Reloading data for short barrel 308 winchester?

[Goshawk]

Has anyone got suggestions on reloading 150gr projectiles in 308 winchester with a short 16.5 inch barrel?
All the reloading data I have got is for 24" barrels. Seems to be a pretty big debate on SkyNet (internet ) about using fast powders for short barrels. Anyone got experience I can lean on here? I will either use Adi powders or Winchester powders.
Cheers

[Gwion]

I have a 17" barrel on my 223. Ok, not a 308, but...

Got a friend to run numbers in QuickLoad with different powders when i shortened it because i wondered if i would need a faster powder than BM2. The program said i would get about 98% burn from my 25.2gn charge in my 17.5" barrel.

Obviously the 308 uses a heap more powder. I'd be looking more at the faster stuff for a complete burn. Say 2206 or even BM8208 or you will just be blowing unburnt powder down range.

[Chronos]

I'd say try your existing loads if you have some then one step faster on the burn rate chart. There was an article on short barrel velocity recently that said in the cartridge tested losses averaged around 14fps/inch

The small difference might see you pick up a few fps if you're worried about velocity.

At the very least it'll make for some cool night photos

Chronos.

[Goshawk]

Thanks for the info . I have load data for 2206 and 2206H. I think the 2206 is faster burning?
Gwion, you like your 17" barrel ?

[Gwion]

Hey Goshawk.

Yeah, i like my short barrel. It points and handles very nicely and is extremely stiff (being a varmint weight short). It's probably lost about 200fps/ish with about 6.5" cut off it from 24". My best load averages under 0.5" at 100m. Pretty good for me. I can even keep it in or near the bull out to 500yd if there isn't to much wind for me to guess about. This is with 223 and 50gn bullets, so accuracy of the shorty isn't a problem.

Below are some links i found interesting when i did the deed and lopped the barrel. They helped me understand what was going to happen.
Give them all a read and it might help you figure out where you will be with velocity etc.

From what i understand, the biggest issue with a shorter barrel is that, all other things being equal, there is less time for internal ballistics to develop; maybe that's the wrong term but basically less length means less room for the powder to burn and develop velocity. So, using a slower powder that would give you a velocity gain in a standard (24") or long barrel (28"+) barrel actually works against you because the bullet leaves the barrel before all the powder is burnt and gases fully expanded (which is what drives your bullet out the end quicker in the long barrel).
The other disadvantages of this are muzzle flash (not good in the hot dry) and simple economics of wasted powder and possibly more powder fouling at the muzzle end. With a faster burn rate you will get the most out of the powder you use and reduce muzzle flash (burning powder exiting barrel).

So, you don't 'need' to use a faster powder but you may get a little more velocity from your charge and wont waste as much powder if you do up the burn rate.

Again, i'm no expert (one link below even kinda contradicts aspects of my basic understanding); least of all on loading for 308, as i only load for the 223 and am about to start loading for 7mm08. I am only passing on my understanding of the principles. The links below are to help you get your head around it for yourself.

Cheers and good luck with your shorty 308win.

308 studied by the inch of barrel length:
http://rifleshooter.com/2014/12/308-win ... 8-to-16-5/
Other cartridges treated the same by the same guys:
http://rifleshooter.com/barrel-length-and-velocity/

Similar experiment with 308win by different dudes- good graphic aids at the bottom:
http://www.thetruthaboutguns.com/2013/1 ... -accuracy/
Article on what to expect from a shorter barrel and "is it worth it?":
http://www.guns.com/2012/02/16/the-myth ... city-loss/

[handofcod]

I'm using 42gr of 8208 in my 18.5" scout with 168gr pills. Don't have a chrony so can't tell you how fast but I can tell you it was definitely the most accurate load for the rifle compared to 44gr of 2208.

Quickload thinks it's going 2570fps compared to 2700fps from a 24" barrel if that tells you anything. 44gr of 2208 was only 15fps faster than 42gr of 8208 interestingly. Would love to test this in the real world.

[Hercl]

Thanks for the info . I have load data for 2206 and 2206H. I think the 2206 is faster burning?

It is. Assuming you end up using 2206, 2206H or 2208 as they're the most common .308 Win powders, burn rates are...

2206 - Faster
2206H - Moderate
2208 - Slower

As for the reloading, I hesitate to give the usual unhelpful answer (which you already know) but here it is... You need to try and see what works

The muzzle velocities quoted along with load data are really only for informational purposes, you'll get less than the stated velocity with your shorter barrel but that isn't really going to change anything as far as development goes.

The shorter barrel obviously doesn't change anything on the chamber end. Initial chamber pressure etc. are the same, the same powders and loads that are safe in a longer barrel rifle are safe in a shorter barrel rifle. Finding an accurate load will come down to tuning it to the rifle as usual.

As already covered a shorter barrel rifle will have a lower muzzle velocity as it may/will not be able to completely burn all powder before the bullet exits. As you know though velocity itself does not equal accuracy so it's not not necessarily something to worry about or avoid.

Something like 2206 may give you a little extra velocity, but that's no reason not to try something like 2208. It may be more accurate while having insignificantly lower velocity.

Try and see (unhelpful spiel finished )

[Boatman]

Burning rates available here for you Goshawk.

http://www.adi-powders.com.au/handloade ... _rates.asp

[headspace]

Mine has a 22 inch barrel and 45.5gn of 2208 with a 165gn Interlock gives me 2,750fps. A faster powder will have a better chance of burning more before the bullet exits the barrel. There's always going to be some sort of trade off in terms of velocity. As long as accuracy doesn't suffer.
JD

[Yelp]

There's always going to be some sort of trade off in terms of velocity. As long as accuracy doesn't suffer.

I'd say the same but for some reason some folk are obsessed with velocity

[Ken]

I'd say the same but for some reason some folk are obsessed with velocity

Anyone with a .243.

Just has to get 4,000 fps out of it

[Fujix]

Same data, just estimate 250-300 fps less at the muzzle.