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19 minutes ago, AdamSouthEast said:

The longer a projectile is in the barrel under pressure the higher the velocity of said projectile; this is obviously subject to diminishing returns, so between say 30 and 32 inches, sure there may be a tiny difference, but make those differences larger and it will become much more noticeable.

Check out this guy's masters paper below. He chopped 2 inches off his Mosin Nagant and did several chronos at each length. 

http://honors.usf.edu/documents/thesis/u82488180.pdf

tl;dr: Graph below

 

 

Capture.PNG

And that's not cast in stone in the past i had 2 Tikka T3 .25.06 same length barrel used the same home loads yet the gave different FPS albeit a small difference eg 15 - 20 FPS 

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I guess the difference in range of that 410 is probably down to wad type and how they worked couple this with say a slight discrepancy in FPS and slight variations in  shot size and any observation errors you could have picked up along the way, and you have got the result you came up with.

I know the old MEC shot cups being stronger than many steel shot wads opened up less and held shot together for a little longer as a result, quite how you could directly compare loads from different bores accurately, i believe would need reloads using similar  wads and loads choreographed to check for identical velocities and shot size to get a true comparison.

I feel if you did this the differences would be negligible at best.

 

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3 hours ago, 6.5x55SE said:

Really. Well Attenborough studied Wildlife and gave the answers NOT me.

Anyway how come other Migratory Birds don't fly in a V !!!!!! 

I've never seen a V of Swallows Starlings Pigeons etc and those can fly at High altitude and very long distance  

:)  We still don't know for sure, never mind how expert we get. 

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The difinitive test of pellet distance a few years ago was that an ounce of number 6 shot through a 12 bore would travel 280 yards and an ounce of number 7 shot would travel 260 yards .  Clay grounds have a safety  zone of 300 yards to accommodate these two loads .

harnser

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25 minutes ago, Harnser said:

The difinitive test of pellet distance a few years ago was that an ounce of number 6 shot through a 12 bore would travel 280 yards and an ounce of number 7 shot would travel 260 yards .  Clay grounds have a safety  zone of 300 yards to accommodate these two loads .

harnser

Don't for one minute pretend to know which is right, but it does seem to me that whereas the 300 yards is correct if those pellets do indeed travel that far then the safety margin is on the low side. Two or 3 cold welded pellets could make a mockery of it.

The old empirical formula for 6s gives 232 yards and for 7s 215. My programme offers 234 yards at 22 degrees and 214 at 27 respectively.

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Would they not have a larger area and therefore more air resistance and shorter range?

I thought wile barrel length is part of speed its more to do with the length of burn of the powder and pressure so if the pressure drops of at say 25 inches the length of the barrel at 30 inches may actually slowed down by resistance of the barrel walls

Just a thought

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4 hours ago, AdamSouthEast said:

The longer a projectile is in the barrel under pressure the higher the velocity of said projectile; this is obviously subject to diminishing returns, so between say 30 and 32 inches, sure there may be a tiny difference, but make those differences larger and it will become much more noticeable.

Check out this guy's masters paper below. He chopped 2 inches off his Mosin Nagant and did several chronos at each length. 

http://honors.usf.edu/documents/thesis/u82488180.pdf

tl;dr: Graph below

 

 

Capture.PNG

Interesting information on shotguns. Oh wait....

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Ok .much appreciate the above ideas (except the why geese fly in a v formation = I dont care ) I suppose geese do but I dont .

 

My theory on why the range of a .410 no6 is much shorter than a 20 b or 12b no6 is not due to the velocity at the muzzle. (As its been shown you need a massive reduction in velocity to get a 50 yd average drop in range .) Also begs the question why manufacturers make high speed carts in the first place ? But thats already been done recently .

 

My theory is that the difference comes about due to a reduction in average bc of the pellets in a .410 compared to a 20b /12b 

My thoughts are .That due to the narrower bore of the. 410( and  lower pellet count ) there is a greater percentage of those pellets in contact with the barrel as they scrape along it .compared to a 20 /12 .this reduces the bc of these damaged pellets slowing them in flight very quickly and also making them spread out quicker too (something I've also noticed how wide a .410 pattern can be at say 20 yds )

As an addition maybe the greater pressures in a .410 cart can damage the pellets more  at the rear of the shot Column leaving only a few /small percentage of pellets in there origional round /higher bc shape .

This  ave reduction in bc would explain the reduced ranges we have noticed and the longer stringing effect over distance .

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The idea of slip streaming pellets for  extending range,  I dont subscribe to much . once the shot Column has reached say 6 yds the pellets have seperated enough for the air to act on them all equally. Yes the shot will have reduced in velocity a fair amount in those 6 yds. But why would this effect be significantly different to say a 12 /20 b.?? I dont see it would be .

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34 minutes ago, Ultrastu said:

Ok .much appreciate the above ideas (except the why geese fly in a v formation = I dont care ) I suppose geese do but I dont .

 

My theory on why the range of a .410 no6 is much shorter than a 20 b or 12b no6 is not due to the velocity at the muzzle. (As its been shown you need a massive reduction in velocity to get a 50 yd average drop in range .) Also begs the question why manufacturers make high speed carts in the first place ? But thats already been done recently .

 

My theory is that the difference comes about due to a reduction in average bc of the pellets in a .410 compared to a 20b /12b 

My thoughts are .That due to the narrower bore of the. 410( and  lower pellet count ) there is a greater percentage of those pellets in contact with the barrel as they scrape along it .compared to a 20 /12 .this reduces the bc of these damaged pellets slowing them in flight very quickly and also making them spread out quicker too (something I've also noticed how wide a .410 pattern can be at say 20 yds )

As an addition maybe the greater pressures in a .410 cart can damage the pellets more  at the rear of the shot Column leaving only a few /small percentage of pellets in there origional round /higher bc shape .

This  ave reduction in bc would explain the reduced ranges we have noticed and the longer stringing effect over distance .

Are bless :yahoo:

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Wads can and do effect max ranges, choke too. How long the shot stays in the wad or stays together increases range, bucket wad slit it just halfway down it will pattern terrible in most cases but shot will go further toughness of wads effects ranges too slightly. as i said before, true comparison identical shot size velocity and same or as close wad type as you can practically get, then i do not think you will see anything like your 50 yards difference.

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20 minutes ago, lancer425 said:

Wads can and do effect max ranges, choke too. How long the shot stays in the wad or stays together increases range, bucket wad slit it just halfway down it will pattern terrible in most cases but shot will go further toughness of wads effects ranges too slightly. as i said before, true comparison identical shot size velocity and same or as close wad type as you can practically get, then i do not think you will see anything like your 50 yards difference.

Correct :good:

Also unless I'm mistaken the .410 was fired with a lighter shot load !!!! 

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57 minutes ago, 6.5x55SE said:

Correct :good:

Also unless I'm mistaken the .410 was fired with a lighter shot load !!!! 

Bore size to wad size too, if you think about it 935 mossbergs and 835s .775 with Sam 1s give30 to 70 FPS more than 30 inch 425 Browning, so unless loads are correctly choreographed before any tests to ensure velocity is comparable it is pointless .  Just adds complication and clouds the facts, which are being over egged to begin with.

If people want to know these  things on range fine its a free country, but i think you have to try to be accurate or you end up confusing yourself as well as others.

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14 minutes ago, lancer425 said:

stringing is overrated,  if its on its on shot string wont save a ill placed shot charge, certainly not to mean anything significant in the real world.

I think we must mean different things by the shot , stringing out ? 

I mean that the best(undamaged) pellets from the middle of the shot Column travel furthest with most energy and highest velocity say beyond 5 yds from muzzle. And that the out side /rear pellets from the column (most damaged /deformed ) travel slowest /least distance and furthest from poa .

Leading to a "string " of shot that hits the ground or target at different times .or distances .

Er:hmm:  is that what u meant ? 

1 hour ago, 6.5x55SE said:

Correct :good:

Also unless I'm mistaken the .410 was fired with a lighter shot load !!!! 

Would that make any difference ? 

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1 hour ago, lancer425 said:

Wads can and do effect max ranges, choke too. How long the shot stays in the wad or stays together increases range, bucket wad slit it just halfway down it will pattern terrible in most cases but shot will go further toughness of wads effects ranges too slightly. as i said before, true comparison identical shot size velocity and same or as close wad type as you can practically get, then i do not think you will see anything like your 50 yards difference.

This i also believe too .

But the carts i have in 20 b and.410 dont have any shot cups at all .the experiment was done all with fibre wads .i do have some plas wads .410s but they are not a cup, just a flat wad. So no holding of the shot to extend range .

So that theory  can be discounted 

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10 minutes ago, lancer425 said:

Bore size to wad size too, if you think about it 935 mossbergs and 835s .775 with Sam 1s give30 to 70 FPS more than 30 inch 425 Browning, so unless loads are correctly choreographed before any tests to ensure velocity is comparable it is pointless .  Just adds complication and clouds the facts, which are being over egged to begin with.

If people want to know these  things on range fine its a free country, but i think you have to try to be accurate or you end up confusing yourself as well as others.

Again I'd have to agree with your thoughts.

 

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9 minutes ago, Ultrastu said:

I think we must mean different things by the shot , stringing out ? 

I mean that the best(undamaged) pellets from the middle of the shot Column travel furthest with most energy and highest velocity say beyond 5 yds from muzzle. And that the out side /rear pellets from the column (most damaged /deformed ) travel slowest /least distance and furthest from poa .

Leading to a "string " of shot that hits the ground or target at different times .or distances .

Er  is that what u meant ? 

Would that make any difference ? 

I'm my opinion Yes as to start with you are firing two totally different size Projectiles .

What i can say for sure is using a eg 100 gr projectile at given FPS then a 120 gr projectile at the same FPS from same rifle the heavier projectile with print higher at say 100yrd  !!!!!!

Personally I'd say Lancer425 is on the right track and could explain the reasoning far far better than myself because as yourself along with others I'm not good at explaining things/Myself well :good: Truthfully lack of education when younger :yes:

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Well I was hoping someone might be able to add an extra layer of understanding or a better theory as to why a .410 doesn't travel as far as a 20b all else being equal .

Instead of trying to devalue the findings jd and myself have found. 

:unhappy:

I was hoping neutron would chip in ? 

 

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53 minutes ago, Ultrastu said:

Well I was hoping someone might be able to add an extra layer of understanding or a better theory as to why a .410 doesn't travel as far as a 20b all else being equal .

Instead of trying to devalue the findings jd and myself have found. 

:unhappy:

I was hoping neutron would chip in ? 

 

But all things are most likely not equal.

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