I did a thread awhile ago about a chance I had to compare an SP2022 in 9mm to one of my P229R's in 9mm. The general jist of the thread was that the difference in accuracy between these two guns in probably overstated most of the time. The "classic" SIGs are probably a "nicer" gun (feel, look, etc.) for most people, but they are not really that much farther ahead in accuracy (if at all). These were the targets:
This is the thread:
http://www.canadiangunnutz.com/forum/showthread.php?t=247831
I only have about 40 rounds down range on an SP2022 (the results of 20 of which are shown in that thread), whereas I have around 9,000 rounds down range in two 229's since I starte shooting them last summer - and the difference in accuracy is not much.
So... all of that droning on is meant to suggest that I think SP2022 in 9mm is a good accurate platform to start from.
Now... what is going on with your shooting? First of all, if you have a new gun or think you might be having any problems adjusting to the gun, don't shoot at 25m. You're just going to frustrate yourself. Start with around 7 yards. Move up from there as you get used to the gun.
Secondly... I've been shooting about 300 centrefire pistol rounds a week for 3 years now (since I finished law school and could afford it!). I've improved a lot in that time, but I still have to remind myself... if I am not willing to commit to good consistent technique on every shot fired, I should not have any expectation of good consistent results. Go back to your fundamentals and focus on them. Trigger control, proper strong hand and weak hand technique, stance, sight picture, concentration. I'm not here to tell you how to shoot, just focus on what has worked for you in the past. That is the best advice, I think.
The other thing is, remember that there is a limit to the practical accuracy of most of these handguns. I have been practicing hard to shoot fast and consistently tight groups. This was a nice set of groups I saved and measured out from last weekend. This is about the best I can do with my favorite gun, favorite ammo, with lots of practice:
Another really nice 229 grouping I saved from ahwile back:
That is the absolute best I can do with a 229 (and that is great shooting if I do say so myself), and the 229 is known as an accurate gun - and I could do almost the same with an SP2022 in my first 40 rounds of trying. So the moral of my story is.... focus on your technique and it will come around. That and move your target closer. Good luck.