WARREN COMMISSION EXHIBIT 399 [stretcher bullet]
Four or Six Grooves?
by Jerry Robertson


There has been a continuing discussion about the physical characteristics
of the bullet shown in Warren Commission Volume 17, Page 49.[CE 399].
The bullet appears to show more than four lands and grooves. The Oswald
Mannlicher-Carcano rifle had four lands and grooves.


The following definitions are found in the Glossary of "National
Institute of Justice Firearms Evidence Sourcebook"


        Striations - Lines generally of a microscopic nature, engraved
        on a bullet as it passes through the barrel of a firearm


        Land - The raised portion of a barrel


        Groove - One of the spiral cuts or impressions in the barrel of
        a firearm.


        Rifling - The grooves and the lands, taken together, are called
        the "rifling."


        Land impression - On a fired bullet, the impression of a land of
        the barrel. To avoid confusion, the fact that a land impression
        is actually a groove on the fired bullet should be ignored.


        Groove impression - In a fired bullet, the area on the surface
        of the bullet that came into contact with the grooves of the
        barrel. Since the grooves do not grip the bullet as tightly as do
        the lands as the bullet travels down the barrel, the groove
        impressions on the bullet are typically not as pronounced as the
        land impressions.


           -----------------------------

I have ten  8 x 10 photos of Mannlicher-Carcano 6.5 millimeter bullets
that have been published in the Warren Commission Hearing Volumes
and the House Select Committee on Assassination Volumes. They
include CE 399 [Stretcher Bullet] and CE 572, CE 853, and CE856, [other
6.5 mm bullets that were test fired through the "Oswald" rifle]. I have
scanned some of these photos and placed them in this Directory.


I cropped the CE 399 photo from  WC Volume 17, page 49 and the CE 399
photo from HSCA Volume 1 Page 297. I placed these cropped photos end to
end to show that the bullet grove [land impression] of both bullets appear
to be the same width. This montage is posted in this directory as CE399-lN.


If it is agreed that the land impressions are the same in each photo,
then by using basic math, the width of the groove impressions can be
determined.


The diameter of the bullet is listed as .264 inches. .264 x 3.14= .829
inch. The "National Institute of Justice Firearms Evidence Sourcebook"
lists the Mannlicher-Carcano 6.5mm as having 4 lands at .081inches
and 4 grooves at .123 inches for a total of .816 inches.


If CE399 in the WC Volume is a 6 land and groove bullet then the 6
land impressions would use .486 inch [6 x .081]. That would leave
.330 for the 6 groove impressions. .330 divided by 6 =  .055
per groove impression.  The "National Institute of Justice Fire-
arms Evidence Sourcebook" does list a Mannlicher 1909 25AUTO
as having 6 land and groove. The land width is .045 and the groove
width as .082
Not even close.


                    
CONCLUSIONS


My conclusions are that all of the photos are most likely of a
four-land and four-groove bullet. I base the conclusion on
the following reasons:


        1 - The land impressions are the same width on all the bullet
              photos.
        2 - All the photos are of different views [4 sides] of the
              bullet.
        3 - CE 399 as shown in HSCA Vol. 7, Page 385, shows a large
              striation in the groove impression. I believe this could be
              mistaken as a land impression in a photo that used different
              lighting.

Jerry Robertson jlrobertson33@insightbb.com 


November 16, 1997