Well, my quest for the ultimate truck and saddle bolt gun has brought me to two Rugers, the .308 Ruger Scout (18.7" model) and the Ruger Guide gun in .30-06.
There are things I like about both rifles. For instance, the Scout already has a peep sight and it's somewhat shorter and lighter; but, I prefer the Guide Gun's hinged floorplate and it doesn't have a ridiculous rail on the barrel that will leave empty screw holes when I take it off.
But one thing I don't know is how either of these cartridges perform from these barrels lengths. So, can anyone tell me how the muzzle blast of a .30-06 from a 20" barrel compares to a .308 from an 18" barrel?
Also, and I know I'm splitting hairs here, but does anyone have an idea about the velocity differences these two setups would show using factory ammunition?

18.7" barrel will be LOUD!

20" isn't all that bad for noise to me.

Anything less seems to be exponentially more annoying.

Wyoming262,

I have a super-accurate 20" barreled T/C Venture in .308. The Black Hills Match 175-grain BTHP load chronographs around 40-50 fps slower than in a couple of rifles with 22" barrels, which fits right in the with general rule of 25 fps/inch. Have killed several deer with the T/C and never noticed it being all that loud, but never tried an 18" barreled .308.

About 20 years ago had a custom .30-06 a military FN 98 Mauser action with a 20" barrel. It got just under 2900 fps with the 165-grain Ballistic and 58.5 grains of IMR4350, which is very close to the same velocity from the same load in several 22" barreled .30-06's. It also didn't seem all that much louder than 22" barreled .30-06's.

Years ago I bought a 19 inch 25-06 and my buddy tried to outdo me by ordering an identical rifle in 300 Win Mag.
They were both loud but he said after sighting his in he would put it away. It was to obnoxious to practice with.
I shot prairie dogs with some guys and they complained every time I fired.
whelennut

I have an 18" Ruger Predator in 308, have had a 20" Winchester carbine in 30-06. My brother had one of the 20" tang safety Rugers in 30-06.

Concerns over lost speed and noise are greatly exaggerated.

No the noise is not greatly exaggerated, I can certainly tell that the shorter barrel and higher exit pressure is louder. Considerably so.

you'll want ear protection even when hunting. i have both in 18" they're not bad otherwise.

I know I'm the uneducated one here asking the question, but I wonder just how much of the noise of short barrels depends on powders and loads. I've heard of people getting their Remington 7400 .30-06 carbines pretty quite with intelligent loading.

Jwp475, as long as somebody is telling the truth, you got no business discointing their own personal experiences; I'd expect every adult to know that. But then, I'd expect that quote in your signature line to make you feel pretty stupid by now too, so who knows.

You should go even shorter

The Rem 660, in 308 is not bad. The Model 7 18" 243 is loud.

My 760 carbine with 18 1/2 inch barrel in 30-06 is bearable to me for a shot or 2 at deer, but when sighting in or just shooting it I like ear protection.

Never had anyone else complain about it but I never shot in close proximity to anyone either.

I used to hunt in a swamp with my brother on a hill in a stand about 600-800 yards or so away from me, with other hunters sort of around my general vicinity. My brother said he could always tell when I shot a deer because the other rifles cracked, and mine was a loud boom.

Last weekend I was shooting a batch of a mild 308 target load (LC brass, 39.5 gr IMR3031, 168 Amax) through three rifles with 26", 24" and 20" barrels. Even with that easy going load and hearing protection, the blast from the 20" barrel clearly had more pop. It wasn't obnoxious, but it was noticeable.

Say it's not so!

I had a Rem Mohawk 600 in .243 that had an 18" barrel, and my daughter always said at the range that it was really loud, even from several tables down.

Now, I ALWAYS wear hearing protection, but I can say that the new 20" barrel I put on it in 7mm-08 is definitely more comfortable to shoot, sound-wise.

Well, I've owned .308s with 16.5, 18.5, 20, 22, and 24" barrels.

The general trend was that the shorter the barrel, the louder the muzzle blast...

To me all centerfires are loud. Some are just louder than others.

Remember a buddy who bought a .222 Remington when I was 20. This was back when hearing protection was just starting to be acceptable (not mandatory) for a lot of he-men, and I'd been reading for years about how part of the reason the .222 was such a good varmint round was it's "mild muzzle blast." So I didn't use any hearing protection when we took it out to shoot the first time. It was LOUD!

I'd expect that quote in bold to make you feel pretty stupid

New a guy who picked up a Sako Mannlicher carbine in 375H&H for cheap back in the 90s, sold it for cheap also.

Jwp475, JRM40 did not say that short barrels are not louder, he said that the expectation of their noise and loss of velocity tend to be greater than they actually are. He seemed to have the experience with these particular cartridges in these particular barrel lengths to back up his claim, but you dismissed his personal experiences outright. That's what I took exception to. Again, he didn't say they weren't louder, he said the noise isn't anything to fear.

As for the quote at the bottom of each of your comments, it is in support of Obama, is it not? If I have missed the underlaying meaning, than mea culpa, I am the stupid one.

You are misunderstanding, JWP is quoting JeffO to remind us all of what a moron he (JeffO) is.

Than I apologize. And I repeat the last sentence of my last comment.

I've had 30-06's with 18.5, 21, 22, 23 and 24"... my preference would be to go no shorter than 21".

I've had 308's with 18.5, 19, 20, 22 and 24"... my preference would be to go no shorter than 20."

I have had several model 7s in several calibers with the 20" barrels and none were as loud as any high power rifle with a muzzle brake.I had a 270 with a 26" barrel and a Vias muzzle brake and every time I shot it at the public range, I got dirty looks from guys wearing ear protection.

Back many years ago I had an old 1903 Springfield somebody had bubba'd. The area I hunted was thick so I cut the barrel down to 20". It was load Years later I got a Remington 660 in .308. Reloads with H335 were viciously loud, and the blast almost concussive in nature. I blame that on that powder. Later loads with one of yhr 4895's was nowhere as near nasty. My current .308 is a Ruger M77 RSI with 18.5" barrel. I don't see much difference on loudness between it and the 20"M660. Probably taker a decibel meter to tell. All your choices will be on the louder side which is why these days when I hunt or go to the range I use hearing protection. I use the kind you can turn on or off. Lost 95% of my hearing in the high frequency range due to too many years shooting without protection. Back than we though cotton balls would do the job . They didn't.
Paul B.

Reminds me of back when in high school. 1972-ish? My compadre traded a Rem. 700 in .243 for an new Model 70 Mannlicher stock, in 30/06 that our local hdwe store got in stock! I think it had an 18" bbl. And quite a bark when fired.

............Your personal preference between the two above Rugers will depend on which one has more quirks that you like.

As far as velocity loss from shorter barrels is concerned, this link will offer you some insight. The 7/08 was the test cartridge using the Ruger Frontier but other Frontier chamberings still apply. Scroll down to the "short barrel long reach" heading.

www.shootingtimes.com/long-guns/longgun_reviews_scout_102606/

Now if 95.5% velocity retention can be gotten from a 16.5" barrel vs a 24" tube (same cartridge and load), then you can figure that your % of loss from either the 20" or the 18.7" lengths is going to be less.

As an estimate, deduct about 2 to 2.5% for the 20" '06 vs a 24" barreled 30-06 and deduct about 3 to 3.5% for the shorter tubed 308 vs a 24" 308. EITHER one in the ballistics dept, would make an excellent performer. Splitting hairs? Kinda.

As to muzzle blast and or noise. Opinions can and do vary 180 degrees. Imo, added noise and blast is somewhat more exaggerated than not. But everyone's tolerances levels are different. So what might be ok for some may not be ok for others. Either way and regardless of what the barrel length and cartridge is, hearing protection should always be worn when firing.

I'll wager that in most cases (not all) of shorter barreled noise complaints, hearing protection was not used.

My long barreled with brake 338-378 Bee Accumark (a scatters 'em at the range rifle), is louder than my 16.5" tubed 300 WSM Ruger Frontier. My 375 Ruger Alaskan falls about in the middle where noise levels are concerned.

Didn't you post that you were deaf? Oh no, you posted that you were dead, not deaf.

Exactly! Some apparently have a problem comprehending what they read.

Facts are pesky little things, the higher the exit pressure the louder the report. Shorter barrels have higher exit pressure and are louder, that is a fact. Muzzle blast is increased as wel another fact. Some feel this is a good trade off for a shorter barrel and overall length.

Sweet Jesus, shorter barrels are loader, water is wet and women lie.

This stuff ain't rocket science. I've been a HELL of a lot more bothered by the 'cumbersome' 24" tubes than I have by a slightly louder 20" tube.

They are tools, pick what works best for your situation and move forward. Who gives a [bleep] about a little extra noise. It's not like you're going from Tony Bennett album to a Megadeth concert.

It's the time of year to agonize over this stuff.

So True

I completely agree with this recommendation.

Double ear protection can easily handle the extra noise level of very short barrels, but it does not eliminate the extra high-pressure, muzzle blast/shock wave.

A M-600 308 with its 18.5" barrel I once owned would give me a headache within 20 rounds or so, just from the shock-wave hitting my face and head.
The fireball when shooting at dusk was fun, though.

I have one, and don't find it as objectionable as my 22" 280. The 375 is more of a Boom, the 280 more of a sharp crack. My 338 (23") is even louder than the 375.

Yeah, my guess is the guy who sold it didn't like the recoil.

A good friend of mine has had a Sako .375 carbine for many years, and used it plenty in both North America and Africa.

A well balanced 20 or 21 inch, 7 odd lbs all up 308 goes a long way in my book.

Kaywoodie, I have one of those Model 70 Mannlicher .30-06's with the 18" barrel. I guess it is pretty loud, but the thing that strikes me - pun intended - is that the darn thing seems to "kick" harder than my 24" barreled Model 70 in .300 Win Mag! The short .30-06 shoots pretty good, though, and seems to group tighter at 200 yards than at 100 when sighting in on a range.

Interesting. My dad always used a .30-06 pump carbine and I never recall being able totell his shots from anyone elses. I always hoped that gun would be mine someday but then the Police killed his brother and my mom died of cancer and my dad is no longer himself. I don't know who the hell he is to be honest and he no longer acknowledges my existence. I do hope he still has that Remington carbine though. It reminds me of when he was still himself.

Here's a .308 20":

Initial Zero by Rick Mulhern, on Flickr