This is my first thread and post though I have spent many hours reading and implementing many of the ideas on this site and a few others. This site and some of the others out there and the users on them have saved me a ton of time and frustration as well as money potentially spent on incorrect supplies, and has been very educational.
I am looking at ways I can take the cheapest cap and ball revolver out there (Cabela's Pietta Brass frame .44 Colt "Navy" ) and make it into a decent reliable somewhat accurate gun that will defy the critics and not shoot loose anytime soon.
My cheap gun came with about a 0.010 to 0.012in gap, which seems reasonable considering what I have read is normal, and I'm sure Pietta did this to avoid having to hold really tight tolerances and also to keep the cylinder from jamming up even if abused and lots of fouling was allowed to build up.
I think this gap should be much much smaller, in fact as small as you can make it and still have the cylinder rotate freely throughout your shooting session.
Cylinder gap in my opinion can influence a number of things, one of which is the longevity of the gun, another may be (theoretically anyway) accuracy, and potentially another would be caps flying off nipples. I'd be interested to see if others agree or disagree with my following ideas or have any first hand experience (I am an engineer so I apologize for the equations, but its interesting to me anyway)
1) longevity:
Many have noticed that once a gun starts to shoot loose, it may then start to get really loose very quickly. This reason most likely is that the impact force of the cylinder hitting the frame when fired is directly proportional to the distance the cylinder has to move (gap) to then impact the frame, the bigger the distance, the faster the cylinder is going when it hits the frame.
Velocity
V = sq rt (2ad) where a = acceleration and d = distance
Energy
E = 1/2 (mv^2) where m = mass (of cylinder and powder, balls, etc) and v = velocity
substituting the first into the second and simplifying gives us:
E = 1/2 m (sq rt (2ad))^2
E = m a d
so the Energy goes up directly proportional to the distance the cylinder can move back before hitting the frame. (this assumes the hand is doing its job of holding the cylinder against the back of the barrel/forcing cone)
a cylinder gap of 0.010in will hit the frame with 5x the energy of one gapped to 0.002in.
There are other threads about how to reduce the cylinder gap. I chose an 0.008in shim behind the cylinder as it seemed like a lot of material to try and remove consistently from the frame/barrel interface.
2) Accuracy:
Since the cylinder will be hitting the back of the frame while the ball or bullet is still in the barrel, it seems that the higher this impact energy is, the more potential it has to detrimentally affect your aim. Now, even with zero gap, the same energy of firing is still transferred into the gun and your hands, but would be exerted as much more of a big push since the cylinder would already be pressed against the frame, rather than having a sudden shock impact near the beginning of that recoil push.
3) caps flying off nipples:
If there is a gap, the cylinder and nipples will both be moving rearward until the cylinder hits the frame at which point the cylinder will stop suddenly and the caps may just want to keep moving rearward (inertia). The sudden shock of the quickly reward moving cylinder hitting the frame and stopping seems like it might dislodge less than ideally seated/fitted caps. A 0.002in gap produces 5x less the shock than a 0.010in gap. General recoil causes the whole gun to move backwards, which shouldn't cause caps to come off as really the cylinder and nipples are trying to move further rearward while the caps are "stationary".
There are other potential problems with excessive cylinder gap, in terms of wasted energy escaping, additional fouling of the front of the cylinder/arbour, blowing off your over ball lube if you use it, larger jump of projectile to rifling, etc.
thoughts?
I am looking at ways I can take the cheapest cap and ball revolver out there (Cabela's Pietta Brass frame .44 Colt "Navy" ) and make it into a decent reliable somewhat accurate gun that will defy the critics and not shoot loose anytime soon.
My cheap gun came with about a 0.010 to 0.012in gap, which seems reasonable considering what I have read is normal, and I'm sure Pietta did this to avoid having to hold really tight tolerances and also to keep the cylinder from jamming up even if abused and lots of fouling was allowed to build up.
I think this gap should be much much smaller, in fact as small as you can make it and still have the cylinder rotate freely throughout your shooting session.
Cylinder gap in my opinion can influence a number of things, one of which is the longevity of the gun, another may be (theoretically anyway) accuracy, and potentially another would be caps flying off nipples. I'd be interested to see if others agree or disagree with my following ideas or have any first hand experience (I am an engineer so I apologize for the equations, but its interesting to me anyway)
1) longevity:
Many have noticed that once a gun starts to shoot loose, it may then start to get really loose very quickly. This reason most likely is that the impact force of the cylinder hitting the frame when fired is directly proportional to the distance the cylinder has to move (gap) to then impact the frame, the bigger the distance, the faster the cylinder is going when it hits the frame.
Velocity
V = sq rt (2ad) where a = acceleration and d = distance
Energy
E = 1/2 (mv^2) where m = mass (of cylinder and powder, balls, etc) and v = velocity
substituting the first into the second and simplifying gives us:
E = 1/2 m (sq rt (2ad))^2
E = m a d
so the Energy goes up directly proportional to the distance the cylinder can move back before hitting the frame. (this assumes the hand is doing its job of holding the cylinder against the back of the barrel/forcing cone)
a cylinder gap of 0.010in will hit the frame with 5x the energy of one gapped to 0.002in.
There are other threads about how to reduce the cylinder gap. I chose an 0.008in shim behind the cylinder as it seemed like a lot of material to try and remove consistently from the frame/barrel interface.
2) Accuracy:
Since the cylinder will be hitting the back of the frame while the ball or bullet is still in the barrel, it seems that the higher this impact energy is, the more potential it has to detrimentally affect your aim. Now, even with zero gap, the same energy of firing is still transferred into the gun and your hands, but would be exerted as much more of a big push since the cylinder would already be pressed against the frame, rather than having a sudden shock impact near the beginning of that recoil push.
3) caps flying off nipples:
If there is a gap, the cylinder and nipples will both be moving rearward until the cylinder hits the frame at which point the cylinder will stop suddenly and the caps may just want to keep moving rearward (inertia). The sudden shock of the quickly reward moving cylinder hitting the frame and stopping seems like it might dislodge less than ideally seated/fitted caps. A 0.002in gap produces 5x less the shock than a 0.010in gap. General recoil causes the whole gun to move backwards, which shouldn't cause caps to come off as really the cylinder and nipples are trying to move further rearward while the caps are "stationary".
There are other potential problems with excessive cylinder gap, in terms of wasted energy escaping, additional fouling of the front of the cylinder/arbour, blowing off your over ball lube if you use it, larger jump of projectile to rifling, etc.
thoughts?
