Main reason for docking barrels?

[I Am Hero]

What is the main reason for people taking a 24 or 26" barrel and having it chopped down to 20 or 22"? I see it all the time and I guess I have just never done my research to see why so I figured you guys could tell me. Is it weight reasons, ballistics, maneuverability or what? I was just curious since I have a 30" barrel on my .338 Lapua why someone would chop their .308 barrel down to 20" as I hear that affects your bullet drop quite a bit at long distances.

 

[bohem]

Re: Main reason for docking barrels?

All the cool kids are doing it.











For some cartridges it makes very little difference in performance in terms of MV, especially with the newer powders hitting the market in the last 10 years.

I have a 20, 21-1/8, and 26" 308 at my disposal. The difference in MV, all with premium, hand lapped, cut rifled barrels across the 6" span is about 40fps.

The guys doing it for a living are doing it for making the rifle handier. There's suppositions of improved accuracy, easier to find nodes, and some other things.

Considering that there are a couple of 1000yd BR World Record groups held by a 30" barreled Krieger I don't give a whole lot of creedence to the "more accurate" statement. Every time that I've looked into someone who's claimed that the rifle was "more accurate" I've found other mitigating factors. Barrel harmonics theory doesn't support the idea of "shorter, stiffer, & easier to load for"


But they shoot well, the performance drop for something of average "overbore" and expansion ratio (ie 223, 308, 6.5 Grendel, et al) do very well with shorter barrels.

The big factor to worry about in today's age of commonly found, high quality LRF and good ammo is generally NOT drop but rather wind drift and other "less scientific" effects that really bring the shooter into the equation. The wind drift of a 20" 338LM is affected, but affected in a manner such that the extended drop trade off for a handier rifle makes it tolerable.

If you're chasing speed records then a short barrel isn't the solution. If you want an all around, handy rifle for many different applications then a 20" 308 is pretty nice in my experience.

 

[kraigWY]

Re: Main reason for docking barrels?

I like rifles and I like pistols, personally I don't see any reason for a pistol barrel on a rifle.

Its not like I'm gonna be riding around in an infantry personal carrier, or doing building searches.

I did a lot of building searches in my time, never needed anything but a pistol (or revolver in my case).

But I doubt I'll ever have to do it again.

 

[Bevan]

Re: Main reason for docking barrels?

Personally, I don't own anything over 20", simply because I run everything suppressed and 20" with 6" of supppressor is long and unwieldy enough.

 

[kraigWY]

Re: Main reason for docking barrels?

Sorry, I didn't think about supressed when I made my post. I can deffentently see where if one was to use a supresser I can see the short barrel ideal.

 

[Beef82]

Re: Main reason for docking barrels?

Looks, maneuverability, some like to run a fat barrel but don't want the weight it entails.

There are factors other than length alone that effect velocity, like throat, rifling, bore diameter, surface, etc. As long as you're burning the majority of the powder charge in the barrel you don't gain allot of fps per inch for going longer, and can reach a point where it starts dropping. Its a matter of diminishing returns. Around 20" seems to be a good compromise for many non magnum short action rounds. Going shorter you often start to lose significant fps per inch, and gain considerable decibels and muzzle flash, unsuppressed.

Personally if conditions are so tight a 24" barrel is a hinderance I'm not interested in carrying a bolt gun. I have semi and lever action carbines and/or pistols for that. I like magnums long, if I didn't want the velocity I wouldn't be burning all that powder.

 

[Guest]

Re: Main reason for docking barrels?

With the powders available today and the use of optical sights(no need for long sight radius), there is no reason other than personal preference to have a barrel over 20" on a .308. I have had barrels out to 28" on multiple rifles and since your never going to break any velocity records with a .308, why deal with the unweildy nature of the longer tube with no appreciable gain in velocity?

On the other hand, my magnums wear longer tubes in the 24-30" range, but I am looking for max velocity...