Heavy loads shooting left, would wood grips help?

[PO2Hammer]

Bought a GP100 last year and have been happily shooting mid range handloads, 158 lead @ ~950 fps. Groups were centered on target with the rear sight slightly to the right of center of it's adjustment range.

Recently loaded up some heavier 158 grain plated loads @ 1,100 fps. Much heavier recoil, flattened magnum primers, very good accuracy, but the groups are hitting 3"-4" left of center @ 30 yards with the rear sight all the way to the right in it's slot.

I suspect the gun is recoiling (twisting) left in my hand or twisting within the soft rubber grip while the bullet is still in the bore. IIRC, Keith talked about that effect in 'Sixguns', but it's been a long time since I've read that.

I'm wondering if a set of wooden grips would reduce that effect by proving more resistance to the twist?

 

[Iggy]

Maybe you're anticipating the recoil and leaning into the gun as you fire it. That's a pretty salty round for the gun.

Don't think wood will help you, The additional felt recoil will make you flinch even more if that is the problem.

 

[BCRider]

If the groups are the same size you normally get but are simply shifted to the left I suspect it's something other than a flinch. Although it still could be.

Are you holding on tighter for the heavier loads? That could also be producing the shift.

Are you shooting one or two handed? If you're shooting one handed and you're using your off side eye to aim like I do that produces a strong cross body angle in the shooting arm. The more powerful recoil will find it easier to push your arm to the side due to the angle. If so something that works for me in a variety of guns and loads is to angle the gun slightly top in towards your body center. About 10'ish degrees seems to make a big difference. No need to go all "homey" and hold it sideways....

Beyond that I can't think of anything. I've never had this issue shooting my own revolvers despite the rubber grips or wood grips.

Speaking of rubber grips, try twisting them on the gun to see if there is any twisting or other play in the grips to frame fit.

 

[Tony_the_tiger]

The rear sight of the Gp100 are adjustable for windage and elevation. Bring a couple loads out for comparison and adjust the sights for whichever load you are most likely to be using for target or defensive purposes. I've had to site mine in a bit for my preferred loads from the factory setting.

You also might try having a friend out to the range with you to see if it is the gun or your technique.

 

[s4s4u]

If you are anticipating the recoil of the heavy loads you might be pushing. Load a cylinder with a mix, every other hole, and give it a spin. A vertical change in POI with heavy loads can be expected, but a horizontal change may be shooter enhanced. Grip consistancy is king.

 

[StrawHat]

Flattened primers in a rifle are a sign of high pressures. In a revolver, you are treading in dangerous waters. Back off on the powder. Then worry about how to correct the point of impact

 

[SharpsDressedMan]

Guys, it is natural for different loads to hit in different places. For instance, a lighter bullet load, probably driven at a faster velocity, will get out of the barrel earlier, and hit low. A heavier, slower bullet loading will hit higher. Whether one is left or right handed will also change impact, especially on heavier & slower bullet loadings, due to the direction the gun is heading from resistance given by the shooting hand. A consistent grip is also required for consistent results. A little upward and leftward impact would be normal for a right handed person shooting slow heavy bullets. Adjustable sights and a record of where different loads strike allow the shooter to change sights, and return them, once all loads and changes are recorded. With fixed sights, you get to explore Kentucky windage (and hold over or under).

 

[pendennis]

Consider also, that you may be pulling the gun to the left with your trigger finger. The fat part of your finger tip should be centered on the face of the trigger. If you move your finger too far toward the first joint, it will cause the gun to be pulled left.

 

[BCRider]

SDM, what you typed is true for elevation. But he's getting a severe windage change as well. In my experience shifting between light wadcutter target ammo to full house Magnums in the same gun all my change in POI was elevation only. This wide shift in windage with a switch from Specials to Magnums just doesn't normally happen.

 

[PO2Hammer]

Revolvers can and do recoil in elevation and windage also. The effect is more obvious in elevation, but it can affect windage as well. The rifling twist also plays a part, or at least that's what Elmer Keith wrote IIRC.

I don't think it's flinch, when I flinch, I flinch down and the groups go to heck.
3" groups at 30 yards is very good for me, especially with a heavy load.

I may be gripping the gun more tightly.

Flattened primers in a rifle are a sign of high pressures. In a revolver, you are treading in dangerous waters. Back off on the powder.

Real, full power factory .357 loads will flatten their primers as well. I am going to back off a bit to reduce recoil, but I don't think I'm over pressure.
Not many real factory loads out there anymore, so you may not be used to seeing that.

 

[.22-5-40]

It's probably the heaver load. Years ago I was shooting a 1980's era Colt re-make 1860 army .44 percussion revolver, using round ball..every powder charge I tried had it shooting way high and to the left..finally got discusted and stopped shooting it.. found a Lyman 450229 hollow-base mould. Using 18grs. 3FG shot about 5" high (normal for these guns)..but windage was perfect.

 

[joneb]

Can the rifling twist impart torque on the gun ?

 

[PO2Hammer]

Yup.
As the gun forces the bullet to start spinning, the bullet puts an opposing twist on the gun, moderated by the guns weight and your grip.
Again, most noticeable with heavy loads. I think 'Sixguns' by Elmer Keith is in re-print now for those who want to study from one of the sages of revolver shooting. I think it's a Kindle book too.

I suspect the gun is twisting in the soft rubber of the Hogues, and I'm wondering if solid wood would reduce that by a noticeable amount.

 

[the Black Spot]

I have a charter arms 44 spec. I shoot a 240 gr xtp with 5 gr bullseye. Resting the frame on something solid so i have a good solid rest, this revolver will put 4 shots in an inch at 15 yds, but hits low and left. When i shoot from a standing two hand hold it is spot on at point of aim.

 

[murf]

po2hammer,

just a couple questions:

are you shooting off-hand, or bench rested?

one hand or two?

isosceles or weaver grip/stance?

grip pressure (weak, strong, firm) on shooting hand?

grip pressure on support hand?

murf

 

[BCRider]

I suspect the gun is twisting in the soft rubber of the Hogues, and I'm wondering if solid wood would reduce that by a noticeable amount.

One way to check would be to compress the Hogues and see if that changes things by some amount.

It'll only be good for a test as it'll change the feel of the grips but if you stretch wind about 3 to 4 layers of vinyl electrical tape around the Hogues that'll provide a surprising amount of squeeze to the grips and should lock them firmly to the frame. I'm talking about a LOT of stretch to the tape as it's being wound around the grips. Not enough to get too close to snapping it but enough that it stretchs to quite a bit more narrow. Then shoot it again and see if your windage troubles are reduced by some amount.

 

[BSA1]

PO2Hammer,


You are hitting the nail on the head (pun intended) when testing for accuracy. I never know on a particular day if I am really testing the gun, the ammo or me, the shooter.

My question is do you have a gun that shoots dead on for you? For example I recently purchased a S&W Model 10 that shoots to the left for me. However to rule out all of the variables I shot it side by side with another Model 10 that I know to shoot dead on for me. I went so far as to use the set of grips and ammo for the same box on the same day. My tests proved to me the problem is with the gun.

Another strong possiblity is are you crossed eyed dominant? I never realized I was until someone pointed out all of my rounds where going well to the left similiar to what you describing. Simply learning to switch eyes got me back on target.

 

[rcmodel]

I gave up on rubber grips on revolvers years ago.

Especially on single-actions.

Just a hard vs soft squeeze on the rubber grips could move POI a couple of inches at 25 yards.

The only time I will use them now is if I expect a hard march through thick wet brush that would ruin my nice wood grips.

When I want accuracy, I use hard grips.

rc

 

[35 Whelen]

I've been shooting my Flat Top .44 Special a lot over the past three or so weeks. After discovering it is crazy accurate, I began doing almost all of my shooting at 100 yds at a steel target. Bullets are two variations of a SWC weighing 255 - 260 grs. depending on alloy. The lightest load runs the bullet around 850, maybe a touch less while the heaviest runs the same bullets a shade over 1200 fps. I see ZERO lateral variation in points of impact with the different loads.
YMMV.

35W

 

[PO2Hammer]

Thanks all, I think I have my answer.