ACHIEVING DESIRED BULLET PULL STRENGTH USING ADHESIVE SEALANTS AND RELATED METHODS
A non-contact jet valve applicator is used to inject sealant into a joint of an ammunition cartridge, including a circumferential case mouth joint and/or primer cup joint. A sealant is selected with adhesive properties to set a pull strength of the cartridge. In a crimped cartridge, the pull strength set by the adhesive sealant is greater than a pull strength otherwise generated by the crimp.
1 . A method of applying a sealant to a circumferential joint in ammunition, the method comprising:
moving a cartridge along a production line to an applicator having a non-contact jet valve;
using the jet valve to inject the sealant into the circumferential joint; and
exposing the injected sealant to ultraviolet (UV) light on the production line to at least partially cure the sealant.
2 . The method of claim 1 , wherein the sealant is formulated to wick around the circumferential joint when injected.
3 . The method of claim 1 , wherein the circumferential joint is at least one of:
a joint between a projectile and a case mouth of the cartridge; and
a joint between a primer cup and a back end of a case of the cartridge.
4 . The method of claim 3 , wherein the production line further includes an additional applicator having an additional non-contact jet valve, using the jet valve includes injecting the sealant into the joint between the projective and the case mouth, and the method further includes using the additional jet valve to inject an additional sealant into the joint between the primer cup and the back end of the case.
5 . The method of claim 1 , wherein the sealant is an adhesive sealant.
6 . The method of claim 5 , wherein the circumferential joint is between a projectile and a case mouth of the cartridge and the adhesive sealant is formulated to achieve a desired pull strength at the circumferential joint.
7 . The method of claim 6 , wherein a crimp is also formed around the case mouth to engage a cannelure in the projectile and the desired pull strength achieved by the adhesive sealant is greater than a pull strength otherwise provided by the crimp.
8 . The method of claim 6 , wherein the case mouth is uncrimped.
9 . The method of claim 6 , wherein the desired pull strength is at least 125 pounds force (lbf).
10 . The method of claim 9 , wherein the desired pull strength is from 125 lbf to 300 lbf inclusive.
11 . A method of achieving a desired pull strength in an ammunition cartridge, the method comprising:
selecting an adhesive sealant to achieve the desired pull strength;
applying the adhesive sealant to a circumferential joint between a projectile and a case mouth of the cartridge; and
curing the adhesive sealant.
12 . The method of claim 11 , wherein the adhesive sealant is injected into the circumferential joint using an applicator having a non-contact jet valve.
13 . The method of claim 12 , wherein the adhesive sealant is formulated to wick around the circumferential joint.
14 . The method of claim 11 , wherein curing the adhesive sealant includes at least partially curing the adhesive sealant using ultraviolet (UV) light.
15 . The method of claim 14 , wherein the adhesive sealant and the UV light are both applied along a production line.
16 . The method of claim 11 , wherein a crimp is also formed around the case mouth to engage a cannelure in the projectile and the desired pull strength achieved by the adhesive sealant is greater than a pull strength otherwise provided by the crimp.
17 . The method of claim 11 , wherein the case mouth is uncrimped.
18 . The method of claim 11 , wherein the desired pull strength is at least 125 pounds force (lbf).
19 . The method of claim 18 , wherein the desired pull strength is from 125 lbf to 300 lbf inclusive.
20 . An ammunition cartridge comprising:
a case having a case mouth;
a projectile at least partially inserted into the case mouth such that a circumferential joint is formed therebetween; and
an adhesive sealant located in the circumferential joint binding the case mouth to the projectile;
wherein a pull strength of the cartridge is determined by a formulation of the adhesive sealant.
21 . The ammunition cartridge of claim 20 , wherein a crimp is formed around the case mouth engaging the projective, the pull strength of the cartridge determined by the formulation of the adhesive sealant being greater than a pull strength otherwise determined by the crimp.
22 . The ammunition cartridge of claim 20 , wherein the case mouth is uncrimped.