 Fidonet: Firearms Echo (1:270/615)  FIREARMS 
 Msg  : #9511 [500]                                                             
 From : Ed Harris                   1:109/120.3006          17 Feb 94  18:53:48 
 To   : All                                                 19 Feb 94  09:12:52 
 Subj : Surplus Powder Part I                                                   

The table which follows in Part IUI of this message identifies Hodgdon powders
and their Olin equivalents.  Before getting to that, however, I want to explain
the basic differences between "Canister" and "Non-canister" powders.

For instance, current Hodgdon H110 is the same powder as Olin W-W 296, but in
non-canister grade, so it does not compare exactly to the canister Olin
product.

"Canister-grade" powders sold for handloading are blended to achieve a uniform
charge-weight-pressure relationship so that you can consistently use a given
weight of charge for a given bullet and have a safe load.  "Non-canister"
powders intended for factory loading don't have to be blended in the same
manner, because the charge weight is determined by firing tests for charge
establishment with each specific lot.   The charge is adjusted in the loading
machine to give the required velocity and pressures.  This is why it is
dangerous to try to determine how much of a powder to load by breaking down a
few factory rounds and weighing them.

Years ago I used WC665 in the .30 M1 carbine and in .357 Magnum using H110 data
and it performed normally, though giving velocities slightly less than H110, as
it is a bit slower. You could use H110 data and not get in any trouble.

WC820 is another noncanister powder sometimes compared to H110, but some
batches runb fast, and you have to stay well below maximum loads until you know
just what you've got.

Olin does not recommend 296 for reduced loads.  Period! When I was at NRA they
tested 18 grs. in a .308 with Saeco 180-gr. bullet, but the
ignition-barrel-time tests were not satisfactory.  I asked Dave Zaidan at
Olin's St. Marks, FL powder operation to test some loads after a rifle was
blown up at a cast bullet match I attended.  Some of the other conditions of
this particular incident were also suspect, but if a powder manufacturer does
not recommend their propellant for reduced loads, I would be inclined to heed
their advice.

Hodgdon seems to have no such reservations about H110 for cast bullet loads,
and I know many shooters who have done so successfully.  Olin's caution is
justified in today's product liability climate, because they will not recommend
any load which doesn't perform satisfactorily under all test conditions.  Their
standard test routine includes elevated (+125 degs. F.) and suppressed (-65
degs. F) temperatures, as well as different powder orientations, powder
forward, powder back, powder leveled, etc.

Marginal ignition in reduced loads is aggrevated by use of a primer which is
lower powered than necessary to ignite the charge.  This happens mostg often
when a pistol primer is used in a large case having more than 50 percent air
space, when the charge is not oriented against the primer.  Some of the ASRFRA
single-shot competitors use pistol primers in order to avoid misfires in
blackpower era rifles, such as Ballards, which have weak hammer springs.
However, this can causes ignition problems with powders having a heavy
deterrent coating, such as H110, when loaded at low loading densities.

A fine-grakined powder like H110 has a small web size of the base grain, and
there is a very high percentage of deterrent to propellant needed to obtain its
slower burning rate, compared to faster pistol powders like 231, which are of a
larger grain size.  Once you are aware of and consider this factor, ignition
problems should not then be surprising.  If you get one of those crazy ignition
situations, you are more likely to ring the chamber, which I have had happen to
me using H110 in reduced loads in the .30-30 T/C Contender.

My advice is to use any powder exactly as recommended by the manufacturer or
supplier.  Don't experiment if you don't know EXACTLY what you are doing!  When
dealing with a surplus powder it is a good idea to  do some comparisons over
the chronograph between the surplus powder and  a similar canister powder, such
as H110, over a range of charge weights covering your region of interest, so
you can get an idea how they compare.  I usually fire 10-shot strings at
increments 2 grains apart in  a case such as the .308 or .30-'06, starting at
the suggested starting load for the canister powder.  If the first two strings
look OK, I go to the next increment.  As I apoproach the velocity level I want,
or if the load may be approaching maximum I go to 1 gr. increments.

As you approach the desired velocity compute the energy in foot lbs., and
divide the striking energy by the powder charge weight in grains.  This gives
specific energy of the charge in ft-lbs/per grain.  Do this for two charge
weights which bracket the velocity you want.  Then you can interpolate and find
what the specific energy should be for the charge which will give you the
desired velocity.  This enables you to estimate an exact charge for a given
velocity with excellent accuracy.

--  CONTINUED NEXT MESSAGE  --

In Home Mix We Trust, Regards, Ed

--- msged 2.05
 * Origin: Home of Ed's Red (1:109/120.3006)


 Fidonet: Firearms Echo (1:270/615)  FIREARMS 
 Msg  : #9512 [500]                                                             
 From : Ed Harris                   1:109/120.3006          17 Feb 94  18:57:30 
 To   : All                                                 19 Feb 94  09:12:52 
 Subj : Surplus Powder, Part II                                                 

     IDENTIFICATION OF SURPLUS HODGDON VS. MILITARY POWDERS
     Hodgdon Powder           Olin Powder

     HS-6                     540
     HS-7                     571
     H110                     296 (before '75 WC825 .30 Carb)
     BLC-2                    WC846 (Ball M80 7.62mm)
     H335                     WC844 (Ball M193 5.56mm)
     H380                     WC852 (Ball M2 Cal. .30)
     H414                     W-W 760 sold to Hodgdon
     H450                     785 (originally WC780)
     H870                     WC870 (20mm)
     HP38                     W-W 231 sold to Hodgdon
     Trap 100                 452AA sold to Hodgdon
     H322                     IMR8208M (M196 TRACER 5.56mm)

                COMPOSITION OF IMR-TYPE POWDERS

The following table dates from 1976, and does not apply exactly to current
Canadian-production (Expro) IMR product.  Post 1976 Canadian made IMR powders
are made from wood linters instead of cotton linters. This results in somewhat
lower nitration, requiring a reduction of deterrent content to obtain
equivalent energy.  Therefore, these powders are somewhat faster burning and
require a charge reduction of about 5%, compared to older Dupont products.
Handloaders are cautioned to use current powder manufacturer's data with
current product and not use old manuals!

The basic composition of DuPont IMR-type powders is 100% NC of 13.15% N
content, to which are added 0.6%DPA and 1% K2SO4.  The only exceptions are
IMR4831, to which the DPA is 1.1% and IMR4895 which is 0.7% DPA.  IMR8208M
contains an ethylene dimethacrylate EDM deterrent.  All IMR-type powders differ
essentially only in their deterrent coating and granulation.

   IMR-POWDER GRANULATIONS AND COMPOSITIONS
     Powder   Dia.   Perf.   Lgth.   Web   Coating  Density
           (.65xdie)       (.93xcut)        (%)     (g/cc)

    4198      .027   .007   .085     .010   6 DNT   .85

    3031      .030   .007   .030     .0015  8 DNT   .89

    4064      .032   .007   .085     .0128  9 DNT   .90

    4320      .034   .007   .042     .014   8 DNT   .92

    4350      .039   .008   .085     .016   5 DNT   .925

    4676      .034   .007   .058     .013   7 DNT   .90

    4895      .033   .007   .058     .013   6 DNT   .90

    4831      .039   .008   .085     .016   8 DNT   .90

     The length and outside diameter are not sufficient for
identification of the powder type.  The extrusion pin for cal.
.30 powders is .015" and inside shrinkage is approximately 55%.
The granulation of a single perforated, extruded rifle powder is
expressed:
                       .049 x .015 x 1/11

in which the first group of figures represents the outside diameter of the
grain, the second group the diameter of the perforation, and the third the
length of the cut or the number of grains per inch, when all dimensions are
expressed  in inches. The web thickness of a single-perforated grain is equal
to 1/2 of the difference between the outside diameter and the diameter of the
perforation.  A 1.0% decrease in web or 0.1% increase in total volatile content
(TV) will increase burning rate by 1%.  A change in TV has ten times as much
effect upon burning rate as a corresponding change in web thickness.

The ballistic effect of a change in powder coating varies with the basic
composition, the granulation and the cartridge in which the powder is used.  A
rough approximation is 0.8 grain in charge for cal. .30, and about four grains
weight in charge for cal. .50 per one percent change in DNT coating, which is
approximately equivalent to 40 f.p.s. or 2000 p.s.i. (Cu). Reference powders
are used  to evaluate the suitability for acceptance of an unknown powder lot
or ammunition lot.

Selection of a "reference lot" is based upon acceptable chemical and physical
characteristics and also depends upon satisfactory ballistic performance in the
cartridges for which it is intended. Care is taken to protect and maintain the
proper content of moisture and volatiles as nearly constant as possible
throughout its existance as a reference lot.  This is done by keeping it in
airtight canisters during either bulk or sub-quantity storage.

Assessments of reference powders are made in five pressure gages which have
been inspected to confirm normal dimensions for the type of proof test weapon
involved, and for which there is from 100 to 300 rounds of previous history,
giving normal performance with reference ammunition.

Charge establishment is fired in one gage equipped with a long piston, using
calibration components of the appropriate type, hand assembled at the time of
testing, so that the average velocity of a 20-round series falls within the
tolerance permitted, preferably near the median velocity specified for the
ammunition type under test.  Each of the remaining four gages is fired in the
same manner, using the charge as established in the first barrel.  If any gage
fired with the long piston deviates from the average of all five gages by more
than +/- 20 f.p.s., it is discarded, and another gage is selected in its place.
If the average velocity of all five gages at the completion of the test fails
to come within the velocity tolerance permitted for the type of ammunition, the
charge weight is re-established in a difference gage and the tests repeated.

After the charge weight has been established, and the established charge has
been fired in each gage with the long (velocity) piston, a 20-round series is
fired in each gage with the short (pressure) piston, measuring velocity and
pressure concurrently. If the average pressure of all five gages falls to fall
within the pressure tolerance permitted, the charge is re-established in a
different gage and the tests repeated.

The procedure described is repeated twice more upon succeeding days, except
that the charge established is first fired in the gage with long piston, then
the long piston is removed and simultaneous pressure and velocity tests are
completed on that gage before proceeding to the next one.  With the possible
exception of the first long piston charge establishment, the long piston and
short piston firings in any single gage are to be completed the same day.

At the completion of testing the average velocity of a 15 round velocity series
and a series of 15 rounds for pressure, with velocities being measured
concurrently, are distributed to the using facilities as proposed assesment
valiues, provided these results are in conformance to the specification
tolerances for ammunition undergoing test.  If the averages fail to conform to
specifications, or if the uniformity or reproducibility of the tests between
series is poor, the entire assessment procedure is repeated.

Simulated assessment tests are made by each facility involved in the
manufacture of powder or ammunition type, upon receipt of the proposed
assessment.  Procedure for conducting simulated assessment tests is the same as
that described for assessment, except the charge weight established at the
master assessing station is used for the entire simulated assessment series.

In Home Mix We Trust, Regards, Ed

--- msged 2.05
 * Origin: Home of Ed's Red (1:109/120.3006)



