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Real-time Muzzle Velocity Feedback System (RMVFS)

Description:

TECHNOLOGY AREA(S): Weapons 

OBJECTIVE: To increase overall Soldier Lethality Capability by providing ballistic calculators, weapon fire control devices, and related apps, with immediate, real-time muzzle velocity information after each shot fired to automatically update ballistic computations to enhance accuracy of follow-on shots. 

DESCRIPTION: Muzzle velocity is the speed of a projectile at the moment it leaves the muzzle of a gun and a key parameter in determining a projectile’s external/exterior ballistics (i.e. flight profile and trajectory). Small arms exterior ballistic calculations, used to predict an aim point in order to hit a target, are based on either estimated muzzle velocities or measured muzzle velocities which are typically taken when zeroing a weapon and before executing a mission. However, muzzle velocities will typically change over time and during operational-use based on several dynamic factors to include barrel cleanliness and wear; rate-of-fire; variations in ammunition composition; ammunition and bore temperatures; and (when available) weapon suppressor conditions. Real-time muzzle velocity measurements, provided in a closed-loop feedback schema, would allow fire control and ballistic calculators to better account for and compensate for these unknown and constantly changing variables, thereby increasing aiming accuracy and probability of (target) hit on successive shots. It is envisioned that this measuring device would eventually be affixed to or incorporated within a weapon barrel. The closed loop feedback between the muzzle velocity measurement device and ballistic solver(s) would be accomplished via either hard-wired or wireless communications. This effort would ultimately increase mission effectiveness and overall soldier lethality. 

PHASE I: Research and propose a viable cost-effective technical solution that satisfies the stated objective. In order to expedite an initial proof of concept, PMSW would like to focus on applying this desired capability to current medium-to-long range sniper weapons since 1) sniper teams require the utmost in aiming accuracy and 2) they currently rely on muzzle velocities with ballistic solvers in determining scope reticle offset holds for target engagements. Potential applicable sniper weapon platforms for consideration include the 7.62mm M110 Semi-Automatic Sniper System (SASS), the .300WinMag M2010 (bolt-action) Enhanced Sniper Rifle (ESR), .50 Cal M107 (semi-auto) Long Range Sniper Rifle (LRSR), and future Precision Sniper Rifle (a multi-caliber 7.62mm/.300NM/.338NM weapon). It is envisioned that once proven, the technology could be scaled to other mission area weapons as fire control capabilities proliferate, especially with Next Generation Squad Weapons. As such and to facilitate Phase I efforts, a surrogate sniper weapon, optic, and ammunition, comparable to the M110, should be used. Likewise, use of a surrogate (computer/smart-phone based) fire-control ballistic solver would be acceptable, but ultimately, PMSW would like initial integration with the Kestrel 5700 Elite Weather Meter with Applied Ballistics, which was recently adopted in Fiscal Year (FY) 2017 by the Army as its Ballistic Weather Meter (BWM) and added as a component to the Advanced Sniper Accessory Kit (ASAK). PMSW would also like the measurement accuracy of this device to be within +/- 1% of the actual (Doppler radar measured) bullet muzzle velocity. This accuracy is commensurate with the Government tested accuracy of the Magnetospeed Ballistic Chronograph (Part #: MS V3BT), which was also adopted by the Army, as its Small Arms Ballistic Chronograph (SABC), and added to the ASAK in FY 2015. Some other investigative constraints to consider include 1) that size and/or form factor does not adversely affect shooter operation; 2) that the device can be mounted/installed in conjunction with and will not interfere with other existing or planned weapon devices (such as existing mounting rails, suppressors, bipods, sight posts, etc…); 3) that the device must not alter the inherent baseline accuracy of the host weapon system; 4) that the device can withstand and operate within anticipated weapon operational shock and temperature ranges; and 5) that the device shall be able to operate within and not adversely contribute to Electromagnetic Environmental Effects (E3). The proposed solution should be the result of an engineering tradeoff analysis conducted among several possible courses of action with a focus on SWaP-C (size, weight, power & costs) considerations. The analysis should detail technical advantages/disadvantages, as well as technical/programmatic risks, and provide rough cost estimates for a fieldable technology. All work performed in Phase I shall be provided in a final report that identifies the best conceptual solution. Breadboard tests to demonstrate technical feasibility are encouraged. 

PHASE II: Design, develop, build, and deliver six (6) prototype Real-time Muzzle Velocity Feedback Systems based on Phase I recommendations that can be demonstrated with a weapon platform that is comparable to the M110 SASS. The M110 SASS is a militarized variant of the commercially available 7.62mm SR-25 from Knight’s Armament Company. The RMVFS is intended to integrate with a ballistic solver software to effectively use that muzzle velocity data to calculate real-time exterior ballistics and provide any adjusted aim-points. The system needs to be tested to prove that the RMVFS muzzle velocities meet the objective accuracy requirements and that muzzle velocity data can be passed and used in real-time by a ballistic solver. Phase II culminates with a report that includes test and demonstration results. A detailed proposal will be developed that delineates required efforts to have a TRL-7 system available to be demonstrated in a military environment as a potential Phase III follow-on effort. 

PHASE III: In conjunction with a military customer, optimize and ruggedize the Phase II prototype system for possible integration with Army small arm fire control systems / ballistic solvers and insertion within Army combat teams. The system has potential commercial applicability for law enforcement, hunters, and target shooters. 

REFERENCES: 

1: "Truing" How-to Calibrate Your Ballistic Solution - Long-range Shooting | Applied Ballistics, National Shooting Sports Foundation (NSSF) https://www.youtube.com/watch?v=lUDdnWT7vyI, 19 July 2017

2:  Chronograph Accuracy Tips – 15 Practical Tips to Increase Accuracy & Reliability, http://precisionrifleblog.com/2012/07/20/chronograph-accuracy-tips-15-practical-tips-to-increase-accuracy-reliability/, 20 July 2012

3:  Lessons Learned from Ballistic Coefficient Testing - Exterior Ballistics.com, http://www.exteriorballistics.com/ebexplained/5th/24.cfm.

4:  External Ballistics, https://www.hornady.com/team-hornady/ballistic-calculators/ballistic-resources/external-ballistics

5:  Howard Hall, External Ballistics Part II – Flight to Target, in Ballistics, http://aegisacademy.com/external-ballistics-part-ii/ , 18 June 2014

6:  Ryan Cleckner, Ballistics Basics: Initial Bullet Speed, https://gundigest.com/more/how-to/training/ballistics-initial-bullet-speed, 20 October 2017

7:  Nicholas G. Paulter, Jr., Donald R. Larson, Reference Ballistic Chronograph, Optical Engineering 48(4), 043602, April 2009, https://ws680.nist.gov/publication/get_pdf.cfm?pub_id=32808

KEYWORDS: WEAPON, AMMUNITION, MUZZLE VELOCITIES, AIM POINT, FIRE CONTROL, EXTERNAL, EXTERIOR, BALLISTIC CALCULATIONS, CHRONOGRAPH 

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