View Full Version : New G17/ New sights.....diagnose my grouping
I picked up a Gen 4 G17 last week and installed 10-8 sights (i put the same sights on my Gen 3 G19 too).
At the range today, the G17 was grouping high left at 10 yards. The group was not tight....maybe the size of my hand.
Now, there were a few variables in play and i havent been to the range much in the past 6 months so im probably a little rusty. I am usually fairly proficient with my G19.....dont shoot it as well as my 1911, but can easily keep a small fist size group at this distance. When i shot the 19 today...the results were the same. Small fist size group. The 17 was all over the map.
The G17 had a weapon light when i started today. Also, i was shooting lawman 147gr ammo.....i normally shoot 124gr. Not sure if either of these things had an impact. The trigger in the 17 is also "mushy"....more creep than the 19 for sure. Once i took off the light and focused with a 6 o'clock hold, the groups improved slightly. Here is my question: What caused the shitty group?
1. Can the light affect POA/POI?
2. Do i need to drift my sights? Get used to a 6 o'clock hold with this gun?
3. Can heavier bullet affect POA/POI?
4. Do i just suck and need more time with the 17 trigger?
Im thinking points 2 and 4 are the problem. I could tell i wasnt feeling the trigger break consistently.
Let me know what you think. Thanks
If it's a new gun and new to you, dry fire and shoot the crap out of it before putting it into service. Every gun I've bought has needed a bit of a break in. And by break in I'm also referring to the loose but behind the trigger to get used to it. I generally don't freak too much about groups and such until past the first 200 RDS. Unless you're patterning like a shotgun things need some time to settle in.
If you're new to lights they can impact POI simply cause the gun balances differently. This will affect your sight alignment and follow through till you get used to it.
Bullet weight can also impact POI. Not only are velocities different, but that particular gun may just not be happy with the particular load. As much as we hate to admit it they have personalities to a degree.
I'd verify with 10-8 that the 17 and 19 use the same front post to be sure.
Don't move sights until you have a few different range sessions with consistent results and different lighting.
I went from 3dot oems to truglo operator pros with u notch and shot left. It was worse in low light. After a few range sessions I found I was subconsciously indexing the front sight to the left of the rear like I would with oems, even though the rear was much wider. A few more range sessions and I was dead on.
New sights, go back to fundamentals and relearn everything to make sure it's not you.
Thanks for the great advice guys. I agree with you 100%.
TAZ, the 17/19 typically use the same front post height, but they do state it can vary on a gun by gun basis. I *might* need a taller front sight, but I will not mess with the sights until i have at least another 500 through it. I think i will shoot the gun without the light until i get dialed in with it.....all my training/shooting has been without a light for the past five years (just bought the TLR-1 last month).
I will try different ammo, but the more i think about it, im pretty sure its me causing the problem. The Gen 4 17 definitely has a different feel than the Gen 3 19, so maybe its a simple grip issue. Also, im positive the trigger on the 17 is worse than the 19 ( i got very lucky with my 19... it has an awesome stock trigger) so that may have something to do with it.
What do you guys recommend to zero the pistol? Slow fire, off hand at 10 yards good? I usually put six orange 1" stickers on a IPSC target and fire a mag at each one, but ive never really "zeroed" a pistol to be honest. They've all hit pretty much on the money until this one......thats why i was shocked that my group was so far off with this gun.
Thanks again
Run dime drills with the pistol set up like you will carry it and use it. If you can perform the dime drill successfully 10 times in a row for a few consecutive days, then you want to consider sight adjustment.
I would not zero the pistol shooting off sandbags or a rest. Standing two handed grip is the method I would recommend. All the applied pressure on the grip should be on the front and the back of the grip. Your hands touch the sides of the grip, but with very little or no pressure.
It's counter-intuitive, but yes the heavier the bullet, the higher the POI. I haven't tested a G17 yet, but with Trijicon HD's and 147gr ammo, my G19 and G26 need taller front sights (.245").
I picked up a Gen 4 G17 last week and installed 10-8 sights (i put the same sights on my Gen 3 G19 too).
At the range today, the G17 was grouping high left at 10 yards. The group was not tight....maybe the size of my hand.
Now, there were a few variables in play and i havent been to the range much in the past 6 months so im probably a little rusty. I am usually fairly proficient with my G19.....dont shoot it as well as my 1911, but can easily keep a small fist size group at this distance. When i shot the 19 today...the results were the same. Small fist size group. The 17 was all over the map.
The G17 had a weapon light when i started today. Also, i was shooting lawman 147gr ammo.....i normally shoot 124gr. Not sure if either of these things had an impact. The trigger in the 17 is also "mushy"....more creep than the 19 for sure. Once i took off the light and focused with a 6 o'clock hold, the groups improved slightly. Here is my question: What caused the shitty group?
1. Can the light affect POA/POI?
2. Do i need to drift my sights? Get used to a 6 o'clock hold with this gun?
3. Can heavier bullet affect POA/POI?
4. Do i just suck and need more time with the 17 trigger?
Im thinking points 2 and 4 are the problem. I could tell i wasnt feeling the trigger break consistently.
Let me know what you think. Thanks
1. Probably not.
2. That can address the windage issue, but focus on grip and trigger control first. You'll need a taller post to correct for elevation.
3. Definitely, though it usually doesn't show up clearly until you get out to 25 yards. Bullet weight can affect group size, too, although heavier bullets tend to shoot better than lighter ones.
4. Maybe. Gen4 triggers tend to be heavier and grittier than Gen3 triggers so they're usually harder to shoot well.
What do you guys recommend to zero the pistol? Slow fire, off hand at 10 yards good? I usually put six orange 1" stickers on a IPSC target and fire a mag at each one, but ive never really "zeroed" a pistol to be honest. They've all hit pretty much on the money until this one......thats why i was shocked that my group was so far off with this gun.
Thanks again
I once polled all of the SMEs on here about pistol zero, who were unanimous that it should hit dead-on at 25 yards. But making that happen can be a tall order if you’re not shooting good groups at shorter ranges.
In your case, I’d try a few different loads and find what your pistol shoots best, then focus on group size. Once you can put five shots nearly touching at 10 yards, move back to 15, then to 25. Once you can shoot a 4-5” group at 25 yards, it’s time to start moving sights around.
Then just get POI and POA to match up at 25 by drifting the rear sight to correct for windage and changing front sight heights to correct for elevation and you’ll be golden. Bear in mind that switching ammo will almost definitely cause your POI to shift again, but you probably won't notice if you're not shooting decent groups and/or if you're staying inside of 10 yards.
Okie John
1. Probably not.
2. That can address the windage issue, but focus on grip and trigger control first. You'll need a taller post to correct for elevation.
3. Definitely, though it usually doesn't show up clearly until you get out to 25 yards. Bullet weight can affect group size, too, although heavier bullets tend to shoot better than lighter ones.
4. Maybe. Gen4 triggers tend to be heavier and grittier than Gen3 triggers so they're usually harder to shoot well.
I once polled all of the SMEs on here about pistol zero, who were unanimous that it should hit dead-on at 25 yards. But making that happen can be a tall order if you’re not shooting good groups at shorter ranges.
In your case, I’d try a few different loads and find what your pistol shoots best, then focus on group size. Once you can put five shots nearly touching at 10 yards, move back to 15, then to 25. Once you can shoot a 4-5” group at 25 yards, it’s time to start moving sights around.
Then just get POI and POA to match up at 25 by drifting the rear sight to correct for windage and changing front sight heights to correct for elevation and you’ll be golden. Bear in mind that switching ammo will almost definitely cause your POI to shift again, but you probably won't notice if you're not shooting decent groups and/or if you're staying inside of 10 yards.
Okie John
Great post. Thanks.
If you bought the sights from 10-8 they will help you get the right one if it's not hitting where it's supposed to (at a discount). Of course you'll have to tighten up your groups and do the math to figure out just how much taller you need. As for Gen4 guns I dislike them and can't shoot them nearly as well as the gen 3. I have a gen 4 Glock 23 that I can't shoot worth crap and hits way left of center. I've been working with my Gen4 Glock 35 and I can get good hits with it but the trigger is just no where as good as the older guns, the slight difference in grip also throws me. As soon as I get my Sig P320 full size dialed in the G35 is up for sale.
Dry fire, dime drills, clean and lube.
UPDATE:
I had some time to get back to the range today with the G17 and figure out this sight issue. I brought four different types of ammo (115, 124, and 147gr) and shot at 10 yards. I took my time and the groups were tight....one ragged hole on all but the 147gr Lawman (this group was still respectable however). All the groups were (almost exactly) 1.5" high.
I repeated this with my gen 3 G19 and the same ammo. This gun had tight groups as well, but was hitting POA/POI. The 147gr Lawman printed ~.5" high as well, but not as bad as the G17.
I emailed 10-8 about this, and they said a .250" front should lower the POI about 3" at 25 yards. So if we extrapolate my 10 yard group to 25, it should be approximately 3", correct? Is there any problem with a gun that needs a tall front sight? I know Grant posted about some Glock barrels shooting sloppy high if it has a poor fit (>.004").....is this something i need to consider before ordering a new sight? I used a feeler gauge, and a .003" fits between the barrel hood and slide, but a .004" doesnt.
Any advice from you guys? Think im gtg with a .250" front? Thanks in advance for the help.
ETA: I forgot to mention the "shooting left" problem in my OP was definitely me. I put more finger into the trigger, and all groups (with both guns) were on point. Only the vertical deviation still exists with the G17.
I shot one mag at 25yds with the 17 and it was pretty nasty. All shots landed on an 8"x10" paper, but 90% hit on the upper 2/3 of the paper....so im guessing ~4-5" high. I dont shoot at this distance often, so part of the problem is my suckiness, but it is fairly consistent with the 10yd group if you extrapolate.
A tall front sight should be no problem. I have a couple of Glocks that have what look like shark fins out there by the muzzle.
Use https://www.ameriglo.net/sights/calculator to figure out which sight you need.
Where does the G19 hit at 25?
Okie John
Thanks for the link, John. The ameriglo website says i need a .242" front sight. I currently have a .215".
10-8 sells a .235" or a .250". Ameriglo sells a .240".
I didnt shoot the 19 at 25 today. I can usually keep my shots inside the rings on a b3 target at 25yds with the 19, but definitely cant put them all in the black. I know for a fact the 17 shot higher (and *maybe* a looser group) than the 19 at that distance. Im not good enough to tell if its me that F'd up or if the sights are off at that distance since my groupings widen so much. At 10 yards, i can keep a tight enough group to see how off from POA i am hitting.
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