OPTIMUM BARREL LENGTH

[aadhaulya]

I believe that the barrel length plays a major role in the range of the bullet fired, This seems to be true to a certain extent only and a barrel longer than the optimum length would reduce the range. My reason for this thinking is as follows.

1. Once the explosive powder of the cartridge is ignited it expand and pushes the bullet out as that is the path of least resistance.
2. The expansion of gasses will be restricted to a certain volume only before it reaches the atmospheric pressure. (The final expanded volume would depend on the quantity of the charge in the cartridge and probably the chemical composition of the charge as well)

Therefore, if the barrel is too short the bullet leaves the barrel before the gasses have fully expanded and the bullet could not get the full advantage of the energy of the cartridge hence the range is also less than could have been achieved by that cartridge.
On the other hand if the barrel is too long (say about 50 meters) the bullet would travel in the barrel till the charge has fully expanded and the friction between the barrel and bullet would cause it to stop some where within the long barrel.

Hence, there has to be a optimum length of the barrel that would be calculated taking into account the 'Explosive Powder' of the cartridge. And probably each gun should have a recommendation on which cartridge would get the best performance for that particular gun.

I am sure professional shooting gun manufacturers calculate all this, but may be it is a trade secret of the manufacturers as I am unable to find any thing with details on the internet regarding this topic

I hope to get some opinion from the people who are regular users of guns and are interested in the technical aspect of guns.

Regards

[bennedose]

The best gun/artilley manufacturers calculate this exactly. The bullet/shell should be constantly accelerated from beginning to the end of the barrel. That means that the pressure behind the bullet/shell should remain constant even as the shell moves down the barrel, but any gases generated after it leaves the barrel would be a waste.

An quick explosion that does not continue to generate gas behind the bullet will only cause the bullet to slow down as it moves down the barel. So the propellant should be relatively slow burning to consume itself as the bullet travels down the barrel - generating enough pressure to keep the bullet in constant acceleration. It is also wasteful to generate lower pressures initally with pressure increasing as the bullet moves down - why not simply reach optimum pressure as quickly as possible and then keep the pressure constant for constant and smooth acceleration down the barrel. The rate of burn of powder is crucial.

I think the weapons where accuracy is absolutely critical - like sniper rifles, artillery pieces and competition guns there is a close match between length of barrel and the exact amunition/propellant used.

[aadhaulya]

Dear Bennedose,

Thanks for confirming my understanding. Now as my purpose of asking this question was to find something on rifle calibers and the ammunition used in India.
As in India there are only IOF products available (new) hence the only choice is among the 12 bore guns. Again as per my understanding, for specific applications like sport (trap & skeet shooting) there would be a specific requirement, like the spread of pellets and the limited range as per the requirement of the sport. Hence,I suppose the barrel length would be recommended.
Now, a short barrel would be easier to handle for moving targets. I long barrel would have a longer range and probably a better balance (not sure) and definitely better looking (my personal opinion).
The DBBL 12 bore guns available are in the range of 22" to 32" barrels (I believe).
Kindly guide what would be the optimum length of the barrel for the maximum range. Or where I can get details on the internet.
I am not a target shooter I would just like to own, a gun for casual use, with max range and accuracy.

Regards

[timmy]

For a .22 LR rifle, the number is somewhere around 16 inches/ 400 mm. There are many different kinds of powder, some of which burns slowly and some which burns quickly. A slow burning powder will be able to take advantage of a longer barrel, usually, while fast burning powder works better in short barrels. High velocity types like "Stingers" might be able to take advantage of a longer barrel. Another special case is the revolver, as the cylinder to barrel gap, combined with barrel length, can affect velocity.

For centerfire rifles, the ammo makers will try to use a load that matches the sorts of rifles in which a particular cartridge is used. The usual length of barrels is 22 inches/560 mm to 24 inches/610 mm.

For shotguns, there are more issues to consider. Things that affect the shotgun shell, besides the powder choice and the primer choice (both of which affect ammunition performance in any kind of gun), one must also consider the shotgun shell hull, which are unique: not only do they differ between manufacturers, but there may be more than one kind of hull within a manufacturer's product line. (To digress here, this is also true with brass cartridges too: thicker cases have less capacity than thinner cases, and if the difference is large enough, this can also have an effect on loading. For instance, military cartridge cases are often thicker and require a somewhat reduced load, compared to commercial cartridge cases.) All of the hull construction issues affect the load. Also, there is the wad: whether felt wads, or plastic pistons are used affect a shotgun load, as well as the number of wads or the construction of the plastic wad.

In general, varying any components is nothing to be taken lightly if you reload, and this is especially true in shotgun reloading.

Specific to your second post and shotguns, the only way you will be able to check the performance of a given type of ammunition in a specific shotgun, with respect to barrel length and choke type, is to get a chronograph and check it yourself by shooting the gun and measuring velocity. Similarly, you will need to check the pattern of the gun by shooting it at a given distance into a sheet of paper and counting the number of pellets that fall into a given diameter. This is how chokes are "measured," since a "full" choke from one manufacturer can differ from one offered by another manufacturer, and there may even be variation between guns from the same manufacturer.

The pattern will also vary by the kind of pellets used: steel vs. lead, and the hardness of the lead will make a difference, too. Harder lead pellets will make the pattern tighter.

[xl_target]

I am not a target shooter I would just like to own, a gun for casual use, with max range and accuracy.

Regards

In India, you will be constrained by ammunition availability and the exhorbitant price of imported firearms.
Now, if you are a millionaire, the sky is the limit but for mere mortals, you're basically stuck with what IOF produces.
So for all practical purposes, it is .22LR and .30-06.

Shotguns are a slightly different story but you are never going to get much range with shotguns.

[bennedose]

I am not a target shooter I would just like to own, a gun for casual use, with max range and accuracy.

Regards

This was my original intention in life after I returned to India - and it was in the days before the local shooting range was operational. I wanted a rifle licence but they gave me a revolver licence - and I ended up not buying one because I could not imagine what I would do with a revolver and 20 rounds sitting in a cupboard at home. After I became a rifle association member - which occurred over a decade later I realized that I was not free to plink as I wanted and I was shooting with smart young men and women who were serious competitive shooters, meaning that rifle shooting was in the prone position - a position that I personally dislike.

In short - unless you live in the US or have a huge estate where you can shoot and a way of accounting to his Highness the Government of India for the bullets you use up - the value of a fiream for a dedicated casual shooter in India is limited in my personal opinion. For rifles a range of at least 50 meters is needed and I would personally love to shoot at ranges longer than that. This is unavailable to all but the most privileged people in India. Since I love shooting as a hobby and I shoot every single day of my life - I decided that I would settle for air rifles for the sport - because I have access to a safe shooting area of up to 25 meters at home. I realize that even in this department I have been lucky.

[brihacharan]

I am not a target shooter I would just like to own, a gun for casual use, with max range and accuracy.

Regards

This was my original intention in life after I returned to India - and it was in the days before the local shooting range was operational. I wanted a rifle licence but they gave me a revolver licence - and I ended up not buying one because I could not imagine what I would do with a revolver and 20 rounds sitting in a cupboard at home. After I became a rifle association member - which occurred over a decade later I realized that I was not free to plink as I wanted and I was shooting with smart young men and women who were serious competitive shooters, meaning that rifle shooting was in the prone position - a position that I personally dislike.

In short - unless you live in the US or have a huge estate where you can shoot and a way of accounting to his Highness the Government of India for the bullets you use up - the value of a fiream for a dedicated casual shooter in India is limited in my personal opinion. For rifles a range of at least 50 meters is needed and I would personally love to shoot at ranges longer than that. This is unavailable to all but the most privileged people in India. Since I love shooting as a hobby and I shoot every single day of my life - I decided that I would settle for air rifles for the sport - because I have access to a safe shooting area of up to 25 meters at home. I realize that even in this department I have been lucky.

> Lights, Camera, Action....That's the story of our lives

Briha