Headspace:
Does
not Exist in a Savage 10ML-II
The term of
"headspace" as used when discussing brass cartridges has
no relevance to a Savage 10ML-II, or any other muzzleloader for
that matter. Like oil and water, they simply do not mix-- you cannot
readily apply brass cartridge terminology to a muzzleloader when
no brass cartridge exists.
Headspacing
is given thorough treatment by Parker Ackley in his Handbook
for Shooters & Reloaders by P. O. Ackley, Volume One. The
chapter entitled "Headspace" is located on pages
151-163. As Mr. Ackley explains, there are four methods of measuring
headspace on cartridges: for rimless cartridges it is from the bolt
face to a point on the shoulder known as the datum line. For rimmed
cases, it is the thickness of the rim or the distance from a locked
bolt face to the forward edge of the seated rim. In the case of
belted cartridges, it is the distance from the locked bolt face
to the forward edge of the belt. For rimless pistol cartridges,
where Ackley cites the .45 ACP, it is the distance from the locked
bolt face to the mouth of the cartridge. None of these measuring
methods are relevant to the Savage 10ML-II, or any other muzzleloader
where no cartridge so much as exists to be measured. Headspace is
applicable to cases; it is not and can not be applicable where no
brass case exists in the first place.
The 209 primer
is located on the bolt face of the 10ML-II by the Savage's patented
horseshoe metal fixture, as you can see from the illustration shown
right in the owner's manual.
It is this
patented bolt face idea that negates the need for plastic primer
holders, discs, or full plastic jackets. It is this patented bolt
face innovation that, while eliminating the need for primer related
consumables, also eliminates the possibility of the primer being
stuck inside the breechplug. The Savage breechplug itself is discussed,
in detail, in the article titled The Magnificent
Savage Breechplug, found right here: http://randywakeman.com/TheMagnificentSavageBreechplug.htm
.
The 209 shotshell
primer is positively located a fixed distance from the bolt of the
Savage 10ML-II, a distance that cannot be modified. This distance
is by design, engineered so that 100% positive ignition is obtained
with the ultra-fast locktime (1.6 ms) Savage short action,
keeping the center of the primer within the proper .050 inch distance
considered to be optimum firing pin projection. A 209 primer cannot
be seated "too far away" from the Savage bolt for
anything less than 100% positive, lightning fast ignition. A light
primer strike is not a possibility. The metal, horseshoe-shaped
permanent primer holder on the bolt eliminates all of these concerns.
There are no
universal standards for 209 primers. They vary by brand, they vary
by lot, and they not only vary in size by brand, they vary in strength
and in the type of primer compound used. And, they all bulge. They
all bulge when used conventionally, in shotshells, of course. The
difference is the press-fit and encapsulation of the primer by the
shotshell hull that mitigates and limits the stretch. Only so much
quality goes into a shotshell primer that costs a cent to make,
so it is just as can be expected. The depriming stations on my MEC
9000G progressive shotshell presses are not "optional"
stations at all-I sure can't flick a spent primer out of a hull
with my fingernail.
So, there is
no headspace from bolt face on a Savage 10ML-II to any part of a
primer; it is fixed by bolt design. There is also no headspace dimension
on the breechplug. The breechplug is precisely positioned at the
factory so the bolt can guide a Winchester W209 primer into it,
and the bolt closes properly. The breechplug is designed with a
positive stop; it is prevented by geometry from being "screwed
in too far" unlike some other muzzleloaders. As one of
the many additional safety features inherent in the Savage design,
the primered bolt cannot be closed at all if the breechplug is even
slightly out of battery, much less fired.
All this is
addressed at the factory with W209 primers. Primers that vary widely
in size by brand and by lot number of course cannot be all addressed.
None of these considerations have anything remotely to do with brass
cartridge headspace by any of the four methods of convention. Original
patent holder, Henry C. Ball, comments, "The only thing
that talk of muzzleloading head spacing shows is that perhaps too
much excess space exists inside of theirs." Headspacing
and caseless muzzleloading applications do not jibe.
209 shotshell
primers bulge and puff when fired; all of them do. The design of
the Savage 10ML-II does not fight this well-known fact: it instead
takes advantage of it. When the primer puffs, it instantly creates
a seal-- a seal so effective in the Savage application that the
10ML-II bolt never needs disassembly for cleaning. That is the unique
"internally sealed action" that only the Savage
10ML-II has been able to brag of for many years by now.
If the occasional
primer sticks to the end of the bolt, Savage has you covered. Close
the bolt and pull the trigger on an empty 10ML-II . . . the firing
pin instantly frees the primer. The "best way"
to stick a primer is to fire it into an unloaded Savage. There is
no substantial backpressure generated as compared to live firing.
The back pressure generated from live firing a Savage 10ML-II is
just enough to naturally free the primer.
I'm currently
using W209 Winchester primers or Federal 209A's. The Federals run
a bit larger. I've not stuck a primer in recent memory; they tend
to fall right off the bolt between shots.
The very best
primer for you is a matter of a small amount of trial and error.
Interior ballistics change contingent on powder, projectile, sabot,
and primer. Change one of these, you may affect them all. The primers
themselves vary based on face geometry, how they indent, and the
resultant tackiness or lubricity after firing. Winchester W209's
work superbly as reported by tens of thousands of Savage enthusiasts
around the country, but you personally might have the best results
with CCI, Remington, or Federals. All it takes is a little trial
and error, and then you'll know what your gun and your load tells
you is the smoothest: you will have found your "Penultimate
Primer."
