.308 Velocity at different barrel lengths

[BattleRifleG3]

I've been wanting to set up a scout rifle.  Well, a quasi-scout rifle.  I don't really need a detachable magazine.  Nor do I need a tiny barrel.  I'm basically thinking of a standard size bolt action just with a long eye relief scope.

One little problem - Only factory scouted bolt action out there is the Ruger M77 Frontier.  Everything about it is acceptable to be, except for one little problem - 16" barrel.

I could come to accept such a thing if I were sure it didn't hurt ballistics or increase muzzle flash all that much.  So what can you folks say about the differences in ballistics and muzzle flash for a 16" barreled 308 compared to an 18", 20", and 22"?

I've read that there's a big difference between 16" and 18", but that the difference is less up with the longer barrels.  That a 308 out of a 16" barrel has the velocity of a 7.62x39mm.  Anyone chrony the same load in different length or know where to find such research?

[Val]

I bought a Swiss K31 Milsurp rifle (extremely accurate rifles) and installed a no drill and tap scout scope mount. I purchased an inexpensive NC Star 2X7 scope. This rifle yields 3 shot groups right at .5". If you go this route it helps a lot to reload since the ammo for this rifle is pretty expensive and hard to find. This set up will cost you less than $200.

[jro45]

I had a different barrel put on my 30/06 and it was 2" longer and that gave me 50 fps faster per inch. It might be different with a different rifle.

[BattleRifleG3]

FPS per inch depends on where those inches are.  They matter less and less each inch you go out the barrel.

My real question was on how the 16", 18", 20", and 22" barrels compare, as all are under my consideration here.

[Slamfire]

I'd guess 25 to 35 fps per inch. That means maybe 25 yards less range with the 16" barrel as compared to the 22". The game won't care, but your ears might. Get a pair of shooters hearing enhancers with a loud noise cut off on the amplification.  

[sgtt]

Doesn't Savage have something out now?  I don't know the barrel length though.

[Lone Star]

How about some facts to answer the OP's question:

From G&A 7/89
Load......22".....21".....20"......19"....18.5"
150FL...2674...2636..2617....2595...2598

From G&A 9/87, handload with IMR4320
Load......24"......22".....20".....18".....16"
180HL..2700...2660...2620...2550...2480

From Nosler 5th Edition Manual
Load.............................24"......14"
150/48.0/IMR4064......2920....2730

.

[nomosendero]

Lone Star

This is good info, thanks. This info, & other data that I have seen shows
that you give up very little by going to a 20" barrel & this is a personal
thing, but I like the way the 20" is balanced. This shows the practicallity
of the Rem. Light Tactical concept or the Savage 20" Tactical Type Rifle.
And you could go to the range & stay competitive out to 600 or so I
think with a rifle that is not too heavy to hunt with. This is one of the good
things about a 308.

[cal sibley]

The general rule of thumb is to add 50fps for each inch you add, and subtract 50fps for each inch you subtract.  That's not exact, but it's pretty close.  I would think shortening the barrel down around 16" would increase the sound by quite a bit, and cause the barrel to spit a rather long flame out the front end.  Best wishes.

Cal - Montreal

[BattleRifleG3]

Yeah, that's what I'm trying to avoid.  Too bad Ruger doesn't make their frontier rifles with longer barrels.

[nomosendero]

Yes, I think the blast would be there with a 16-18" tube, yet another reason I like the 20", especially with stout loads.

[AZ223]

I had an old Remington semiauto in .30-06 with an 18" barrel, and man, was it LOUD!!! Used to drive people away at the range. I'd go for the 20" for that reason alone; the 700 LTR and TR at the link both look nice.

[7x57mm]

BattleField: If you are looking for a sweet rig, take a gander at the CZ 550 full stock. My bro has one of these in 7x57mm and it is one honey of a rifle that is sub MOA with 160 grain Nosler Partititions. The barrel is 20.5 inches long. You can get an idea what it looks like by going to the GunBroker.com website and in the search engine, type in CZ 550. When the pages of the CZs come up, scroll down until you see the full stock model. It will have a photo of the CZ 550 full stock. This may be wall off base from what you want, but what the heck, it is worth a look. Tom Purdom

[BattleRifleG3]

I'm looking at a lot of things.  Particularly, my girlfriend hates standard eye relief scopes due to proximity to her eye.  He has yet not to be bitten by one.  When she fired my 300 Ultra Mag, I had her point and shoot.  Now I on the other hand suck with open sites.  So a scout rifle is a neat way to get the best of both worlds.  But dog gonnet I want maximum ballistics and minimized noise.  My ideal scout concept differs from Cooper's in that I'm basically just thinking of a standard bolt action with an extended eye relief scope and backup iron sites.  Everything else I just want basic synthetic bolt gun.  My girlfriend also really likes Mausers, and the Ruger action is one of the closest comparisons.

[BattleRifleG3]

I may end up going such a route rebarreling a Mauser of some variety in 308.  8mm's great but hard to find in non-corrosive form.  I'm not averse to barrel cleaning, but it kind of stinks if you only shoot a few rounds that day.

Far as barrel length goes, I'm from the old school.  I have a shortened pattern Brown Bess Dragoon Carbine.  It has a 30" barrel, and they call it a carbine.  The 20" barreled SKS was called a carbine too.  The 98 Mauser was called a K model when they shortened it to 22".  I have no problem at all considering a 20-22" barreled rifle handily sized.

[Ramrod]

I'm not a big fan of the Scout Rifle concept, but I think you are selling the Mauser action short, pun intended, when you go to a .308 length round. On other forums, I see post after post whining about how all the great rounds based on the 7 or 8 mm x57 case don't work well with a "short action", but have all these advantages if you could just seat the bullets out a litlle further. Not many posters are old enough to say hey, wait a minute, there is an in between action length that was actually designed for these rounds, and has been in production since 1898! And guess what, it has one of Cooper's original criteria, it can be loaded from a stripper clip!

[Squeeze]

On the topic of muzzle velocity, in short barrels, I have a Savage
Striker, in .308 Win, with a 14" barrel, that doesn't have a
muzzle break, so it is a true 14" barrel.  Measured velocity,
for my 130 gr. Barnes XBT load, driven with a near max charge
of W748, is 2775 fps average.  If you want to shoot short barrels,
load with fast powders.  This load is sub MOA accurate, and
literally turns northern whitetail vitals to jello.  It gives new
meaning to DRT.  Yes there is significant muzzle blast, but
in hunting situations, I never notice it, and the deer aren't
around long, to complain about it.  I have my own range, so
I don't get complaints, from fellow shooters.   I wouldn't
be concerned about a 16" scout rifle, having decent MV,
given what I have learned through my Striker experience.
Just get fast powder hand loads, and lighter weight stoutly
constructed bullets, and you will be pleasantly surprised
at the effectiveness of this combo.

Squeeze