PDA

View Full Version : POI difference: 124gr +P vs 147gr, same gun



MEAT
10-12-2012, 07:42 PM
I'm curious if anyone has noticed a considerable change in POI while shooting HST 124gr +P & 147gr rounds through the same gun? I know every gun is different, and there are a ton of variables, but I figured there might still be a pattern. If there is a significant POI change, what distance does it start to really show? 10/15/20/25yds?

GJM
10-12-2012, 07:55 PM
I'm curious if anyone has noticed a considerable change in POI while shooting HST 124gr +P & 147gr rounds through the same gun? I know every gun is different, and there are a ton of variables, but I figured there might still be a pattern. If there is a significant POI change, what distance does it start to really show? 10/15/20/25yds?

By chance HST 124+P and 147, are the two 9mm JHP loads I use. Out to 25 yards, in Glock and HK pistols, I haven't noticed any difference in POI, although the 124+P has more felt recoil. Perhaps with a RDS, a difference might be discernible.

Excepting M&P 9mm pistols, I notice little difference in POI of impact in semi-auto pistols in 9, 40, 10 and 45. I see big differences in POI of impact in revolver cartridges, especially shooting 44 special in .44 magnum handguns. I actually have different Scandium 329 revolvers for use with .44 special for training, as opposed to .44 magnum which requires a tall front sight, as the S&W adjustable rear doesn't have enough range.

Alaskapopo
10-13-2012, 12:05 AM
I'm curious if anyone has noticed a considerable change in POI while shooting HST 124gr +P & 147gr rounds through the same gun? I know every gun is different, and there are a ton of variables, but I figured there might still be a pattern. If there is a significant POI change, what distance does it start to really show? 10/15/20/25yds?

147 shoots about 3 inches high for me at 25 yards.
Pat

DocGKR
10-13-2012, 12:58 AM
M&P9 zeroed at 25 yds shooting the following loads at 25 yds:

147 gr Fed AE9FP FMJ--note this shoots to the same POA/POI as P9HST2 147 gr duty ammo
http://www.tridentconcepts.org/alumni/Portals/0/NTForums_Attach/1128135662071.jpg

124 gr Fed P9HST3 +P JHP
http://www.tridentconcepts.org/alumni/Portals/0/NTForums_Attach/1128135674554.jpg

Josh Runkle
10-13-2012, 09:10 AM
I shoot 115gr and 147gr, but rarely 124. I do not notice any POI shift at all. The farthest I actually ever shoot though, might be an x ring at only 7 yards or so. I don't notice any difference shooting 1" dots at 7 yards either. Last week I was shooting a full-sized IPSC steel target at 100 yards with 147gr ammo, and the sight picture appeared normal "theoretically", but as I don't do this with 115gr commonly, I have nothing to compare it to.

GJM
10-13-2012, 09:29 AM
DocGKR, have you run the same test with your Glock pistols to determine if here is POI shift between 147 and 124+ P?

A RDS certainly shows up any variation in POI of impact better than my eyes with iron sights.

MEAT
10-13-2012, 12:06 PM
Thanks for all the help guys. Part of the reason I'm asking, is that 124gr +P's are printing 4-6" high @ 25yds with a .215 Sevigny sight (GEN 4 G17). According to Dawson's calculator, I need the .245 height front to get the correct POI for that load. If the 147's are printing 4" higher, I'll need a .275" high front, which seems ridiculously tall. I'll have to do some more testing, but either way I need a taller front.

Alaskapopo
10-13-2012, 09:54 PM
I shoot 115gr and 147gr, but rarely 124. I do not notice any POI shift at all. The farthest I actually ever shoot though, might be an x ring at only 7 yards or so. I don't notice any difference shooting 1" dots at 7 yards either. Last week I was shooting a full-sized IPSC steel target at 100 yards with 147gr ammo, and the sight picture appeared normal "theoretically", but as I don't do this with 115gr commonly, I have nothing to compare it to.

Off topic but if your only shooting at 7 yards and in you have a huge whole in your training/practice. Gun fights with pistols do happen at longer ranges at times. There was a recently shooting with a LEO where the bad guy was shooting at the officer from 60 yards out and almost killed him. Luckly the officer got his rifle ready before and was able to kill him. Here in Alaska I know of a shooting involving a Trooper at 35 yards. There is also a shooting with a MP that happened about 15 years ago taht was over 70 yards with a M9 Beretta. You need to train from muzzle contact to at least 25 yards and I go all the way out to 100 at times.

(Edited missed the part about you shooting at 100 yards on steel carry on)
Pat

DocGKR
10-14-2012, 01:22 AM
"have you run the same test with your Glock pistols to determine if here is POI shift between 147 and 124+ P?"

I will be happy to do that next time I am at the range.

Mr_White
10-14-2012, 07:23 PM
M&P9 zeroed at 25 yds shooting the following loads at 25 yds:

147 gr Fed AE9FP FMJ--note this shoots to the same POA/POI as P9HST2 147 gr duty ammo
http://www.10-8forums.com/ubbthreads/ubbthreads.php?ubb=download&Number=7972&filename=M&P9%20Fed%20147%20gr%20FMJ.jpg

124 gr Fed P9HST3 +P JHP
http://www.10-8forums.com/ubbthreads/ubbthreads.php?ubb=download&Number=7973&filename=M&P9%20Fed%20124%20gr%20+P%2025%20yds.jpg


DocGKR, have you run the same test with your Glock pistols to determine if here is POI shift between 147 and 124+ P?

A RDS certainly shows up any variation in POI of impact better than my eyes with iron sights.

Incidentally, I just checked this issue for myself about a week ago. DocGKR's pictures closely mirror what I see shooting Gen3 G34s at 25 yards, with both Ameriglo Operators and Ameriglo Defoor sights, using 124gr + p Gold Dot, and 147 gr. HST.

DocGKR
10-14-2012, 11:34 PM
One person reports results, another person repeats the effort to verify or refute the initial findings; amazing how the scientific method works...

Spr1
10-15-2012, 04:24 AM
And a few extra milliseconds of bore time....... :)

GJM
10-17-2012, 08:43 PM
Shot my P30 at 25 yards with HST 147 and 124+P today. No variance in either windage or elevation, and similar group size.

GJM
12-09-2012, 04:20 PM
Unusual circumstances today, had me verifying zero at 25 yards with a G4 G17 with a T1, and a G4 17 with an RMR. Previously I have not noticed differences in POI with 124 versus 147 grain ammo in the P30, but have read on PF that 147 grain ammo hits higher in Glock pistols. I decided to test this hypothesis in Glock pistols, by shooting Aguila 124 ball, Fed AE 147 FMJ, HST 147 and HST 124+P amp. Since I was carrying a iron sighted G4 Glock 34, I decided to also test that. The neat thing is the optics allowed for a level of precision greater than with iron sights. Conditions were light snow, 11F, 25 yards braced sitting, and I alternated between nomex flight gloves and bare hands (although that didn't seem a factor).

I first shot the G17/RMR. After tweaking the zero (just back from Mark Housel for a back-up sight change), I shot 10 rounds of AE 147 and 10 rounds of Aguila 124 at separate two inch dots on a PF target. I noted little difference in point of impact between the two loads, with the Aguila perhaps a half inch higher which easily could have been me, and both groups around 2.5 inches for the 10 shots. I then shot the 147 and 124+P HST from the same pistol, and was surprised the 124+P struck about an inch higher than the 147 grain.

I next shot the G17/T1. Very little difference in accuracy and POI between the 124 Aguila and 147 AE. Interestingly, the HST 124+P shot about two inches higher than the 147 HST. I was surprised enough, I repeated strings, and confirmed the 124+P was indeed shooting higher. Interestingly while the T1 4 moa dot was easier to place on the two inch aiming dot, the smaller dot wiggled more, and I found it easier to shoot groups with the RMR.

Then I shot the Glock 34 with 5 rounds of 147 HST, followed by 5 rounds of 124+P HST, followed by 5 rounds of AE 147 FMJ, and finally 5 rounds of 124 Aguila, all to the 3x5 card as it was a convenient aiming point. Here are some pics with the G34:

5 rounds of 147 HST:

http://i250.photobucket.com/albums/gg251/GJMandes/91.jpg

then the first 5 plus 5 rounds of 124+P HST:

http://i250.photobucket.com/albums/gg251/GJMandes/92.jpg

then the first 10 plus 5 rounds of 147 AE ball:

http://i250.photobucket.com/albums/gg251/GJMandes/93.jpg

finally the first 15, plus 5 rounds of Aguila:

http://i250.photobucket.com/albums/gg251/GJMandes/94.jpg


My conclusion with the 34, is the Aguila 124 shot a smidge lower, but I am not sure I shot enough to draw a firm conclusion, and the difference in POI wasn't great. Interestingly, I enjoyed shooting the groups most with the iron sighted 34, and shot them a lot faster, as I am not accustomed to the wiggle of the red dot, and how much is acceptable.

My take away is each of these pistols, even amongst 3 G4 Glock 9's has its own personality as regards accuracy, POI and load preferences, and while it hardly matters for 7 yard work, if you are serious about precision or longer range shooting with them you need to figure out what loads your pistol likes and how your sighting system is regulated.