Velocity difference in 9mm loads

Dr Killdeer · April 10, 2011, 08:44 AM

I’ll keep this question general and simple. What is an acceptable velocity variation for a ten shot string of 9 mm handgun ammo?
I don’t own a 9mm, nor have I ever reloaded ammo for one, but a guy at the range saw my Chrony and asked if he could clock his reloads. For a ten shot string off a rest, the low was 690 fps and the high was 905 fps. To me a 215 fps difference would send up a red flag, but I elected to go about my business rather than take issue with it. Is that the norm for 9mm loads?

Jim Watson · April 10, 2011, 09:04 AM

That is not the norm. It is, in fact, dreadful.
The last time I chronographed any 9mm, the extreme spread over 5 rounds ran from 6 to 61 fps for 7 different loads. The worst was a factory load at that.
I only chronograph 5 shot strings, my main interest is in making the required power factor for IDPA and avoiding grossly erratic ammunition like you saw. I once saw some statistics to indicate that a 10 shot string would vary APPROXIMATELY 30% more than a 5 shot string.

m&p45acp10+1 · April 10, 2011, 09:06 AM

I am not sure as to the fact that I have never used a chrono. Though it appears that the guy has some deviation in his powder measuring. Out of a 10 shot string at 15 yards most of mine will be inside of 9 on a b27 target. If any are outside of it they are usualy in the 8. They feel the same to me, and have not given any problems after running through several different pistols.

FrankenMauser · April 10, 2011, 12:54 PM

That sounds like the consistency I've seen come from reloaders trying to push their progressive presses to the maximum possible production rate. It gets especially bad when using a bulky powder in an already-mediocre load.

You're likely talking about a powder charge deviation of more than 0.5 gr, probably more like 0.6-0.7 gr, for most powders. ...Which sheds some light on people that think +/-0.3 gr is fine; but are always complaining about accuracy and performance

The other option, is that he made a very poor choice for powder selection, and is using something like H110/W296, 4227, etc. Combine the wrong powder with a position-sensitive load, and you can get very erratic performance.

Clark · April 10, 2011, 01:17 PM

I put my chronograph way out there so the gas from the muzzle does not affect the measurement.

That combined with my poor handgun marksmanship, means I only fire one shot from a handgun over the chrono for a load.
A chronograph will last about 10 handgun shots and costs $100, so that is $10 per measurement.

The handgun range report look like this:
Kel-Tec PF9 3" barrel
1) 124 gr FN Honady bullets and [XX] gr Power Pistol. 1336 fps.
2) 100 gr Hirtenberger +P+ 1275 fps

But the rifle range report gets multiple velocity entries:
7mmRM
a) 70 Re22 180 gr VLD 3.48" 78kpsi loaded 45 [already pressure threshold tested] decap, reprime, 15 WW half hard going in, one RP easy in.
..1) Ruger #1 26" barrel, 6X scope, , 3016, 3023, 3030 fps, and 0.82" 3 shot group at 100 yards from the bag 11 pounds with scope, sling, bi pod

relictrader · April 10, 2011, 02:32 PM

I found that just trying to make POWER FACTOR in order to shoot is tough.
I must trust my loading and make sure that tight hold with mimium recoil is used when velocity is checked for a soft hold will read 1 to 200 FS slower.

Gary

KW Gary M · April 10, 2011, 02:43 PM

That is a huge difference. Even the high of 905 fps is very slow for a 9mm. In most cases loads shouldn't vary more than 50-60 fps. Even for heavy bullets 905 fps is pretty slow for a 9mm. I load my target 9mm around 1,100 fps with 125 grain bullets and my carry 9mm over 1,200 fps with 115 grain.

Dr Killdeer · April 11, 2011, 11:27 AM

The feedback I got from knowledgeable 9mm folks confirms what I thought. Something is rotten in Denmark. I probably should have said something to that guy, but since I don’t know 9mm loads from shinola, I just backed off. In retrospect, that was a mistake. When I need to know something that a book can’t tell me, I turn to other sources. This forum is one of them. Thanks again!

LarryFlew · April 11, 2011, 05:45 PM

At least he isn't going to blow anything up at those numbers. 45 numbers at half the weight of bullet hhmmmmm

madlink · May 13, 2011, 11:09 PM

The only time I have had that much variation in speeds was when I was loading .45 Colt using Trail Boss powder and not crimping the bullet tight enough. (Yes, I know that this thread is about 9mm loads, but this isn't actually too much of a rabbit trail!). Trail Boss is a slow-burning low-density powder, and with a light crimp the pressures apparently weren't high enough and/or the bullet was leaving before all the powder could ignite.

Not the same problem for 9x19, for which I use Bullseye (a fast powder) and a light crimp on the bullet. Using a Dillon powder bar I get very consistent speeds: standard deviation of about 10 f.p.s. out of a Glock 17 with average speed about 1050 f.p.s. with a 124gr RN/FMJ bullet. I have never seen the kind of variation that guy had!

g.willikers · May 14, 2011, 10:54 AM

Holy Cow, Clark, that's an expensive hobby you have, there.
Shooting chronographs long distance, that is.
Have you tried putting a piece of cardboard in front of the chrony, to stop the muzzle blast from messing up the readings?
Of course, that's no absolute guarantee that you can't still shoot it.
I've wounded mine a few times, but it ain't dead, yet.

Japle · May 14, 2011, 01:05 PM

Well, a lot depends on the gun.

A 9mm load with Silhouette powder I used to use produced and average velocity of 935 fps and extreme spread of 38 fps in my CZ75 SA.
The same load in my new XDm 3.8 gave me an AV of 806 fps and an ES of 581 fps!!

Changing powders to TiteGroup gave me an AV of 907 fps and an ES of 30 fps.
In the CZ75, I got an AV of 927 fps and an ES of 19.4 fps.

Guess which load I use now!!

April 10, 2011, 09:06 AM	#3
m&p45acp10+1 Senior Member Join Date: May 3, 2009 Location: Central Texas Posts: 3,930	I am not sure as to the fact that I have never used a chrono. Though it appears that the guy has some deviation in his powder measuring. Out of a 10 shot string at 15 yards most of mine will be inside of 9 on a b27 target. If any are outside of it they are usualy in the 8. They feel the same to me, and have not given any problems after running through several different pistols. __________________ No matter how many times you do it and nothing happens it only takes something going wrong one time to kill you.

April 10, 2011, 12:54 PM	#4
FrankenMauser Senior Member Join Date: August 25, 2008 Location: In the valley above the plain Posts: 13,424	That sounds like the consistency I've seen come from reloaders trying to push their progressive presses to the maximum possible production rate. It gets especially bad when using a bulky powder in an already-mediocre load. You're likely talking about a powder charge deviation of more than 0.5 gr, probably more like 0.6-0.7 gr, for most powders. ...Which sheds some light on people that think +/-0.3 gr is fine; but are always complaining about accuracy and performance The other option, is that he made a very poor choice for powder selection, and is using something like H110/W296, 4227, etc. Combine the wrong powder with a position-sensitive load, and you can get very erratic performance. __________________ Don't even try it. It's even worse than the internet would lead you to believe.

April 10, 2011, 01:17 PM	#5
Clark Senior Member Join Date: December 4, 1999 Location: WA, the ever blue state Posts: 4,678	I put my chronograph way out there so the gas from the muzzle does not affect the measurement. That combined with my poor handgun marksmanship, means I only fire one shot from a handgun over the chrono for a load. A chronograph will last about 10 handgun shots and costs $100, so that is $10 per measurement. The handgun range report look like this: Kel-Tec PF9 3" barrel 1) 124 gr FN Honady bullets and [XX] gr Power Pistol. 1336 fps. 2) 100 gr Hirtenberger +P+ 1275 fps But the rifle range report gets multiple velocity entries: 7mmRM a) 70 Re22 180 gr VLD 3.48" 78kpsi loaded 45 [already pressure threshold tested] decap, reprime, 15 WW half hard going in, one RP easy in. ..1) Ruger #1 26" barrel, 6X scope, , 3016, 3023, 3030 fps, and 0.82" 3 shot group at 100 yards from the bag 11 pounds with scope, sling, bi pod __________________ The word 'forum" does not mean "not criticizing books." "Ad hominem fallacy" is not the same as point by point criticism of books. If you bought the book, and believe it all, it may FEEL like an ad hominem attack, but you might strive to accept other points of view may exist. Are we a nation of competing ideas, or a nation of forced conformity of thought?

April 10, 2011, 02:32 PM	#6
relictrader Junior Member Join Date: January 3, 2011 Posts: 5	9mm have great loads world wide I found that just trying to make POWER FACTOR in order to shoot is tough. I must trust my loading and make sure that tight hold with mimium recoil is used when velocity is checked for a soft hold will read 1 to 200 FS slower. Gary

April 10, 2011, 02:43 PM	#7
KW Gary M Senior Member Join Date: January 28, 2009 Location: Key West Posts: 162	That is a huge difference. Even the high of 905 fps is very slow for a 9mm. In most cases loads shouldn't vary more than 50-60 fps. Even for heavy bullets 905 fps is pretty slow for a 9mm. I load my target 9mm around 1,100 fps with 125 grain bullets and my carry 9mm over 1,200 fps with 115 grain. __________________ *To say that guns kill people is to say that automobiles drive drunk and matches commit arson....*

April 10, 2011, 08:44 AM	#1
Dr Killdeer Senior Member Join Date: August 22, 2009 Location: Newburgh, NY Posts: 127	Velocity difference in 9mm loads I’ll keep this question general and simple. What is an acceptable velocity variation for a ten shot string of 9 mm handgun ammo? I don’t own a 9mm, nor have I ever reloaded ammo for one, but a guy at the range saw my Chrony and asked if he could clock his reloads. For a ten shot string off a rest, the low was 690 fps and the high was 905 fps. To me a 215 fps difference would send up a red flag, but I elected to go about my business rather than take issue with it. Is that the norm for 9mm loads? __________________ Man is the only animal on the planet that is capable of saying "I'm sorry." Further, he's the only one who creates the need to say it.

April 10, 2011, 09:04 AM	#2
Jim Watson Senior Member Join Date: October 25, 2001 Location: Alabama Posts: 18,541	That is not the norm. It is, in fact, dreadful. The last time I chronographed any 9mm, the extreme spread over 5 rounds ran from 6 to 61 fps for 7 different loads. The worst was a factory load at that. I only chronograph 5 shot strings, my main interest is in making the required power factor for IDPA and avoiding grossly erratic ammunition like you saw. I once saw some statistics to indicate that a 10 shot string would vary APPROXIMATELY 30% more than a 5 shot string.

April 11, 2011, 11:27 AM	#8
Dr Killdeer Senior Member Join Date: August 22, 2009 Location: Newburgh, NY Posts: 127	The feedback I got from knowledgeable 9mm folks confirms what I thought. Something is rotten in Denmark. I probably should have said something to that guy, but since I don’t know 9mm loads from shinola, I just backed off. In retrospect, that was a mistake. When I need to know something that a book can’t tell me, I turn to other sources. This forum is one of them. Thanks again! __________________ Man is the only animal on the planet that is capable of saying "I'm sorry." Further, he's the only one who creates the need to say it.

April 11, 2011, 05:45 PM	#9
LarryFlew Senior Member Join Date: June 15, 2009 Location: Minnesota CZ fan Posts: 902	At least he isn't going to blow anything up at those numbers. 45 numbers at half the weight of bullet hhmmmmm

May 13, 2011, 11:09 PM	#10
madlink Member Join Date: April 19, 2011 Location: Durham, NC Posts: 30	similar problem The only time I have had that much variation in speeds was when I was loading .45 Colt using Trail Boss powder and not crimping the bullet tight enough. (Yes, I know that this thread is about 9mm loads, but this isn't actually too much of a rabbit trail!). Trail Boss is a slow-burning low-density powder, and with a light crimp the pressures apparently weren't high enough and/or the bullet was leaving before all the powder could ignite. Not the same problem for 9x19, for which I use Bullseye (a fast powder) and a light crimp on the bullet. Using a Dillon powder bar I get very consistent speeds: standard deviation of about 10 f.p.s. out of a Glock 17 with average speed about 1050 f.p.s. with a 124gr RN/FMJ bullet. I have never seen the kind of variation that guy had!

May 14, 2011, 10:54 AM	#11
g.willikers Senior Member Join Date: September 28, 2008 Posts: 10,442	Holy Cow, Clark, that's an expensive hobby you have, there. Shooting chronographs long distance, that is. Have you tried putting a piece of cardboard in front of the chrony, to stop the muzzle blast from messing up the readings? Of course, that's no absolute guarantee that you can't still shoot it. I've wounded mine a few times, but it ain't dead, yet. __________________ Walt Kelly, alias Pogo, sez: “Don't take life so serious, son, it ain't nohow permanent.”

May 14, 2011, 01:05 PM	#12
Japle Senior Member Join Date: October 12, 2004 Location: Viera, Florida Posts: 1,340	Well, a lot depends on the gun. A 9mm load with Silhouette powder I used to use produced and average velocity of 935 fps and extreme spread of 38 fps in my CZ75 SA. The same load in my new XDm 3.8 gave me an AV of 806 fps and an ES of 581 fps!! Changing powders to TiteGroup gave me an AV of 907 fps and an ES of 30 fps. In the CZ75, I got an AV of 927 fps and an ES of 19.4 fps. Guess which load I use now!!