Comments by "" (@neutronalchemist3241) on "AG42 Ljungman: Sweden Adopts a Battle Rifle in WWII" video.

  1. Elklund describes it as a piston action in his patent. Direct impingment doesn't exist. Both this, the direct derivate Hakin/Rasheed and the MAS 49/56 are piston actions.
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  2. @ "direct impingment" doesn't exist. Pressure doesn't work that way. The supposed "open tube" of the Ljungman and of the MAS49/56 has an esternal diameter so much bigger than the gas key of an AR 15 (despite the gas pipe being practically equal) because they are pistons, like the piston of an M1 Garand. What pushes the carrier rearward is pressure for surface of the piston. A smaller diameter "gas tube" (mantaining the diameter of the gas pipe, so with exactly the same quantity and speed of the gasses carried) wouldn't have worked, because the pressure would have been there, but not the surface. "direct impingment" is an expression that Stoner used in his patent, referring to the patent of Elklund, to artificially separate that one to his "internal gas piston". But in reality, the only thing Stoner patented, are the gasses in contact with the bolt (while, in Elklund's patent, the gasses are only in contact with the carrier). Both are piston actions.
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  3. No, it's a piston. It's not an open tube. Elklund's patent describes it as a piston, and it has the same external diameter than a standard gas piston (IE that of the M1 rifle) because it's a gas piston, while what's in the carrier is a cylinder. "Direct impingment" doesn't exist. What pushes the bolt carrier back is pressure (of the gasses) for surface (of the piston), like in any gas action. That means that, had that piston had a smaller diameter (mantaining the same internal gas tube) the action wouldn't have worked. Because the pressure would have been the same, but the surface wouldn't have been enough. Most rifle pistons (IE, again, that of the M1 rifle) have "no gas sealing mechanisms" or "rings". The machining is accurate enough to retain enough pressure for the action to work. In this case, also, there is the protruding cylinder of the carrier going into the receiver, and making very difficult for the gasses to escape.
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  4. That's not the Ljungman definition. Elklund clearly describes it as a piston action in his patent. Direct impingment doesn't exist. Both this, the direct derivate Hakin/Rasheed and the MAS 49/56 are piston actions. The term "direct impingement" had been used for the Ljungman by Stoner, in his patent, to artificially differentiate his "internal gas piston" system to the previous "direct impingement" ones.
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  5. Elklund describes it as a piston action in his patent infact. Direct impingment doesn't exist. Both this, the direct derivate Rasheed and the MAS 49/56 are piston actions. That's also why the "gas tube" has the external diameter of a standard rifle gas piston (and way larger than the diameter of the internal gas pipe). Because in a piston action what moves the carrier is pressure for surface. A smaller piston, (thus with the same internal diameter of the gas pipe, and so the same pressure) wouldn't have had enough force to move the carrier.
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  6.  @jimmyh6579  This isn't direct impingment either. In his patent, Elklund clearly say it's a piston action.
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  7. @ The cylinder is what here is named "cup" that happens to be a cylinder. Many gas pistons don't have any gas ring, IE that of the M1 Garand (or, even better, the Degtyaryov DP-27, whose gas setup is practically identical to this gun, in having a "static piston" solidal to the barrel, and a cylinder/cup in the rod solidal to the carrier) . Here, enough sealing is provided also by the fact that the rim of the cylinder in the carrier protrudes and precisely enters in a slot in the receiver. Any gas piston action is "different in operation", but all of them are gas piston actions.
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  8. At that time it was a REAL PROBLEM to manufacture a magazine that was enough well and consistently built to not have feeding issues and cheap enough to be discarded on the field.
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  9. The barrel and the gas tube expand differently while heating. That means that the gas tube "forces" the barrel upward or downward, changing the harmonics in respect to a cold shot. It's like firing with, or without, a weight attached to the muzzle.
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  10. At that time it was a REAL PROBLEM to manufacture a magazine that was enough well and consistently built to not have feeding issues and cheap enough to be discarded on the field. That's why still post-war battle rifles like the M14 and Canadian FAL were intended to be fed primarily with stripper clips.
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  11. Nor this, nor the directly derived Hakim/Rasheed, nor the MAS49/56 are "direct impingment" actions. Direct impingment doesn't exist. No rifle action ever was actuated simply by the "kick" of the gasses. In Elklund's patent (mind that the guy's main job was to design hydraulic pumps, he knew a thing or two about pressure) this is clearly described as a PISTON action. The "open tube" is actually a piston, and it has the diameter of a piston, because a piston works thanks to pressure X surface area. That's why the external diameters of the "open tubes" of the Ljugman and MAS49/56 are so much larger than the gas key of an AR15 (despite the internal gas pipe being practically the same). Because they need surface area to work. The only difference between this, or that of the MAS49/56, action, and that of the Mini14, IE, is the location of the piston and cylinder. "direct impingement" is how Stoner described Elklund's action in his own patent, to artifically differentiate it from it's "internal piston" action. In reality, the ONLY thing that's patented in Stoner's patent is that, in his design, the gasses are in direct contact with the bolt (while, in Elklund's patent, they are in contact with the bolt carrier, not the bolt).
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  12. @ You are welcome. If you are interested, look at the gas setup of the Degtyaryov DP-27, because it's exactly the same of the Ljungman (and probably inspired it). Only, in that case, the static piston (without sealing rings, exactly like in the Ljungman), holed in the center to let the gas pass, is at the end of the barrel, and, consequently the mobile cylinder/cup, solidal to the carrier, is at the end of a rod.
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  13. Nor this, nor the directly derived Hakim/Rasheed, nor the MAS49/56 are "direct impingment" actions. Direct impingment doesn't exist. No rifle action ever was actuated simply by the "kick" of the gasses. In Elklund's patent (mind that the guy's main job was to design hydraulic pumps, he knew a thing or two about pressure) this is clearly described as a PISTON action. The "open tube" is actually a piston, and it has the diameter of a piston, because a piston works thanks to pressure X surface area. That's why the external diameters of the "open tubes" of the Ljugman and MAS49/56 are so much larger than the gas key of an AR15 (despite the internal gas pipe being practically the same). Because they need surface area for the pressure to work. The only difference between this, or that of the MAS49/56, action, and that of the Mini14, IE, is the location of the piston and cylinder. "direct impingement" is how Stoner described Elklund's action in his own patent, to artifically differentiate it from it's "internal piston" action. In reality, the ONLY thing that's patented in Stoner's patent is that, in his design, the gasses are in direct contact with the bolt (while, in Elklund's patent, they are in contact with the bolt carrier, not the bolt).
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