This fits all Remington and Remington aftermarket short action firing pins. Both ends are ground and the spring stressed relieved. The spring will not snake on factory or after market pins. I have priced the spring at a very fair price, paying 3x's the price does not get you a better spring. Chrome silica wire, is chrome silica wire!
I want to tell you about my experience with firing pin springs. The gun is a Stiller Viper LV in 6ppc with Krieger barrel. I installed one of your firing pin springs with a shim to give 23.2 pounds at cocked length. Pin fall is .220", protrusion is .060". August 2018 at a small match in Selkirk Manitoba Canada the gun shot a .1760" agg and won 3 yardages. https://benchrestforum.ca/index.php?topic=1315.0
May 30th 2019 I installed a Duo spring with no shim, 24 pounds at cocked length and tested a new lot of Barts 65 grain boat tails. The gun agged .3062". Either it didn't like the new lot of bullets or the Duo spring, which gives a big WHACK! and the crosshairs jump.
I put your spring back in, the same one that I shot the teen agg with and the gun agged .210" in the next test.
What does this prove? I can take a proven good shooting gun and knock it right out of tune with the wrong firing pin spring.
I recommend a Duo spring to everybody I shoot against.
Kenora Ontario Canada