Talk:Airsoft gun

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We received your report, and you have some interesting results. Typically we expect more findings and conclusions to be summarized in the executive summary - we need clear conclusions to work with, and it is difficult to dig for them. Overall, the detailed documentation of components is impressive, although it would be helpful to have more professional documentation introducing each section and helping the report to flow. Detailed comments follow:

• One major customer need is to emulate an actual gun - which attributes are important in this regard?
  • The appearance is typically the most important attribute that users will look for. The most common airsoft guns are automatic electric guns (AEGs), which are powered by a motor that drives a gearbox. Because many guns are approximately the same shape, in terms of having a handle and a trigger, though a few have variations, most gearboxes are about the same shape, and for the different variants of guns, the new gearbox can be made to fit. Gearboxes generally all function the same way, and their power and durability relies on the internal components, like what material the gears are made of or how strong the spring is. Because of this, the determining factor for airsoft guns is generally what "real steel" gun it is modeled after. Another common attribute, though not as important, is usually the weight or "feel" of the gun. People will buy airsoft guns sometimes to have the feel of holding and shooting something that looks like a real rifle, while not needing a gun licence.
• The description of functionality is quite clear, but it would help to include a figure with labeled components
  • Added Some diagrams to show how some of the pieces fit together.
• You mention child users - please discuss this further and address safety issues.
  • A bit was added in the user groups in terms of younger users. One concern with safety and younger users is that they may not be as mature as an older user might, and may not treat the gun like a real gun and would be more inclined to shoot it at people and things and not consider personal safety and think about their actions in terms of what the consequences are.
• Stakeholders - you mentioned crime as an issue, does this imply additional stakeholders?
  • Yes, a few more stakeholders were added for when it is used for crime.
• Nice bill of materials, but you do not show how all of these parts fit together, other than the trigger assembly. It is not obvious just from the list.
  • Added pictures of the assemblies and how they fit together.
• It is difficult to tell from the pictures, but you might reconsider that some parts that have constant thickness but a bent shape may be produced through forging / stamping / bending rather than casting.
  • Some of the manufacturing processes have been changed, but for some of the parts, there is a seam around the part, which indicates it may have been cast. Parts like the safety switch, (T 01) have sharp corners at the bends that seem to indicate that the part was not bent or stamped.
• The manufacturing term for “lathing” is turning
  • Parts with this manufacturing process have been corrected.
• Reaming may be necessary for the barrel - you might consider
  • While we are not completely sure what method was used for producing this particular barrel, the process shown at the following site, http://www.madbullairsoft.com/English/index.php?main_page=product_info&cPath=7&products_id=44, is one method for producing barrels with a precise inner diameter. Reaming may or may not be the process used also due to the length of the barrel. It would need to be very accurate, since tolerances on airsoft barrels tend to be tight, ranging from very "tight" 6.01 mm inner diameter to wider 6.14 mm inner diameters. The barrel would also need to be very straight in order to get this accuracy, since either the reamer or the barrel must be turned and any bends or deviations may cause the inner barrel to not be accurate.
• Please provide an introduction to each section rather than beginning with a table of data.
  • Fixed
• You mention in the FMEA that one of the most likely failure modes is fatigue of the spring from users storing the gun cocked. A users manual warning is okay, but we know from experience that this will not do the trick for most users. Is there another way to avoid this failure mode?
  • The gun could be outfitted with a mechanical device that would uncock the gun if it has been cocked for more than a few hours
• LCA - you did not discuss major sources of GHG, pollutants, dominant life cycle phase, etc. Should we be worried more about manufacturing of the gun or of the BBs?
  • Major source of GHG, pollutant, etc were not discussed as we do not have a benchmark for these factors. The Economical Input Output Life Cycle Assessment gave results for small arms, but airsoft guns make up less than 10 percent of that market. We feel that it would be unfair to considering the effects of the manufacturing an airsoft gun with a small firearm as the material makeup and build process of an airsoft gun is very different from a small arm. For small arms though, the LCA reviewed that the metal working and the power generation had the largest effect on the environment.
  • Since many bottle of BBs may be used throughout the course of the life of an airsoft gun, we should be worried about the manufacturing of both the gun and the BBs. Plastic BBs might not degrade for 100 years and the same holds true for the plastic that makes up the airsoft stock.
• DFMA is a nice list, but more detail and supporting information would be helpful
• Can you justify why the trigger mechanism is so complex? It appears that the same function could be performed with a single spring, since the only output is to move the lever out of the way of the piston release.
  • The trigger mechanism is complex due to the built in safety features. There are three mechanical safeties that prevent the trigger from accidentally being pulled. One safety, the safety switch (part T 01), slides into a position where it blocks the lever (part T 12) and prevents it from rotating, thus preventing the gun from firing. Another safety is the bolt safety, which prevents the gun from firing when the bolt handle is not rotated downward. There is a groove in the bolt assembly that lines up and when out of position, pushes the bolt safety (part T 14) down, which in turn pushes the bolt safety lock (part T 16) into a position where the lever is blocked and cannot rotate, thus preventing the gun from firing. The final safety is just the double trigger. The smaller trigger must be pulled in order to allow the primary trigger to be pulled, allowing the gun to shoot.
• In your calculations it looks like you measured spring constants by attaching known weights and measuring deflection? Please explain what you are doing, otherwise we cannot follow where the equations and numbers are coming from.
  • Added more of an explanation of how the spring constants were measured
• Your final result is that the force required to pull the trigger is 2.5 N based on experiment, but your calculations seem to show 1.72. Please explain the discrepancy. Also, what does this result tell us? Is this force too high? Just right?
  • The discrepency between the 2.44N trigger pull and the 2.00N trigger pull has hopefully been cleared up. The 2.44N value is the total force needed to pull the trigger, and the 2.00N value is the value that was being calculated and is the force required to pull the main trigger if the safety trigger was not there. The difference between the calculated and actual values is most likely due to friction. Because the force the piston exerts on the piston release is probably about 15 to 25lb (from reading online about related products), this will be the amount of force pushing along the axis of rotation of the lever, point O, there is potential for a lot of frictional forces both between the lever and bolt release, as well as friction on the pin at point O.
  • As for the result, I don't have any other numbers to compare this value to, so I am unsure if this value is a lot or a little for trigger pulls. From my personal experience, I feel like this is relatively light for a trigger pull, which is a good thing to have when using a sniper rifle, wince you do not want your single shot to be affected by pulling on the trigger. There is an existing product that is called the zero trigger, or something along those lines, which is supposed to have a very light trigger pull. I would need to do more testing with other products to know how this result compares, though.