.308 vs .30-06 for 20" Barrel?

S

Stick Man

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Today I've been thinking about giving my Winchester Featherweight Compact in .308 (which, for those who saw my question about the VX-2 1-4, I've decided to just keep it's 2-7 Vortex Viper on it rather than replacing it with a lighter, less powerful 1-4 scope) to my considerably younger sister as I'll finally admit that I prefer a bit more LOP (I know that problem can be solved with slip on recoil pads or plastic spacers, but on blue and walnut M70, that just wouldn't look right) and because I want her to be happy.
This got me thinking about what I would replace my trusty carbine with. I thought maybe a rugged, reasonably cheap, and surprisingly light Ruger Hawkeye Standard (only has a half inch more LOP that the Compact 70, but when I replace the silly, thin, red pad from the factory with an appropriately thicker pad everything will be just about perfect) might just be the ticket once I have the barrel sawed down to 20". But if I go with a Hawkeye, I'll have a choice I didn't have with the Featherweight: 30-06 or .308.
For normal rifle I'd always go with the .30-06 when given the choice, but short barrels make things more confusing. I understand that the .308 is better suited to shorter barrels and while I can find velocity charts for the .308 out of a 20 inch tube, I can't for the 06.
Any personal reports/chronograph results from an 06 of of a 20 inch tube? I've been told that it loses enough to make the velocity differences between it and a .308 out the same length barrel meaningless. I don't necessarily believe that, but would like to hear some real world reports.
The other concern is blast. I'm well acquainted with the blast of a .308 out of a 20" (and it isn't bad) but my 06s all wear longer tubes. Basically I just want to hear how bad you think it is, a personal comparison between the two is even better.
If I decide that I prefer the 30-06, I might splurge and get a M70 Sporter and saw some barrel off of that.
Thanks for any comments.
 
Personally, if I were going with the shorter barrel already as a carbine then I've already except some loss of ballistics and I'd be going with the .308 for less recoil, shorter action and ammo variety.

When you say you might saw some barrel off the M70, I hope that's code for cut it down and having it faced off, trued, and crowned on a lathe by a competent machinist (including yourself if you are one)
 
"When you say you might saw some barrel off the M70, I hope that's code for cut it down and having it faced off, trued, and crowned on a lathe by a competent machinist"

Yep.
 
I've had both, with 22" and 20" barrels. It is impossible to predict how much faster or slower one will shoot when comparing 2 different guns, especially from 2 different manufacturers.

When you take a rifle barrel with a known velocity and cut it shorter expect a 308 to lose 10-20 fps for every inch you cut it shorter. Expect a 30-06 to lose 20-30 fps for every inch you cut it. In theory you'll lose about 20-30 fps more from the 30-06. But since a 30-06 starts with 100-200 fps more speed it will still be faster. It will also be a lot louder.

But when comparing two different rifles all bets are off. It is quite common to see 25-50 fps difference in speed between 2 barrels of equal length and I've personally seen over 100 fps once. I have three 30-06 rifles with 22" barrels. With the same loads the fastest is consistently 60-90 fps faster than the slowest gun. The heavier the bullets, the greater the difference. The other rifle is always 15-25 fps slower than the other, not enough to matter.

With that in mind you could actually see an individual 20" gun shoot slightly faster than another 22" gun. Or it would be possible to see the 22" gun 150 fps faster. The difference in individual barrels is often greater than the difference 2" of barrel makes.

All things considered I'd choose a 308 if I wanted a 20" barrel. That is primarily because of noise, not bullet speed. But if maintaining more speed, is important then 30-06 will still be faster. The noise from a 20" 30-06 is there, I certainly wouldn't go any shorter. On a 308 about 18" is as short as I'd go.
 
As near as I can tell from years of reading about the comparison between the .308 and the '06 from short barrels (plus some shooting I've done), it APPEARS
that for factory ammo of 150 or 165 grains, they are pretty much equal. I'm guessing, within 100 ft/sec.

Purely in the FWIW department: For some forty years, my father's '06 handload for deer hunting used the old Hornady 150-grain spirepoint. The powder charge replicated the GI M2 Ball load. Muzzle velocity around 2,700 ft/sec.

Per witnesses to three different kills, that load was plenty good for Bambi out to 500 yards.
 
"...I can't for the 06..." Likely due to the receiver length. Just a WHAG though. Either way, a 20" barrel will give you about the same ballistic results as any length. About 100 fps difference with like bullet weights. A .308 will be short receiver, a .30-06 a long receiver though. Still have a big muzzle blast and flash at dawn and dusk out of a 20''.
"...can be solved with..." Doesn't have to be a slip on or spacers(that don't have to be plastic or white). How much more LOP do you need? Most screw on pads add an inch.
Plan 'B' might be a custom LOP on a stock from Boyd's. Won't empty your 401K either.
 
I have a 20" .308 and seriously doubt a 30/06 would show much improvement in velocity. The .308 already blows a lot of fire and gas and the 06 would be worse (due to more powder) w/o making much more speed.
 
I've got both - 308 and 30-06 w/20" barrels.
Both lose about the same velocity from longer barrels.
the 06 is still about 100+ fps faster w/ same bullet wt.
Both are loud!
 
That is correct about 150-165 grain bullets shooting at approximately the same velocity from .308 or 30-06. The 30-06 will have an edge, but not enough to worry about.

It is with the heavier bullets 180 and up where the 30-06 does significantly better.
 
I really really like the .30-06 in a 22" barrel, but if it had to be a 20"er, I would definitely go .308. If you are indeed going with a .308 short barrel, consider a 17.25"-18" threaded barrel with a flash hider.

If you want a short barrel, go all the way short or stick to about 22".

20" has zero benefit over ~18" and the extra two inches makes a big difference in the brush (in the bush too).
 
"20" has zero benefit over ~18"

I have looked into it to be sure. - It turns out that the laws of physics have still not been repealed.

More barrel still means more velocity, less blast.

Unless you are trying to scare the deer to death with loud noise, the 20" barrel will still be more effective by giving you more velocity than an 18" barrel.

The difference is not Earth-shaking but is it "zero difference"? - Nope.
 
Can't say much on the 30-06 with shorter barrels other that back in the 1950's I had a 1903A3 Springfield that was bubba'd when I got it. Was hunting northwest California rain forest at the time so cut the barrel to about 18.5" as I recall. Very loud.
One short barreled .308s, My old Remington 660 that I bought back in 1973 with 20" barrel took a 200 plus pound Mule Deer at 426 paces using a top load of H35 and the 150 gr. Sierra Pro-hunter. I have no idea of what the velocity might have been but the deer had been wounded by my hunting partner and running like hell. Took the shot and the deer dropped.
My other short barreled .308 is a Ruger M77RSI, the one with the Mannlicher style stock and 18.5" barrel. Longest shot I've had with it is a Mule Deer at 250 yards laser measured. Weird story as the gun is a one trick pony that took two years of load development to find one that would work. I got into it cheap as the guy that owned couldn't get it to shoot. I figured if I could find a load that would do 1.50" consistently, that would be good enough. I found the load but it's a tad slow, 2550 FPS using W760 powder and the 165 gr. Speer Hot Core. Change to a different 165 gr. bullet and groups become patterns. I've taken deer with that one at ranges from about 35 feet to the 250 yards mentioned and all were one shot kills. FWIW, that RSI is probably my favorite deer rifle.
Paul B.
 
i have used rem 760-7600 pump 3006 carbines(18.5") for over 50 years and have developed loads for the 165gr nosler BT at 2650 fps. i never had a deer complain(over 60 with those carbines) and they will shoot into three shot 1-1.5 at 100yds from a bench.it may be nice to shoot bug holes, but for deer out to 250 yrds or as close as 20 feet in thick brush i,ll take my carbines. eastbank.
 
I personally see no point in going shorter than 22" for '06, and anything above '06 should be at least 24" or more. People sometimes use even 14" for .308 in tactical rifles, but by that point, you've got an almost neutered yet VERY loud and flashy .308. Your barrel length should absolutely be matched to caliber.
 
I believe that FairWarning has the right idea, here.

If a really short, handy rifle is a must, then I would look at either a bullpup, or a single-shot design.

I once owned a Winchester 1885 single-shot in 270WSM that came with a 28" tapered octagon barrel. After reducing the barrel to 24", it was a lot handier but still allowed the WSM cartridge to develop its potential.

1885-24_zps18d11c9b.jpg
 
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