I have put back together the new in the Air Rifle Headquarters box Anschutz 250 that I bought a few weeks ago. 56 years in the box, never shot, no rust, perfect wood. Stunning looking rifle, perfect in every way. I really love the 220 I have and this 250. No plastic anywhere, except for the seals from John at Custom Gun Parts UK.
I now know how everything works, what every part is for except the short spring and the two thick washers that go inside the mainspring shaft. Does anyone know the purpose of these parts?
Below is some experimentation you may be interested in:
Placing the 250 on a flat set up table and placing small blocks of wood if front of and behind the stock and then pulling the trigger, I knew there was some forward and backwards motion. When holding, or on bench rest bags, this motion is not felt. I took a slow-motion video to see what was going on.
Do you have a Mac computer? If so, you will be able to manipulate the slow-motion video I took on my iPhone that I have attached. When you open it up in iPhoto, in the upper right corner is an edit button, press that and you get the screen that allows for .01 second manipulation. The upper left has the magnification control.
I removed the stock and placed the receiver / barrel on the setup table. (To protect the metal, I put a layer of clear packing tape over the area first) There is reference line just behind the end of the receiver. Two, the closest one is hard to see.
In the video, at 2.73 seconds (probably .ooo1 of a second after the slide catch releases) the receiver moves back minutely, and at 2.74 stops and starts to move forward again to the starting position, and at 2.75 starts moving backwards again.
My analysis: The piston has less mass than the mainspring shaft and the hydraulic cylinder (mshc), and there is more friction between the receiver tube and the mshc than the piston and the cylinder wall. Once the trigger is pulled and the slide catch releases the piston, the greater friction between the mshc and the receiver wall pulls the receiver / barrel backwards a smidgen, then as the piston gets close to the end of the cylinder it pushes the receiver / barrel forward again to the starting point. This first back then forward motion of the receiver / barrel is the same as a regular spring gun, and there is probably some piston bounce.
During the time since the slide catch was released, the mshc has been moving aft, and around 2.75 the combination of friction between the mshc and the receiver wall, plus the force from the hydraulic damper overcomes forward motion and starts dragging the receiver aft again.
When the stock is attached, and bench shooting or being held by the shooter, these motions are hardly felt. The surface the receiver/barrel was on was somewhat low friction. If the surface was near frictionless, such as ice just below the melting point, the final motion aft would have been much longer because not much to slow it down, and the first aft then forward motion probably somewhat longer in length, though the same time intervals. If you placed a regular spring piston gun on a sled with a frictionless surface it would do the same, minus initial aft motion.
Even though the shooter may not feel anything, what would a rigidly mounted scope feel? There is the rearward, stop, forward motions of a typical springer, with the additional stop and 2nd rearward motion.
I do not know if there is a technical term for the Anschutz system, but it can be described as a "free floating opposed mass mechanism”?
The more ideal test would be done with the with the stock on and very sensitive force meters employed. In fact, it would be interesting to test all the recoilless springers, pcp’s and pneumatics this way.
As far as accuracy goes, since all the motions of the 250 are in line with the barrel, these motions probably do not have an adverse effect.
All things being equal, if the same barrel is put on all the different systems, it is the length of time from when the trigger is pulled till the pellet exits the barrel, and the way the air is guided as the pellet exits that are the primary things that affect accuracy?
I now know how everything works, what every part is for except the short spring and the two thick washers that go inside the mainspring shaft. Does anyone know the purpose of these parts?
Below is some experimentation you may be interested in:
Placing the 250 on a flat set up table and placing small blocks of wood if front of and behind the stock and then pulling the trigger, I knew there was some forward and backwards motion. When holding, or on bench rest bags, this motion is not felt. I took a slow-motion video to see what was going on.
Do you have a Mac computer? If so, you will be able to manipulate the slow-motion video I took on my iPhone that I have attached. When you open it up in iPhoto, in the upper right corner is an edit button, press that and you get the screen that allows for .01 second manipulation. The upper left has the magnification control.
I removed the stock and placed the receiver / barrel on the setup table. (To protect the metal, I put a layer of clear packing tape over the area first) There is reference line just behind the end of the receiver. Two, the closest one is hard to see.
In the video, at 2.73 seconds (probably .ooo1 of a second after the slide catch releases) the receiver moves back minutely, and at 2.74 stops and starts to move forward again to the starting position, and at 2.75 starts moving backwards again.
My analysis: The piston has less mass than the mainspring shaft and the hydraulic cylinder (mshc), and there is more friction between the receiver tube and the mshc than the piston and the cylinder wall. Once the trigger is pulled and the slide catch releases the piston, the greater friction between the mshc and the receiver wall pulls the receiver / barrel backwards a smidgen, then as the piston gets close to the end of the cylinder it pushes the receiver / barrel forward again to the starting point. This first back then forward motion of the receiver / barrel is the same as a regular spring gun, and there is probably some piston bounce.
During the time since the slide catch was released, the mshc has been moving aft, and around 2.75 the combination of friction between the mshc and the receiver wall, plus the force from the hydraulic damper overcomes forward motion and starts dragging the receiver aft again.
When the stock is attached, and bench shooting or being held by the shooter, these motions are hardly felt. The surface the receiver/barrel was on was somewhat low friction. If the surface was near frictionless, such as ice just below the melting point, the final motion aft would have been much longer because not much to slow it down, and the first aft then forward motion probably somewhat longer in length, though the same time intervals. If you placed a regular spring piston gun on a sled with a frictionless surface it would do the same, minus initial aft motion.
Even though the shooter may not feel anything, what would a rigidly mounted scope feel? There is the rearward, stop, forward motions of a typical springer, with the additional stop and 2nd rearward motion.
I do not know if there is a technical term for the Anschutz system, but it can be described as a "free floating opposed mass mechanism”?
The more ideal test would be done with the with the stock on and very sensitive force meters employed. In fact, it would be interesting to test all the recoilless springers, pcp’s and pneumatics this way.
As far as accuracy goes, since all the motions of the 250 are in line with the barrel, these motions probably do not have an adverse effect.
All things being equal, if the same barrel is put on all the different systems, it is the length of time from when the trigger is pulled till the pellet exits the barrel, and the way the air is guided as the pellet exits that are the primary things that affect accuracy?
