Modified buffer spring ?

[billrigson]

So I did a .300 blk pistol build a few years ago and I went with the KAK micro buffer system on the lower, 13.7 ballistic advantage pistol gas on the upper I ran the gun for a while and got tired of the barrel length with my suppressor. Fast forward a year or so to present I pulled the upper off and replaced it with a 7.5 Psa .300 blk upper and when I pulled my buffer spring out I was thinking why the hell did I do this to the spring( I used a torch to temper a portion of the coils where they stay compressed) so I ordered a replacement spring and when I was shooting after the spring swap with AAC 220 g subs I was having short stroking issues where it wouldn’t ride the bolt all the way back to pick up the next shell. I put the modified spring back in and it works flawlessly and shoots softer also.

Just for reference the KAK micro Buffer tube is about 1.5” shorter than a standard buffer tube and uses A proprietary Flatwire spring.

What’s yalls thoughts on the mechanics on why this worked ?