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Conclusions
Much is self
evident from the results achieved but having
said that - there have been some hard-to-explain
phenomena both in this test and in test #2 also.
I have been thinking on some of these things
and present some musings.
First and foremost - results from wetpack testing.
Now I have stated before, this method is far
from ideal - just a way to obtain some data
and not in my view deserving of the label ''definitive''
(I am thinking
of other ways to test expansion). We see some
examples of bullet distortion and unequal expansion
and yes, this can be due to a tumble factor
with some ammo however - I put this to you...
My wet packs are made up of 80% std daily newspaper,
but in order to increase thickness (heck, I
only get one local paper per day!) ... I add
in some of the extra stuff that sometimes comes
- advertizing guff for the most part which is
smaller in size than the broadsheet local rag.
This means that there are internal portions
of wetpack that have a change in uniformity
- possibly even slight voids, where smaller
stuff is sandwiched between large, and presents
folded edges etc. I wish I had dozens of phone
books!!
I do think it possible that in some instances,
a bullet enters the pack but quickly yields
to a small change in density or uniformity and
so veers off just a little before expanding.
Enough perhaps at times to present us with the
non symmetrical result we have seen. Contentious?
maybe, but worthy of consideration perhaps.
Now .. look at the pic below. This is a recovered
Speer bullet .... a 124 grain, with incomplete
and asymmetrical expansion. Notice the rifling
engraving. It is more pronounced on one side
of the bullet than the other .... suggesting
it was not fully lined up along its long axis
whilst travelling out the barrel - thus suffering
an induced tumble effect on exit. I am not sure
how this can occur because the diameter of the
skirt is 0.355 ... the same as the barrel major
diameter (minor dia is 0.352). It should have
obturated perfectly.
It does tho look as if this is a candidate for
some tumble and thus the lack of symmetrical
expansion ... not explainable by my thoughts
on wetpack internal density variations. As an
experiment - I placed a virgin 115 FMJ bullet
in the chamber of the R9 barrel ... tapped it
with a hammer via an aluminum rod - and then
removed it. The very beginnings of rifling engraving
were 100% symetrical and so once the bullet
has ''jumped'' it meets totally uniform rifling.
It is therefore, for now at least, difficult
to see how this has occurred. I hope to find
an explanation... (see below this pic)
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Explanation
for the above.(late edit)
I waited
prior to releasing this test material
in order to check some aspects with Eric
and Karl .... after a discussion with
Karl it is now quite clear why and how
this can happen.
The design of the barrel is such that
there is a significant freebore of 0.250"
- the reason for which being pressure
control. As we all know I think, the 9mm
Parabellum round is a high pressure round,
even at standard pressures. This small
delay before bullet engagement with rifling
permits the immediate pressure peak to
dissipate to a safer level - sparing the
barrel/slide mechanism some extreme trauma.
This is both desirable and necessary with
the design of such a small gun using this
round.
Further to this - it can probably be imagined
therefore that not every bullet of every
type will engage the rifling with absolute
symmetry, per the example above. This
then also explains why there are occasions
also where a perceptible degree of bullet
tumble is seen after exit from the gun.
I have stated elsewhere - this gives me
no cause for concern, seeing as the likelhood
of long range engagements is remote. It
being much more likely that ''things''
would be happening within ten feet or
so. At this distance I doubt if
an assailant is going to make much complaint
if he is hit by a 100% stable bullet -
or one which started to tumble a little! |
I mentioned my malfunctions .. two FTF's with
WWB 147 grain JHP's and one FTE from the WWB
115 JHP (marginal problem ... last shot, case
not quite clear of eject port before closure
- easy to clear). This raises issues for some
people, the fact that anything malfunctions
- I would say broadly that, we must regard this
miniscule 9mm pocket pistol as a thorobred ...
and as such it requires premium feeding. It
also requires to be kept clean.
My test session fired off approx 100 rounds
total without an interim clean. The WWB failures
were early on .. so that was not a crud issue
I think .. it was ammo. Conclusion??
NOT ALL ammo suits this gun ..... but we can
say I think safely that God Dot in particular,
is the fodder of choice. Folks however want
(and need) to practice with a carrry piece -
understandable. Concommitant with that is a
desire to use cheaper ammo - that figures. My
suggestion is to use WWB FMJ or similar BUT
- expect and ACCEPT the occasional failure ..
it is no big deal. This gun is cutting edge
.. and the occasional failure during practice
is something we need to accept as possible ...
in order to keep costs down.
I might
add one other thing here .... I have checked
a number of factory bullets at random and found
many were 0.354" .... 0.355" and 0.356"
being much more desirable. Karl has found over
a large sample of measurement a frequent two
thou tolerance - I can believe it. This in a
short barrel with generous freebore can have
its effects.
Let me add this final caveat - repeating myself
really! The likelehood of this gun being used
in a defence situation is, for the most part,
something very few of us will experience - I
hope! However, the odds are heavily for the
fact that any confrontation will be very ''up
close - and personal''.
Because of this, I personally find no major
problem with the fact that the occasional round
seems to have a slight tumble predisposition
.... because if say, at seven to ten feet distance
a round flies slightly off axis, there is little
doubt in my mind that damage will be done!!
Reliability is the main concern and as has been
proven, though my gun at least - the recommended
ammo choice of Speer Gold Dots is the way to
go.
All ammo data to date thru R9 is collated on
one page if you wish to see all results so far
together. Go
Here. |
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