Cartridge length

[getthegat]

So at 6.15 on a Sunday morning, I'm lying in bed viewing cartridge prices ( I know, I should be out using them, not browsing, but no time today and I don't shoot on Sunday) anyway, I saw that the same load comes in different lengths. Now I know shorter shells are for older guns, but I was wondering why make a longer case if it will all fit in a shorter one and what extra is in the longer case. Is one better than the other? Is one easier/cheaper to make ( I have this theory that everything comes down to money in the end) I think it might be about the wad, though it seems even wads can be the same in different length cases. Never having reloaded my own, I'm not familiar with the internals nor all the variables. 

Edited September 9, 2018 by getthegat
Misspelt word

[stumfelter]

Some semi autos work better with 70mm cartridges (mine certainly does) but don't know if that's the answer to your question.

[TIGHTCHOKE]

1. Buy some different shells.

2. Cut some open and save the contents.

3. Shoot several of each at the Pattern Plate and record your findings.

4. Reach a conclusion.

5. Publish your conclusion with supporting evidence.

6. Buy the cheapest shell you can buy regularly, shoot it and ENJOY!

[getthegat]

Yeah, makes sense. It was just an early morning "I wonder why" question.

[Stonepark]

Cartridges evolved over time from 2 inch to 2.5 inch to 2.75 inch to 3 incg and lately to 3 1/2 inch.
Shotgun chambers also evolved to take increasing lengths, however to get the best cartridge performance out of any gun, the fired cartridge length should be for all intents and purpose the same length as the chamber, primarily to prevent a pressure drop by escaping gases of combustion which can damage the shot/pattern.

Cartridge manufacturers know this and whilst it may save money to use 2 1/2 inch for oz loads,  most serious clay guns are 2.75 as were most performance clay cartridges going back to the 1 1/4 oz clay loads (which would be more difficult to stuff into 2 1/2 and still allow adequate wadding) and most modern 1 oz loads or less use longer wads as fillers but which apparently (and i take a large pinch of salt here) cushion the loads better.

Most modern game guns are 3 inch to give the most flexibility to the user but patterns do suffer as a result of using sub 3 inch cartridges

In a semi-auto the disturbance to pressure pulse/gas caused by using  cartridges of 1/2 inch shorter  (2 1/ 2 inch in 3 inch chamber) than required often shows up as ejection issues.

 

 

 

 

 

 

[getthegat]

Ok, that makes sense. Having 2 ( and by next week 3) semi autos, that is useful advice and info. I don't know if I can bring myself to cut up a cartridge or 3, but when I get my latest acquisition, a Raptor 20 guage, I'll be testing different shells with different chokes for sure. I'm think if I use the same load in my 20 as in my 12 bore, but with more open choke, the pattern may be the same? so until I get use to it and, as someone on another thread said about a 410, "I learn to shoot", this may help me get use to the new fire stick😁

[TIGHTCHOKE]

One other point, research the term "a Square Load" it has a point in each of the gauges and is what a lot of old loads were based upon.

Practice, cutting open a few shells, more practice and even more practice are the way forward.

 

[The Burpster]

3 hours ago, getthegat said:

Ok, that makes sense. Having 2 ( and by next week 3) semi autos, that is useful advice and info. I don't know if I can bring myself to cut up a cartridge or 3, but when I get my latest acquisition, a Raptor 20 guage, I'll be testing different shells with different chokes for sure. I'm think if I use the same load in my 20 as in my 12 bore, but with more open choke, the pattern may be the same? so until I get use to it and, as someone on another thread said about a 410, "I learn to shoot", this may help me get use to the new fire stick😁

From a ballistic point of view, if you have decent quality chokes and use the same load (say 28g 1400 FPS and plastic wads), you should get the same pattern using the SAME choke. 

[Stonepark]

2 hours ago, getthegat said:

 I'm think if I use the same load in my 20 as in my 12 bore, but with more open choke, the pattern may be the same? so until I get use to it and, as someone on another thread said about a 410, "I learn to shoot", this may help me get use to the new fire stick😁

 

If you are using a 12 bore load in your 20 bore (say 28g), the 20b will be operating at higher pressure, as long as this is still less than what is required to deform the lead, then given the same theoretical choke, both 12 and 20 will shoot the same pattern.

Often though the 20 chokes are in same steps as 12 bore (10 thou steps) the same choke in 20b will actually be tighter than the 12 bore with the same choke and can result in denser patterns with high antimony shot (5%) as this prevents the deformation of the pellets by making them harder.

 

[getthegat]

Just found a discussion on " square load" holy moly what a mind mucker. 😵🤔

So excuse me if I'm missing something or being more than a bit dim, but what am I looking for when I cut up cartridges?

[wymberley]

16 minutes ago, getthegat said:

Just found a discussion on " square load" holy moly what a mind mucker. 😵🤔

So excuse me if I'm missing something or being more than a bit dim, but what am I looking for when I cut up cartridges?

Probably a load of round shot rolling around and off your work top, all over the floor and occasionally in your coffee and sandwich.

[Continental Shooter]

Longer cases reduce pressure when the load is equal

on a shorter case you ill find a different wad and less powder compare to the same payload in a 70mm hull

the rational is that 70mm load can take a tight star crimp closure (factory ones are all spin over too) no bother whereas the  67mm needs adjusted (wad, -0.5 g powder and -1 g lead compared to the 70mm) and for 65mm hulls you either reduce the load alltogether or close RTO.

Since factories are set up to star crimp (for the majority) at a certain height and loads are developped with bespoken powders not available to home loaders (even if they carry the same name) the 70mm hull is a solution that generates less maintenance cost (with 67mm hulls the next best thing).  

also, nowadays, the 70 mm is the rule and hull price is not that cheaper between the 3 measurments so, in the balance that's the most economical choice.

[Esca]

Gents this is a great thread

[getthegat]

So top and bottom of it is; a 70mm case is better in every way, assuming your gun can take the legnth. And the pellets in my sandwich and rolling off my bench, made I laaff😁

[wymberley]

On 09/09/2018 at 09:19, Stonepark said:

Cartridges evolved over time from 2 inch to 2.5 inch to 2.75 inch to 3 incg and lately to 3 1/2 inch.
Shotgun chambers also evolved to take increasing lengths, however to get the best cartridge performance out of any gun, the fired cartridge length should be for all intents and purpose the same length as the chamber, primarily to prevent a pressure drop by escaping gases of combustion which can damage the shot/pattern.

Cartridge manufacturers know this and whilst it may save money to use 2 1/2 inch for oz loads,  most serious clay guns are 2.75 as were most performance clay cartridges going back to the 1 1/4 oz clay loads (which would be more difficult to stuff into 2 1/2 and still allow adequate wadding) and most modern 1 oz loads or less use longer wads as fillers but which apparently (and i take a large pinch of salt here) cushion the loads better.

Most modern game guns are 3 inch to give the most flexibility to the user but patterns do suffer as a result of using sub 3 inch cartridges

In a semi-auto the disturbance to pressure pulse/gas caused by using  cartridges of 1/2 inch shorter  (2 1/ 2 inch in 3 inch chamber) than required often shows up as ejection issues.

 

 

 

 

 

 

Because I don't dispute anything you're saying, what it boils down to is that we're going to have to get used to using products which give inferior performance. A fact which has become increasingly obvious over the passed few years.

[motty]

I don't worry about any potential issues due to shorter cartridges and long chambers. 67mm cartridges kill well enough out of my 3 1/2 chambered guns.

[MAB1954]

4 hours ago, motty said:

I don't worry about any potential issues due to shorter cartridges and long chambers. 67mm cartridges kill well enough out of my 3 1/2 chambered guns.

+1. Same here for 2.75" out of 3.0" . 

[Vince Green]

Without going into too much depth, the cartridge length is a throwback to the black powder days when a bigger cartridge was needed to hold more powder and more shot

[hambone]

17 minutes ago, Vince Green said:

Without going into too much depth, the cartridge length is a throwback to the black powder days when a bigger cartridge was needed to hold more powder and more shot

Not sure I agree with you as chambers on older guns are often shorter than modern 

[Old farrier]

Or maybe a shorter chamber allows for the building of a lighter gun and better balance due to lesser forward weight 

 

although it’s probably down to cost of build and market forces along with the change in types of shooting 

[The Burpster]

19 minutes ago, Old farrier said:

Or maybe a shorter chamber allows for the building of a lighter gun and better balance due to lesser forward weight 

 

although it’s probably down to cost of build and market forces along with the change in types of shooting 

There maybe mileage in that, because shorter cartridges and lesser pressures mean thinner chambers and lighter barrels. 

My understand was that guns chambered for 3-1/2 shells are to accommodate heavy loads and magnum shells. If there is no need or intention to use those shells (ie a lightweight sxs English game gun) why chamber it for length and higher pressure shells. 👍

It is ideal to use the correct length shell case for shotgun chambers as there is minimal over expansion of the wad as it leaves the case and before it gets squashed in the forcing cone. There will much less pellet deformation if the wad (or pellets in fibre wad) do not expand to the full size of the chamber before being pushed into the forcing cone. Less deformation results in more accurate patterning, less clumps and more even patterns. 

[Old farrier]

11 minutes ago, The Burpster said:

There maybe mileage in that, because shorter cartridges and lesser pressures mean thinner chambers and lighter barrels. 

My understand was that guns chambered for 3-1/2 shells are to accommodate heavy loads and magnum shells. If there is no need or intention to use those shells (ie a lightweight sxs English game gun) why chamber it for length and higher pressure shells. 👍

It is ideal to use the correct length shell case for shotgun chambers as there is minimal over expansion of the wad as it leaves the case and before it gets squashed in the forcing cone. There will much less pellet deformation if the wad (or pellets in fibre wad) do not expand to the full size of the chamber before being pushed into the forcing cone. Less deformation results in more accurate patterning, less clumps and more even patterns. 

Well I’ve certainly shot a lot of Game with a 2.1/2 chambered gun 

maybe they knew a bit in the old days 

they even bored and regulated for your specific cartridge 😊

[The Burpster]

1 minute ago, Old farrier said:

Well I’ve certainly shot a lot of Game with a 2.1/2 chambered gun 

maybe they knew a bit in the old days 

they even bored and regulated for your specific cartridge 😊

There are very few of any “new ideas” when it comes to firearms. 

[Vince Green]

1 hour ago, hambone said:

Not sure I agree with you as chambers on older guns are often shorter than modern 

That is not something to disagree or agree with its a historical fact. Black powder was much bulkier and the general rule of thumb was that an equal volume of black powder was needed to propel the charge of shot. So 1+eighth oz was 2 1/2" . 1+quarter oz was 2 3/4" and 1oz was 2" and each of those charges filled that size of case.

There was nothing bigger, ie longer, because they just went up in bore size if they wanted bigger charges. 

Back 100 or more years ago, with black powder, or the later black powder equivilents like Shultz or Smokeless Diamond, shotguns shot much softer almost like a nudge compared to the modern aggressive fast burning powders of today.

I shoot BP shotguns today with 1-1/8th and you hardly know they have gone off, except for the smoke of course.

Edited September 10, 2018 by Vince Green

[wymberley]

31 minutes ago, The Burpster said:

There maybe mileage in that, because shorter cartridges and lesser pressures mean thinner chambers and lighter barrels. 

My understand was that guns chambered for 3-1/2 shells are to accommodate heavy loads and magnum shells. If there is no need or intention to use those shells (ie a lightweight sxs English game gun) why chamber it for length and higher pressure shells. 👍

It is ideal to use the correct length shell case for shotgun chambers as there is minimal over expansion of the wad as it leaves the case and before it gets squashed in the forcing cone. There will much less pellet deformation if the wad (or pellets in fibre wad) do not expand to the full size of the chamber before being pushed into the forcing cone. Less deformation results in more accurate patterning, less clumps and more even patterns. 

This also applies to 3" chambers and probably more so as I would imagine that game guns are more likely to be chambered at the 3" rather than the 3&1/2. My latest acquisition certainly is and I'm pretty sure we all know why this should be. As no game (or clay) loads are currently made in the two longer lengths.......... don't think I need to say more as it's patently obvious why.