Heavy springs and now shooting low

[tek4260]

I finally got around to shooting a couple of my 45's that I installed #26 mainsprings in and both shot about 6" lower than they did with the factory springs. Still noodling it but haven't came up with a reason why yet. It must be the way I am gripping it and squeezing the trigger. Less lock time = less rise from trigger break until it fires with the way I grip it I guess.

Still, 6" @25 yards is a lot.

 

[flatgate]

Still, 6" @25 yards is a lot.

Off hand? One hand hold or two?

flatgate

 

[Donaldjr1969]

Could you by any chance be inadvertently pulling the gun down with the heavier mainspring? I would venture a guess is that your muscle memory is attuned to the old mainspring.

 

[MOUNTAIN WILLIAM]

Could you by any chance be inadvertently pulling the gun down with the heavier mainspring? I would venture a guess is that your muscle memory is attuned to the old mainspring.

Bingo!

 

[tek4260]

Still, 6" @25 yards is a lot.

Off hand? One hand hold or two?

flatgate

Kinda both. I shoot with my forearms rested on the railing of my deck, just ahead of my elbows. I find too much poa/poi difference when shooting off a sandbag rest.

As far as muscle memory, I don't know. Seems that if I were pulling it down, it would have hit higher with the faster lock time.

I'm in the process of loading another 500 325's to shoot before I make any sight adjustments. My groups were doing strange things as well. The first 3 shots would make a large 4" triangle, then the last 3 would cluster nearly touching in the center of it. The order was the same. Low, high, left, then 3 in the middle of that cluster. Did the same for four 6 shot groups from 2 different revolvers(8 groups total)

 

[flatgate]

I was going to say that you have some minute chamber/throat differences but then when you said 2 different revolvers I'll say shooter error or inconsistent reloads.

What powder? Who's bullets? Primer brand? Using a separate "crimp die" as a 4th step or just a standard seater/crimper? COL? Bullet diameter? Throat diameter? Bullet velocity?

I also think that your "forearm" rest may be causing trouble when trying to develop a "load".

JMHO,

flatgate

 

[tek4260]

I was going to say that you have some minute chamber/throat differences but then when you said 2 different revolvers I'll say shooter error or inconsistent reloads.

What powder? Who's bullets? Primer brand? Using a separate "crimp die" as a 4th step or just a standard seater/crimper? COL? Bullet diameter? Throat diameter? Bullet velocity?

I also think that your "forearm" rest may be causing trouble when trying to develop a "load".

JMHO,

flatgate

The groups were with the Ruger Only Mihec HP and the LBT 325K. Both were cast by me loaded over 23 and 24gr of H110, CCI 350, FCD, .452 bullet/.4525 throat.

Over on castboolits, 44man mentioned that the heavy hammer spring was causing the revolver to dip when it impacted and that I was tightening my grip throughout the group. That may be the case as it would explain the last 3 shots touching and also the lower impact as compared to the factory spring.

 

[guitarpicva]

Another thought. If you are working so hard to pull the trigger that you pull your shots low, have you done a basic trigger job on the thing? Smoother pull means less "attitude adjustment". Food for thought and confusion.

 

[tek4260]

Another thought. If you are working so hard to pull the trigger that you pull your shots low, have you done a basic trigger job on the thing? Smoother pull means less "attitude adjustment". Food for thought and confusion.

Of course. It is somewhere around 2#.