How Do They Do This?

[wymberley]

Only talking fibre wads here.

Up 'til now, all I need to know about a cartridge is that it suits my chambers, is my prefered shot size and load weight, goes bang when I pull the trigger and throws my preferred .pattern. At the moment, I'm having trouble with the latter. Amongst others I've tried - and this applies to 3 other guns - there are two decent cartridges. One you'd simply class as 'game' and throws somewhere between Imp+ and 1/4 in three 3/4 nominal chokes and one 1/2. The other, which is apparently designed for 'higher birds' will consistently throw 3/4 in all 4 guns. Being a simple chap, my idea of making a cartridge is to push a primer in the case, pour in the requisite amount of powder, stuff in a wad and then the shot before finally closing it. So, how do the makers get two similarly designed bits of kit to behave so differenetly? Neither can be classed as slow, with a spec' of 1450 ft/sec which I'm pretty sure is at V2.5.

Edited June 19, 2017 by wymberley

[neutron619]

Wad: composition, density, malleability, affecting crush at firing, degree of obturation and number of pellets remaining in the wad or disturbed at the muzzle.

 

Powder: different burning rates producing different pressure and acceleration curves, reducing or increasing crush forces at firing and the length of the barrel at which the pellets scrub at high-medium-low speed, affecting individual pellet deformation.

 

Speed: one or more manufacturer may be telling porkies about the velocity of the shot column.

 

Shot composition: It might all look like lead balls rolled in graphite dust, but harder shot will generally pattern better. Lots of manufacturers appear to be using quite a lot of cheap, soft lead at the moment, if the .410 testing I've done over the last 9 months is anything to go by. The imports tend to be the worst.

 

Loading method: Run the machine faster and harder and more shot gets damaged as you load it. I've cut open cartridges with split pellets in the 10's recently and shot that won't roll down some pretty steep inclines. Again, the imports tend to be the lowest quality.

 

After that, it's luck on the day of patterning and the particular geometry of your gun's chokes interacting with the shot column that makes up that particular cartridge.

Edited June 19, 2017 by neutron619

[wymberley]

Wad: composition, density, malleability, affecting crush at firing, degree of obturation and number of pellets remaining in the wad or disturbed at the muzzle.

 

Powder: different burning rates producing different pressure and acceleration curves, reducing or increasing crush forces at firing and the length of the barrel at which the pellets scrub at high-medium-low speed, affecting individual pellet deformation.

 

Speed: one or more manufacturer may be telling porkies about the velocity of the shot column.

 

Shot composition: It might all look like lead balls rolled in graphite dust, but harder shot will generally pattern better. Lots of manufacturers appear to be using quite a lot of cheap, soft lead at the moment, if the .410 testing I've done over the last 9 months is anything to go by. The imports tend to be the worst.

 

Loading method: Run the machine faster and harder and more shot gets damaged as you load it. I've cut open cartridges with split pellets in the 10's recently and shot that won't roll down some pretty steep inclines. Again, the imports tend to be the lowest quality.

 

After that, it's luck on the day of patterning and the particular geometry of your gun's chokes interacting with the shot column that makes up that particular cartridge.

Proper job, many thanks.

What surprised me was the open shooting cartridge had top qhality polished shot and threw lovely game patterns - just too open for me. The tighter load, although well sized and round, was as your highlighted description.