boudreux Posted August 17, 2018 Share Posted August 17, 2018 Whats the difference in the point of impact between the 9mm 115 grain vs 124 grain. Say 10-15 yards. Is there any? I've always shot 124 and that is what my dot is sighted for, but I've come across some really cheap 115's and if the POI is not any different I will pick it up for practice ammo. If there is a discernible difference I'll stick with my 124. Link to comment Share on other sites More sharing options...
Steve RA Posted August 17, 2018 Share Posted August 17, 2018 Only way to really tell is to try it and see. Link to comment Share on other sites More sharing options...
crmcdm Posted August 18, 2018 Share Posted August 18, 2018 Agreed the only way to know for your gun, your load etc., but my experience across an array of guns and loads is that I don't see much difference between 115s and 124s. "Discernable" might be better than I can shoot. Link to comment Share on other sites More sharing options...
boudreux Posted August 18, 2018 Author Share Posted August 18, 2018 Yea i agree with you both but I can only get a case of it. If I could buy a box I’d shoot it and see. But I Don’t want to spend the money on a whole case and have to re-zero the dot if the point of impact isn’t close. Link to comment Share on other sites More sharing options...
pjb45 Posted August 18, 2018 Share Posted August 18, 2018 How about you look at the velocity of both rounds. The faster bullet will drop less, or the laws of physics are not applicable where you live. At that short of a distance, there might be little difference. However, 35 yr plate racks might be interesting. Link to comment Share on other sites More sharing options...
zzt Posted August 18, 2018 Share Posted August 18, 2018 On 15 yard targets my P226 printed a little bit lower with Blazer 115s (1145fps) than it did with Blazer 124s (1090fps). The 124s were a little hotter, so that may account for the some of the difference. Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted August 18, 2018 Share Posted August 18, 2018 17 hours ago, boudreux said: 10-15 yards. Can't be much difference that close. Maybe at 25 yards. Link to comment Share on other sites More sharing options...
ima45dv8 Posted August 19, 2018 Share Posted August 19, 2018 Open/CO gun? Link to comment Share on other sites More sharing options...
jpm2953 Posted August 20, 2018 Share Posted August 20, 2018 In my Glock 34 there was a 3” vertical difference in 115 to 124 my CZ’s don’t seem to care Link to comment Share on other sites More sharing options...
Hi-Power Jack Posted August 20, 2018 Share Posted August 20, 2018 Believe it or not, you might actually get some horizontal dispersion, also. Don't know why, but I've had it Link to comment Share on other sites More sharing options...
boudreux Posted August 20, 2018 Author Share Posted August 20, 2018 17 hours ago, ima45dv8 said: Open/CO gun? Glock 34 Carry optics gun. 13 minutes ago, jpm2953 said: In my Glock 34 there was a 3” vertical difference in 115 to 124 my CZ’s don’t seem to care 3" difference is a lot. What distance? Link to comment Share on other sites More sharing options...
Garmil Posted August 20, 2018 Share Posted August 20, 2018 Haven't seen enough poi difference to care in any of my guns. Link to comment Share on other sites More sharing options...
RippinSVT Posted August 20, 2018 Share Posted August 20, 2018 On 8/17/2018 at 11:37 PM, pjb45 said: How about you look at the velocity of both rounds. The faster bullet will drop less, or the laws of physics are not applicable where you live. At that short of a distance, there might be little difference. However, 35 yr plate racks might be interesting. External ballistics having an appreciable effect on POI inside 50 yards is a fallacy for everything but the slowest 45acp and 38 Special loads, where it's still only a few inches. 99.9999% of the time appreciable POI changes over distance is as a result of the sight plane being out of parallel to the bore axis, often as a result of a real close zero. This is exacerbated with a tall dot. The further you can zero your pistol, the better your average POA/POI will be over distance, at least out the point where external ballistics really start playing with the equation and appreciable drop occurs, which is around 70-80 yards with a minor 9mm 115/124gr load. A solid 50yd zero will often vary +/- 1" all the way back to 10 yards or so, with low impacts occurring below this distance due to the height of the sight above bore centerline (plus the inherent 1* or 52 minute downward tilt of a 1911 barrel). Actual load to load POI variance at practical distances is more closely related to recoil impulse, twist rate, bullet design, etc. I know there's gonna be people who dispute me based on their experience, and none of what I've said covers every factor/situation, but I have tested perhaps 100k pistol rounds and hundreds of loads, just from a bench, over the years for accuracy, from 10-100yds and what I said above is an opinion based on that data and nothing more. Link to comment Share on other sites More sharing options...
usmc1974 Posted August 20, 2018 Share Posted August 20, 2018 (edited) 12 hours ago, Garmil said: Haven't seen enough poi difference to care in any of my guns. Yep I found this to be true in all my 9mm guns. 115 to a 147 at 15 yards I point at the x I hit the x or very close to standing shooting free style. I take into account I shake just a might, close enough for me. Edited August 20, 2018 by usmc1974 Link to comment Share on other sites More sharing options...
jpm2953 Posted August 20, 2018 Share Posted August 20, 2018 18 hours ago, boudreux said: Glock 34 Carry optics gun. 3" difference is a lot. What distance? I thought the same thing! 20 yards Link to comment Share on other sites More sharing options...
Jim Watson Posted August 20, 2018 Share Posted August 20, 2018 I cannot tell a difference by bullet weight at 10 yards, or even at 15 at match rate of fire. 20-25, you bet. I loaded some sub-minor ammo, the least that would function the gun, for GSSF. Even slow 115 strikes higher than standard 115, never mind heavier bullets. Link to comment Share on other sites More sharing options...
agksimon Posted August 13, 2020 Share Posted August 13, 2020 (edited) Different guns will have different POA to POI impacts. My Walther PPQ gave me a 3" difference at 25 yards, but a CZ 75 had almost none. My Sig 320 X5 Legion had about 2 inches. There was some crosswinds though. Edited August 15, 2020 by agksimon Link to comment Share on other sites More sharing options...
AverageJoeShooting Posted August 13, 2020 Share Posted August 13, 2020 ive shot both 115s and 124s/5s out of my open gun and theres no difference in POI even out to 30 yards. I put the dot in the same place regardless of 115 or 124 and have no issues cleaning plate racks. at a certain point it becomes the shooters ability and not the weight of the bullets that are causing missed shots Now if your shooting bullseye or usps out to 50 or 75 yards there might be a couple inches of drop out that far Link to comment Share on other sites More sharing options...
NoSteel Posted August 14, 2020 Share Posted August 14, 2020 You probably will see little to no difference. Bigger question is, are these the same profile bullet from the same manufacturer? If not, that could be an additional factor and added together may show a larger change... , Link to comment Share on other sites More sharing options...
IVC Posted August 14, 2020 Share Posted August 14, 2020 On 8/20/2018 at 9:31 AM, RippinSVT said: External ballistics having an appreciable effect on POI inside 50 yards is a fallacy for everything but the slowest 45acp and 38 Special loads, where it's still only a few inches. You underestimate the level of under-loading at level 1 matches. Declared PF of 125, can barely perforate the paper. Poppers that will get knocked over by wind standing up after a few hits... Link to comment Share on other sites More sharing options...
IVC Posted August 14, 2020 Share Posted August 14, 2020 (edited) On 8/20/2018 at 9:31 AM, RippinSVT said: Actual load to load POI variance at practical distances is more closely related to recoil impulse, twist rate, bullet design, etc. I know there's gonna be people who dispute me based on their experience, and none of what I've said covers every factor/situation, but I have tested perhaps 100k pistol rounds and hundreds of loads, just from a bench, over the years for accuracy, from 10-100yds and what I said above is an opinion based on that data and nothing more. On a serious note, ^^^^ this. Physics is pretty clear as to how gravity affects trajectory (virtually no effect at close distances) and geometry is pretty clear about how sights above the bore affect sighting process at different distances (zero offset at sighting distance all the way to the height of the sights offset at the muzzle). The remaining parts, also the unknowns, are gun while bullet travels through the barrel and is being spun, bullet spin at the muzzle and through the air, and interaction of the bullet with the air. These more often affect accuracy (spread) than precision (POI), but they can (and will) affect both in certain situations. Edited August 14, 2020 by IVC Link to comment Share on other sites More sharing options...
Joe4d Posted August 14, 2020 Share Posted August 14, 2020 Hypothesis. As I have observed same thing. Lighter/faster bullets hitting lower than heavy slow bullets at 25 yards. Faster bullet exits the barrel sooner so the gun has had as much time to flip up. Slower bullet traveling down the barrel and the gun has rotated up more. Look above at the couple of posts wheres folks said gun A "heavy steel" didnt change much, but gun B 'light polly" did. Link to comment Share on other sites More sharing options...
boudreux Posted August 15, 2020 Author Share Posted August 15, 2020 I cant believe this post was revived after 2 years. I've shot thousands and thousands of just about every factory brand of ammo you can think of in 115 and 124 grain since my original post. Haven't noticed any POI difference between any of them at typical USPSA target distances. Link to comment Share on other sites More sharing options...
agksimon Posted August 15, 2020 Share Posted August 15, 2020 UPDATE: I went out again today and using a pistol rest, shot two groups of five shots each at 25 yards, using my Sig P-320 X5 Legion with a Trijicon SRO on it. The gun is sighted in with American Eagle 124 grain fmj. I tried Blazer Brass 124 grain and it shot to the exact same point of impact as the AE124 grain. Next up was Blazer Brass 115 grain and it shot almost 3" to the right, but the elevation was perfect center. Next was Federal 115 grain and it also shot almost 3" right, with elevation the same perfect center. Lastly, I tried Blazer Brass 147 grain ammo. It shot a perfect center windage, but the elevation was 2" low. Groups with the AE 124 and Blazer Brass 124 were a very tight sub 2". Groups with the Blazer Brass and Federal 115 ran just over 3". Groups with the Blazer Brass 147 ran just under 3" Link to comment Share on other sites More sharing options...
IVC Posted August 15, 2020 Share Posted August 15, 2020 5 hours ago, boudreux said: I cant believe this post was revived after 2 years. Ooops, sorry, I didn't realize it was an old thread (I wasn't the one to resurrect it, but I still commented on it...) Link to comment Share on other sites More sharing options...
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