Cold, Extreme Weather Powder Considerations for the 10ML-II
Chris R. writes:
Hi Randy,
I am currently using your pet load of 57 gr. of V.V. N120 and the 300 gr. Barnes Original along with the Federal 209A primer in my 10 MLII.
I am seeing excellent results both at the range and in the field. However it gets fairly cold up here in Saskatchewan during whitetail season, and I have had a couple of misfires during these conditions using this recipe.I have heard from a couple of sources that V.V. N120 is not the most reliable powder to ignite in cold conditions - in your opinion is this a true statement? If so I am looking for a comparable substitute, and I would hate to give up using the Barnes Original bullet.
I'm wondering if you have tried A.A. 5744 with the 300 gr. B.O. as I haven't been able to find this combo on your website. A word back with any advice or suggestions you may have would be greatly appreciated!!!Thank you very much,
Chris Repski.Hi Chris,
This is a very good question that does come up from time to time, and has no absolute yes or no answer for all hunters in all seasons. I'll try to give you the trade-offs.
As a generalization, single based powders (such as N110, N120, SR4759) are more hygroscopic than double-based powders like Accurate Arms 5744, a term that just means they suck moisture. Smokeless powders do not absorb moisture nearly to the extent of black powder and the so-called subs, but although not water-soluble they do hold a small amount of moisture, clearly more than doubled-based powders. Dick Quisenberry at Alliant powders has discussed this extensively; he refers to double-based powders as having the benefit of a "plasticizing effect" when nitro is added to nitrocellulose. It is geometry that primarily controls what single based powders do-- when nitro is added, the energy content is controlled as well.
Back to Vihtavuori N120: personally, I have not been able to reproduce a misfire with it at 10 degrees F., but I've not tried really hard. Some folks store their 10ML-II's loaded. I don't, and consider that a very poor idea for a number of reasons with any muzzleloader. Doubly so with the Savage 10ML-II, as you already have the benefit of non-corrosive powders. You will increase your reliability if you discharge your gun harmlessly into the dirt at the end of the day. You need no cleaning, and it takes only a few moments to give your gun a fresh charge in the morning prior to the hunt, and makes no noise. The number of variations out there such as in and out of a warm cabin or vehicle is asking for potential problems.
A sabot seals well, but not perfectly until you fire your gun and the base obturates into the rifling. Cold, rain, and temperature variations can combine to give you the "perfect storm" of a blooper. A fresh charge every morning and a drilled-out breechplug minimizes that. I like all-weather loads, a load that will group at 90 degrees as well as below freezing. That is one of the factors that I include when looking at a load, and why I like 57 grains of N120 with 300 grain saboted bullets. However, most chemical reactions slow down in concert with temperature. If you know you are going to be hunting in very cold weather, bumping up your load by two or three grains (59 - 60 grains) gives you more surface area of powder, and may offer better ignition for you.
Without question, Accurate Arms 5744 is the easiest to ignite of the Savage 10ML-II powders. It is a double-based powder, containing 20% nitro. It is well-known as a "position insensitive powder," developed from the Hercules .50 BMG "Spotter Tracer" propellant dating back to 1991 or so. To get a reliable burn with extruded rifle powders, that includes the N110-N120 family, you need 2000 PSI or so of backpressure to sustain ignition, as a rule of thumb. Ball rifle powders are the worst, needing 5000-6000 PSI to keep burning-- a reason they don't work at all well in the Savage 10ML-II application.
Accurate Arms 5744 needs only 500-1000 psi of back pressure, according to my good friend Johan Loubser of Accurate Arms / Western Powders, widely regarded as one of the top senior ballisticians in the world today. Another interesting facet about double-based powders is that if you get them cold enough, down to the point where nitro crystallizes-they speed up. The way Johan likes to explain it is that a single-based powder has to sit there and "doodle along" until you have adequate pressure build up to get things moving. Not so with 5744, as the 20% nitro content helps itself along.
So, to sum things up, yes-- without question Accurate Arms 5744 is the easiest to ignite Savage 10ML-II powder, ideal for rugged or adverse conditions. The sole reason to opt for N120 with 300 grain bullets is velocity. 44 grains of AA 5744 nets you 2000 fps, give or take, with 300 grain bullets. That doesn't sit well with velocity worshipers, as N120 gives you 2300 fps without hassle.
5744 has given me superb groups with the 300 gr. Barnes Original .458 / 50 MMP Orange sabot combination. Ballistically, an approximation is a 200 year 6 in. kill MPBR load, retaining about 1500 fps and 1500 fpe at that range. So, center of the body out to 200 yards and you are good to go: not much can live on the difference. A 2300 fps load gives you about 20 extra yards of MPBR range-- out to about 220 yards.
Total reliability or twenty yards of additional straight thorough the body hold is our choice in a nutshell.
Contact: Randy Wakeman, 12362 S. Oxford Lane, Plainfield, IL 60585
By phone: (815) 254-2135 Email: randymagic@aol.com
