Handgun Optic Zero?

pilot25 · Sep 5, 2018

Decided to zero a Sig Romeo 1 optic as perfect as I could today and was going bananas.

I read somewhere on Sig's website the iron sights of all Sig hanguns come out of the factory zeroed to 25 yards. So I slaved the red dot to the iron sight just to start. I measured out 25 yards, set up a bench rest in the prone position. Shots were all over the place. I assumed it was either me or the ammunition. Being set into a rest I didn't think it was me. I switched from AE 115 FMJ to Speed Gold Dot 124 TMJ and got the same result. I moved the target to 20 yards and was able to group, with the rest, within a tiny fraction of each other. The group was slightly left of target so I adjusted the red dot. 5 shots as spot on as if I went up to it and poked it with a pencil.

Moved the target back out to 25 yards and I'm all over the place again. Groupings at 25 yards are 8 - 10 inches apart and nothing resembling a pattern. After an hour I put the target back to 20 yards and pinpointed the center again and called it a day. So I'm zeroed at 20 yards with irons and the red dot but 25 yards I have no idea. Free handed 5, 10, and 15 yards and was accurate so I was happy but am baffled why 25 yards is such a problem.

How can I be so far off just 5 yards further out with a solid bench rest? Ammo inconsistency?

IX-3 · Sep 5, 2018

pilot25 said:
I read somewhere on Sig's website the iron sights of all Sig handguns come out of the factory zeroed to 25 yards

The FAQ's on Sig's website says:

"My SIG SAUER pistol is not accurate. Why? What should I do?

All SIG SAUER production duty/combat pistols are set up to use a “combat” sight picture. This is where the front sight completely covers the bullseye of the target. Using a six o’clock (“pumpkin on a post”) or center mass (“half’n’half”) sight picture will result in low impact. SIG SAUER, Inc sights in all non-sporting and non-target pistols for 2 inch groupings @ 10 yards. If you are still having trouble please contact Customer Service for further help and instruction. Please have your serial number ready. There are also very helpful free Internet sites that cover pistol group analysis."

I saw an older post on another site where it use to be at 15 yards.

pilot25 · Sep 5, 2018

IX-3 said:
The FAQ's on Sig's website says:

"My SIG SAUER pistol is not accurate. Why? What should I do?

All SIG SAUER production duty/combat pistols are set up to use a “combat” sight picture. This is where the front sight completely covers the bullseye of the target. Using a six o’clock (“pumpkin on a post”) or center mass (“half’n’half”) sight picture will result in low impact. SIG SAUER, Inc sights in all non-sporting and non-target pistols for 2 inch groupings @ 10 yards. If you are still having trouble please contact Customer Service for further help and instruction. Please have your serial number ready. There are also very helpful free Internet sites that cover pistol group analysis."

I saw an older post on another site where it use to be at 15 yards.

Trying to find where I read 25 yards. Clearly wasn't won the Sig site. I do see your quote on their FAQ page. Well, it doesn't matter now. I'm POA-POI at 20 yards with both irons and red dot. They are suppressor sights. Maybe that matters. At 25 yards it is accurate but not at all precise. Weird that 5 more yards would be so much different. Has to be human error of some sort and I'm hesitant to touch the iron sights.

erwos · Sep 5, 2018

Were you keyholing?

One last ammo to try would be 147gr subs.

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pilot25 · Sep 5, 2018

erwos said:
Were you keyholing?

One last ammo to try would be 147gr subs.

Sent from my ZTE A2017U using Tapatalk

No and why subs? Does the lower velocity make that much of a difference at 25 vs. 20?

erwos · Sep 5, 2018

pilot25 said:
No and why subs? Does the lower velocity make that much of a difference at 25 vs. 20?

I am wondering if you're going transonic past 20yds.

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pilot25 · Sep 6, 2018

erwos said:
I am wondering if you're going transonic past 20yds.

Sent from my ZTE A2017U using Tapatalk

I have a bunch of 147g Speer Lawman I'm going to try.

Thanks.

Bob A · Sep 6, 2018

erwos said:
I am wondering if you're going transonic past 20yds.

Sent from my ZTE A2017U using Tapatalk

I'm thinking max velocity is at the muzzle; but dropping back into subsonic at 20+ yds might be an issue?

Magnumite · Sep 6, 2018

pilot25 said:
Trying to find where I read 25 yards. Clearly wasn't won the Sig site. I do see your quote on their FAQ page. Well, it doesn't matter now. I'm POA-POI at 20 yards with both irons and red dot. They are suppressor sights. Maybe that matters. At 25 yards it is accurate but not at all precise. Weird that 5 more yards would be so much different. Has to be human error of some sort and I'm hesitant to touch the iron sights.

Not being insulting, but the pistol can’t be ‘accurate but not precise’, as the terms are typically used relative to firearms. It sounds like the gun groups okay and there is no keyholing. The group distance away from closer range sight POA has to do with the sight regulation. Neither should yield 8-10 inch degradation over 5 yards. It seems to me one of two things are going on, both shooter induced. The first being you are not focused on the front sight or dot, depending on which you are using. Or second, where you are holding at the further distance (25 yds) is actually different from where you are holding at the 20 yard and closer distances, because of the smaller appearance of the target. It could be both. A third comes to mind...using too small a target bull.

Biggfoot44 · Sep 7, 2018

Precise = Group Size
Accurate = Relationship to intended point of aim

All statement to the effect of X pistol with fixed sights is factory sighted for Y distance should be taken with a healthy grain of salt . If the statement is more specific as to Xgr bullet @ Z fps you can reduce the amount of salt slightly .

But stil variables with how you hold and grasp the gun, and how your eyes see the sight picture .

Sometimes the intended ammo is strongly infered . Sometimes the intended factory zero actually is . But don't count on it until verifying yourself .

Suppressor Sights implies taller then "normal" sights, this can effect the * Percieved * trajectory .

Basic background out of the way :

What I think I'm reading is tight groups @ 20yds, and scattered @ 25yds ? Tight being hypothetically +/- 2in @ 20yd, and 8-10in @ 25yd ?

I'm scratching my head and being perplexed . I can't think of even an obscure mechanical defect that could do that . A bbl with no rifling at all might do that @ 25 , but wouldn't be tight at 20 . I also have to think it's somthing shooter related .

You mention about from rest . Is this meaning a mechanical device , or that you are using sandbags or whatever to support your hands/ arms ?

Is your eyesight such that you can see clearly @ 20yds, but blurry beyond ? Is this an indoors range ? If so was the lighting good @ 20, but shadows and dim @ 25 ?

Magnumite · Sep 7, 2018

I know we have a difference of semantics. From statistics and the reading in firearms I have done over the past nearly 39+ years: precision is how tight the groups are; accuracy is the measure of repeatability of the precision; sight regulation is the POA/POI relationship.

The M&P Pro9 I had shot around 9" groups at 25 yards and was hitting 5.5" low. 'Tis true. I was not a precision shooter, it wasn't accurate because regular fliers took those groups to even bigger numbers with an occasional smaller group (6"), and the sights were obviously improperly regulated.

Bountied · Sep 7, 2018

pilot25 · Sep 7, 2018

erwos said:
I am wondering if you're going transonic past 20yds.

Sent from my ZTE A2017U using Tapatalk

Out of Bullseye = AE 115g 25 yards.
Bullseye = Speer Lawman 147g 25 yards.

Either you are correct or I unconsciously do something when I pull the trigger with the AE ammo.

Bountied · Sep 7, 2018

erwos said:
I am wondering if you're going transonic past 20yds.

Sent from my ZTE A2017U using Tapatalk

You really think that it would drop below 1125 fps at 25 yds to affect accuracy like that?

I think that the Speer lawman may just be better ammo vs AE 115 fmj. Or it could have to do with the twist rate, bullet speed/bullet grains for the twist and stabilization?

pilot25 · Sep 7, 2018

Bountied said:
You really think that it would drop below 1125 fps at 25 yds to affect accuracy like that?

I think that the Speer lawman may just be better ammo vs AE 115 fmj. Or it could have to do with the twist rate, bullet speed/bullet grains for the twist and stabilization?

I'm thinking the same thing but doesn't really matter. I'm definitely switching for my practice ammo. When I shot those 5 shots I was astonished at the difference.

If I could only be that accurate without a rest.

Magnumite · Sep 7, 2018

Last time and I’ll leave it alone. Agree to disagree.

pre·ci·sion

noun
the quality, condition, or fact of being exact and accurate.
"the deal was planned and executed with military precision"
synonyms: exactness, exactitude, accuracy, correctness, preciseness; More
marked by or adapted for accuracy and exactness.
modifier noun: precision
"a precision instrument"
technical
refinement in a measurement, calculation, or specification, especially as represented by the number of digits given.
plural noun: precisions
"this has brought an unprecedented degree of precision to the business of dating rocks"

ac·cu·ra·cy
ˈakyərəsē/Submit
noun
the quality or state of being correct or precise.
"we have confidence in the accuracy of the statistics"
synonyms: correctness, precision, preciseness, exactness, exactitude; More
technical
the degree to which the result of a measurement, calculation, or specification conforms to the correct value or a standard.
plural noun: accuracies
"the accuracy of radiocarbon dating"
synonyms: correctness, precision, preciseness, exactness, exactitude; More

pilot25 · Sep 7, 2018

This is what I was referencing. I thought it was normal shooting nomenclature.

erwos · Sep 9, 2018

So, it occurs to me I was somewhat more terse than I intended to be with my "you're going transonic" answer.

What I think is happening is some sort of combination of:
1. Barrel isn't stabilizing 115gr/124gr particularly well. I don't know if you've seen Recoil's tests of Glock barrels, but a fair number of them got SUBSTANTIALLY tighter at 25yds when using heavier bullets.
2. Going trans-sonic probably hurts, but I agree it's not the primary problem.
3. Most people shoot 147gr better due to how the recoil impulse is.

I will certainly say I shoot 147gr/160gr MUCH better than I do 115gr/124gr when it's for groups.

Magnumite · Sep 9, 2018

Do you know the twist rate of that barrel?

erwos · Sep 9, 2018

Magnumite said:
Do you know the twist rate of that barrel?

Most budget after-market Glock barrels are 1:16. I don't think it's a big deal either way, TBH.

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