Bev Fitchett's Guns Magazine

Bullet Weight Loss on Firing

A test was conducted to determine the weight loss of some bullets after discharge. Results are given in Table 20.3. From the limited experimental data it would appear that, as expected, the full metal jacketed bullets lose less than the soft unjacketed bullets. The FMJ bullet with its base enclosed lost less than its equivalent with its base exposed. This is also predictable as the exposed base is subject to erosion during discharge. The .38 SPL + P unjacketed bullet

Table 20.1 Particles on New Ammunition

Ammunition Pb Only Sb Only Pb, Sb Brass

Observations

GECO 9 mm Large Luger. number

Brassjacketed bullet

None

GECO .32 S&W long. Unjacketed Pb bullet

Large number

None

Very Small small number number

Unjacketed Pb bullet

None

Very Large small number number

None Large All the brass particles were number irregular shaped whereas the Pb-only particles were a mixture of irregular and spherical. The Pb-only particles contained some or all of Al, Ca, Cl, Cu, S, Si, Ti, Zn at minor or trace level.

A few Fe particles were present. Unusual particles detected were Bi, P, Al major, Si minor, Ca, Fe trace; Cr, Fe major, Si, Zn trace; Zn major, Fe, Cu minor, Si trace; Si, Al, Fe major, Ca minor, Mn, Zn trace.

All the brass particles were irregularly shaped whereas the Pb-only particles were a mixture of irregular and spherical. The Pb-only particles contained some or all of Al, Ca, Cl, Cu, S, Si at minor or trace level. The few Pb, Sb particles were spherical. Unusual particles detected were Fe, Cr major, Ni minor, Mn trace; Ti major, Fe, Si minor, Al trace.

None Numerous Pb, Sb particles and a few Sb only were detected. No other particle types were detected. The particles were mainly spherical. All particles contained Sn and Ti at minor or trace levels in addition to Ca, Cu, Fe, S, Si at minor or trace level.

Table 20.1 Particles on New Ammunition (Continued)

Ammunition Pb Only Sb Only Pb, Sb Brass Observations

GECO .38 Special. Unjacketed Pb bullet

Large number

None

Unjacketed Pb bullet

None

None

LAPUA 9 mm Luger. Cu Jacketed bullet

Small Very number small number

None None Numerous Pb-only particles and a few Fe particles detected. No other particle types detected. The particles were a mixture of irregular and spherical shapes. All the Pb-only particles contained Sn and Ti at minor or trace level in addition to S, Si.

None None None of the particles contained Pb, Sb, or Ba. A large number of predominantly irregular particles were detected containing some or all of the following: Al, Ca, K, Fe, Si, Ti at major, minor or trace level, Cr, Mg at minor or trace level, Cl, Cu at trace level.

Small Very All the brass particles were number small irregular whereas the Pb number only, Sb only, and Pb, Sb particles were all spherical. There were numerous particles containing some or all of the following: Al, Ca, Cl, Cr, Fe, Mg at major, minor or trace level, K, Ni at minor or trace level, Cu, Ti at trace level. Unusual particles detected were Fe, P, Si major, Ca minor, Cl, Cu trace; Fe, Cr, Cl major, Si trace.

Table 20.1 Particles on New Ammunition (Continued)

Ammunition	Pb Only	Sb Only	Pb, Sb	Brass	Observations
LAPUA .38	Large	None	Very	Large	All the brass particles were
SPL.	number		small	number	irregular whereas the Pb-
Unjacketed			number		only particles were a
Pb bullet					mixture of irregular and spherical. The Pb, Sb particles were spherical. Several Fe particles were detected. Unusual particles detected were Zn major, S, Si minor, Ca, Cr, Fe, trace; Cr, Fe major, Si minor, S trace.
LAPUA .357	Very	None	Large	Very	All the brass particles were
MAG.	small		number	small	irregular as were the Pb-
Brass case	number			number	only particles. The Pb, Sb
and primer					particles were a mixture of
cup					irregular and spherical and
Half Cu					accompanying elements
jacket, Pb					were Ca, Cu, S, Si at minor
H.P bullet					or trace level.

Note: See Glossary for firearms/ammunition-related abbreviations.

Note: See Glossary for firearms/ammunition-related abbreviations.

showed a marked increase in loss. Again, this is predictable as the bullet travels at a considerably higher velocity (pressure) than the .380 revolver bullet and is consequently subjected to greater stress. Barrel length and rate of rifling twist may be among other contributing factors. The three sources of weight loss are erosion of the base by the hot propellant gases, engraving of the outside surface by the rifling of the barrel, and friction. It has been noted in casework that fired bullets with exposed bases frequently have powdered lead at the base area. Also noted on some occasions are embedded propellant granules or indentations caused by the granules, in the base of the bullet.

Although the weight loss may appear to be insignificant in terms of the total weight of the bullet, it is not insignificant in terms of its potential to

Table 20.2 Particles on Unloaded Ammunition

	Pb, Sb,		Ba, Ca,			Pb	Sb	Ba
Ammunition	Ba	Sb, Ba	Si	Pb, Ba	Pb, Sb	Only	Only	Only
GECO 9 mm	37	1	None	6	24	>100	10	None
Luger
GECO .38	18	2	2	1	>100	>100	3	1
S&W

Note: See Glossary for firearms/ammunition-related abbreviations.

Note: See Glossary for firearms/ammunition-related abbreviations.

Table 20.3 Bullet Weight Loss on Firing

	Weight	Weight
	Range	Range	Weight	Weight	Average	Average
	Before	After	Loss	Loss	Weight	Weight
Bullet Type	Firing (g)	Firing (g)	Range (g)	Range (%)	Loss (g)	Loss (%)
9 mm P	7.4322	7.4206	0.0111	0.1485	0.0119	0.1592
Blazer FMJ
(base	7.4741	7.4630	0.0125	0.1678
enclosed)
9 mm P RG	7.5166	7.4951	0.0176	0.2316	0.0224	0.2942
FMJ (base
exposed)	7.6288	7.6033	0.0284	0.3770
.380 REV R.P	9.3935	9.3535	0.0271	0.2862	0.0364	0.3850
Unjacketed
Pb	9.5412	9.4936	0.0476	0.4989
W-SUPER-W	10.2137	10.1214	0.0625	0.6104	0.0840	0.8490
.38 SPL +P
Unjacketed	10.2679	10.1962	0.1051	1.0277
Pb

Note: See Glossary for firearms/ammunition-related abbreviations.

Note: See Glossary for firearms/ammunition-related abbreviations.

produce a large number of discharge residue particles originating from the bullet. This work supports the proposition that the bullet makes a contribution to the discharge particle population.

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