[uofaengr]

Been doing some tweaking with my current 9mm load and have been doing some reading as well. For 9mm, do you personally find longer loaded rounds to be more or less accurate than shorter ones in general? It seems there are quite a few people that claim they find their loads to be more accurate on the shorter side when it comes to 9mm. I was surprised thinking in terms of loading rifle ammo for less jump to the rifling.

My 9mm load is shot exclusively out of Glocks, and the OAL is nominal 1.130" so I have room to spare in either direction. However, my pet .45 ACP load is 1.260" which is on the longer side and is very accurate out of both a 1911 and two G21s, but again we're talking 9mm. I know the answer is make some different loads and try them, but curious to hear others' first-hand experiences.

The projectile in question is 124gr FMJ RN (RMR). A factory load I've shot a few thousand of is Aguila 124gr which I think has a similar profile and has an OAL of 1.110". Accuracy is more than acceptable at 25 yards. I believe Zero loads their 124gr FMJ RN factory ammo to 1.110" as well according to their data sheet (with 5gr of HP-38..seems hot!) but have never shot any.

 

[fredj338]

Many will claim better accuracy, but I don't think one gains much loading right to the lands. The 38spWC is quite accurate & pretty darn far from any rifling. Your OAL with the 9mm has nothing to do with the 45acp. So any comparison there is not applicable. AOL is always bullet & barrel specific. Bullet fit in the bore will show appreciably better accuracy than how far from the rifling in my exp. This is very true with 9mm as the barrel specs seem to be all over the place.

 

[uofaengr]

Many will claim better accuracy, but I don't think one gains much loading right to the lands. The 38spWC is quite accurate & pretty darn far from any rifling. Your OAL with the 9mm has nothing to do with the 45acp. So any comparison there is not applicable. AOL is always bullet & barrel specific. Bullet fit in the bore will show appreciably better accuracy than how far from the rifling in my exp. This is very true with 9mm as the barrel specs seem to be all over the place.

Yes I was hoping to gain some insight from vets like yourself on this.

I'm considering working up a ladder at 1.110" just to compare to my ladder at 1.130", but am curious how much to reduce the charge moving back .020".

 

[fredj338]

Seating 0.020" deeper doesn't move the pressure needle much unless you are already at max. In my chrono testing, vel gains didn't really start showing up until you went 0.060" deeper with midrange loads. Even then, vel gain, which often means higher pressures, wasn't dramatic. A 0.020" diff isn't even 1/32" which isn't very deep.

 

[fredj338]

If I were searching for better accuracy, look at the bullets you are using. Cheap plated bullets rarely give top accuracy. I get the best accuracy from good hjp like the XTP or Sierra. I get pretty good accuracy from coated lead bullets, better than plated. Bulk fmj are ho-hum accuracy wise too. Nothing makes a poor bullet shoot well.
The other variable is how are you testing your ammo? Unless you are a world class bullseye shooter, you need to use a rest at a minimum or a mechanical rest like the Ransom to remove shooter error. I can shoot some pretty good off hand 35y groups but if I want to know how accurate my gun/ammo is I shoot off a bench rest.

 

[uofaengr]

If I were searching for better accuracy, look at the bullets you are using. Cheap plated bullets rarely give top accuracy. I get the best accuracy from good hjp like the XTP or Sierra. I get pretty good accuracy from coated lead bullets, better than plated. Bulk fmj are ho-hum accuracy wise too. Nothing makes a poor bullet shoot well.

They are RMR FMJ. I'm not a plated fan myself. The Armscor bulk FMJ I use in my .45 loads are surprisingly accurate.

I'm not really looking for bullseye comp level accuracy, just a nice all-around affordable training load that suits my needs and am still tweaking to find it...part of the fun of reloading. I was just surprised in my research of the number of people who had better luck loading 9mm shorter which could be coincidence.

Sorry, just saw your edit. I rest on bags to test accuracy. Having access to a Ransom would be nice though.

 

[fredj338]

They are RMR FMJ. I'm not a plated fan myself. The Armscor bulk FMJ I use in my .45 loads are surprisingly accurate.

I'm not really looking for bullseye comp level accuracy, just a nice all-around affordable training load that suits my needs and am still tweaking to find it...part of the fun of reloading. I was just surprised in my research of the number of people who had better luck loading 9mm shorter which could be coincidence.

Sorry, just saw your edit. I rest on bags to test accuracy. Having access to a Ransom would be nice though.

With good bench technique, I can shoot the same groups as my ransom, I just cant do them as consistently. That is where the ransom is great, it never gets tired or distracted.
You just have to decide what is acceptible accuracy. For service guns, I am happy with sub 2" groups at 50ft. For iron sighted hunting handguns, I want the same at 25y. That usually gets me 3" or better at 50y. Though my scoped 44 rbhh will do that at 100y.

 

[Mr Meeseeks]

I’ve found shorter COAL to give better accuracy in multiple barrels with 124gr and 115gr Precision Delta JHP’s. Not totally sure why. I wonder if reduced case capacity results in a more consistent, cleaner burn even if pressures aren’t appreciably increased. I’m talking about 4ish grains of N320, Sport Pistol, and Titegroup. This is my fumbling around on a sandbag shooting 2” +/- groups at 25 yards.

 

[9x45]

For 9mm, look at premium jacketed bullets like Montana Gold. OAl is not a indicator of accuracy, it's not like a rifle. I've loaded 9mms to between 1.060" and 1.175" OAL, no real difference. The only reason is that bullet shape determines OAL. The 1.175" was a 125 JHP Montana Gold to make the major power floor of 165 for USPSA Open Division (1,340 fps). You load long to get as much powder possible. On a Glock, you also have to finish chamber ream to accept 1.175". The only reason you can't go longer, like running 9mm in an STI, is that Glock mags will not go more than 1.180" to feed (depending on bullet shape, most will not go that long)

 

[9x45]

For ultimate mechanical accuracy in a Glock, get an oversized barrel and have it hand fitted by a gunsmith. Then finish ream the chamber to your exact hand loads.