Overshot Issues?

Hi; I am a fairly new weaver(about 1 year).  I recently tried an overshot pattern.  The pattern was done correctly, but it came out really elongated.  It was supposed to form a circle but was a long oval.  The weft patterns threads were all separated instead of filling in a section.  I'm thinking it's because I can't beat very hard on my small 22" Norwood loom.  I almost always come out with a smaller number of ppi.  But usually it doesn't affect the look of the pattern.  Anyone else have this issue?