Limp wrist?

I've been shooting a lot of 4.1 gn of N310 with a 185 gn LSWC with a 12lb spring without any function issues. I just started trying the same load with a jacketed bullet and I'm having occasional light hits, failures to feed, stovepipes and failures to chamber. I thought the load was too light for the spring so, yesterday I tried the load with 2 lighter springs (11 & 10) but I still had the issues.

After much frustration and discussion and analysis, I think the problem may be the firmness of my grip/wrist/elbow. When I tightened up my grip/wrist/elbow the problems seemed to go away. (also my shooting improved)

I'll have to do some more testing to confirm.

Thoughts?

Your load sounds a little light.  I think others running that powder user 4.4.

That does to be a common consensus but it does point out some flaws in my process to work on. Firming up the grip will help with recovery. Got kind of spoiled with the 22 and light loads on the 45. I've got some 4.3 & 4.5 already loaded for testing.

Here is a list I compiled of high scoring shooters and the loads they use, take a look at it and see if this helps,
https://www.bullseyeforum.net/t1209-pet-loads-of-top-shooters-loads-from-the-past

mspingeld wrote:I've been shooting a lot of 4.1 gn of N310 with a 185 gn LSWC with a 12lb spring without any function issues. I just started trying the same load with a jacketed bullet and I'm having occasional light hits, failures to feed, stovepipes and failures to chamber. I thought the load was too light for the spring so, yesterday I tried the load with 2 lighter springs (11 & 10) but I still had the issues.

After much frustration and discussion and analysis, I think the problem may be the firmness of my grip/wrist/elbow. When I tightened up my grip/wrist/elbow the problems seemed to go away. (also my shooting improved)

I'll have to do some more testing to confirm.

Thoughts?

Check you OAL.   Could be that the rounds are a little long for the chamber of your gun.  Also the shorter the round, generally the more velocity.  
While I agree that the loads may be a little light, and a limp wrist can cause an occasional problem, Your loads should not be so light as to be on the edge of not functioning unless you have perfect form.

IMO, if a load will malf on you if the grip gets loosened a little bit, either your load is too light or the gun needs work.

There are more things to do than just try a lighter spring.  Smoothing things up all through the operating cycle might be worth another look, right down to the magazines and the extractor and the breechface.

The closer you get to that lower edge of power to cycle the slide, the more perfect everything has to be.

Random limp wrist will do exactly as you describe.
The problem is when in recoil you are releasing your index finger to reset the trigger.  During recoil there is a LOT happening.  your other fingers that should be "gripping" during this process also relax simultaneous with the index finger reset.  The energy that should be going into cycling the slide and ejecting your spent case,  now goes into your loose gripping fingers.
You don't do this all the time.  But often enough that one shot in the sustained fire string will eventually hang up.
Okay how to fix.  Don't reset the trigger in recoil.  Hold the trigger back during recoil which helps all fingers maintain a steady grip through recoil and recovery.  With the trigger held back, you will need to reset it prior to the "next" shot.  So in recovery, once the front sight comes back into the rear notch and the blurry target black is framing up the crisp sights; your shot process should be reset and squeeze. reset and squeeze, reset and squeeze.  Hey whaddya know that is a waltz cadence.  (I would never have admitted that in public) but have been using it for a while now.  Long short short, long short short.  Oh no, I don't suffer OCD.  I quite enjoy it...