Heavy 10mm recoil spring vs accuracy

[Estimator]

I reciently purchased a S&W Model 1076 and had primer problems. Two batches of shells were loaded. One with WLP primers and the other with Wolf LP. about every 4th wolf primer failed to fire due to a light firing pin strike. (NOT GOOD!) So, Ordered new spring set and replaced the hammer spring with 22 lb spring and the problem was solved. However, at the same time I replaced the recoil spring with a 20 lb to replace the factory 17 lb figuring it would be easier on the pistol for heavier loads. Now all groups are noticably high compared to the 17 lb spring. Rear sight is not adjustable for elivation.
Does anyone know of front sights available in different hight increments or rear sight that will fit the 1076 dovetail that is adjustable?
Thanks to all who reply!
Estimator

 

[BLUEDOT37]

10mm rear sight

I've never heard, nor had it happen to me, that the recoil spring affected POI. (I added a 22# spring to mine too.)

My 1076 had the LPA TPU10WE30 rear sight, for the S&W autos, installed on it when I bought it. Fully adjustable & works with the standard front sight.

Precision Sales International, Inc.

PS: Did you replace the firing pin spring & clean out the firing pin tunnel too?

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[Groo01]

Groo here
The recoil and hammer springs will change when the barrel unlocks
mostly the hammer spring.
The barrel and slide is still forward as the frame rotates hitting higher.
The lighter springs allow the slide barrel group to slide back
a "touch" sooner so the bullet has "left the building" somewhat lower in its rotation.

 

[stansdds]

Very good explanation by Groo.

 

[BLUEDOT37]

By the time the barrel unlocks & starts moving rearward the bullet is already long gone.

Going from a healthy factory recoil & mainspring to heavier ones isn't going to change the unlocking, relative to the bullet leaving the barrel, & the bullet won't be affected.

If those same springs were grossly weaker then yes the barrel might be unlocking too soon & affect the bullet's trajectory.

If this had been the OPs problem then I think that going to new springs would have, if it mattered at all, lowered his groups, not raised them as he said.

Too many variables & not much detail. He never even told us what the POI difference was.

The OPs original problem was light hammer strikes & FTFs, which I've never encountered with any of my 3rd Gens either. He never told us if that was resolved either & that was 9 years ago.

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