Thread: Short barrel calibres?

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Originally Posted by gundoc

Most small to medium capacity cartridges in the .223 - .308 range will be acceptable in shorter barrels within reason. Velocities can be kept up by the correct use of faster powders and light to medium bullet weights. While large capacity cartridges can be used, they are not efficient in short barrels and will produce a ball of flame at the muzzle when fired in fading light. Powder is too expensive to use to raise global warming!

Hi @gundoc
What is correct use of faster powders ?
Wouldnt the same loads still be better than traditional ones in standard length barrels ?
Can you avoid the ball of flame with a different powder or is it just the amount of powder ?

Indeed are short barrel optimised loads dangerous in standard length barrels ?

powders are on a spectrum of speed of burn

shorter barrel velocity can improve with a faster burn where as with a longer barrel velocity/case pressures are often better with a slow push of a slower powder

slow powders in short barrels spit flames

The correct load data is in the books. The powders shown for a specific bullet weight are ranked fastest at the top to slowest at the bottom. Faster powders burn within the barrel while slower powders require full barrel length to burn completely, hence the ball of flame in short barrels. Faster powder loads that are safe in short barrels are perfectly safe in long barrels. The difference in velocity between short (18") and long (24") barrels is usually about 200-250 feet per second which really doesn't matter much inside of 300 metres. 16" barrels will lose another 100 fps, and barrels longer than 24" are for heavier bullets with a slow powder to develop good speed for long range shooting. Barrel length has no effect on accuracy subject to finding a good performing load.

Originally Posted by Bagheera

Indeed are short barrel optimised loads dangerous in standard length barrels ?

Not related to barrel length, but if you are firing the load in a longer barrel you are obviously using a different rifle, so yes, the load could potentially be dangerous

Thanks for that gundoc.
So for a short barrel you want a fast powder ?
That would limit you to light for calibre bullets wouldnt it ?
I suppose that to get enough lead a bigger calibre is better ? Eg a 120gr 308 rather than a 120gr 260 ?

Now, is a short case just as good as a long case ? Eg comparing 30-30 308 and3006. Would the extra powder in the 3006 all be wasted in flame or would the ‘06 pig have a worthwhile edge over the 30-30 ?

I think what GUNDOC means is this.

your load data dose not change with a short or long barrel.
However a short barrel with a heavy(for calibre) bullet will loose a lot more performance than a light bullet with a faster powder.

The heavy bullet will still be accelerating all the way down the longer barrel so a short barrel here will give a big flash of burning powder and larger loss of velocity.
a Light bullet with a faster powder will accelerate quicker and will have a much more complete powder burn in the short barrel so less loss of velocity with barrel length.

Also a lighter faster bullet will shoot flatter and generally give better terminal performance. (at Shorter ranges)
Z

Originally Posted by ZQLewis

I think what GUNDOC means is this.

your load data dose not change with a short or long barrel.
However a short barrel with a heavy(for calibre) bullet will loose a lot more performance than a light bullet with a faster powder.

The heavy bullet will still be accelerating all the way down the longer barrel so a short barrel here will give a big flash of burning powder and larger loss of velocity.
a Light bullet with a faster powder will accelerate quicker and will have a much more complete powder burn in the short barrel so less loss of velocity with barrel length.

Also a lighter faster bullet will shoot flatter and generally give better terminal performance. (at Shorter ranges)
Z

Partially, there is also the powder factor with the same bullet weight.

Let’s use a 150gr .308 for instance.
Let’s say you have a load developed for a 24” barrel with a slow powder to maximise burn in the long barrel.
When used in a 16” barrel you will lose a lot of speed and have a huge muzzle flash as a lot of the powder will be exiting the barrel unburned.

By switching to a faster powder, with a lower load still within safe specs, you can gain some of that loss back as you will be burning more of it in the barrel.
Thus you will have the fastest, most efficient load for a 16” barrel, but not a 24”.

The faster powder will never be as fast as the tailored load in the 24” barrel, but will be faster in the 16” barrel as it is more efficient use of energy in the place that matters, which is in the barrel driving the bullet.

Hope that makes sense!


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