Hi All, I don't think you need to stress over the compression chamber. I used Plymouth brand chromoly tubing, it has a very smooth finish on the inside.
I am suprized however, that alternate barrels have not been more fully explored for the existing mechanism of the 46M ....I have tried to add the 16inch barrel version here...Perhaps a simpler stock and the mentioned 550 fps would be adequate enough for you.The standard barrel length in .22 got just above 400 fps ...perhaps a .22 16 inch barrel version?For the record, I was usually getting approx 25 fps per inch with the couple of SSP I modified.The 1.5 inches extra in the 75 giving 35 fps at 8.25 inches, for a total of 440 fps from 405 fps stock....with a decent 8 grain pellet.
My price goal for a SSP rifle, that looks, feels and shoots like a HW 30 or 50; would be to sell it at that same price as those springers. Of course, if one sold the design, the manufacturer and distributor would sell it at whatever they think they can get. The AV 46M was selling for $600. That is a nice way to put costumers off. Especially if it does not work as well as the Izzy version.Rather than make a target rifle, my goal is to make a sporter / plinker that is easier to hit with than the equivalent springer. Just because something is new, different or scarce, does not mean it is very good. It needs to be good enough, and much easier to extract that potential than a springer. Also, none of the spiky cocking force of even something like the wimpy Daisy 753 or Beeman P17. So, good value for money and user friendly; rather than a $2000 target rifle.Anyway, this thread was dormant, until someone woke me up
Quote from: subscriber on January 15, 2021, 11:07:58 AMMy price goal for a SSP rifle, that looks, feels and shoots like a HW 30 or 50; would be to sell it at that same price as those springers. Of course, if one sold the design, the manufacturer and distributor would sell it at whatever they think they can get. The AV 46M was selling for $600. That is a nice way to put costumers off. Especially if it does not work as well as the Izzy version.Rather than make a target rifle, my goal is to make a sporter / plinker that is easier to hit with than the equivalent springer. Just because something is new, different or scarce, does not mean it is very good. It needs to be good enough, and much easier to extract that potential than a springer. Also, none of the spiky cocking force of even something like the wimpy Daisy 753 or Beeman P17. So, good value for money and user friendly; rather than a $2000 target rifle.Anyway, this thread was dormant, until someone woke me up Hi Sub, just an FYI that way long ago, I had a SSP 12fpe rifle from Parker-Hale in the U.K. called the Dragon. Brilliant concept with a mechanically-advantaged looong single pump stroke that was relatively low effort and actually worked, but was eventually prone to leaks:https://www.pyramydair.com/blog/2008/07/parker-hale-dragon/Sold it cheap to a buddy who was "gonna fix it" but I never heard of any success.
Quote from: clarky on January 15, 2021, 09:29:12 PMI am suprized however, that alternate barrels have not been more fully explored for the existing mechanism of the 46M ....I have tried to add the 16inch barrel version here...Perhaps a simpler stock and the mentioned 550 fps would be adequate enough for you.The standard barrel length in .22 got just above 400 fps ...perhaps a .22 16 inch barrel version?For the record, I was usually getting approx 25 fps per inch with the couple of SSP I modified.The 1.5 inches extra in the 75 giving 35 fps at 8.25 inches, for a total of 440 fps from 405 fps stock....with a decent 8 grain pellet.My 46M generates 4 FPE at the muzzle with its stock 11" barrel, after I cranked up the compression setting. This is 495 FPS with a 7.4 grain pellet. If the gains you promote with a 16" barrel exist, then it should produce 495 + (5 x 25) = 6.3 FPE with the longer barrel. I seriously doubt that this will happen, because the velocity gained is actually not linear with barrel length. Because the pressure in the barrel keeps dropping as the expansion volume increases. With such a low power airgun, pellet to barrel friction will easily dominate. Thus, velocity gains observed are more likely due to reduced barrel friction, than increased length. To prove this, start with a 16" barrel; test it, and lop off and inch at a time. Comparing a few different barrels and suggesting the velocity differences with them are due to the length differences are, shall we say; not scientific.If every additional inch increased pellet velocity by 25 FPS, how long does a 46M barrel have to be to exceed 12 FPE? Never going to happen. Apart from adding a butt stock to my 46M, I have no interest in butchering it. Unless its accuracy potential is retained, I really don't need it to shoot at 620 FPS. A long skinny barrel might look interesting to some. I think you will see more gains by increasing the input energy, rather than than by trying to improve system efficiency by means of barrel length only. To increase the input energy, you need a larger swept volume...Consider that the Baikal factory made MP-532 rifle; using the same mechanism as the 46M shoots at the same velocity, despite its longer barrel:https://www.pyramydair.com/blog/2019/10/izh-mp532-target-rifle-part-1/https://www.pyramydair.com/blog/2019/10/izh-mp532-target-rifle-part-2/https://www.pyramydair.com/blog/2019/10/izh-mp532-target-rifle-part-3/Could owners of this 46M based rifle, hotrod the velocity? If so, do they? If not, why not...
Advertise Here
Share This!