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From: (Norman F. Johnson)
Newsgroups: rec.guns
Subject: Re: **** WARNING TO RELOADERS ****
Date: 2 May 1995 21:19:15 -0400
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 47

# Recently a poor guy found some of his old .44mag rounds
# on the shelf. They were covered with particles and partly
# oxidated so he descided to make them nice and shiny before
# firing. He put them into his tumbler for half an hour.

# When firing the first round he discovered that, apart from
# making the rounds look nice, the tumbling had converted
# his magnum powder into VERY FAST BURNING PISTOL POWDER.

# #Is it safe to tumble loaded ammo?

This has been a practice of many of us for a good many years
despite the advice of many on this net.

Our police range which is open to the public, and sells its
reloaded ammo to that same public, has for at least 20 years used
a regular cement mixer to tumble the loaded ammo to remove resiz-
ing lube.  The media used is ground corn cobs and mineral spirits
which shines the brass like a mirror.

In the ancient past, I have run test batches of .38 and .45 ACP
ammo, increasing time, for up to a number of days (no records
here) in my TEC vibrators.  Each day I would remove a sample of
the ammo and use Ken Water's method to indicate any pressure

There was no pressure increase after a few days so I stopped the
test knowing that there was no hazard to that practice if kept
within reason - the time required to clean off the lube being a
VERY small percentage of my test times.  In practice I leave mine
in from a couple of hours to overnight.

This is yet another piece of "conventional wisdom" that the gun
writers pass back and forth without ever trying it for
themselves.  We have enough real but little understood hazards to
watch for without adding false ones.

For those who still do not feel comfortable with this practice,
simply clean the brass after sizing but before charging.

God Bless!


From: (Morten B Jepsen)
Newsgroups: rec.guns
Date: 6 May 1995 22:04:17 -0400
Organization: Stolt Comex Seaway A/S
Lines: 137

In my first article i wrote:
#WARNING to reloaders
#Recently a poor guy found some of his old .44mag rounds
#on the shelf. They were covered with particles and partly
#oxidated so he descided to make them nice and shiny before
#firing. He put them into his tumbler for half an hour.
#When firing the first round he discovered that, apart from
#making the rounds look nice, the tumbling had converted
#his magnum powder into VERY FAST BURNING PISTOL POWDER.
#RESULT: The revolver disintegrated and he spent some
#time in hospital.

Here I am back with more information regarding accident described

Sorry for not responding earlier, but from the reply to my first
article, I could see that this subject was "burning hot". I decided
to make my homework and I have collected information from powder
manufacturer and the source of the "accident story".

Below you will find the facts from my investigation along with
my personal opinions.

The incident is published in "Vaapenjournalen Nr. 8 - 1994"
page 18 - 19. The article is titled "Hvordan man lager en
haandgranat" - "How to make a handgrenade".
Vaapenjournalen is the Norwegian equivalent to "Guns and Ammo".
This magazine is quite serious and they do normally not publish
anything without proper documentation. The authors are Erik Braathen
and Svein Solli. They are also the authors of "Ladeboka", a
Norwegian handbook for reloaders, 694 pages worth reading and used
 throughout Scandinavia.

The powder was Vithavuori N110, the fastest burning of Vithavuori's
rifle powders. It is the most popular powder in Norway for reloading
Magnum ammo for handguns.
For comparison with Hercules power I have found the following loading
data both for Lyman 429421 Pb, 250 grain bullet:

N110     22.0 grain     1500 f/s
2400     22.0 grain     1495 f/s

Vithavuori is a well known Finish powder manufacturer established in
1922. They produce rifle and handgun powders for the European market
and they are currently producing powder for US defence and they are
approved in accordance with AQAP and SFS-ISO 9001 standards.

N110 is a cylindrical powder with 94-98% nitro-cellulose content. It
has a hole through the cylindrical grain which gives a continuous
burning rate (according to the factory). The reason is that the burning
surface does not noticeably diminish during the burning. The outer
surface of the grain diminishes while the surface area of the hole
grows correspondingly.

The burning rate of the Vithavuori powders is primarily controlled
by the grain size  (Vithavuori does not provide any information
regarding surface treatment of the powder). Smaller grain size gives
a higher burning area to the grain weight and thereby a higher burning

Our unlucky friend was using a steel sizer die so he had to use case
lubricant, but he was to lazy to remove the lubricant after loading,
so he threw the ammo in the tumbler. In my first article I stated that
the cases was partly corroded. This was wrong. after the incident, the
remaining rounds was inspected and no sign of corrosion was mentioned.

The revolver was a S&W M29. There was no indication of failure in the
revolver before the incident.

The article show a picture of the gun after the accident. Unfortunately
I do not have a scanner, so I have to describe the damage. The top of
the frame is missing along with the rear sight. Approx. 1/3 of the
cylinder is missing, two chamber completely opened. No other visible

After the accident the bullets was pulled from the remaining rounds.
It was confirmed that the powder was in fact N110 and that the weight
of the powder was correct. Nothing wrong with his scale. However, most
of the powder was broken down to much smaller grains than the original
N110. Smaller grains, higher density, higher burning area, higher
burning rate.

The tumbler is for empty brass only. Never put loaded rounds in the
tumbler. As a matter of fact, all tumblers sold in Norway (mostly
from USA) comes with a warning: "Do not put loaded cartridges in the


N110 is quite safe to use with magnum loads. Even a  very compressed
load with N110 will not blow up your S&W N29 or 686.

One of the comments to my first article was that ammo can ride in a
truck for long time without any accidents. Consequently, thumbing will
not represent any danger. I disagree with this argument. Vibration in a
truck is low frequency and high amplitude. In a tumbler you have high
frequency and low amplitude. This is the reason for the brass coming out
clean and shiny. Think of a heavy pile with lots of corrosion and rust
scale. You swing it from side to side with a crane and nothing happens.
You then work it with a small vibrating hammer and the rust scale will
come off instantly. If the pipe is filled with grains of porous material
you will transform that into fine powder.

The effect of thumbing may vary with type of tumbler, type of powder
etc. You may be in for a big surprise if you change tumbler or powder.

While composing this article I suddenly remembered a mysterious
incident a few years back. The Norwegian police use S&W M10 as their
sidearm. Some years ago the police bought a large quantity of .38
special ammo from Norma. This ammo was cheap reloaded ammo for
training. Within a few months after this ammunition was introduced
four police revolvers blew up. The investigation was unable to
identify the cause of the accidents, but it was concluded that the
cause lay with the ammunition. Norma ammunition was banned and the
police now uses CBC for training. Since then there has been no more
accidents. Was the Norma ammo thumbled after reloading?

Finally, you can thumble your ammo if you want, but do not stand next
to me on the shooting range.

Morten B Jepsen

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