This past weekend a few friends and I decided to conduct a 500 round stress test to compare the Mossberg 930 SPX ($600ish) I just bought with the FNH SLP Mk. I ($1,000ish) that my friend just bought. The results were very interesting.
The full report is here on Google Docs: Stress testing Semi-Automatic Competition Shotguns
The authors of this paper conducted a 500 round stress test to determine if either of two semi-automatic shotguns, an FNH SLP Mk. I or a Mossberg 930 SPX, would experience mechanical difficulties in order to determine if one was better suited for 3-gun competitions. Testing was conducted using one lightly used shotgun (<200 rounds) of each model which then fired 500 rounds in under 4 hours using two different ammunition types commonly found in stores and rotating through 6 shooters to ensure operator error was controlled for. Data was collected during the testing which was later analyzed, showing that the FNH SLP Mk. I malfunctioned an average of 5 times for every 25 rounds while the Mossberg 930 SPXâ€™s malfunctions were not statistically significant. Based on this and other data this report concludes that the Mossberg 930 SPX is a superior semi-automatic shotgun for 3-gun competitions.