Accuracy is down to the match of your paint to your barrel basically. Closed bolt vs. Open bolt and that garbage is a bunch of crap. Low pressure markers are thought to have better ball-on-ball consistency because of having a "more stable shooting platform" (which is only true if they ALSO have a low reciprocating mass), but basically, you're shooting a ball of round gelatin through the air, there's only so much you can do. The purpose of putting a Jackhammer reg on an Impulse is to have an adjustable LPR pressure. The LPR isn't "whacked on the front of the expansion chamber", it's put there to take in the air coming into the marker and cut it's pressure down. In an ordinary impulse, your input pressure is your solenoid pressure, that is, the air coming into the valve chamber is the directed straight to the solenoid without being regulated first. So if your input pressure is too high, you risk destroying your solenoid. The Jackhammer reg takes your input air, regulates it to your desired pressure, then directs it to the solenoid, giving you more control, and making it less likely that you'll kill your 'noid. How does that affect range you ask? It doesn't! Any marker shooting 300 fps is going to have equal range to any other marker shooting 300 fps. And since accuracy is down to your paint to barrel match, and your ability to control your marker, that pretty much solves your question: Neither gun "wins", it's all down to preference.
