[Silver_Is_Money]

Do you have a chronograph to test fire your loads?

Unfortunately no. But, perhaps yes. I've had a 30+ year old PACT Model 1 stored away in my garage for about the past 23 years. I doubt that it works, but who knows until I dig it out and try it. To get rifle shots to register over it I had to shoot just over the shadow sensors, and it didn't give me much leeway in that regard. Even if it did somehow still work, I'd probably have trouble avoiding shooting the shadow sensors with a shotgun.

 

[pumpgun]

Even if it did somehow still work, I'd probably have trouble avoiding shooting the shadow sensors with a shotgun.

Friend of mine has one of those, and I recall it being finicky on clear days. I have a Competition Electronics Pro Chronograph, and it works great, I use it all the time. With the wild lot to lot variances of the Alliant powders, I weigh and chronograph every new lot of powder.
Looking at the existing data, I'd guess you'd need about 14.5 gr of N340 to get over 1200 fps in an HS hull.

 

[Silver_Is_Money]

Friend of mine has one of those, and I recall it being finicky on clear days. I have a Competition Electronics Pro Chronograph, and it works great, I use it all the time. With the wild lot to lot variances of the Alliant powders, I weigh and chronograph every new lot of powder.
Looking at the existing data, I'd guess you'd need about 14.5 gr of N340 to get over 1200 fps in an HS hull.

The 28S1 wads which I use are pressure builders extraordinaire, and Cheddite CX-2000's are hotter than CCI209's by a good margin, and hotter than Win. 209's by a somewhat lesser margin, so I decided to play it safe and begin with only 13.3 grains of N340. But indeed the AA-HS hull should reduce pressures vs. what Vihtavuori's circa 1995 data indicates for the AA-CF hulls they used... Even if I used a chronograph to confirm 1,200 FPS I still wouldn't know what nominal chamber pressure the N340 is exhibiting.

Worst case is that if you're correct in presuming 14.5 grains for 1,200 FPS, then my 13.3 grains will likely give me about 1,100 FPS. Plus any 28S1 wad boost, plus any CX-2000 primer boost. So perhaps 1,150 FPS. I can live with that.

 

[Silver_Is_Money]

I have a Competition Electronics Pro Chronograph, and it works great, I use it all the time. With the wild lot to lot variances of the Alliant powders, I weigh and chronograph every new lot of powder.

The Competition Electronics Pro Chronograph gets far and away the most rave reviews of any chrono mentioned on this and other forums. I'm going to have to break down and get one.

 

[pumpgun]

Just got in on some W209s from Natchez, grabbed a one pounder of N340 to play with

 

[Silver_Is_Money]

Here are the pressure and velocity results for the Vihtavuori N340 powder in 28 Gauge AA-HS hulls. The SAAMI MAP for 12 Gauge is 12,500 PSI, so all loads are safe. I'm thinking that something in-between like ~14.5 grains to be just about ideal going forward.

 

[patch44]

Is the CB wad a clone of the Federal? Very little difference!

Are you not loading Herco anymore?

 

[rhodeislandhntr]

CB is a clone for the winchester oem wad.

 

[pumpgun]

Thanks so much for submitting these loads. It looks like N340 would be a suitable choice for 7/8 oz. 20g also. I'll likely switch once my 20/28 is gone.

 

[Silver_Is_Money]

Is the CB wad a clone of the Federal? Very little difference!

Are you not loading Herco anymore?

As already stated, the CB5034 is more along the line of being a WW28AAHS wad imitator. Close in general appearance, but certainly not a measurement by measurement clone by any means.

I'm still a fan of Herco, and it burns very clean, but it is borderline too fluffy. The N340 is more dense and yields a more comfortable fit for excellent stack height. It's density basically splits the difference between 572 and Herco. It seems that in my tests the N340 is somewhat slower burning than Herco, but that may just come down to single base (N340) vs. double base (Herco). The people who stitch together the various of relative burn rate charts should likely IMHO put out separate charts for single and double base powders. It's hard to judge them head to head. The real key to N340 may come down to how clean it burns. That and if it remains price favorable to Herco, such as is the current case. And then there is the issue of availability...

I had a collaborator in this process, and if that person would like to step in and take half of the credit (as is fully deserved) they are most certainly free to openly do so.

 

[patch44]

As already stated, the CB5034 is more along the line of being a WW28AAHS wad imitator. Close in general appearance, but certainly not a measurement by measurement clone by any means.

I'm still a fan of Herco, and it burns very clean, but it is borderline too fluffy. The N340 is more dense and yields a more comfortable fit for excellent stack height. It's density basically splits the difference between 572 and Herco. It seems that in my tests the N340 is somewhat slower burning than Herco, but that may just come down to single base (N340) vs. double base (Herco). The people who stitch together the various of relative burn rate charts should likely IMHO put out separate charts for single and double base powders. It's hard to judge them head to head. The real key to N340 may come down to how clean it burns. That and if it remains price favorable to Herco, such as is the current case. And then there is the issue of availability...

I had a collaborator in this process, and if that person would like to step in and take half of the credit (as is fully deserved) they are most certainly free to openly do so.

How does the density of N340 compare to something like Longshot, which is another popular 28ga powder?

 

[Silver_Is_Money]

How does the density of N340 compare to something like Longshot, which is another popular 28ga powder?

The VMD of Longshot should be very similar to that for 572. The Hodgdon bushing chart places them together in the same column. My lot of 572 has a VMD of ~0.0856, my N340's VMD is ~0.1017, and my Herco's VMD is ~0.1261.

 

[txrpls]

How does the density of N340 compare to something like Longshot, which is another popular 28ga powder?

From data provided by @Silver_Is_Money, the VMD is about the same as 20/28, and both are fluffier than Longshot. The nice thing about 20/28 and Herco is that they are very clean-burning. LongShot leaves a lot of residue. If the N340 burns cleanly, it may be a good replacement for 20/28 as N340 is easier to find.

 

[patch44]

Hmm, wishing now I would have picked some up a couple months ago when I saw it at an LGS. What’s a good going price for N340?

 

[Silver_Is_Money]

Hmm, wishing now I would have picked some up a couple months ago when I saw it at an LGS. What’s a good going price for N340?

$161 for 4 Lbs. is what I paid before tax. That plus HazMat.

They called it free HazMat, but then they jacked up the not-free shipping rate until it might as well have been HazMat...

 

[patch44]

Silver, are there any density or drop charts for any of the Vihtavuori powders? Curious about N350 as well and maybe 3N37.

 

[Silver_Is_Money]

Silver, are there any density or drop charts for any of the Vihtavuori powders? Curious about N350 as well and maybe 3N37.

I can only report for the one I've briefly experienced, as refined down to my specific lot number.

That stated, LEE provides VMD's that are decent starting points. Simply compare and match the Vihtavuori VMD's to other more well known powders.

 

[Silver_Is_Money]

Since I've now fired a number of Vihtavuori N340 fueled shotshells I can report that it works as expected and does what shotshell powders do. As to cleanness I'd have to say that it's dirtier burning than Herco, but not as dirty burning as 572, being roughly between these two far more typical 28 Gauge powders. I've lowered my initial 0.1017 VMD estimate slightly and brought it down to ~0.1009, via splitting the VMD difference between my 3D printed bushings #16 and #18 to arrive at an average of 0.1009. If I had real Mec bushings in this range I could get a more accurate overall VMD. My 3D bushing sizes are simply not as consistent at the real thing. But since bushings between the #16 and #18 are in the perfect stack height range for the CB5034 wad and 3/4 Oz. of lead shot, I'm a happy camper. Crimps are factory perfect.

My educated guess is that 14.2 grains of N340 should hit 1,200 FPS at about 10,730 PSI for the AA-HS hull, CX-2000 primer, CB5034 wad, and 3/4 Oz. of Lead Shot, as derived via splitting down the middle my lab tested results received for 13.3 grains and 15.0 grains respectively.

 

[Silver_Is_Money]

On the MEC bushing chart I'd have to say that Vihtavuori N340 drops a bit less than Alliant 20/28 for each bushing size, and a bit more than Hodgdon Universal, roughly splitting the difference between 20/28 and Universal in this regard.

 

[toptechX6]

Thank you for posting this, very helpful with many powders and primers being difficult to find.