired, it will never be an issue. That is not the case, however, in most instances. Especially so in contrived field positions. I even have adjustable objectives on my lowly 22 LR's that go to the squirrel fields.
Yes, it can be a significant factor when one is attempting to generate clover leafs at a variety of distances, and is one more variable that can be eliminated with good equipment allowing it to be dialed out at any given range.
It's likely the reason we hear some arguing their arms generate horrid groups at 100, and then their slugs settle down and start doing miracle clover leafs at some extended range.
If it cannot be dialed out, some of the better scope makers can set ones unit up to be parallax free at a specific range. I.e. if one is a 1000 yard competitive shooter, then have his fixed power scope assembled for that range.
It also becomes more of an issue with increases in magnification.
Have a good one,