Winter Project - Nelson Magazine Springs

When I owned a Ruger MKIV, I purchased some "extra power" magazine springs (~25% increase) from Volquartsen, which helped with stripping rounds and overall feeding. At first I tried the normal (online) suggestions on replacing the factory spring, feed-lip dimensions, lubrication, etc., but with ten rounds in the factory magazine, the top round would sometimes not chamber, instead being pushed down into the magazine. So I bought some of the Volquartsen magazine springs, and that solved the problem with the ammo I was using. 

I've been having the same problem at times with my Nelson (polymer) magazines, so I thought I'd investigate a similar solution. In general, the magazines are otherwise reliable. A new Nelson factory magazine spring is approximately 6" long, with a mean diameter of 0.311". The wire diameter is 0.027". When you calculate an estimated k value, it is roughly 1.06 Lbf/in using basic compression spring equations. I tried to find a single spring (available online) that would work, but I could not find one. I was also not willing to blindly experiment with the myriad of candidate gun springs out there, having no real useful technical specifications. 

I found a spring online that could be stacked in series (2 total), increasing the magazine spring force. From Axcess Spring, part number: PC031-345-19250-MW-3100-C-N-IN. Two stacked on top of each other are 6.2" long, similar diameters, each spring with a k value = 2.48 Lbf/in. So with two in series, the (effective) 1/k_eff value is 1/2.48 + 1/2.48, thus k_eff = 1.24 Lbf/in, which is about a 17% overall increase over the factory spring. They stack perfectly, and sufficient to still hold 10 rounds. With 10 rounds, compressing the springs requires noticeably more effort, and you can see a small increase in feed lip separation with 10 rounds inserted. I worry that the small hole in the follower might crack prematurely when pulling down on the follower with the Nelson tool, but feeding is reliable. I only load 5 rounds at a time; overall much improved.