Getting to know n340

[Duke Nukem]

I got curious about VV n340 powder for my 9mm loads, so I picked up some to try out.  The bullets I wanted to use were Missouri small ball gl 124 grain coated lead.  I found with those bullets and my chamber, my maximum workable OAL was 1.13", but I couldn't find data on this exact bullet and powder combination.  The VV site data for 124 grain FMJ-RN bullets shows OAL of 1.142 with a starting load of 4.5 gr and a max load of 5.1 at 1181 fps.
  I started with 4.5 grains and loaded five each from 4.5 to 4.9.  Yesterday at the range with the chrono gave me fps averages of 1105, 1124, 1144, 1155 and 1168.  One shot in the 4.9 group made 1180, so I guess that would be my max load.  The narrowest spread of speeds was the 4.8 group at 14 fps, second narrowest spread was 4.6 at 17 fps.
  Is this enough data for me to proceed, or should I have loaded ten or more of each?  Right now I'm liking 4.8, although 4.6 looked good as well and would save powder.

[FireMoose]

I usually do 5 each while working up a load. I'd take the 4.6 and do a batch of 50 and see if I still liked them.

[Wobbly]

• You were right to stop at 1180 and 4.9gr.

• Statistically speaking, you want as large a test group as possible. In a lab they might shoot 30, but I think for your purposes 8 to 10 in more reasonable. 8 to 10 is what I do for the reports here on CZF.

• What I would tell you to do now is to go back to the loads that you highlighted. Focus in and use the 8 to 10 method at your areas of interest, 4.6gr and 4.8gr. Check out the differences. If there really are none, then as you thought... go with the lighter load.

• You might even see how your loads compare to those of others.... https://czfirearms.us/index.php?topic=104486.msg810285#msg810285

[Duke Nukem]

I suppose I was getting higher velocities than the VihtaVuori examples because I was seating the bullet deeper, reducing the cartridge volume, but maybe that's not right.  I see another 124 grain bullet- the Alsa Pro FMJ that they show 981 fps at 4.6 grain load.  I don't understand why that is so slow for the same weight bullet unless it is again cartridge volume coming into play.

At their starting load of 4.5gr they were getting 1086 fps while I was getting 1105, both with a 124 gr. projectile.  I think there is room below 4.5 gr. to be explored, just so I've tried them all.  Would I consider their 1086 fps to be the speed for my minimum load?  Of course, I'll be paying attention to how the gun is cycling and how far the empties are thrown.

I could make up another ladder going down from 4.5 grains of powder and see how low I can go and if there is any advantage to doing that.

BTW, I was using these cartridges in my P10-C and the targets were at 10 yards.  All the brass was Speer headstamp and the primers were Winchester SP.

[SoCal]

I suppose I was getting higher velocities than the VihtaVuori examples because I was seating the bullet deeper, reducing the cartridge volume, but maybe that's not right.  I see another 124 grain bullet- the Alsa Pro FMJ that they show 981 fps at 4.6 grain load.  I don't understand why that is so slow for the same weight bullet unless it is again cartridge volume coming into play.

Coated lead is often faster than FMJ also your are correct, shorter OAL usually results in slightly higher velocities as well as different barrels will give different velocities.  There are many more variables as well. 

4.6, 4.7 and 4.8 all seem to be within safe limits, now load more and do further testing including accuracy testing but I bet all will test well.  Then I would do as Wobbly said and go with the lightest load that does what you want it to.

[Wobbly]

I suppose I was getting higher velocities than the VihtaVuori examples because I was seating the bullet deeper, reducing the cartridge volume, but maybe that's not right.

That's exactly correct. Anything that produces more Chamber Pressure then produces higher bullet velocities.

At their starting load of 4.5gr they were getting 1086 fps while I was getting 1105, both with a 124 gr. projectile.  I think there is room below 4.5 gr. to be explored, just so I've tried them all.  Would I consider their 1086 fps to be the speed for my minimum load?  Of course, I'll be paying attention to how the gun is cycling and how far the empties are thrown.

• 4.5gr at 1086 is not the true minimum. Book minimum is simply 10% (0.4gr in this case) below maximum. So they simply find what the safe maximum is, and then subtract 10%.

• Remember that testing was done in a single-shot "rifle" to gain accurate Chamber Pressure readings. The published load range has noting to do with slide operation, stripping the next round off the mag, or case ejection performance. That part of "performance" is left for the reloader to discover.

Consider that if you had one of those 9mm revolvers, then the minimum load skips all the feeding and ejection issues and focuses solely on getting the bullet to exit the barrel !! The minimum load might be 2.5gr for a revolver !!

• You can definitely go lower, especially if you have a reduced recoil spring. Just realize that they may fail to lock back the slide in your buddy's gun that 's sprung slightly differently.

[Duke Nukem]

Thanks, Wobbly, that helps.   

[Wobbly]

This is what a lab "test barrel" looks like. It's a single shot hunk of steel, and not a handgun at all.

[M1A4ME]

Over the years I've had some great shooting loads with slower burning powders in handguns and rifles both.  Compressed charges usually.  Burns more powder but the groups are hard to beat.

I usually load up ten at each increment level.  I shoot a five shot group with each, and compare.  Sometimes I get will shoot that last five rounds from the same pistol at the same range trip but I like to use the second 5 rounds of each powder charge level in a different pistol to see how the load works out.  Usually what shoots nice in the CZ pistols don't shoot nice in the M&P pistols and vice versa.  I keep looking though.

After that first session I'll load up more.  Sometimes 25 each of the two best grouping charge levels and head to the range again and let the pistols tell me which one to go with.  It's usually not the max charge level batch but one a level or two below that.  0.2 to 0.3, some times a bit more that gives me the best groups.

Good luck with it.  It can be fun.

[Duke Nukem]

Good luck with it.  It can be fun.

Thank you, I am having fun with it.  I know there's still a lot for me to learn, so I'm taking it slowly.  It's nice to have information shared from the more experienced reloaders.

I have been using Sport Pistol and that was working okay, but I began to wonder if I could do better.  Early impressions make me think so, but I've still got a ways to go with testing. 

[Wobbly]

There was a rumor that N340 was being used in some factory SD loads by Speer. I don't remember the details, but it makes sense in that N340 has a flash suppressant and has no trouble getting 124gr bullets up past 1100fps.

Have you looked inside your gun after shooting N340 ? It's the cleanest powder you'll ever encounter.

[twentytwocal]

I load 9mm subsonics with N340 and 147gr bullets. I love it.

[Duke Nukem]

Have you looked inside your gun after shooting N340 ? It's the cleanest powder you'll ever encounter.

I made it to the range yesterday, and the gun was cleaner than usual (still needed cleaning, though). 

I tried the smaller charges- 4.4, 4.3, 4.2, 4.1 and 4.0.  They all did okay, by the time I got to the 4.0 the cases were flipping out and landing by my feet, but the gun still cycled.  The most accurate of that bunch was the 4.4, but still not as good as the higher charges.  I made up 25 cartridges each at 4.6 and 4.8, and it was clearly the 4.8 that was better for me.  These were all shot at 10 yards, I didn't chrono anything yesterday.

[Duke Nukem]

After that first session I'll load up more.  Sometimes 25 each of the two best grouping charge levels and head to the range again and let the pistols tell me which one to go with.  It's usually not the max charge level batch but one a level or two below that.  0.2 to 0.3, some times a bit more that gives me the best groups.

Good luck with it.  It can be fun.

You were right on all counts; it sure is nice to get advice from someone who's been there and done that.  Thank you!

[Wobbly]

As a very general practice... Sometimes I'll skip loads in the beginning... like 5 each at 4.2, 4.4, 4.6, 4.8gr. Then when I find that 4.4gr did really good, I'll come back with 10 or 12 each at 4.3, 4.4 and 4.5gr. Then, if I can't see a difference between 4.4 and 4.5gr, I'll come back with whatever a full mag count is.

It's sort of the same procedure as a lot of things... a rough guess on the first pass, then as you get closer you get more and more "focused".