N120 vs 1680

[mdf99]

I'm wondering if anyone has experimented with N120 in the 357 Max, or other calibers? I have an 8 lb can of it that I use in a Savage smokeless muzzleloader. I'm thinking of trying it in my 7.5" barrel Ruger 357 Max with 200gr cast bullets from a Ballisticast 919 / H&G 319 mold. Wondering if its too slow for my short barrel? I don't have any 1680, have been using 296 and 4227 so far. Thanks.

[dougader]

pdf.textfiles.com/manuals/FIREARMS/vihtavouri.pdf

their burn rate chart shows N120 between SR4579 and IMR 4227. It also shows 357 max data with N120 in 180 and 200 grain bullets on page 50.

Here's their newest data:

www.lapua.com/en/products/reloading/vihtavuori-reloading-data/relodata/6/26

[bradshaw]

mdf99.... Trust you have a chronograph to go with your supply of Vihtavuori N120. While I haven't loaded .357 Maximum with N120, I tried the long stick powder IMR 4198 COMPRESSED under 200 grain bullets. Astounding accuracy----albeit with this warning: you must hold like you're shooting a flintlock, as this powder gives the bullet a LONG BARREL TIME. A trace of wiggle in your hold, and the bullet will be off exploring other landscape. For this lack of forgiveness, and despite setting an international record with it, I consider IMR 4198 too slow. Vihtavuori N120 might repeat that performance----superb accuracy with a heavy bullet at modest velocity with very low extreme spread, and unforgiving BARREL TIME.

The old Winchester 680 and Accurate 1680 ball powders under heavier bullets provide excellent accuracy----with velocity. A chronograph would be a big help in sorting out N120 in the .357 Maximum. Between the target and the chronograph, the target is more important. However, the chronograph is the instrument for the correlation of excess velocity spreads to vertical stringing, and for explaining why a long barrel time generates a push sensation on recoil.

David Bradshaw

[bradshaw]

To reiterate, Vihavuori N120 may share a combustion profile with IMR 4198 in the long, straight wall case. That is, a compressed charge under a heavy bullet----to promote even ignition of the powder column----may produce very fine accuracy with a tight velocity spread. The downside is necessity to hold and squeeze and follow through steady as a machine... to head each shot to the same place. And to not expect velocity to equal that achievable with 296/H110 or Win 680 or Accurate 1680. Or 4227.

If i had a store of Vihtavuori N120, I'd be tempted to try it. For me to continue using it, the powder would have to defeat my above expectations.
David Bradshaw

[mdf99]

I appreciate your insight Mr. Bradshaw. I'm making progress, had the lead pot hot last night and casted a pile 919s from my BC mold. They're dropping at 0.361".



Edit: Yes indeed I have a chronograph, will post some velocities soon as I shoot these, hopefully Friday, going to load a dozen each at 20, 20.5 and 21.0 and see how it goes.

[mdf99]

Also, just checked my cylinder throats w pin gauges. Four of six will take a 358 and 2 will take a 357. My sizing die is a 358. These bullets may not even chamber in all chambers, will update.

[mdf99]

Bullets fit in 4 of 6 throats from exit end of cylinder. Damnit man. I reckon Ill proceed to load these and fire where they fit b4 I send off cylinder for ream. I've fired mainly jacketed Rem 180 hp's thus far with no issues.

[dougader]

Tight throats don't always destroy accuracy. I had a S&W 625-6 with tight throats and the crazy thing still shot more accurately than I could hold. Not so, however, for a Ruger SA revolver I own...