Chamber length

[30-6]

There's a piece in one of the magazines (it's all been said before I know), on about how using a shorter cartridge than your chamber length is detrimental to the pattern expected, i.e. using say a 2 1/2" cartridge in a 2 3/4" or 3" chamber, especially with fibre wads.

 

But most modern guns these days come as 3" standard chambers, and in my Beretta sporter (3") and Lanber field (2 3/4") I almost always use 2 1/2" cartridges.

 

Does anybody purposely match their cartridge to chamber, or do they just use whatever?

 

NOTE - never use a cartridge that is longer than your chamber length.

[Hunter]

As you have said above, its very important not to use a cartridge too long for the given chamber of the gun. Even a 3" cartridge will fit into a standard chamber, because the cartridge is mesured in its fired length, not unfired length.

The crimp will cause massive compresion at the neck of the chamber, and possible KB* of the barrel in older models.

 

Its also important not to mix the wrong cartridges together, example, 12b and 20b, as a 20b cartridge will drop down the barrel and stop at the neck of the chamber. Then if you pop a 12 bore cartridge in, you will have a big problem when you fire. Almost certain barrel KB*.

 

Theres a myth going around that the pellets will strike the neck at the end of the chamber and become deformed, but this has been proven false varius times.

 

Whats more important is to find a cartridge that works well with

A) Barrel length,

the choke you are using

In order to get the best pattern. Some people swear by the colour of the cartridge, and will ONLY use a given colour because it looks good. I have seen this quite a bit, but im not fussed. If it gives them confidence.. why not.

 

 

* KB = Kaboom, were the barrel or action of a gun is damaged or blown apart.

[30-6]

Hunter

 

"Theres a myth going around that the pellets will strike the neck at the end of the chamber and become deformed, but this has been proven false varius times."

 

Look at page 98/99 of Dec 06 of Sporting Shooter, there's the proof of pellet damage shown quite well.

[njc110381]

The theory is that when the shot leaves a short case in a long chamber, it can expand to the chamber diameter before being forced back to the barrel diameter by the forcing cones. If the cartridge is the full length of the chamber when the crimp is open, this wider part is filled with case so the shot doesn't have space to spread out. If the pellets have to be forced back to the narrower part of the barrel after spreading out, the ones on the outside of the pack get deformed on the forcing cones and fly off from the rest of the pattern at fairly short range, not making it to the target. That said, I use 2 3/4 cases in my 3" chamber and still hit things, as do many other people

[MC]

I must admit I have read the article and to be honest while theoretically possible I do not belive that A/ the shot is in the chamber long enough to even consider worrying about it, and B/ I would have though the choke would deform more pellets.

 

If you think how long it takes the shot charge to travel say 25yds at 1000 ft per second and thyen equate that back to how long the shot takes to travel at the most 3/4" then I wouldn't even think that einstein could work out whether the shot is damaged or not.

 

Personally I use cartridges suitable for the job in hand and do not even consider chamber length, apart from obviously not exceeding the designated chamber length.

[Hunter]

I must admit I have read the article and to be honest while theoretically possible I do not belive that A/ the shot is in the chamber long enough to even consider worrying about it, and B/ I would have though the choke would deform more pellets.

 

If you think how long it takes the shot charge to travel say 25yds at 1000 ft per second and thyen equate that back to how long the shot takes to travel at the most 3/4" then I wouldn't even think that einstein could work out whether the shot is damaged or not.

 

Personally I use cartridges suitable for the job in hand and do not even consider chamber length, apart from obviously not exceeding the designated chamber length.

 

Its not the speed or time in the chamber that causes damage. Its if it hits the neck of the chamber.

 

But I aggree, its pointless to worry about

If any shot damage occurs, id say its either from the choke, damaged shot prior to loading of the cartridge, and possible high velocity shock damage to the lead apon firing. Neither of these things will cause more then the odd flyer. But what does it matter if there are hundreds of other pellets in the pattern?

 

 

P.S,

I dont buy shooting mags. Like newspapers, they are a crafty tool to get people to buy stuff. This forum is full of enough information for me, though most people have forgotten more about guns then I will ever get to know. Slow learner

[browningstalker10g]

most of my guns have 3 1/2 chambers and my cartridges range from 2 3/4 to 3 1/2, ive never noticed any problems or had any complaints, thing is people will always say things to consider and if u worry abut every little thing then u will have no fun atal, just shoot find out what is good for u as things will always be differebt from person to person

[njc110381]

At the end of the day, looking at the figures quoted in the mag, you could lose 20% of your shot in extreme cases. That means that a 30g cartridge will have 24g of effective pellets left, and those lost will be the ones on the outside of the pattern anyway. There will always be some fliers after going through the firing stage of their travel, and 24g of pellets should be more than enough to knock down most targets if hit properly. All this is assuming you lose the maximum 20%. There shouldn't be a problem hitting things. Even with a perfect chamber, there is still choke to consider anyway. I spent some time thinking about this article, and decided that it wasn't worth worrying about!

[mry716]

But its all dependant on what size 12 bore it is. Just as choke is relative to bore size so is the effect the cone has on the shot deformation. The larger the 12 bore the less effect the cone will have.

 

Before you start worrying check what size 12 bore you have. ie 710 719 729 740 etc

 

The same applies to other bore sizes as well.