I have the SD 40 and it seem to be shooting 6" to 8" low. I am new to the hand gun area so alot if not all is probley shooter. Lineing all three dots up and at 15 yards it seems that it is dropping. I am using federal 180 grain FMJ FN. I fired 100 rounds no issues other then the drop. I realy feel that I am just using my sights wrong and using proper alignment. What ammo does work well for this firearm should I drop down to the 165 grain? Thanks ahead of time for any and all response

What is happening is you are using to much finger. When you are pulling the trigger you are pulling the muzzle downward. Try only using above the first joint on you trigger finger. This may be you last joint, don't know. Its the one that your finger nail is also on. Anyway just use that part of your finger and slowly squeeze the trigger. What you are doing is classic for a gun based on Sigma or an actual Sigma. The SD is the new Sigma BTW. Be sure you have enough lube on the critical parts also. these are the parts that move at all, not just where the manual says to lube.

In addition, this may be of help to the reason why:

http://smith-wessonforum.com/smith-w...#post135886672

"But what you didn't say was what sight picture you were starting with. The Sigma sights are made to cover the bull, not lollipop like most of us were taught. That can obviously lead to low shots.
As far as shooting left, that's somewhat of a normal comment about the Sigmas. Mostly it's a matter of dealing with the long/hard trigger.
And then the final factor is the bullets you're shooting. My 40 shoots lower with lighter rounds. "

Sounds like a simple case of anticipating recoil.