brush buster

I bought one used andnever really shot it till this year , it is inconsistant even at the range after a lot of shooting it started shooting high at 100 yards. Ididn't try any shots over 100 yards that was in a gun vise and just bagged , it kicks and I was shooting 150 grain bullets with a load in the middle of market load andtop max load, that my boss loads for his 270 did not try any of my store bought 130 grain, probably should have .Its only 3 feet long and the barrel is 22 inches of that , it is a handi riflr sb2by new england manf. I have been curios as to how these shoot is yours similar ? I was wondering what the range iswith this rifle. The guy I bought it from said he could hit cosistantly at like 300 yards he said 1000 feeet dunno ,the barrel is so short . and I had a problem with the shells sticking in the breech when I went to eject, sent me home a couple times but thes were reloads and may not have been resized correctly. I will be doing a lot of practising with this gun to see how it shoots, hope its not the gun just me.well don't wanna ramble on forever really want to hear your input.