They key to long range is consistency. Sure you'll get occasional hits if you can dial your dope but every squirrel gets a nut once in awhile. If you want to do well by getting consistent hits you'll need to upgrade your glass and definately dump the stock. The tupperware stock on your hog hunter is your biggest liability. There is just too much flex in the stock. Your goal is to do it cheap and I can appreciate that. The Hog hunter is a great donor rifle and the barrel will do the job. I have run 175 SMK hand loads out to 1000 with the HH barrelled action but not with the stock rifle. Actuall the Mueller APT will do the job although with some effort on your part. The glass is OK but at those distances mirage and wind will make it difficult. My suggestion is at minimum a Boyds Tacticool with the pillars out of your hog hunter stock. The Tacticool is cheap but stiff enough to keep the rifle steady. A Bell and Carlson or HS Precision with an aluminum bed will be even better. Also get one of the target accutrigger springs which cost about $8 but will drop your trigger to 1.5lbs. You would not think the difference between 1.5 and 3lbs would be huge but when shooting those distances it makes a difference.

Good shooting!