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.
