New gun shooting low

mac1911

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Try setting your targets at shorting distance 20 feet is to much for a hand gun in my opinion
Really depends on your end use and hand gun used?
cmp/NRA service pistol is shot at 25/50 yards with aprox 5” aiming black/bull

some manufactures will include info in owners manual that the platform is sighted in for X yards with Y ammo and must impact with in A” of aiming point to get the GTG stamp.

what needs to be established is what hold you want to use , where do you want the bullets to hit (ex when shooting at a 5” black bulls eye at 25 yards many shooters hold at 6oc and need impacts aprox 2.5” high) then expected target size you want to hit and at what distan

Then a decent understanding of point blank range

then see how You do in more realistic
Scenarios? In a self defense position you will be hard pressed to even see your sights let alone line them up.

End result if you/pistol/ammo are shooting POA=POI at 30 yards and then 4”high/ low at 5-10-12-15 yards its YOU not the gun or ammo
 
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meh

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The "baliatic" path of a 9mm bullet does not vary much above or below your line of sight.
As I stated before if your not shooting 1" groups your not likely to see the shift no matter your zero be it 0-50 yards.

With 147 grain bullet a 50 yard zero , if all things are good your impacts will be less than a inch higher at 20 yards.
How are you calculating this? External ballistics alone lead to negligible differences at short range. My understanding is that the reason lighter, higher velocity loads tend to print lower at short range is due to less muzzle rise before the bullet leaves the barrel.
 

cams

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Jesus. How is the OP (new shooter?) going to wade thru 3 pages of online instructors and numerical equations to adjust a 1” low issue. lol

OP, keep it simple man, put down the engineers pencil and calculator and just have a good instructor watch you fire at the range. Then have him/her fire it. Otherwise you’ll drive yourself crazy trying to figure this out online. This is simple shit, don’t overthink it.

Once that’s done and it’s good to go, then you can even start using the term “running” my new Glock while you just practice as much as you can.
 

mac1911

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How are you calculating this? External ballistics alone lead to negligible differences at short range. My understanding is that the reason lighter, higher velocity loads tend to print lower at short range is due to less muzzle rise before the bullet leaves the barrel.
Yes there could be slight changes when you change ammo or have your sights zeroed for a specific load

for example my wad cutter loads out of my 1911 are 185 grain at very low velocity so when I switch to say 185 gn hollow points at 1200 fps they will Impact different , only slightly

Again this is why clarification of intended ammo /use/distance / platform is important .
So yes 115s might impact high/lower than 147s and even vertically change but when changing distance with ONE/SAME bullet/ammo weight if your impacts are several inches lower or higher its
Not the ammo. Ballistically speaking
Especially at 20’ like the OP is shooting
 
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mac1911

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Yes there could be slight changes when you change ammo or have your sights zeroed for a specific load

for example my wad cutter loads out of my 1911 are 185 grain at very low velocity so when I switch to say 185 gn hollow points at 1200 fps they will Impact different , only slightly

Again this is why clarification of intended ammo /use/distance / platform is important .
So yes 115s might impact high/lower than 147s and even vertically change but when changing distance with ONE/SAME bullet/ammo weight if your impacts are several inches lower or higher its
Not the ammo. Ballistically speaking

this is also why if You find ammo you and your gun like buy as much as the same lot # as possible.
 

mac1911

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Just came back from the range shooting rounds through my factory new Gen 4 G17. Practice target at 20 feet, the gun shoots consistently low, approximately 3-4 inches of where I am aiming. I've tried center mass, 6:00, and dead-on holds with same results. Using 115 grain 9mm Federal ammo. I have had others shoot it as well with the same results.

This is my first Glock. Could it be possible that the sights are calibrated for other grains 124 or even 147 grain. Doesn't that mean it would shoot lower since velocity (FPS) isn't as high as 115 grain. I haven't tried other grains but want to rule out anything else before I shoot other types of ammo.
Just because Im bored I looked up the gen 4G17 owners manual . I might have over looked it but did not see anything about ammo choices other than sammi spec ammo ?
Although on page 43 the do say there are different rear sight heights available for fixed sight configurations but with no details on why or what/how to use those different heights. useless for a new shooter ?
Then if you look at older 17 manual it list muzzle velocity https://www.google.com/url?sa=t&sou...FjABegQIAxAB&usg=AOvVaw0gT4QvCAwTcSI_dGbdK1_N

@ 1180 fps which leads me to think they "zeroed" with 124 gn ammo. They also state they have 3 options for sight heights 2 taller than 1 shorter than "normal"
Again though with zero info on how/why/when?

When you buy a new glock does anyone in sales ask you what sight height you want? Why does glock not include at least the different sight heights in the plastic ones.
 

Dennis in MA

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Have you checked ambient humidity and atmospheric pressure of your shooting space yet??? Did you remember to factor in the coriolis effect when shooting? Did your son? (Making sure you both either did or didn't.). What about elevation? Is it reasonably close to Austria? If not, did you factor that in? Did your son? Finally, did you use the mantra "POLYGONAL" as you were pulling the trigger to keep the bullets centered in Glock rifling?
 

mac1911

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Have you checked ambient humidity and atmospheric pressure of your shooting space yet??? Did you remember to factor in the coriolis effect when shooting? Did your son? (Making sure you both either did or didn't.). What about elevation? Is it reasonably close to Austria? If not, did you factor that in? Did your son? Finally, did you use the mantra "POLYGONAL" as you were pulling the trigger to keep the bullets centered in Glock rifling?
I was going to say air density will play more into it than bullet in barrel time
 

meh

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Well, to step back from the theoretical here, I thought Paul Harrell's latest video had something sort of apropos in it.


He's reviewing the CZ 97BD, but the part sort of relevant here is that he has some experienced handgun shooters shooting that handgun, and others, for the first time. Interesting to see how the elevations of the groups differ.
 

mac1911

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Well, to step back from the theoretical here, I thought Paul Harrell's latest video had something sort of apropos in it.


He's reviewing the CZ 97BD, but the part sort of relevant here is that he has some experienced handgun shooters shooting that handgun, and others, for the first time. Interesting to see how the elevations of the groups differ.
Matter of sight picture and hold point for the most part, get rid of the large torso target and put a 2” aiming bull I I wager a jelly donut thier groups will be “closer”

everyone shoots a bit different but in the end Your gun has to be “zeroed” to you and the ammo used.
Maybe Im wrong but manufactures ship their fixed sight guns either for specific ammo like a milspec 1911 with 230 grain fmj or say glock with 124gn 9mm but give you sights that will fit into that grey area of a few diffetent commercial load offerings.

also what does glock base any “zero” or “accuracy” on
The -0 zone 10”t X 6”w on a torso target at 10 yards? If so holding center on that target do you thing 115/124/147 will fall out of 0- section , well only if you cant hold a 4” group at 10 yards to begin with? You will get some misses for sure.
 

Vincent_Diesel

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Just got back from the range. First off thanks everyone who contributed. Very helpful, even all the nerdy ballistics stuff :p

Getting used to this Glock trigger and taking some of these posts into consideration, I have to say that MOST of my shots seem to have been corrected, I stress MOST. 75 percent of the time I hit my target, fist pump. Then the low and left comes rearing it's ugly head every so often. So at this point lack of technique seems like the answer to my problem.

The advice that helped me the most was to find the wall first (which on this G17 is noticeably tougher to find) then continue the trigger motion. I also noted, that shots were much better when I following through with that looooonnng ass trigger pull, until I could not pull back anymore, pause and release till the next shot. BUT, here is where I started to doubt what I was doing earlier. Closer to the end of the session I opened a fresh box of my newly chosen HD round, 124 grain hollow point, not the 115 green full metal jacket that I was previously shooting. From the first pull, doing nothing different than above, I hit the center of the bull but slightly higher, fist pump again. I mean technique is paramount, I get it, but the 124 grain hp was sent down range with absolute authority, and to make sure it wasn't chance I also sent down a few more. All follow ups were inches apart. Not the best grouping for sure but certainly better than the 115 grain practice rounds I was using. Scratching my head here.
 

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mac1911

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Just got back from the range. First off thanks everyone who contributed. Very helpful, even all the nerdy ballistics stuff :p

Getting used to this Glock trigger and taking some of these posts into consideration, I have to say that MOST of my shots seem to have been corrected, I stress MOST. 75 percent of the time I hit my target, fist pump. Then the low and left comes rearing it's ugly head every so often. So at this point lack of technique seems like the answer to my problem.

The advice that helped me the most was to find the wall first (which on this G17 is noticeably tougher to find) then continue the trigger motion. I also noted, that shots were much better when I following through with that looooonnng ass trigger pull, until I could not pull back anymore, pause and release till the next shot. BUT, here is where I started to doubt what I was doing earlier. Closer to the end of the session I opened a fresh box of my newly chosen HD round, 124 grain hollow point, not the 115 green full metal jacket that I was previously shooting. From the first pull, doing nothing different than above, I hit the center of the bull but slightly higher, fist pump again. I mean technique is paramount, I get it, but the 124 grain hp was sent down range with absolute authority, and to make sure it wasn't chance I also sent down a few more. All follow ups were inches apart. Not the best grouping for sure but certainly better than the 115 grain practice rounds I was using. Scratching my head here.
Your pistol might just like those 124s better.
You really want to scratch your head and bang your forehead get into pellet guns for accuracy and change pellets or even lot numbers....most fickle thing I shoot!
 
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