Originally Posted by mountainman13
How does altering the feed lips effect accuracy?
Some people are reporting a change in POI and group size from one magazine to another. Many report better accuracy with Ruger 20rd mags as opposed to the Ruger 5 round magazines. The thought is the spring tension and lip configuration play a roll in the amount of force on the undeside of the bolt causing some difference.
With the 5 round magazines many report a consistent 3 and 2 pattern. Three shots grouped tightly and then another two offset and also fairly tight. Some people report just the first round off from the other four with the grouped four being very tight.
One school of thought is the first round is stripped using just the manual retraction and release of the bolt. The rest being stripped by the gas system propelled movement of the bolt. And this causes a change in the flight path in some way.
Tri70 has labeled each of his mags to track performance and has come up with these tweaks. He seems to have done the most extensive tracking.