Senin, 12 Januari 2015

Tracking Point Precision Guided Firearms – sniper rifle (USA)

Tracking Point Precision Guided Firearms bolt action rifle in 7.62х51 (.308)

Tracking Point Precision Guided Firearms semi-auto rifle in 7.62х51 (.308)

Tracking Point Precision Guided Firearms bolt action rifle in .338 Lapua Magnum

Tracking Point Precision Guided Firearms semi-auto rifle in  .300 Winchetser Magnum
Display view of the Tracking Point system a moment before "guided" shot is taken at the game

A line of hunting and sniper rifles, designed and sold by American company Tracking Point Inc under the brand “Precision Guided Firearms” is one of most innovative approaches in blending well-matured small arms technologies with rapidly evolving state-of-the-art computer applications such as image processing and recognition, ballistic calculations, visual data recording and transmission etc. Unlike previous computerized sighting systems for small arms, Tracking Point has integrated computer into the most important part of the shooting process – making the shoot exactly when the rifle is positioned as it should be to hit its intended target. Many previous systems allow automatic calculation of point of aim depending on actual distance to the target (measured by a laser rangefinder), atmospheric conditions and ballistic properties of the specific cartridge and rifle combination, preset by user. However, it is still up to the shooter to properly align the calculated point of impact with his desired point of aim, and pull the trigger at this specific moment. To solve the problem of the inherent instability of the human hands that hold the rifle, especially when shooting from unsupported position or under stress, Tracking Point used several technologies previously used in combat aircrafts. Some of these key technologies are image recognition and automated target tracking, plus use of a human operator input only as a general permission to release ordnance (or fire a shot, in this case), with actual moment of release or shot being calculated by a computer, based on a real-time ballistic solution against an automatically tracked target.
In general, shooting of any rifle (Precision Guided Firearm) by Tracking Point in its most automatic mode involves following steps:
-          Acquire intended target on the display of the digital optical sight, using variable zoom options if required.
-          Place the tag marker (dot shown on the display) over the desired point of impact on the target, and press the “tag” button at the front of the trigger guard. This forces built-in computer to do several steps, including: measure actual distance to the target, calculate ballistic solution based on the pre-programmed rifle and ammunition data, and to start automatically tracking the target within the field of view of the sight. This automatic tracking aligns visual tag mark on the screen with same spot of the tracked target, regardless of minute movements of the rifle as well as target’s own movements
-          Align the aiming reticle (which designates calculated point of impact) with the visually tagged spot of the target. Once the aiming reticle is properly aligned with the tagged target, reticle color is changed, indicating that the rifle is actually “on target” and can be fired with high chances to hit intended spot.
-          Pull and hold the “guided trigger”. This final user input actually serves as “permission to engage” for the system. As long as the trigger is pulled, computer dynamically and in real-time calculates relative positions of the tagged spot of the target with predicted point of impact, and automatically fires the gun as soon as these two calculated spots are converged.

Use of the integrated computer allows for dynamic tracking of moving targets, with real-time adjustments of the tag and calculated point of impact, which greatly simplifies shooting at real-life targets such as hinting game or enemy personnel, which rarely remains static for any noticeable amount of time. Other variables automatically taken into account by computer are external temperature, air pressure, ballistic properties of the ammunition and rifle, horizontal angle of rifle and its cant. Also, built-in laser barrel reference system ensures that sight would hold its factory-set “zero” regardless of how often sight was taken off and re-installed on the same rifle, and despite minor changes in the barrel due to temperature changes.

And as if it’s not enough for successful precision shooting, this highly integrated system offers much more. Thanks to Wi-Fi interface, built into its core computer, any Precision Guided Firearm can stream real-time sight picture (with all relevant computed information) to an external device, such as smartphone, handheld computer or digital glasses. This streamed video information can be viewed by others (i.e. instructor or spotter), stored for later review, or used for remote (over-the-corner) aiming and shooting of the gun. Also, at least in theory, and provided sufficient computing power and software upgrades, same system could be used to for multi-target “tag-tag shoot-shoot” scenarios, where operator can tag several targets within his point of view (i.e. small group of terrorists clustering together) and then proceed to move through tagged targets while pressing and holding the trigger, with rifle automatically shooting at each selected target as soon as the aim is true. Alternatively, if single target requires several hits, system can automatically restore tag to the same location over the target after each shot.

All in all, this integrated system allows for quantum leap in real-life shooting performance, especially at medium and long distances and against moving targets. It also allows for simpler engagement modes, where electronic sight is used to calculate ballistic solution to selected target but target “tagging” and “guided” trigger are not used.

The Tracking Point claims that its 5.56mm semi-auto rifle can effectively engage moving targets at ranges of up to 500 meters with target moving as fast as 16 km/h (10 mph). Semi-automatic Precision Guided Firearm in .308 Win / 7.62 NATO can be used to effectively engage targets as far as 800 meters (0.5 mile) with target speed of up to 24 km/h (15 mph), and bolt action Precision Guided Firearm in .338 Lapua is claimed to do the job on ranges up to 1200 meters (0.75 mile) and with target moving as fast as 40 km/h (25 mph). Judging from available limited end user reports, Tracking Point rifles live up to their initial promises, allowing even relatively inexperienced shooters to achieve reliable hits with .308 Win Tracking Point rifle at ranges of up to 800 meters.

Precision Guided Firearm by Tracking Point is an integrated system, which, in minimal configuration, consists of a custom-built rifle with electronically controlled “guided” trigger and battery power pack integrated into the shoulder stock of semi-automatic rifle or into the sight itself for bolt action rifles. The core of the system is an electronic sight, which is mechanically attached to the top accessory rail of the rifle, and connected via the wiring to the trigger unit and battery pack. A the present time, Tracking Point rifles are pre-programmed for just a few factory-selected types of (match grade) ammunition, but this may change in future.

Host rifle can be semi-automatic or bolt action; current Tracking Point models are built on AR-10 / AR-15 style semi-automatic platforms in .223 Rem, .308 Win and .300 Win Mag calibers, as well as on manually operated, rotary bolt action rifles with detachable box magazines in .308 Win, .300 Win Mag and .338 Lapua Mag. These rifles represent more or less traditional high end designs modified with guided triggers and battery packs, as described above.

The sight unit is a proprietary system, which consists of reprogrammable microcomputer, input video camera (image sensor) with objective lenses, built-in color display and an array of sensors that measure environmental conditions (temperature and pressure), position and movement of the rifle (compass, angle and cant sensors, accelerometers), range to the target (laser range finder), and relative alignment of the sight and barrel (laser). Additional modules include external interfaces (wired and wireless) used to upload new software and data to the sight and to transmit visual data to external devices such as virtual glasses, smartphone or iPad.
Computer performs all the calculations necessary to recognize and track the tagged target, calculate ballistic solution in real time, display all necessary info to the shooter and control the trigger in the “guided” firing mode.

Jumat, 09 Mei 2014

MSBS Radon assault rifle (Poland)

MSBS Radon assault rifles, Radon-B (bullpup) top and Radon-K (standard) bottom
Photo: Leszek Erenfeicht, STRZAL gun magazine (Poland)

MSBS Radon assault rifles, Radon-B (bullpup) top and Radon-K (standard) bottom
Photo: Leszek Erenfeicht, STRZAL gun magazine (Poland)

MSBS Radon-B (bullpup) rifle, partially disassembled
Photo: Leszek Erenfeicht, STRZAL gun magazine (Poland)

MSBS Radon-K (standard) rifle, partially disassembled
Photo: Leszek Erenfeicht, STRZAL gun magazine (Poland)

 5.56x45 NATO
Gas operated
Length, mm
900 / 670
Barrel length, mm
Weight, kg
Rate of fire, rounds/minute
Magazine capacity, rounds

MSBS Radon modular weapon system is an indigenous development of Polish Military Technical Academy (Wojskowa Akademia Techniczna) and Fabryka Broni „Lucznik” – Radom weapons factory. MSBS stands for “Modułowy Systema Broni Strzeleckiej” – modular small arms system. It is scheduled to enter initial production for Polish army trials late in 2014. As of now, MSBS system consist only of two weapons - MSBS-5.56B Radon-B bullpup assault rifle, intended for Special Forces, and MSBS-5.56K Radon-K standard configuration rifle intended for infantry and other units. Future versions of the MSBS also may include heavy barreled Designated Marksmen rifle and Squad Support Weapon (light machine gun).

The backbone of MSBS system is an inverted U-shaped receiver, made from aluminum alloy. This receiver, along with bolt group, return spring, barrel and gas system are common for both current versions of MSBS rifles.
MSBS is operated using short stroke gas piston, located above the barrel, and its gas system has manual gas regulator. Breech lock is achieved by a conventional rotary bolt with seven radial lugs that lock into the barrel extension. Ejection windows are made on both sides of the receiver, and weapon can be set up to eject to either side; this requires partial disassembly of the gun and installation of the ejection port cover on the side opposite the “active” ejection window. Non-reciprocating charging handles are located on both sides of the receiver.

Polymer stocks are made integral with magazine and trigger unit housings (pistol grips are separate Ar15/M16-compatible parts), and available in two versions – standard (with side-folding, telescoping shoulder stock) and bullpup (with fixed buttplate). Both versions feature ambidextrous safety / fire mode selectors located at the top of the pistol grip, and ambidextrous magazine release buttons located in front of the trigger guard. Bolt stop release buttons are located on the underside of the stock, behind the magazine housing. Both stock versions are interchangeable and attach to receiver using cross-pins. Polymer forends also interchangeable. MSBS rifles are fed from STANAG-compatible (M16-type) magazines. Sighting equipment is installed using Picatinny rail at the top of the receiver. Both MSBS-5.56B Radon-B bullpup and MSBS-5.56K Radon-K standard rifle can mount proprietary knife-bayonet (above the barrel) and specially designed 40mm grenade launcher (below the barrel).

Minggu, 20 April 2014

The 17-357 RG Project Cartridge

I was staring at a couple of 17 HMR and 357 SIG cartridges, while trying to scrape some recently fallen tuna and mayo off of my keyboard, when my brain merged the images of the two rounds into what looked like a miniature WSM. I opened RCBS.Load and QuickLOAD, working different case configurations and powder alternatives, until I realized there was potential for a nifty 17-357 RG cartridge. Before I get a pile of email advising me that Kit Coyote, the famous Shooting Guns editor made the same cartridge in '03, I would like to go on record saying I don't care, and Kit is welcome to the fame he deserves from the original effort. In fact, there are a number of .172 cartridges out there, some with similar capacity cases. 
The .17-22 Hornet Ackley Improved with a 13.7 grain capacity case, the .17 Bumble Bee with 9.2 grains of capacity, and the modified .30 carbine case .17 Pee Wee with 14.4 grains of capacity all  have been with us for a long time. My interest in a 17-357 RG is related to its short length, its large diameter rimless case and perhaps a different pressure curve than the other noted cartridges.

The Design
No, this is not actual size, but it might help you develop a feel for the real thing. It is a 357 SIG, or 40 S&W necked down to .172" caliber. The shoulder has been set back a bit and changed to a 40 degree angle, the case headspaces on the shoulder.
If you handload the 357 SIG, you know it has minimal surface area gripping the bullet. This case configuration will provide .200" of neck length which is substantial for the .172" diameter bullet and should hold all bullet weights 30 grains and below, adequately.

Powder capacity is about 12.5 grains, below the neck, which should be more than I need for a short barrel application. If my calculations hold up, and my powder selections, I think the 17-357 RG will be good for 2,000 fps out of a 4" barrel and about 3,000 fps out of a 15" barrel. At some point in time, the 17-357 RG might find it's way into a relatively short barrel varmint rifle where I believe 3,500 fps is a real potential. Fortunately, I have a lot of 357 SIG brass to work with over the next few months.

You'd think a tiny case would be less work....
...but it isn't really.  Primary ingredients to this type of process are knowledge and experience. I quickly came to the realization I had only limited amounts of both but, to my credit, I knew where to find them in abundance. You'll frequently see me reference CH4D in the context of dies and handloading tools and accessories. Dave Davidson's shop has a lot to offer, including friendly guidance and helpful information. The 17-357 RG is a different flavor of wildcat cartridge for me. More than simply necking up or down or blowing out a case, the 17-357 RG requires significant reshaping of brass, a task I could not have approached without assistance. 
Changing a small 357 SIG (Left) case into a 17-357 RG (Right) requires finesse. There are a number of areas to consider. Cartridge brass needs to be coaxed into shape in small increments. What are the appropriate increments? I don't exactly know, and I don't think there is a rigid rule to follow. Generally, one caliber size change is not a big deal, maybe one and one half is reasonable. I make .358-378 RG brass out of .378 Weatherby and .338-378 Weatherby brass all the time without much effort. I've also frequently committed the crime of changing 40 S&W brass into 357 SIG cases in a simple resizing operation. The degree of change across these examples is quite different. .017" reduction to 378 brass, .020" expansion to the .338-378 brass and .045" reduction to the 40S&W brass. The latter is the equivalent to the non-stop neck down of a .308 Winchester case to a .260 Remington. So the answer regarding acceptable increments of change varies.

Dave, offered a rule of thumb to use when determine step increments of case forming. He was also quick to note specific determination would have to take into account what surfaces of the case were being formed, what stresses were being exerted and what were the characteristics of the material. Not so much as a representation of a rigid formula to follow, this is an illustration of the changing conditions that develop as cases are formed.
Neck OD / [10+((shoulder angle - 25)/3)] = Increment
Step 1   .381 / [10+((18-25)/3) = .0497" 
Step 2  .331 / [10+((35-25)/3) = .0248"
Step 3  .306 / [10+((40-25)/3) = .0204"
In reality, the progression isn't linear, the ever diminishing increments would eventually reach the handloader's equivalent of black hole singularity. In a non Star Trek universe,  the project requires 6 forming dies, a sizer, a seater and a reamer die; about 3 more than a turret head full. My guess is that I will need to anneal brass part way through the process, as it work hardens and becomes fracture prone when bent, pushed or shoved a few times. Proper annealing returns the brass to a properly tempered state and allows it to be worked further without splitting. This is something that will require a degree of experimentation after the dies are delivered. In any event, CH4D production lead time and cost were more than reasonable so I placed an order for the die set. Since they are such a reliable shop, I was able to move on to other areas of the project, confident the dies would be completed without a need for continual follow up.

Other dimensions and cutting chambers
The last item on the die list, the reamer die is also something a little different for me. A significant degree of necking size reduction results in a build up of brass, a ring of undersized material at the interior intersection of the case neck and shoulders. I do have a pilot/reamer for my lathe type trimmers, but this type of reamer  would only cut following the existing inside neck opening and not necessarily make it parallel to the outside neck surface. A reamer die locates to the outside of the case neck, the same surface that controls alignment of the case in the chamber, and clears the inside of the case neck to this alignment. I expect I will try both methods as well as some outside neck turning to get a uniform cylindrical case neck. Which takes us to the next issue, the neck diameter.

Most .172 caliber cartridges have an outside case diameter of .199". When case necks are reduced in size, the brass wall thickens, the increase proportional to the degree of change. Following recommendations from CH4D, I had the reamer made to cut the chamber for a nominal .205" neck. The sizer dies will form brass to a .203" neck, a .423: head and a .422" shoulder. Hopefully the result will be cases that chamber without excess clearance, and room for a neck that will not require outside turning. The dies can be tuned to fired brass at a later date. The barrel throat will be .200" long and very close to .172". I ran sample bullets through the comparator to arrive at the throat length with some margin of safety. 

The Chamber Reamer
This time I tried Pacific Tool & Gauge for the reamer. The initial service level was good, the prices reasonable and lead time was consistent with other credible suppliers. I was looking for a simple fixed pilot straight fluted finisher, and got a removable pilot reamer and a headspace gauge for less than the price of just a fixed pilot reamer from Clymer, and they didn't forget my name is "Joe", twice, in a five minute phone conversation.

Barrel work and project guns
I asked Dennis Olson if he could modify barrels for me . He indicated he would, as long as he didn't have to make the autoloader version cycle. There is just something about the energy of a 25 grain bullet and moving an autoloader slide that isn't appealing to most people. I will also send him a Contender barrel for modification, but he doesn't know this at the moment. The result should be a 17-357 RG P229 SIG and a T/C Contender. Getting a custom Contender barrel takes a little work. Probably one of the better sources for T/C barrels, Encore and Contender, is E. Arthur Brown. They sell factory barrel, Thompson Center custom shop barrels and their own custom barrels. They also provide gunsmith service. Lead time on customs runs between 8 and 12 weeks, however, so my current plan is to have Dennis line one of my Contender barrels, and place a 15" barrel on order.

Other things .172 related
This photo isn't an attempt to shrink the apparent size of a .172" bullet by putting it next to a 50 BMG slug, these are all relatively common calibers. Pictured R-L: .338" 270 grain Swift, .277" 150 grain Nosler, .224" Sierra Varminter, .172" Hornady 20 grain and .172" Hornady 25 grain. Berger catalogs a long list of .172" bullets also, some very long for bore size. As an example, their 37 grain is .865" in length and requires a very tight rifling twist, something on the order of 7". On general, .172" bullets are inexpensive, between 9 and 12 cents per from Hornady, about 16 to 20 cents from Berger, and about...oops, there is nobody else. Perhaps with the release of a number of sub .22 cartridges, there will be more. For now, between the two companies there are lots of choices.

When I started shooting a Marlin 17 HMR I had to find undersize cleaning rods and jags. With the addition of handloading the small caliber, I had to add a .172" funnel, a new .17 pilot for the trimmer and a .17 pilot reamer for the same. The shell plates are all SIG standard so I was all set for the rest of the equipment, however, I am sure something else will come up along the way. 

So the question one might ask is "Why?" or even, "No. Really. Why?". The answer is performance with low noise levels, lightweight equipment and pretty good reach. Even with my limited .17 HMR experience I can understand why people would enjoy shooting a 17 caliber gun. The performance potential is actually pretty interesting from short barrel firearms. With a 3" target size, a 3.9" barrel would give you a near 150 yard point blank range and a 15" barrel would extend that to 200 yards; 250 yards with a 5" drop. It would be great to have a super lightweight bolt gun with an 18" barrel that could generate 3,500 fps. Then again, my calculations and assumptions could just be all wrong , in which case and I will be the proud owner of a low speed, low power SIG with a manually cycled slide. 

A general note on custom cartridge or firearm projects
Before I finish falling off my soap box - Outside services have a great impact on projects. It is quite possible to have limited choices when creating a wildcat, or designing a custom rifle, because an outside service has a limited amount of imagination and/or skill. I haul a Ruger No. 1 chambered for the 358-378 RG up to the range and shoot sub MOA groups all of the time. The rifle handles well, recoil is moderate and I run full up handloads through it. The gun even has the appearance I wanted, that of a standard No. 1. It's a great firearm and I feel a lot of pride of ownership in the result. But before the gun became a reality, before I could even start the project, I had to work my way through several large industry mainstay operations who could not offer enough bad advice and editorial criticism. One such shop told me the Ruger could not be chambered for a 378 Weatherby based cartridge; it would blow up. Another told me the Ruger was inherently inaccurate and would never perform well. Yet another told me a button rifled barrel could not be profiled without a drastic loss of accuracy, and original barrel hardware could not reasonably be transferred. With a little persistence and assistance from talented services, the finished product exceeded my expectations; my original thoughts, plus the improvements suggested by quality services. The 17-357 RG is off to a good start.