Only use the case for the one reload session, the primer pocket is normally cactus by the end of it. I measure web expansion after every shot - after the first shot from new is the critical measurement as a basis for the other shots, not the new case dimension. Full length resize each time. Excessive expansion = excessive pressure.
The most important factor is the chrony - once the linear increase in velocity (i.e. say 40fps for each 0.5gr of powder added) changes (slows) you basically have reached the max for the rifle - adding more powder is only increasing pressure, not velocity. I have found that this pretty much equates with the time the case head expansion becomes excessive.
Probably only needed at most about 6 or 7 reloads to get to this stage so no problems with the neck but the case head/pocket area is pretty much toasted.
Load Development - what do YOU do?
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crowbuster
HiWall when you measure web expansion, is that the case diameter next to the case head, & what do you consider excessive expansion 
I agree with your comments regarding using a chrono. They are invaluable for determining actual velocities (instead of predicted) and also to warn when approaching dangerous pressures & diminishing returns for the powder charge.
Nick Harveys manual is a great source of information Dr G, & I recommend you get your hands on it if you are new to reloading (approx $30 & money well spent).
CB
I agree with your comments regarding using a chrono. They are invaluable for determining actual velocities (instead of predicted) and also to warn when approaching dangerous pressures & diminishing returns for the powder charge.
Nick Harveys manual is a great source of information Dr G, & I recommend you get your hands on it if you are new to reloading (approx $30 & money well spent).
CB
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trevort
- Spud Gun
- Posts: 12710
- Joined: Thu Sep 14, 2006 9:21 pm
- Favourite Cartridge: Tater
- Location: Melbourne
I need the ladder load concept explained.
I load up rounds with either 3 or 5 exactly the same, then the same number with more powder, probably 5 differrent charges in all.
I fire off the bench to see which one groups best. Then I try .1 of a grain either side of the best load.
I dont get what firing one shot per charge proves. Not saying its wrong, i just dont understand.
I load up rounds with either 3 or 5 exactly the same, then the same number with more powder, probably 5 differrent charges in all.
I fire off the bench to see which one groups best. Then I try .1 of a grain either side of the best load.
I dont get what firing one shot per charge proves. Not saying its wrong, i just dont understand.
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bushchook
- .223 Remington
- Posts: 420
- Joined: Tue Oct 31, 2006 11:23 pm
- Favourite Cartridge: .220 Swift
- Location: Wheatbelt W.A.
Ladder concept in brief .
Shooting at 200 - 300 yards minimum you shoot a group with powder charges increasing incrementally for each shot . Essential to plot the position on the target of each consecutive shot .
Normally the point of impact will climb with each increase in powder charge . When you reach an accurate "node" you will find that a number of consecutive shots will group at the same point . Normal procedure is to select a load with powder charge in the middle of the range that produced this accurate group .
Works OK with a powder and projectile that your rifle likes . Can waste a lot of ammo and end up chasing your tail with a combination that your rifle doesn't like or with a rifle that isn't particularly accurate .
I shoot 3 shot groups with charges increasing in 0.3gn increments until I reach what I consider to be a maximum usable load that won't root my cases in 1- 5 shots .
I look for loads with minimal vertical dispersion . I retest these with 5 shot groups . At the end of the day it achieves the same thing . Accurate loads exhibit minimal vertical dispersion . Horizontal dispersion is usually a wind , rifle or shooter problem .
Shooting at 200 - 300 yards minimum you shoot a group with powder charges increasing incrementally for each shot . Essential to plot the position on the target of each consecutive shot .
Normally the point of impact will climb with each increase in powder charge . When you reach an accurate "node" you will find that a number of consecutive shots will group at the same point . Normal procedure is to select a load with powder charge in the middle of the range that produced this accurate group .
Works OK with a powder and projectile that your rifle likes . Can waste a lot of ammo and end up chasing your tail with a combination that your rifle doesn't like or with a rifle that isn't particularly accurate .
I shoot 3 shot groups with charges increasing in 0.3gn increments until I reach what I consider to be a maximum usable load that won't root my cases in 1- 5 shots .
I look for loads with minimal vertical dispersion . I retest these with 5 shot groups . At the end of the day it achieves the same thing . Accurate loads exhibit minimal vertical dispersion . Horizontal dispersion is usually a wind , rifle or shooter problem .
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crowbuster
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