Load Testing: VihtaVuouri N320 powder

[IDescribe]

This is WAY overdo.  Here's the preview.  These ladders will be shot tomorrow.  If you see any problems or have any questions or requests, feel free: 

______________________________

Bullet:      Hornady 115gr HAP
Powder:      N320
Primers:      Federal SPP
Brass:         Starline -- virgin
OAL:           1.08
 
Load data being referenced is from Vihtavuori website and is for the Hornady 115gr XTP:  4.0-4.5.  The Hornady XTPs and HAPs are supposed to have the same profiles so that load data may be used interchangeably.  While I am a little leery of that assumption, and I considered dropping the starting load, the current starting load of 4.0-4.2 is a common minor power factor competition load range for N320 with 124gr JHPs that have longer shanks and deeper seating depths, so I?m confident that 4.0 isn?t a problem as a starting load.

4.0gr     
4.2gr     
4.3gr     
4.4gr     
4.5gr     
____________________________________

Bullet:      Montana Gold 124gr JHP
Powder:      N320
Primers:      Federal SPP
Brass:         Starline -- virgin
OAL:           1.07 

Load data being referenced is from Vihtavuori website and is for the Megashock 124gr JHP, PLUS a boatload of forum published loads for these two very common components, including load data from a CZfirearms forum regular whom I trust.  I suspect 3.9 will put me around a PF of 133.  We will see.

3.5gr     
3.7gr
3.8gr   
3.9gr     
4.0gr     
_____________________________

Bullet:      XTreme 147 RN-HPCB
Powder:      N320
Primers:      Federal SPP
Brass:         Starline -- virgin
OAL:           1.16   

Load data being referenced is from Vihtavuori website and is for the Hornady 147gr XTP:  3.1-3.9.  I have experience with this bullet with other powders, one faster than N320, and everything points to 3.1 being a perfectly safe starting zone.  As well, I?ve found working loads from competition shooters with this bullet and N320 that also indicate 3.1 is a safe starting load.  BAWunder also posted his data for N320 with an XTreme .356 147 RN, and 3.3gr gave him an average PF of 134.  I?m actually looking for little faster than a PF of 134, and I?m seating shallower, as well, so I suspect I?ll need more than 3.3 to get where I want to be.

3.1gr   
3.2gr   
3.3gr     
3.4gr     
3.5gr     
__________________________________

Bullet:      XTreme 135 HP (Heavy plated)
Powder:      N320
Primers:      Federal SPP
Brass:         Starline -- virgin
OAL:           1.09   

This is honestly a little educated guessing.  The load data here is the same ladder as I?m using for the 147gr RN-HPCB above plus .2gr at each rung.  I will shoot the 147gr ladder first to see how things line up with Viht?s XTP data.  If those are too hot (I can't imagine they will be), this ladder will not be shot.

3.3gr
3.4gr     
3.5gr     
3.6gr     
3.7gr     
___________________________

[burlycz]

Nice experimental setup. I did the same with Titegroup over in the free samples thread. I like seeing the velocity/powder curves and difference OAL makes. Been wanting to try N320, so can't wait to see your data. What are you planning for N value?

[IDescribe]

What are you planning for N value?

You have gone above my knowledge base with this question.    


I think you may be thinking I'm looking to get more out of this than I am.  I've been sitting on some N320 for a long time without doing load development.  I'm just looking to work up minor PF loads with loads 2,3,4 and see how they perform and how they feel.  With load #1, I wouldn't personally load 115gr for minor PF, but one of the regulars said he'd be interested in seeing how the 115gr HAPs did with N320 and AA#7 for longer range bullseye, and so I figured since I had the 115 HAPs and was going to have a hopper full of N320, I'd start working up a load for that, as well. 

[painter]

 

Watching intently.

[Wobbly]

If you see any problems.... feel free: 

I have a problem. I can't be there to help. 

[IDescribe]

It's only an eight hour drive. 

[burlycz]

What are you planning for N value?

You have gone above my knowledge base with this question.    

How many of each load?

[Joe L]

ID--are you going to chronograph each load, 5 rounds of each?  Shoot from a rest and quantify group size?  In case you can't tell, I've never done this, although I have watched some guys do some testing at the range...while I was practicing. 

Looks like fun to me.  Sorry I'm not there with three cameras, charged batteries, and a handfull of SDHC cards, LOL.

Joe

[IDescribe]

BurlyCZ, these will be 10 round strings.  I've found that the improvement in precision/consistency you get in regard to average velocity with 10 round strings over 5 round strings is significant, and it's worth the effort to run 10 round strings.  I have also found the improvement in precision going up to 20 round strings to be not significant enough vs 10 round strings to be worth the effort.

EDIT:  Nicky, I just reread and saw you asked about the rest and not the press.  I will not be using the Ransom Rest.  I still haven't built a mount for it.

I'll also mention here that while the Hornady powder drop has been great for me, it's stumbling a little with the N320.  Every now and then it binds, and every now and then it throws a charge a tenth of a grain heavier than what it was consistently throwing over and over and over.
 
Joe L, if you were here, I'd be running the camera while you were painting pretty targets.     I'll be shooting two-handed on a wrist-rest, probably a rolled up towel.  As mentioned, each charge weight will get ten rounds, and I will fire all over a chrono.  I gave up trying to run targets while chronoing loads because it's too much running back and forth to the standard.  I actually hook my chrono up to my laptop, so I don't have to leave the bench while chronoing unless I want to.  My accuracy goal is to avoid hitting the chrono.    What I was thinking about doing, and what I'll probably do is put up a fresh target if I think a string is likely to hit 133 PF for the 124gr and the 135gr bullets, and PF 136/137 for the 147gr bullet, as those are my preferred power factors for those weights, and I'd be curious to see targets there, but even then, I'll likely be shooting at 15 yards, so it's not likely to show much.  I'll also throw up a target for the top 115gr load.  I'll do some legit accuracy testing when I get the Ransom Rest up and running, sometime between this Thursday and July 4.   

[1SOW]

 

I suspect 3.9 will put me around a PF of 133.

Nice test!  Looking forward to your results.

On the MG,  I've never loaded that short,  but my "guess" is above 133PF,  but I tend to overestimate the effect of OAL on pressures. 

[IDescribe]

On the MG,  I've never loaded that short,  but my "guess" is above 133PF,  but I tend to overestimate the effect of OAL on pressures.

I'm guessing the extra .02 is worth a tenth of grain.  And if I get there at 3.8 instead, so much the better. 

[Riptide439]

Put me on that list of "waiting patiently for results"
Thanks ID

[Joe L]

ID--Just don't clean the gun until you are finished.  Wouldn't be prudent...uh...scientific.   

My 97 is starting to look like my Kadet, which is good. 

Joe

[burlycz]

BurlyCZ, these will be 10 round strings.  I've found that the improvement in precision/consistency you get in regard to average velocity with 10 round strings over 5 round strings is significant, and it's worth the effort to run 10 round strings.  I have also found the improvement in precision going up to 20 round strings to be not significant enough vs 10 round strings to be worth the effort.

Awesome. I use 10rd strings as well for the same reason. Look forward to the results. If you check out my recent post in the bullet giveaway thread you can see my spreadsheet format. I ended up having to take a screenshot and post an image of it to get it to look reasonable on multiple devices.

[IDescribe]

I built these ladders after posting last night, and there was a change to one of the bullets.  I moved again recently, and I can't find my Montana Gold 124gr JHP.  I assume they're hiding in a closet somewhere.  I replaced that ladder with XTreme 124gr HP, but that was the final ladder, and the sun came out and ruined that.  More on that in that section.  Anyway, the other three are good.


Bullet:      Hornady 115gr HAP
Powder:      N320
Primers:      Federal SPP
Brass:         Starline -- virgin
OAL:           1.08
 
4.0gr      Avg fps - 1061  fps  |  PF-122  | SD-10  | ES-38
4.2gr      Avg fps - 1059  fps  |  PF-122  | SD-15  | ES-48
4.3gr      Avg fps - 1097  fps  |  PF-126  | SD-10  | ES-34
4.4gr      Avg fps - 1123  fps  |  PF-129  | SD-20  | ES-59
4.5gr      Avg fps - 1134  fps  |  PF-130  | SD-10  | ES-27

On the 4.4gr string, only eight shots registered on the chrono, and on the 4.5gr string, only six shots registered.  It could have been the sun, but I had another sun issue later on with another bullet, and it didn't cause missed shots; it caused the velocities to go wild.  No idea.  I did put up a fresh target on the 4.5gr string.  I'll upload and post that shortly.

Next run with these bullets and this powder will be 4.4, 4.5, 4.6, 4.7.  I'm hoping to get to around 1170.


___________________________________


Bullet:      XTreme 147 RN-HPCB
Powder:      N320
Primers:      Federal SPP
Brass:         Starline -- virgin
OAL:           1.16   

3.1gr      Avg fps - 786  |  PF-115  | SD-8  | ES-27
3.2gr      Avg fps - 837  |  PF-123  | SD-27  | ES-78
3.3gr      Avg fps - 847  |  PF-125  | SD-20  | ES-60
3.4gr      Avg fps - 866  |  PF-127  | SD-15  | ES-40
3.5gr      Avg fps - 895  |  PF-132  | SD-7  | ES-22     

Next run with these bullets and powder will be 3.5, 3.6, 3.7.
___________________________________

Bullet:      XTreme 135 HP (Heavy plated)
Powder:      N320
Primers:      Federal SPP
Brass:         Starline -- virgin
OAL:           1.09   

Note: Slight change to initial plan.  I had a heck of a time getting the powder drop tuned in to 3.4gr.  It kept going back and forth between 3.3 and 3.5, so after a few tries, I said "Screw it; I'm skipping 3.4 and upping the top end."    I was confident this ladder was going to be light anyway. 

3.3gr      Avg fps - 872  |  PF-118  | SD-21  | ES-69
3.5gr      Avg fps - 879  |  PF-119  | SD-24  | ES-83
3.6gr      Avg fps - 899  |  PF-121  | SD-16  | ES-53
3.7gr      Avg fps - 903  |  PF-122  | SD-16  | ES-51
3.8gr      Avg fps - 933  |  PF-126  | SD-9  | ES-28


Next run with these bullets and powder will be 3.8, 3.9, 4.0, 4.1.  I'd like to get these around 980. 
___________________________________


Bullet:      XTreme 124 HP (Heavy plated)
Powder:      N320
Primers:      Federal SPP
Brass:         Starline -- virgin
OAL:           1.09   

3.8gr      Avg fps - 937  feet/sec  |  PF-116  | SD-15  | ES-47

And that's where that ladder ended.  The clouds broke completely after this string, and at 11:40 in Florida, that's bad news for the chrono.  I didn't have the sun screens with me, nor have they worked well in the past.  I usually use a target stand to cast a shadow across the chrono instead, and that has worked great, but our new stands at the range are too short now for that to work that close to noon, so once the clouds broke and the 3.9gr string went wild, I called it off and went home. 

Just so people can see what direct sunlight can do to your chrono, here's the data from the 3.9gr string:

Average fps -- 1183
Standard dev --137
Extreme Spread --382
Velocities -- 1039, 1039, 1076, 1104, 1113, 1173, 1191, 1322, 1357, 1421

I'm no scientist, but that data looks a little suspicious.     I will rebuild the 3.9gr string and continue with what I've got.

___________________________________

Overall, I found N320 be quite pleasant, and I like the smell.  I'm no stranger to fast powders in 9mm, faster than n320, even, but even with that, rounds were surprisingly soft.  Even the 115gr HAPs weren't as sharp as expected at the top load.  And that 147gr cartridge has great potential.  I'm going to load again tonight, and I think I'm going to do the dirty deed -- Titegroup.     But I'll continue at least two of the ladders above, as well.  Stay tuned.