Can someone explain why dry firing a springer damages it? Every since I got back into airguns everyone seems to agree that it's bad for a springer but can someone explain why?
Dry firing a springer
- Thread starter blackdiesel
- Start date
Because without the pellet in the barrel there is no resistance to the high pressure air generated by the piston, without the resistance from The pellet the piston slams into the end of the chamber,I've actually cracked a piston in half from a Chinese b3-3 underlever just from one dry fire. So it's bad to many parts of the gun,some guns can handle it more than others but I just don't do it
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Hey BD
The piston is designed to be hurled against a column of air between itself and the pellet. It acts like a cushion. Take the pellet away and you take away the column of air. You are now slamming hard parts directly into other hard parts. For some reason, dry firing also heats up the piston seal more than usual. Shortening it's life. This is what I've been told and what I've read over the years. I have a Beeman R9 Goldfinger .177, Beeman HW97k .177 and AA TX200HC .22 and have always made sure to not dry fire them.
Matt
The piston is designed to be hurled against a column of air between itself and the pellet. It acts like a cushion. Take the pellet away and you take away the column of air. You are now slamming hard parts directly into other hard parts. For some reason, dry firing also heats up the piston seal more than usual. Shortening it's life. This is what I've been told and what I've read over the years. I have a Beeman R9 Goldfinger .177, Beeman HW97k .177 and AA TX200HC .22 and have always made sure to not dry fire them.
Matt
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That's also why they say light Lead free pellets are bad for spring guns, because the lighter the pellet the less resistance the Piston has when firing and slams into the end of the compression tube harder than with heavy pellets,it goes both ways tho too heavy a pellet and you get piston bounce
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There is no pressure build up behind the pellet to slow down the piston. The piston can slam into the end of the cylinder, possibly causing damage. The rapid compression can cause a lot of heat igniting lube in the cylinder. This could cause excessive pressure build up. Damage from dry firing can range from damaged seals to bent or broken parts.
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Piston bounce is normal. From the excellent Cardew book on airguns; "A graph of typical piston travel against time is shown in fig. 5.1 It can be seen that the velocity is approximately constant after the initial acceleration, until it nears the end of the cylinder, when it slows down abruptly and stops for an instant at about 1/10 inch away from the cylinder end. From this position it bounces back to a point nearly 1/2 inch away from the cylinder end, it then returns and comes to rest against the end of the cylinder. If there had been no pellet in the breech that piston would have carried on at the same velocity until it crashed into the end of the cylinder, doing no good to anything!"
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Well if I had any sense I would not comment because I am not in
agreement with most of you. Let me try to explain why.
The volume of air in the piston chamber is being forced out through
a small hole. As the piston gets closer to the end of the chamber
the air becomes more and more compacted the pressure in that
portion of the chamber gets higher and higher because the air cannot
be forced through the hole faster than the piston can get there.
Its that pressure that keeps the piston from slamming into the end
of the chamber. And its not dependent on something on the other side
of the opening to work.
Even with no pellet the piston should act very much like it does in a loaded gun.
agreement with most of you. Let me try to explain why.
The volume of air in the piston chamber is being forced out through
a small hole. As the piston gets closer to the end of the chamber
the air becomes more and more compacted the pressure in that
portion of the chamber gets higher and higher because the air cannot
be forced through the hole faster than the piston can get there.
Its that pressure that keeps the piston from slamming into the end
of the chamber. And its not dependent on something on the other side
of the opening to work.
Even with no pellet the piston should act very much like it does in a loaded gun.
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In most guns that not the case. The tp is in close relation to the swept volume of air (more efficient). To get the most out of the rifle is why there are different weights of pellets. If you go to lite you can get piston slam. You go to heavy you get piston bounce. In either case spring life is rather short same as seal life. Not arguing because I have seen to small of a tp with a heavy spring do exactly like you described and also piston bounce horribly with just about all weights of pellets.
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No way! The Cardew brothers did extensive testing in this area and include a pressure chart in their book. The pressure in the chamber does not begin to build up significantly until the piston is about 1/2 inch from the end of the chamber. At this point, the pressure goes up dramatically from around 120psi to 1200 psi at 1/10th inch from the end when the piston stops. This dramatic increase is only because the pellet is totally blocking the escape of any air. At around 1200psi, the pellet releases it's grip and accelerates up the barrel. Without the pellet, there will not even be close to enough pressure to stop the piston so the piston will slam into the end of the chamber. And as stated, a very light or loose fitting pellet may start on it's way before there is enough pressure to stop the piston from hitting the end of the chamber.
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