My own N340 Data (357 mag). Does it look OK...?

Centella

Centella

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Joined
Jan 21, 2023
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91
Hello friends,
I have been using N340 to handload 357 magnum for about a month now and I'm very happy with the results. The only issue I'm having is that data is very difficult to find. I've been looking at the data page from Vihtavuori's site and it works just fine, but the data there seems to be pretty "basic." At this point I feel ready to take my handloads to full power.
According to other handloaders, N340's velocities increase in a predictable linear pattern as you increase the amount of powder. Using this idea, I came up with my own loading chart taking Vihtavuori's data from their website as a starting point. Do you guys think this chart looks reasonable/safe?

357 magnum
Bullet: Berry's 158gr FP-TP

Powder(grains) Velocity(fps)
7.1 >>>> 1188
7.2 >>>> 1196
7.3 >>>> 1205
7.4 >>>> 1214
7.5 >>>> 1222
7.6 >>>> 1231
7.7 >>>> 1240
7.8 >>>> 1248
7.9 >>>> 1257
8.0 >>>> 1266
8.1 >>>> 1274
8.2 >>>> 1283
8.3 >>>> 1292
8.4 >>>> 1300
8.5 >>>> 1309
8.6 >>>> 1318
8.7 >>>> 1326
8.8 >>>> 1335
8.9 >>>> 1344
9.0 >>>> 1352
9.1 >>>> 1361
9.2 >>>> 1370
9.3 >>>> 1378
9.4 >>>> 1387
9.5 >>>> 1396
9.6 >>>> 1405
9.7 >>>> 1414
9.8 >>>> 1422
9.9 >>>> 1431
10.0 >>>> 1440
10.1 >>>> 1448
10.2 >>>> 1457
10.3 >>>> 1466
10.4 >>>> 1474
10.5 >>>> 1483
10.6 >>>> 1492
10.7 >>>> 1501
=========================
(MAX is velocity for this bullet is 1500fps according to Berry's)
 
Vit's N340 load data stops at 7.7 gr for that bullet. As long as you load to the same OAL with the same brand of cases they use, it should be safe up to 7.7 grains as long as you look for pressure signs and stop if you get bad pressure signs before getting to 7.7 grains.

It would not be safe, according to Vit's data, if you exceed 7.7 grains on N340.
 
I have never heard of load data being linear. Increases in pressure can and often do change a powder's performance, characteristics. A 10% increase may cause a 20% increase in pressure.

One hint, find load data before you buy/choose components. Many fewer headaches and questions that way...
 
fxvr5 said:
Vit's N340 load data stops at 7.7 gr for that bullet. As long as you load to the same OAL with the same brand of cases they use, it should be safe up to 7.7 grains as long as you look for pressure signs and stop if you get bad pressure signs before getting to 7.7 grains.

It would not be safe, according to Vit's data, if you exceed 7.7 grains on N340.
Click to expand...

Thank you.
The bullet, however, is not exactly the same as in Vit's data. The bullet I'm using is Berry's 158gr FP-TP (thick plate with cannelure), which according to Berry's can be shot at a max velocity of 1500 fps. The bullet on Vit's site is 158gr FP (no cannelure, no thick plate). I will follow your advice about not exceeding 7.7 grains just to be safe, but I'm curious about how to load a more stout 357. I already went up to 7.9 and got nice results (accurate shots, good kick, no visible issues), but will go back to 7.7.
 
Centella said:
Thank you.
The bullet, however, is not exactly the same as in Vit's data. The bullet I'm using is Berry's 158gr FP-TP (thick plate with cannelure), which according to Berry's can be shot at a max velocity of 1500 fps. The bullet on Vit's site is 158gr FP (no cannelure, no thick plate). I will follow your advice about not exceeding 7.7 grains just to be safe, but I'm curious about how to load a more stout 357. I already went up to 7.9 and got nice results (accurate shots, good kick, no visible issues), but will go back to 7.7.
Click to expand...
The bullet generates resistance and is a factor in the equation just like the tires in gas milage. Just because your tires may be zz rated to 200 miles per hour, one does not red line their car and break every speed limit to verify the companies claim. Pressure makes everything in a firearm work. Excessive pressure makes bad things happen fast...
 
ballman6711 said:
The velocities "could" be reasonable, but it's certainly not safe. VV data is 7.7gr for that bullet, which I would not exceed.

chris
Click to expand...

Thank you.
The bullet, however, is not exactly the same as in Vit's data. The bullet I'm using is Berry's 158gr FP-TP (thick plate with cannelure), which according to Berry's can be shot at a max velocity of 1500 fps. The bullet on Vit's site is 158gr FP (no cannelure, no thick plate). I will follow your advice about not exceeding 7.7 grains just to be safe, but I'm curious about how to load a more stout 357. I already went up to 7.9 and got nice results (accurate shots, good kick, no visible issues), but will go back to 7.7.
 
Centella said:
Thank you.
The bullet, however, is not exactly the same as in Vit's data. The bullet I'm using is Berry's 158gr FP-TP (thick plate with cannelure), which according to Berry's can be shot at a max velocity of 1500 fps. The bullet on Vit's site is 158gr FP (no cannelure, no thick plate). I will follow your advice about not exceeding 7.7 grains just to be safe, but I'm curious about how to load a more stout 357. I already went up to 7.9 and got nice results (accurate shots, good kick, no visible issues), but will go back to 7.7.
Click to expand...

For more speed, select a gunpowder based on its results in a loading manual. With Vit's data, 3N37, N105 and N110 provide a little more speed, albeit not much for this bullet. If you want more speed, you'd be better off using a different bullet that has a higher speed at max load. Check out their data for the Hornady 158 HP/XTP, for example. That bullet can go faster, but again, don't exceed their max load for that bullet. And work up your load to make sure it's safe in your gun.

Berry's only says that is the 'speed limit' for that bullet, beyond which the plating might come off and produce leading. The thicker plating provides that ability. It does not mean it can be pushed to that speed with any powder. In fact their standard plated and thick plated bullets (of the same weight and shape) will likely use the same data. As a reloader, you have to stick to load data in manuals to be safe. Exceeding published data means excess pressure which can damage the gun and injure or kill the shooter and bystanders when the gun explodes.
 
fxvr5 said:
For more speed, select a gunpowder based on its results in a loading manual. With Vit's data, 3N37, N105 and N110 provide a little more speed, albeit not much for this bullet. If you want more speed, you'd be better off using a different bullet that has a higher speed at max load. Check out their data for the Hornady 158 HP/XTP, for example. That bullet can go faster, but again, don't exceed their max load for that bullet. And work up your load to make sure it's safe in your gun.

Berry's only says that is the 'speed limit' for that bullet, beyond which the plating might come off and produce leading. The thicker plating provides that ability. It does not mean it can be pushed to that speed with any powder. In fact their standard plated and thick plated bullets (of the same weight and shape) will likely use the same data. As a reloader, you have to stick to load data in manuals to be safe. Exceeding published data means excess pressure which can damage the gun and injure or kill the shooter and bystanders when the gun explodes.
Click to expand...

Thank you. Yes, will stick to published data. Your explanation makes total sense.

Best.
 
AJC1 said:
If you need more velocity for whatever your doing get n110. It's the right fuel to go fast.
Click to expand...
I'm also interested in max "kick." That is part of the fun for me, but I'm pretty sure I'm not ready to shoot a 44 magnum. I'm trying to work my way up to that...
 
Centella said:
I'm also interested in max "kick." That is part of the fun for me, but I'm pretty sure I'm not ready to shoot a 44 magnum. I'm trying to work my way up to that...
Click to expand...
The slower powders with more volume generate more recoil because there is more velosity and more material being consumed... as an added bonus you get a fireball as well.
 
Centella said:
I'm also interested in max "kick." That is part of the fun for me, but I'm pretty sure I'm not ready to shoot a 44 magnum. I'm trying to work my way up to that...
Click to expand...

With respect to recoil ("kick"), there are two things to consider.

1. Powder weight. If two gunpowders produce the same speed with the same bullet, the one that requires more powder weight will produce the most recoil. The powder is part of the 'ejecta' and is part of the formula for recoil.

https://en.wikipedia.org/wiki/Recoil#Including_the_ejected_gas

2. Heavy bullets and light bullets have a different felt recoil when pushed to the same power factor (power factor is a defined measure of momentum, but you could also think of it as a typical speed where the lighter bullet is faster). The light bullet has to accelerate faster to reach its speed, and tends to produce a 'snappier' recoil impulse.

Some explanation here: https://www.shootingtimes.com/editorial/power-factor-recoil-bullet-weight-gives-edge/99399
 
AJC1 said:
If you need more velocity for whatever your doing get n110. It's the right fuel to go fast.
Click to expand...
I’m looking at the VV app on my iPhone and the max loads for both N340 and N110 peak at 1240/1257fps respectively. It seems VV doesn’t want to push that Berry’s FP bullet past 1270fps. There’s probably a good reason for that - though I can’t imagine what it might be.
Either that or my iPhone app isn’t listing current data or I have the wrong Berry’s 158gr. FP plated.
 
Attached are the pressure ratings for .357 - 35,000 PSI or 45,000 CUP depending on what system the loading manuals use. As you have exceeded the recommended loading data, it's likely that you are far exceeding the Maximum Average Pressure that most arms manufacturers build to.

I would bet the recoil was pretty heavy. You might want to take a hard look at the top strap just in case.

As you can see in the chart, none of these figures are bullet-weight dependent. As fxvr5 says, if you want maximum speed, search reloading powder manufacturer's sites for a powder that increases your speed, but does not exceed the max pressure as shown here. For instance, I used to use Blue Dot in 9mm when I wanted to go fast.

Berry's bullets used to be rated for much less fps - I think it used to 1,100 fps. My experience was that you got some plating melt if you went much faster. It's nice to have 1,500 these days - I just loaded some myself.

Stay safe

upload_2023-5-1_13-55-16.png
 
GeoDudeFlorida said:
I’m looking at the VV app on my iPhone and the max loads for both N340 and N110 peak at 1240/1257fps respectively. It seems VV doesn’t want to push that Berry’s FP bullet past 1270fps. There’s probably a good reason for that - though I can’t imagine what it might be.
Either that or my iPhone app isn’t listing current data or I have the wrong Berry’s 158gr. FP plated.
Click to expand...

Possible because Vit's data is for Berry's standard plated bullet, which Berry's suggests to not load past 1250 fps.

https://www.berrysmfg.com/product/bp-38-357-158gr-fp
 
NMexJim said:
Attached are the pressure ratings for .357 - 35,000 PSI or 45,000 CUP depending on what system the loading manuals use. As you have exceeded the recommended loading data, it's likely that you are far exceeding the Maximum Average Pressure that most arms manufacturers build to.

I would bet the recoil was pretty heavy. You might want to take a hard look at the top strap just in case.

As you can see in the chart, none of these figures are bullet-weight dependent. As fxvr5 says, if you want maximum speed, search reloading powder manufacturer's sites for a powder that increases your speed, but does not exceed the max pressure as shown here. For instance, I used to use Blue Dot in 9mm when I wanted to go fast.

Berry's bullets used to be rated for much less fps - I think it used to 1,100 fps. My experience was that you got some plating melt if you went much faster. It's nice to have 1,500 these days - I just loaded some myself.

Stay safe

View attachment 1149076
Click to expand...
Thank you.
 
Centella said:
Do you guys think this chart looks reasonable/safe?
Click to expand...
No
Centella said:
I already went up to 7.9 and got nice results (accurate shots, good kick, no visible issues)
Click to expand...
Until it happens.
Centella said:
I will follow your advice about not exceeding 7.7 grains just to be safe
Click to expand...
Smart.
Centella said:
I'm also interested in max "kick." That is part of the fun for me, but I'm pretty sure I'm not ready to shoot a 44 magnum. I'm trying to work my way up to that...
Click to expand...
Start with .44 Spl range loads in .44 Mag brass, work up from there. :)

Y'all be careful out there. :)
 
Centella said:
According to other handloaders, N340's velocities increase in a predictable linear pattern as you increase the amount of powder. Using this idea, I came up with my own loading chart taking Vihtavuori's data from their website as a starting point.
Click to expand...
I’ve said this based on my testing but for a very small load range and other factors like COL. It only appears linear but that’s a very small section of the curve where that approximation works. Where on VV’s site did you get this data? I’ve only found 2 data points for a particular load, start and max. If you took only those points and tried to plot a straight line, I’d suggest you chrono your loads between start and max and see how they do. If you want to go beyond max, there’s a reason THR has a special disclaimer you need to add to your post.
If you’re looking for max velocity out of your .357, look at the VV (or other published data) and choose an appropriate powder/bullet combination first.
 
Berry’s 158gr plated bullets are too expensive…more so than FMJ’s.
$164 vs $128. I never understood their mass appeal.
 
I'm sending this link not to encourage high-pressure loads but to possibly give some insight into what overpressured cases look like. I think from my experience that this is pretty good info. I've been looking at punched-out primers for years. Anyway, all of this info concerns 9mm loading and should not be compared to .357.

Centella, you might take a few of your cases and check their measurements as shown in this link.

9MM Major Loads (natoreloading.com)
 
Centella said:
I'm also interested in max "kick." That is part of the fun for me, but I'm pretty sure I'm not ready to shoot a 44 magnum. I'm trying to work my way up to that...
Click to expand...
You,d be surprised, a 44 Magnum isn’t that much more of a kick with the proper grip.
Try a 460S&W or a 45-70.
Here is a friend shooting my S&W 460V.
Unfortunately you can’t see the fireball and feel the heat in your face.
https://youtube.com/shorts/Ughhey7WH-o?feature=share
51344-B32-4871-4-C89-B0-AC-BA094-E8-E59-B5.jpg
 
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