Thread: Short barrel calibres?

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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