reloads shooting left of POA

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azrocks

azrocks

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Backstory: 4 9mm handguns (2 glocks, 2 walthers). All have shot pretty much POA with at least 2 brands of factory ammunition... 115g Magtech FMJ & 115g Federal FMJ. I've run other ammo through as well and never noticed much variation in windage.

Now all 4 guns are shooting left with my reloads: 1" - 2" left of POA at 30 feet.

I'm using 4.1g titegroup, federal brass, win spp primers, Precision Delta 124g FMJ bullets. OAL is 1.133 for the Walthers and 1.142 for the Glocks (these OALs gave me the tightest groups). Crimp is between .377 & .379 (.378 avg).

I thought the lower velocity (these are softer-shooting than factory) was the culprit, but I've tried charge weights of 4.2 & 4.3g titegroup also, and it didn't seem to change the lateral component of POI.

Is this normal, and if so, what variables are likely the source of the change?

No idea what ammo the factory used for their test target, but their hits were also centered on the bullseye, just like the aforementioned factory loads.
 
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All firearms will shoot all ammo differently. You've added another 'brands' by using a 124 grain bullet with a different load vs factory 115's.
Your OAL should be the same. There is no 'Off-the-Lands' stuff with pistols. Isn't necessary for rifles either.
Crimps don't get measured. The correct amount of crimp is "enough to hold the bullet in place and no more."
You work up to 4.1 of Titegroup or just pick it and hope? That's the max load for a 124 grain jacketed bullet too.
And then there's this.
http://www.targetshooting.ca/docs/Pistol_Shot_Analysis.pdf
 
Sunray said:
Your OAL should be the same. There is no 'Off-the-Lands' stuff with pistols. Isn't necessary for rifles either.
Click to expand...

I bench-rested loads ranging from 1.122" to 1.152" OAL (in .010 increments), using multiple powder charges. The glock(s) grouped tightest at 1.142 (with 3.9 to 4.2g TG). The Walther grouped tightest at 1.133 OAL (within the same powder charge range). I performed these tests multiple times and got the tightest groupings repeatedly at these OALs.

Sunray said:
You work up to 4.1 of Titegroup or just pick it and hope? That's the max load for a 124 grain jacketed bullet too.
Click to expand...

I started at 3.6g TG and worked up to 4.3. Speer recommends a starting charge of 4.0 grains and a max charge of 4.4, at an OAL of 1.090 using an FMJ with nearly identical dimensions. Even at my shortest OAL I was still .032 longer than Speer, and the shortest OAL I tested at 4.3g was 1.133. Perceived recoil at anything below 4.3 was noticeably less than factory, and brass showed no signs of overpressure. 4.1 grains of Titegroup under a 124g FMJ is a very common load for uspsa minor, so I think the chances of it being 'too much' are slim to none.

Sunray said:
Crimps don't get measured. The correct amount of crimp is "enough to hold the bullet in place and no more."
Click to expand...

Well, I measured mine. Using bullets averaging .355", and brass with ~ .0120" case wall thickness, that comes out to ~.379". So I figured my average of .378" was just about right. I'm not experienced enough to just eyeball things. Measuring makes sense to me.

Sunray said:
And then there's this.
http://www.targetshooting.ca/docs/Pistol_Shot_Analysis.pdf
Click to expand...

It's not my shooting technique. I have absolutely no problem putting rounds with higher perceived recoil (factory) on my POA. ;) That's what I said in the first sentence: factory loads hit dead center.
 
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ArchAngelCD said:
IMO the difference is being caused by you using a 124gr bullet in your handloads and comparing them to 115gr factory ammo.
Click to expand...

That's what I thought was most likely. I was wondering if this is a common experience.

Also wondering if polygonal barrels (which both the Glocks & Walthers have) are contributing factors?

My next task is to find some 124g production ammo and see if it performs similarly.
 
azrocks said:
That's what I thought was most likely. I was wondering if this is a common experience.

Also wondering if polygonal barrels (which both the Glocks & Walthers have) are contributing factors?

My next task is to find some 124g production ammo and see if it performs similarly.
Click to expand...
I have experienced higher and lower POI from different weight bullets but that doesn't mean drift isn't possible.

If you are going to shoot those bullets from now on just adjust the sights to match the POI to POA.
 
Aim a little more to the right.:)

NewChart.jpg
 
Zendude said:
Did all of the different workup loads with different powder charges and OALs seem to shoot left?
Click to expand...

Pretty much. Some a little more, others a little less, but all were left of POA in all guns tested.
 
ArchAngelCD said:
I have experienced higher and lower POI from different weight bullets but that doesn't mean drift isn't possible.

If you are going to shoot those bullets from now on just adjust the sights to match the POI to POA.
Click to expand...

That's what I plan to do, but I would like to understand the reason for this behavior if possible.
 
azrocks said:
That's what I plan to do, but I would like to understand the reason for this behavior if possible.
Click to expand...

For a completely WORTHLESS response: I used to shoot 115 gr. factory loads, and now I shoot 124 gr. plated and FMJ 124 gr. loads, coincidentally using 4.1 gr. of Titegroup, and I do not see this issue in any of my three 9mm handguns (2 sigs, and one H&K).
 
azrocks said:
shooting left with my reloads: 1" - 2" left of POA at 30 feet
Click to expand...
And I thought I was the only one. Bought a CZ-75B and my reloads shot left on a bench rest an inch or two at 50 feet, depending on the bullet (115 gr. XTP, 125 gr, Bluebullet RN, and 147 gr. TMJ. Put in a zero bushing, changed the sights, and it still shot left. Rahter than push the fixed sight off the slide, changed to an adjustable sight and . . . it seems that the gun is shooting less left?!!? Easily centered by the adjustable sight.

As a new gun, could it have needed to be broken in? I haven’t shot store-bought ammo through it.
 
As a raw new shooter I grouped low & left. Imagine that.
As I progressed I tightened up to poa/poi.
Different weight bullets will shoot to different poi but usually vertical variations. If you are shooting really light loads I could see how shooting heavy bullets might exaggerate lateral variation if your trigger technique is not perfect.
Best guess is to get someone experienced to watch you shoot and critique your trigger control/grip.
I say this because my poi problems are invariably of my own doing. I bet yours are, too.
 
OP when you shot the factory ammo, was it bench rested as well? If not, then maybe the difference in how you held the gun before to this time with the bench rest likely caused the change.
Click to expand...
Excellent question!
For me POI changes when I use a rest vs when I am holding the gun with both hands.
Since I shoot with both had that's where I have the sights set. Makes things a little off if I use some type of rest.
 
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your only variable here is the bullet. Load up a good jacketed bullet and see if it still shoots left.

luck,

murf
 
Don't hold the gun sideways.:D
It is probably technique.
A Machine rest would show the truth.
I have experienced this with different guns eg switching between .32 long and .40 and just changed how I pulled trigger and poi went back to poa.
 
Remember that even in a heavy pistol it does begin to move as the bullet is travelling down the barrel. It's slight, but enough to move the impact point around depending on how the recoil force has worked on the gun. Being as the gun is held in the hand...which is less than perfectly solid, then throw in rifling twist and things move around a bit which can and will throw off the impact. That's why they make the sights adjustable on many firearms, and in the case where yours might be fixed you need to experiment with ammo to find which will hit POA for you if you insist on such things, or learn where it hits and apply the appropriate correction in your aim.
 
Thanks for the great responses. Now I'm doubting myself again :)

I'm going to revisit this problem and make SURE I've eliminated any variables that may be causing me confusion.

I'll check back in once it's figured out.

At the very least, I need to test factory 124 vs my 124s and see if they print in the same area. Comparing 115 to 124 isn't working. And I'll make sure to shoot them both from the bench.
 
Here's a test for you, which I have not seen posted here as of yet:

You are 1-2" off at 30ft.

Shoot at 60ft. Are you 2-4" off?

Shoot at 15ft, are you 1/2"-1" off? Shoot at 30yrds, are you 3-6" off?

If you find a non-linear drift, there's something amiss with your technique. If it stays true, drift your rear sight and be merry.
 
That's good advice, Varmin. I'll eliminate 'me' before I continue. And no, I have not done that yet.
 
Back in my PPC days, we thought we could reduce recoil even below .38 wadcutter, with 120 gr truncated cones. Although a nominal 9mm mould, they came out large enough for our Pythons.
They were powderpuffs to shoot, and X ring at 7 and 15, but for some reason they shot left. We were well accustomed to cranking elevation up and down but did not want to bother with windage adjustment to get back to wadcutters for 25 and 50 yards. So we quit.
 
ArchAngelCD said:
Maybe this was said and I missed it but have you had someone else shoot your gun? Before you buy or change anything try that first.
Click to expand...

Here's the thing, which is another reason (of many) that I seriously doubt it's user error:

The Glocks are owned by a relative, and their groups shifted left along with mine with my reloaded 124s compared to factory 115s. So unless there's a trigger-finger virus going around...
 
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