Recoil Spring Length Modifications

Question for those in the know. I have a new-to-me used wad gun (1995 era Caspian frame and slide, Kart barrel and bushing, dot with slide mount, 18Ib. trigger spring). The recoil spring that came with it is 4.75" long and compresses to 9Ibs.. A full length 10Ib. spring from Wolffe has identical diameter wire and coil spacing and does, in fact, compress to 10Ibs. Test targets came with it showing excellent accuracy with 3.5gr. of Bullseye/200 SWC bullets.
In testing loads the shorter spring cycles 4.2gr. of WST/185 swaged bullets about half the time. The full length spring is reliable with the same load.
My question is this, why the short spring instead of a full length 9Ib. spring instead? No idea who 'smithed it in the first place.

Have you tried 3.5 of BE with the 200 swc, or have you tried 3.9-4.2 of BE with the 185?

You have found a gun that someone found an accurate load for and then cut the spring to function with that load. 

If the 10lb spring works better with your load and you think that your load is as accurate, go for it.

I was just wondering if trimming recoil springs is a common mod. Otherwise, agree with you 100%.

Pretty common if you are cheap or need an expedient solution, but should be a temporary solution until you can install the correct spring.

Generally, cut down springs are not recommended as spring length is critical is certain applications, although 1911 recoil springs are usually long enough to clip a bit, but it would be best if you didn’t.

It is easiest to go buy a variety pack of low power recoil springs and play with them.  You will learn what it too much and too little and how to get it tuned a bit.

You can play with the hammer spring as well to tune the function and trigger pull.  This is not a good spring to cut down unless you are sure what you are doing as there is not a whole lot to play with.

I would not say someone “‘smithed it” as if they were a professional.  If a good pistolsmith worked on it, then the proper spring would be in there. More like “someone took a shortcut with my pistol.”