9mm Factory Ammo - 115 or 124 grain for GSSF?

I think most people just go for cheap.

I focus more on the power factor and whether the ammo shoots good groups from my gun.

power factor: bullet weight (grn) x muzzle velocity (fps)/1000

The lower the power factor the less felt recoil you are likely to experience, all else equal. It’s not perfect and different bullet weights will give you a different recoil impulse, but it’s a better guide than bullet weight alone.

I use either 115grn or 147grn ammo, depending on which is available in the factory ammo I shoot. Most of my friends that reload are using 115grn bullets.

@Danke Glock is spot on. Power factor is the key.

I tend to shoot 147 gr. with a reasonable/lower power factor. Also, 147 gr. POI tends to be a little higher for me. YMMV

I like the 124 and 147 grainers when I actually use factory. Lately I’ve been shooting 124 Blazer Brass because I’ve found it fairly cheap.

Can anyone really tell the difference between 115 & 124 grain when shooting FMJ range ammo from a G17?

Bullet weight alone really doesn't tell you anything about what the recoil is going to be like when comparing two different loads. i.e. Some 115gr factory ammo is loaded pretty weak and some 124gr is loaded kind of hot. Keeping power factor the same, heavier bullets will give you milder feeling recoil. PF = bullet weight * velocity /1000 with anything right of the decimal point just ignored (not that the dividing by 1000 matters for the purpose of comparison).

for me - 115 seems snappy to me, 124 isn't. powder cheaper than bullet weight otherwise i'd go 147.

your mileage may vary

I find 115s to be a little snappier than 124s when compared to the same brand. So 114 Blazer vs 124 Blazer or 115 S&B vs 124 S&B. But one brands 115 could be less snappier than another brands 124 and vice versa. The best thing to do is test out a lot of different loads and pick one that does best. When you find a winner, buy a case or two as performance can also vary from lot to lot.

I tried all three weights before I settled on 147 grain for EDC (Gold Dot) and Competition (Lawman, WWB or American Eagle). In my experience, 147 grain delivers the least felt recoil.

I honestly can't tell much difference in recoil between 115 grain and 124 grain. That's comparing the same brand and type of ammunition. I'd choose whatever was the most accurate.

I think the 124's are a little less snappy. That's what I've been using.

Bottom line, YMMV. 🤷‍♂️

Ok, gotta ask, for us 43/43X/48 slimline gun folk, does the 147 work or will 124 be a good option.

Any factory ammo will work.

Sent from my SM-A716U using Tapatalk

Having the same brand and bullet weight and knowing your holds with your sights is far more valuable then 115,124,147 production ammo.

I don’t reload. Blazer alum, blazer brass is mostly my go to unless a steal of a deal pulls me away. But then I’m back to verifying holds in all my competitive guns. So when that happens how much did I “really save”.


Sent from my iPhone using Glock Talk

battousai said:

Having the same brand and bullet weight and knowing your holds with your sights is far more valuable then 115,124,147 production ammo.

I don’t reload. Blazer alum, blazer brass is mostly my go to unless a steal of a deal pulls me away. But then I’m back to verifying holds in all my competitive guns. So when that happens how much did I “really save”.


Sent from my iPhone using Glock Talk

Click to expand...

If you mixed 125 rounds of 9mm factory ball in 115, 124, 147 gr in my mags I doubt I could tell the difference. As far as POA/POI, should any of those weights have more than 1/2 inch difference at GSSF distances? We are shooting at an 8” circle.

BamaTrooper said:

If you mixed 125 rounds of 9mm factory ball in 115, 124, 147 gr in my mags I doubt I could tell the difference. As far as POA/POI, should any of those weights have more than 1/2 inch difference at GSSF distances? We are shooting at an 8” circle.

Click to expand...

I hear you. I am mostly looking at my g26.3 which seems to be the most ammo sensitive. Also you know I'm a pleb so I don't always transition to the middle properly haha.

Whichever groups better

DaSvenska said:

Ok, gotta ask, for us 43/43X/48 slimline gun folk, does the 147 work or will 124 be a good option.

Click to expand...

I shoot a G48 MOS with Holosun 507k gr dot sight (and a few mods) and I generally shoot whatever I can get cheap, but I'm now in the process of standardizing on 124 gr. (because that's what my "social" ammo is). I came in 2nd in our last indoor match so it appears to be working okay.

I don't really feel much difference between 115 and 124 grain freedom seeds and when I get my (won in the raffle) G34 in, I doubt if I'll feel any difference.