Unjacketed bullets

Type of ammunition—Jacketed bullets produce substantially fewer FDR particles than unjacketed bullets. Primer type (size, composition, burning characteristics) can influence the number of primer particles produced. The temperature and pressure achieved by the burning of the propellant determines the power and velocity of the bullet which can influence the number of particles deposited. 

The vast majority of the total particle population was due to lead only particles originating from the bullet in the case of the RNL (round nosed lead) ammunition whereas the JHP (jacketed hollow point) ammunition produced a much smaller proportion of lead only particles because the base and side of the bullet are enclosed in the jacket, with the only exposed lead at the nose of the bullet.175 This partly explains the much larger particle population experienced with unjacketed bullets. 

Note Examination of the copper and zinc relationship revealed that for the unjacketed bullet, 94% of the particles contained copper only and 6% contained both copper and zinc, with copper > zinc. For the jacketed bullet, 90% of the particles contained copper only and 10% contained both copper and zinc, with copper > zinc in 9.5% and copper = zinc in 0.5%. 

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... 

It is interesting to note that in all tests in which mercury was present in the primer, it was detected on the perimeter of the bullet hole. The unjacketed lead bullets all gave a large quantity of lead on the perimeter, although this was not confined to unjacketed bullets. The copper results were similarly confusing. 

There is also a wide variety of bullet core/bullet jacket designs without even considering compositional differences. Bullets are unjacketed, or... 

In the majority of bullets the lead base is exposed to the hot propellant gases. This applies to unjacketed and jacketed bullets (excluding total metal jacketed bullets). Some bullets incorporate a gas check in the base to prevent erosion by the hot gases. Such erosion can upset the symmetry of the bullet and consequently the accuracy. The base of the bullet maybe filled or covered with a substance, for example, Alox base lubricant, that is unaffected by the... 

Another round of ammunition developed specifically for law enforcement use is the BAT (Blitz-Action-Trauma) ammunition. It is designed for high stopping power and for the projectile to have a short range of travel. The bullet is unjacketed and is made from solid copper alloy with a differing diameter hole all the way through the bullet from nose to base. This is illustrated in Figure 11.10. 

Detailed analysis of the perimeter residue often yields useful information, for example, whether the bullet is unjacketed or jacketed and the nature of the jacket material. Primer type may occasionally be inferred and the presence of strontium or magnesium indicates a tracer or incendiary bullet, respectively. 

Detectable FDR is mostly particulate in nature. Unjacketed lead bullets produce residue in which greater than 70% of the particles are lead. Coated bullets give the same result, except that a substantial proportion of the lead particles contain copper from the coating material. With jacketed or semi-jacketed bullets the proportion of lead particles in the residue is greatly reduced. It was concluded that most of the lead in the residue comes from the bullet rather than from the primer. This has subsequently been confirmed by experiments involving the use of radioactive tracers.172... 

GECO. 32 Large None S W long. number Unjacketed Pb bullet... 

LR Walther pistol U Unjacketed. Brass wash on bullet. Pb-only primer ND ND ND 20 ND 36... 

Ml, Norma triclad, bullet. 38 S W, Kynoch, bullet. 38 Equaloy, bullet Cu/Ni-coated Fe jacket/Pb core (trace Sb) Unjacketed Pb (trace Sb) Al bullet outside skin (Al, Ti, major Cl, Fe, P, S, trace), inside Al only... 

Eley, bullet. 450, Kynoch, bullet. 455, Kynoch, bullet 7.62 NATO, RAUFOSS, bullet 7.62 NATO, 47-RA-77, tracer bullet Unjacketed Pb Unjacketed Pb (trace Sb) Unjacketed Pb Brass jacket/Pb core (trace Sb) Cu jacket/Sr and Fe at tail end Pb sheath, Fe core at nose end... 

AUTO, R-P, round. 32 AUTO, GECO LT, round. 32 AUTO, RWS, round Cu jacket/Pb core, double-based propellant Ni-coated brass jacket/Pb core, brass case Unjacketed Pb bullet, brass case, Cu primer cup, black powder... 

UMC, round Lubricated unjacketed Pb bullet, brass case, Cu primer cup, black powder... 

S W, Kynoch, round Unjacketed Pb bullet (trace Sb), brass case, and primer cup... 

Bullets of various types (unjacketed, semi-jacketed, and full-jacketed) and skin samples from gunshot entry woimds Pb isotope ratios Q-ICP-MS [15]... 

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