Tim Wescott on Fri, 06 Sep 2013 12:38:17
-0500 typed in rec.crafts.metalworking the following:
On Fri, 06 Sep 2013 20:58:57 +0700, John B. wrote:

On Fri, 06 Sep 2013 07:13:25 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

John B. fired this volley in
:

I think that you are talking about the dimensions of the part of the
bullet that sticks out of the case,
which, other then overall length, isn't much of consideration, at
least for a .25 Browning.

No, John. What he wants to know is the overall length of the projectile
itself (showing that portion that's seated in the cartridge), so that he
can draw a bullet SEPARATELY from the cartridge, for the purposes of
showing it elsewhere in the firing path, besides just in the wheel, just
in a loaded cartridge.

Lloyd

That is going to be difficult to find as while the diameter is constant
the length of the bullet will depend on the weight and possible the type
point, although for a .25 auto it is likely that there are few different
bullets available.

So, the first question would be, what make of ammo and what bullet
weight as I find reference to several weights. 35, 45 and 50 gr. all of
which would be different length.

He might have a look at the SAMMI (sporting arms and ammunition
manufacturers institute) http://www.saami.org/ who publish a lot data
about commercially loaded ammunition. I downloaded a document from SAMMI
(205.pdf) that shows both the standard cartridge dimensions and the
standard chamber dimensions, including the standard throating.

Case diameter us shown as 0.278 and length is listed as 0.615 - .020".
Overall cartridge length is 0.860 min/.910 max.

The standard chamber is 0.2828 in diameter, and tapers to 0.2798 at the
front and is 0.0.638" in length. The cartridge appears to headspace on a
semi-rim.

I'm still a bit vague about the need for bullet length as it is never
really used in fitting a barrel or action. The action needs to be able
to handle the maximum cartridge length, the ejection port the maximum
case length, and the bullet is long gone down the barrel.

I've only seen Bullet length taken into consideration when deciding on
the rifling twist which in turn effects bullet rotation and ultimately
bullet stability.

It seems like it'd have a strong impact on the gun operation if it sticks
out the front of the cylinder, though.

Presumably you want to decide on what ammo you do and do not want to
support, and either accept a long cylinder, or accept that there's some
ammo that's just too long to fit.

(Is it common to have ammunition that does not fit some particular make
and model of revolver? I.e., is there some popular revolver out there
that comes with the statement "well, those bullets won't work in that
gun: everyone knows that!")

38 special v 357 - same diameter, different lengths (I think)

As I'm reading the documents SAAMI Says - the cartridge is to be
no more than C inches over all length And the brass is to be no more
than B inches in length. The Bullet can be anywhere from 1 mm to C
minus the thickness of the base. I'm sure that somewhere in between
is an optimal size.

It seems that I am going to have to make up a table of calibers
and bullet weights, then figure OAL lengths from that. It also seems
that someone else would have been as compulsive on this subject , and
already done that - and "published" the figures.
Wait, don't I have some reference manuals tuck away on the
external hard drive ...?



--
pyotr filipivich
"With Age comes Wisdom. Although more often, Age travels alone."