sk8242 Posted December 16, 2022 Share Posted December 16, 2022 (edited) Hi, New to the forum and to reloading and was hoping to get some thoughts on an observation. I made up a load ladder with the following with the intent of starting to load for 9mm minor: -147gr TC poly coated lead bullets from DG Bullets (.356" diameter) -mixed brass, full length resize, untrimmed -Federal Match SPP -Case mouth flare to ~0.382" -2.8 to 3.4 grains of Shooters World Cleanshot -Loaded to an OAL of ~1.135" -Crimped to ~0.378-0.379" with a Lee factory crimp die -All cartridges loaded on a Lee Classic Turret press, with Lee dies -Chrono'd using a Labradar chronograph -- target @ 25 yards, muzzle @ 6" lateral offset from the radar -32F ambient temp -10 shot average for each powder charge -- STDEV charted as error bars and generally very consistent measurements shot to shot -Tested out of a Beretta LTT Elite Centurion (4.25" barrel) and an M&P 2.0 Metal (4.25" barrel) -As a baseline control, I checked average velocities out of 2 factory loads -- 150gr Federal Syntech, and 147gr American Eagle -- I saw the same 40-50fps difference between the two same guns Very quickly during the testing it became clear that the M&P was sending projectiles on average 40-50fps faster than the Beretta. From my limited research, it seems that this is pretty common. But it's still a pretty significant difference when considering the overall muzzle velocity of the projectiles and the fact that I'm trying to load to as low of a PF as possible while still taking into account normal variations from cartridge to cartridge. Looking at the data, it would suggest that I can load as much as 0.4 grains less if shooting out of the M&P and still make 130 PF (under these testing conditions), while the Beretta requires that much more propellant. While doing plunk tests to determine what OAL I should start loading at, I noticed that the Beretta chamber was essentially at the max SAAMI spec of 1.169", while the M&P had a slightly shorter leade, closer to 1.145" or 1.150". I'd be interested in hearing from others regarding their experience, if any, with a similar situation. Did you end up changing propellants, or just load for the slower barrel? Would the OAL cause this effect this in any way, or is it primarily dependent on barrel/chamber dimension variations from manufacturer to manufacturer? Please see attached images for the graphed data. Note a velocity of 851fps is the minimum to make PF with a 147gr projectile. ? Edited December 16, 2022 by sk8242 Link to comment Share on other sites More sharing options...
Alaskapopo Posted December 16, 2022 Share Posted December 16, 2022 Barrels are different I have a 5 inch 357 that has slower velocity than my 3 inch barrel with the same loads Link to comment Share on other sites More sharing options...
SteelCityShooter Posted December 17, 2022 Share Posted December 17, 2022 If you are loading to different cartridge lengths for the two guns then the shorter LOA cartridges will develop more pressure for the same powder charge due to the smaller net case capacity. That could account for the velocity difference. That said, as mentioned above, every barrel is a world unto itself and some are faster than others. I've noticed that my two M&P2.0s (a 5" Pro and a 4.25" Metal Frame) both have short chambers and require an LOA of 1.105 with a 125 gr Blue RN to "plunk" properly. Link to comment Share on other sites More sharing options...
superdude Posted December 17, 2022 Share Posted December 17, 2022 It's not unusual to see barrels of the same length produce different speeds, and for shorter barrels to be faster than longer barrels. https://www.ssusa.org/articles/2021/8/16/pistol-barrel-length-and-velocity Link to comment Share on other sites More sharing options...
Farmer Posted December 17, 2022 Share Posted December 17, 2022 Try loading to the shorter length for the S&W and see how they work in the Beretta. I’ve done tests where I loaded rounds at .010, .020 and .030 from the lands and many times the .020 will be the fastest. Link to comment Share on other sites More sharing options...
HesedTech Posted December 17, 2022 Share Posted December 17, 2022 21 hours ago, sk8242 said: But it's still a pretty significant difference when considering the overall muzzle velocity of the projectiles and the fact that I'm trying to load to as low of a PF as possible while still taking into account normal variations from cartridge to cartridge. Not a significant difference at all. Barrel length is only part of the equation, rifling, barrel diameter, chamber, throat and probably other things all effect the velocity. If I load for 130 PF in my CZ Shadow 2 it will barely make PF in similar length Tanfoglio. Also the CZ using the same load is significantly more accurate than the Tanfoglio. If you want to build just one load then do it for the slowest barrel you will be shooting and then not worry about the difference. In the heat of a stage the last thing you will notice is a 5 PF difference. Honestly I load to an average PF of 133 to cover variations and not worry about Chrono stage. Link to comment Share on other sites More sharing options...
GMM50 Posted December 17, 2022 Share Posted December 17, 2022 Not exactly what you're talking about, but consider the following. We manufacturer coated bullets. We use Hi Performance bullet coating. Out bullets are brinell 12. When comparing lubed bullets to coated bullets, we consistently see velocities in the coated bullets higher than the lubed. Also, for about 10 to 20 rounds, the coated bullets keep increasing in velocity. Our only explanation is that the coated bullets are cleaning the barrels. So be sure you take enough samples to make sure your setup has stabilized. Link to comment Share on other sites More sharing options...
Cuz Posted December 18, 2022 Share Posted December 18, 2022 I see the same kind of difference between my gen3 and gen5 Glocks. The gen5 barrels are considerably slower with the same ammo. Link to comment Share on other sites More sharing options...
Scotty_JR Posted December 18, 2022 Share Posted December 18, 2022 I've got a friend with a fullsize LTT that shows similar results. His barrel is considerably slower as well. He has to run a few tenths over max of Clean Shot to make 135PF. Link to comment Share on other sites More sharing options...
Farmer Posted December 19, 2022 Share Posted December 19, 2022 On 12/17/2022 at 8:09 AM, HesedTech said: If I load for 130 PF in my CZ Shadow 2 it will barely make PF in similar length Tanfoglio. Also the CZ using the same load is significantly more accurate than the Tanfoglio. Found the same thing between my brothers 4.5”Witness in 10mm and my 3.8” XDM 10mm. The XDM even though gives up .7” of bbl it’s still faster. Actually it’s only 50-70 fps slower than my 5.25 bbl. Link to comment Share on other sites More sharing options...
shred Posted December 19, 2022 Share Posted December 19, 2022 I've had 3 otherwise-identical Bar-Sto barrels in the same Open gun over the years. All of them have been more than 50 FPS different from each other with the same loads. Barrels vary, it is what it is. Link to comment Share on other sites More sharing options...
Laughing_jackal Posted December 20, 2022 Share Posted December 20, 2022 I saw massive differences comparing a Walther PPQ to a Glock. In that case, I learned that the Walther PPQ had a stepped chamber, and I attributed the velocity difference to that. In my situation, to keep things simple between guns, I just ran the same load for both guns as it was. In the precision rifle game, we've definitely seen "Fast" barrels and "Slow" barrels come from the same barrel maker, cut with the same reamer, same length, same twist rate, etc. Link to comment Share on other sites More sharing options...
ysrracer Posted December 20, 2022 Share Posted December 20, 2022 Name: 9mm: 147gr: Cleanshot 3.5gr: Mixed Case: OAL 1.140 Notes: Para 1911 5" Shots: 7 Average: 901 ft/s SD: 12 ft/s Min: 874 ft/s Max: 912 ft/s Spread: 38 ft/s Power Factor Average: 132 Power Factor Low: 128 Power Factor High: 134 Barometric Pressure: 30 in Hg Temperature: 68 F Weight: 147.0 gr. Powder: Cleanshot 3.5gr Case: Mixed Primer: Rem SPP Bullet: 147gr Gun: Para 5" 1911 Link to comment Share on other sites More sharing options...
Khaot1c Posted January 1, 2023 Share Posted January 1, 2023 If you need more data to show how important it is to test EVERY barrel you're going to go to a major match with... I have 4 KKM barrels for my SIg 320 Legions. Each will post slightly different Average Velocity, Extreme Spread, and Standard Deviation. Even though they are the "same" barrel. Probably manufactured within a close timeframe of one another since I ordered (and received) all four in the same internet order from KKM. Link to comment Share on other sites More sharing options...
ysrracer Posted January 2, 2023 Share Posted January 2, 2023 On 12/16/2022 at 10:58 AM, sk8242 said: Very quickly during the testing it became clear that the M&P was sending projectiles on average 40-50fps faster than the Beretta Yes. Link to comment Share on other sites More sharing options...
Bakerjd Posted January 7, 2023 Share Posted January 7, 2023 Yeah pretty normal. Link to comment Share on other sites More sharing options...
floater Posted January 9, 2023 Share Posted January 9, 2023 I have a Beretta 92 that is the slowest barrel I have. Link to comment Share on other sites More sharing options...
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