When somebody says a mainspring is weak, how do you test that? when military rifles are sporterized do you replace the springs with custom ones or continue using military?

thanks

Red

It's customary to replace the springs.

Dago Red,
On most military bolt actions, it's real easy. Pull the bolt sleeve/pin/cocking piece ass'y out, place a block of wood on a weight scale (30# chemical or baby scales are better if have one), & tare it to zero.

Then slowly press the FP tip down into the wood (straight down or it will slip sideways), holding the ass'y by the bolt sleeve. When the CP/firing pin starts to move up, immediately read the scale poundage.

I replace the spring if the inital force is 20% less than standard issue, i.e. the standard issue Mauser M98 is roughly 17# uncocked & 19# at "fully cocked". Anything less than 14# initial is weak & replaced on an issue M98.

Most miltary main springs are still avaialble from Wolff & they even list the standard miltary "full cocked" poundages on their website. If I remember, they start at 19# & go up tp 24# for late model Mausers.

Yes I do understand that this is the initial "uncocked force", and the force will increase as the spring is further compressed all the way to the "cocked length", but this initial has always worked great me. You could even check the full cocked force if you can meauser the CP protrusion out of the bolt sleeve & read the scale all at the same time, but you'd need three hands to do it.

However, if the cocking piece is speedlocked or the fall shortened, then the preload will probably be in the 20 pound initial range...

For semi's like Garands & others, you've got to lathe a collared shaft to fit inside & then compress the spring to a measured compressed length, then compare the scale reading against spec poundage.

Hope this helps.