Your amp will probably handle a load of 8 or 4 ohms. I believe the SWR is an 8 ohm cab and the Hartke is 4 ohms. This will give you a load of 2.67 ohms and is not a good match.
"If you don't want the truth don't ask. Make up your own like everyone else does". (Michael Pare as Eddie Wilson/Joe West in Eddie and The Cruisers II).