Does filing the kick change the position of the spring?

[TheChunk91]

It's a matter of degree. Since the kick is extending the spring, changing the height will change the position of the spring. Whether or not it noticeable will depend on how much and how good your eyes are.

I think it's important to mention that... flush springs are more an artifact of the hafting process than something meaningful. The springs are ground flush along with the handle material. Since it is the result of grinding, it is not a matter of precision (though it often is mistakenly addressed by collectors that way). In contrast, Victorinox finishes all the parts prior to assembly and the springs are not ground flush. It's done this way for several reasons but the plastic and anodized aluminum handles are not well suited for grinding the backs. I suspect Buck may not grind the backs on the 301 but I'm not 100% sure.

If the parts were cut with such precision that they were flush without grinding, that would be impressive. But they're just ground flush. Similarly, it's not a matter of precision when blades are centered by annealing the tangs and bending the blades straight.

That is a good, complete answer.

 

[Will Power]

Well, I really messed up the springs on a CASE Med Stockman whose high riding Sheepfoot I found offensive and uncomfortable. Down came the Sheepfoot's kick, the blade lowered nicely but due to recklessness it sank the spring significantly on open making it rough and uncomfortable in the hand. Go very carefully.

Not going to risk that again as flush spring(s) open/closed are an absolute must for me. Others don't mind it though, I can't stand it

 

[Ernie1980]

Sv-97, thanks for the visual!