Need Help...Shooting To The Left?

[Theodore LeDurt]

Finally picked up my gun on Friday (DH with 32" tubes and straight stock)and went sporting clays shooting today. Probably should have done some pattern board testing, as my score was below 20. Normally I shoot in the mid to low 40's with other sxs. Must admit the 3" drop and no cast intimidated me, so upon returning home I patterned the gun and noticed on 75% of my shots, mounting with a low gun, patterned 12"-18" left, but centered, especially after taping a 1/2" piece of foam to the top of the stock.

Would this shooting to the left be caused by the lack of cast, or perhaps a bit more pitch than I'm used to? I am 6'4", 300lbs, with long arms. Normally I put on a leather slip on, but needed a a larger size and CSMC are presently backordering them. The lop was still 14 1/2", but normally 15+" is required.

Thanks for any help. Signed, "Embarrassed At The Range In Wisconsin"