Spring rate & tuning.

My Giles hvy slide .45 had/has some vertical from the RR w/wad loads.  One hint I was given was a bit heavier recoil spring to ensure consistent lock up.  I popped for the deeee lux pkg and started working my way through them.

My load is 4.25 of Clays, 185 Zero coming off a Sq Deal B.  An odd powder charge you say?  I cycle multiple cases through to get things shook up/settled in then run 10 through and dumping onto a Scott Parker tuned 10-10.  I ended up  with 42.5 gr reading.  This was an increase from 3.94 w/200gr (ran out of them).

Last night I had a couple of alibis in sustained fire at league.  I also had maybe one during the two SF stages.  I thought I may have just started to relax a snidge as shot was breaking/no follow through/limp wrist.  The cases were all trapped horizontally, no stove pipes.  My best SF group started with a 7  and ended same (grrrr) + an 8 and 2 9s.  I've been in a lonnng slump and am having a hard time climbing out.

So, was it me?  Is it the +/- .1 in the equipment?  Some rounds were a bit sharper I noticed.  Being a BE shooter, the less felt recoil, the better so want to stay as low as possible w/100% functioning naturally.  IF and I say IF, I'm just on the edge where maybe 2-3% of the shots are less rigidly held and the recoil spring is just a tad too stiff...........here is my question:

Is there any merit to the concept of backing down 1 lb on the spring and putting a short filler in the plug, say 1/4" or a bit more for more preload?  Maybe another .1 of powder won't be the end of the world either.

I will say when I started changing out springs, I was dismayed to find the previous owner had cut the one in the Giles.

IMO the loads a tad light for a full metal jacket in your gun, heavy and long slides require more energy to cycle correctly , clays is close to bullseye in burn rate, 4.5 is what does well for almost everyone shooting the zero 185 fmj-hp so id up it to 4.5, or drop the spring a lb or two and try that.

I assume you did not change primers.  It isn't mentioned often, but the primer can make a big difference with a light "borderline functional" load.  I know that in my wadgun a load developed with Win primers, for instance, will not function reliably with Fed primers; it needs more powder.

I don't know what Giles did, but in his day cutting springs was common.  The wide variety of spring weights we enjoy has not always been available.

From the RR.. right?
The RR can be very tricky at times... I pull mine apart before a test and clean the clutch disc and plates..
The consistency by which the RR moves is super important to eliminate the stringing tendency... If I am stringing, and the gun is tight in deflection, I immediately check my plates, spring tension and take care to fully reset exactly the same every time.... I use a leather boot lace to activate the trigger bar, to remove human touch.. The boot lace goes limp at the instant of recoil, whereas a human may still be exerting pressure on the bar.. The "Random Rest"

I didn't think to mention that these Zeros are their swaged offering in SWC, not the HP. I have both but had the practice ones with me, not the HPs.

The same RR was used a bit later that AM or was it earlier?  Either way, a Springfield had 10X w/no cheap Xs at the std 50ds.  The rest owner is well seasoned so I'm pretty comfortable with his execution.  However, the string idea is GOOD.  I'll mention that to him.   Primers were WW.