Theory of operation the compromise of duplex
Jul 10, 2009 23:49:17 GMT -5
Post by rbinar on Jul 10, 2009 23:49:17 GMT -5
8-)Those wincing over the difference in the load Edge shot with single powder and the duplex should consider what he said about the breech plug having a vent AND a bushing.
10X would (and could) shoot to the pressure at this level as a single. What Edge describes is an ignition issue. There is not enough primer energy and not enough frictional resistance to confine the energy to a small space.
This load is NOT a duplex but simply a method to overcome lack of sufficient ignition.
A true duplex is designed to adjust powder burning speed. That requires that the primary be slower than any normal powder shot for the bullet and caliber in use. 10X is a normal 300 grain bullet powder for 45 caliber (Edge's Bore), at least in heavy charge weights.
It follows the same thing I brought up with Varget in 40 caliber. Varget may well shoot to speed and accuracy as a single in 75 to 80 grain (or slightly more) charge weights. So is Varget a single powder or candidate for duplex? At this point it's not really known but it seems to be on the verge with some success as a low level duplex. But in the end the proper speed is just as likely to be a fast bullet single.
In the load Mark mentions the starter powder should be limited to as small a charge as possible and still have quality ignition. Whereas a true duplex would allow for considerable adjustment room for tuning and bullet speed regulation.
There is mention of how much a booster changes things with a small difference. Those things can occur but they should be predictable. One has to be able to tell what type of load is being developed.
The same thing happened when the 4350/n110 duplex was being developed in 40 caliber. At some point the booster has acted to change the burning speed sufficiently. At that point no more booster should be added. Speed can be adjusted by adding or subtracting primary powder at that point.
All of this forms a base for the "bottom up" load developing style as described in the "rocket fuels " page www.shootingandrocketfuels.com/Smoke.htm called "theory of operation". In this method all changes are made slowly and when a small change in primary makes a large change in bullet speed (also pressure) booster level is at saturation and should be reduced to the last workable level. All adjustments are from then on either down or primary only. Even when adjusting primary care can be taken to monitor pressure closely.
10X would (and could) shoot to the pressure at this level as a single. What Edge describes is an ignition issue. There is not enough primer energy and not enough frictional resistance to confine the energy to a small space.
This load is NOT a duplex but simply a method to overcome lack of sufficient ignition.
A true duplex is designed to adjust powder burning speed. That requires that the primary be slower than any normal powder shot for the bullet and caliber in use. 10X is a normal 300 grain bullet powder for 45 caliber (Edge's Bore), at least in heavy charge weights.
It follows the same thing I brought up with Varget in 40 caliber. Varget may well shoot to speed and accuracy as a single in 75 to 80 grain (or slightly more) charge weights. So is Varget a single powder or candidate for duplex? At this point it's not really known but it seems to be on the verge with some success as a low level duplex. But in the end the proper speed is just as likely to be a fast bullet single.
In the load Mark mentions the starter powder should be limited to as small a charge as possible and still have quality ignition. Whereas a true duplex would allow for considerable adjustment room for tuning and bullet speed regulation.
There is mention of how much a booster changes things with a small difference. Those things can occur but they should be predictable. One has to be able to tell what type of load is being developed.
The same thing happened when the 4350/n110 duplex was being developed in 40 caliber. At some point the booster has acted to change the burning speed sufficiently. At that point no more booster should be added. Speed can be adjusted by adding or subtracting primary powder at that point.
All of this forms a base for the "bottom up" load developing style as described in the "rocket fuels " page www.shootingandrocketfuels.com/Smoke.htm called "theory of operation". In this method all changes are made slowly and when a small change in primary makes a large change in bullet speed (also pressure) booster level is at saturation and should be reduced to the last workable level. All adjustments are from then on either down or primary only. Even when adjusting primary care can be taken to monitor pressure closely.