What powder for a 16" .308 barrel?


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1911JMB
December 9, 2006, 04:45 PM
I recently got into reloading with a Classic Lee Loader. Yes its slow, but I'm poor and it works. I know very little about different powders and things, but I do know that handgun powders burn faster, and that factory loaded powders in .308 ammo are typically slower burning powders designed for 20-24 inch barrels.

So I want to know, for optimum performance with my 16" barrel, what powder should I use?

By the way, I know I should get a reloading manual, but at this point in time all I really want to do is make one .308 load and leave it at that.

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Jim Watson
December 9, 2006, 05:16 PM
Your Classic Lee loader should have come with a leaflet of instructions and a few safe loads that its dipper would deliver. Use one of them.
Trying to fine tune loads for a particular barrel length is pretty much a waste of time. Especially if you are not equipped to weigh power charges.

Zak Smith
December 9, 2006, 05:26 PM
If optimum performance means max velocity, you'll still want those slow burning powders, you'll just get a bigger fireball in return.

1911JMB
December 9, 2006, 05:27 PM
Jim, I could easily get a set of dippers, and I could also get a scale.

I loaded up and shot some 150 grain FMJ's with IMR4831. Worked just fine, and according to the chart they should have been going at about 2,200 FPS. I just find it very hard to believe that I couldn't get a significant performance boost from switching to a faster burning powder, and my primary thought was that a handgun powder of some sort might be good. I just don't know much about this stuff yet, and the extremely simplified chart that came with my el cheapo reloading kit isn't very educational.

Edit- So it really doesn't make a difference Zak? How can that be? I would like to understand the science of how faster burning powder would make a bigger fireball but not yield more velocity from a smaller barrel.

Zak Smith
December 9, 2006, 05:33 PM
my primary thought was that a handgun powder of some sort might be good.
No, seriously, DO NOT DO THAT.

4831 is not an appropriate powder for 308, it is WAY too slow for 99% of the loads possible in that caliber.

Look at powders like 4895, Varget, 2460, 4064, RL-12, RL-15, Winchester W748.

My personal recommendation would be to use either Varget or IMR4895, develop a decent load, and then stop.

The point I was making in my first reply was that the same load that gives max velocity in a 24" barrel will "likely" be the same load that is fastest in the short barrel, because most of the area under the time/pressure curve is when the bullet is still within the first 10 inches of travel.

-z

Zak Smith
December 9, 2006, 05:36 PM
If you are going to reload, you need to buy at least one reloading manual (I recommend Hornady) and READ IT, and get the necessary scales and equipment. There is no substitute and not being thorough and careful WILL get you blown up.

The slower-burning powder will give a larger fireball because more un-burned powder is present at the muzzle, regardless of barrel length.

Faster-burning powders "peak" in pressure very quickly and as a result hit the maximum allowed pressure without much "building up".

For maximum velocity, you want the pressure to be higher for longer, which generally means a powder that "peaks" slower, aka a slower-burning powder.

Jim Watson
December 9, 2006, 06:09 PM
You need the book(s). And a scale.
My FIRST reloading purchase was the 44th edition Lyman of 1967, bought in 1969 or 1970. I was well familiar with the literature before I ever ordered my W.H. English Pak-Tool (I looked at the Lee Loader but did not want to be beating on primers with a mallet, so I paid a little more for a leverage hand tool.) I know this is the Internet age and all that stuff, but you cannot learn to handload one question at a time.

But while we are here,

4831 is not an efficient powder for any barrel length .308.

No pistol powder is an efficient powder for any barrel length .308, even the big single shots pistols of handgun metallic silhouette. Easy to get into unsafe conditions.

I won't post a "recipe". I might get it wrong... or you might. But Zak is right, the .308 would work best in any barrel length with one of the medium burning rate RIFLE powders. I just got through loading some .308s with Accurate Arms 2520, for example. Varget is at least as good but is coarser grained than the Ball Process AA2520 and does not measure as precisely.

db_tanker
December 9, 2006, 07:06 PM
If your looking for loads for the 308 in that short of a carbine barrel, might I suggest loads that are to be used in a Thompson Center Encore? These loads are generally optimized for a 15" pistol barrel...you look in the pistol sections of some loading manuals and they will show loads for rifle cartridges that are used in a pistol length barrel.


hope this helps a little!

D

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