Trying to find out what pound recoil spring my 9mm Springfield range officer came with from the factory. My manual from Springfield seems to only list the .45 and shows 16 lbs.. I have spoken with many people and have had answers of 9 & 10 pounds. It seemed the spring was a bit weak so I put in a Wilson Combat 13 lb. spring. Went shooting today and found that occasionally the slide would not lock open when the magazine was empty. This has never been an issue so I was wondering if the new spring might be the culprit. Thanks in advance!