swan40 Posted March 7, 2018 Report Share Posted March 7, 2018 (edited) hi all If two cartridges were both the same load weight and speed, but one had a higher pressure what effect would this have on the pattern ? also would this affect recoil Edited March 7, 2018 by swan40 Quote Link to comment Share on other sites More sharing options...
Stonepark Posted March 7, 2018 Report Share Posted March 7, 2018 24 minutes ago, swan40 said: hi all If two cartridges were both the same load weight and speed, but one had a higher pressure what effect would this have on the pattern ? also would this affect recoil No easy answer, to either.... lead is malleable and pressure causes it to deform, as long as the increased pressure was less than required to deform the lead you wouldn't likely see any difference, however if the pressure limit is exceeded and the lead deformed your pattern will go out the window. recoil depends on a number of factors and again powder burn speed is probably more noticeable than pressure change due to a few extra grains of powder to increase the pressure.. Quote Link to comment Share on other sites More sharing options...
swan40 Posted March 7, 2018 Author Report Share Posted March 7, 2018 Any idea how high the pressure would have to be to deform the shot significantly because some .410 loads are fairly high-pressure , could this account for a few wild patterns The reason I ask is because it seems to me that most loaders are trying to get lower rather than higher pressures , is this important so long as the pressure is at a safe level Quote Link to comment Share on other sites More sharing options...
Stonepark Posted March 7, 2018 Report Share Posted March 7, 2018 (edited) 410's generally run in the 10250 to 13000 range depending on how hot the loading is, therefore anything less than 5% antimony lead risks poor patterns. Most game lead is 3%, so 410 pressure often exceeds this resulting in poorer patterns. Edited March 7, 2018 by Stonepark Quote Link to comment Share on other sites More sharing options...
Continental Shooter Posted March 7, 2018 Report Share Posted March 7, 2018 Geenrally speaking, as said, lower pressure generally results in tighter patterns whislt the higher pressure migth disrupt the pattern (the higher the pellet deformation the bigger hte spread) However, there are also other key factors and components to take into account like the Wad. Is it plastic cup, fibre , non toxic? each will have a different input on the pattern Also, much would depend on what propellent each shell uses to throw the pellet charge. Quote Link to comment Share on other sites More sharing options...
swan40 Posted March 7, 2018 Author Report Share Posted March 7, 2018 if all components were the same and velocity also the same, just different powders to give different pressures would you expect much of a change in pattern at safe levels? Quote Link to comment Share on other sites More sharing options...
Benthejockey Posted March 8, 2018 Report Share Posted March 8, 2018 I don’t know so don’t shoot me down if I’m wrong but at a guess the pressure wave travels down the barrel in a concentric ring and once it exits the barrel it expands rapidly. I would imagine a pressure wave going slower to do everything more gently so as it exits the muzzle it takes longer to expand and holds a tighter pattern without disrupting the shot pattern whereas a fast wave might explode out of the muzzle and expand very quickly and as well as deforming the lead shot may cause a disturbance in the pattern that makes the lead arrive at the target differently. I could be wrong and that’s just my tired brain making that all up! Quote Link to comment Share on other sites More sharing options...
figgy Posted March 8, 2018 Report Share Posted March 8, 2018 Be good to see some high speed camera shots of what happens with pressure wave. Quote Link to comment Share on other sites More sharing options...
Continental Shooter Posted March 8, 2018 Report Share Posted March 8, 2018 5 hours ago, Benthejockey said: I don’t know so don’t shoot me down if I’m wrong but at a guess the pressure wave travels down the barrel in a concentric ring and once it exits the barrel it expands rapidly. I would imagine a pressure wave going slower to do everything more gently so as it exits the muzzle it takes longer to expand and holds a tighter pattern without disrupting the shot pattern whereas a fast wave might explode out of the muzzle and expand very quickly and as well as deforming the lead shot may cause a disturbance in the pattern that makes the lead arrive at the target differently. I could be wrong and that’s just my tired brain making that all up! Yeah, that is pretty much what happens hence why, generally speaking, the higher pressure one would throw a wider pattern. However, if the powder is different, it might only mean the one with higher pressure has a powder that struggles to throw the lead charge at same speed (more energy is required to launch the pellets). And although I'd be inclined to say the pattern will be worse, I've seen instances where that is not totally true. Quote Link to comment Share on other sites More sharing options...
figgy Posted March 8, 2018 Report Share Posted March 8, 2018 Barrel length will play a big part as the pressure will reduce as the charge moves up it towards the muzzle the longer the barrel the less pressure at the point of exit. Quote Link to comment Share on other sites More sharing options...
Guest cookoff013 Posted March 8, 2018 Report Share Posted March 8, 2018 pressure at 1" in the chamber has very little significance at x distance. Quote Link to comment Share on other sites More sharing options...
timps Posted March 8, 2018 Report Share Posted March 8, 2018 Regarding recoil and from a scientific perspective the equation has got to balance, energy cannot be created or destroyed it can only be transferred. Therefore, if the pressure at the chamber is greater on one but the velocity out of the gun for the 2 different carts is the same then there has to be a difference in recoil. Before anyone says, this difference in recoil might only be able to be measured as a scientific exercise not actually felt by the shooter. Force =Mass x Acceleration Greater chamber pressure but same velocity means either greater acceleration of shot or increased friction of the wad/shot if they both have the same velocity out of the gun. If the initial acceleration is quicker, then the equation says the force has to be greater but over a shorter period of time (more of a thump). If the friction is greater, then the pressure is higher as it exits the muzzle to overcome this increased friction and as the ejecta has a mass and will accelerate once in atmospheric pressure creating a higher force. Or The shot has be accelerated to a higher velocity inside the barrel to compensate the added friction in the remaining barrel higher velocity again higher force. Either way the recoil cannot be the same, whether you or I can feel that difference is a whole other subject but on paper there has to be a difference. Quote Link to comment Share on other sites More sharing options...
swan40 Posted March 8, 2018 Author Report Share Posted March 8, 2018 Thank you all .Certainly has given me something to think about . I suppose the bottom line is lower pressure is better if only from the point of shot damage and wear and tear on the gun. Do you think the increase in recoil would be noticable to the shooter as it seems to me that many 28 gram cartridges of the same supposed velocity vary considerably. Quote Link to comment Share on other sites More sharing options...
hatsanmad Posted March 8, 2018 Report Share Posted March 8, 2018 There's to many factors that can disrupt or affect the pattern. Generally a high pressure load will give more recoil. Also are we talking lead or steel? Steel normally runs a higher pressure compared to lead shot. Speeds are normally the main thing that can have a impact on a pattern especially with lead. Quote Link to comment Share on other sites More sharing options...
figgy Posted March 10, 2018 Report Share Posted March 10, 2018 One thing for sure whether you feel it or not your body feels it and over time it will show, its why lots of clay shooters develop a flinch. Quote Link to comment Share on other sites More sharing options...
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