Home Forums Hunting & Shooting Ask The Gunwriters 308 velocity in 16 1/2 inch and a 20 inch barrel

What kind of velocity can one expect in a 308 with a 16 1/2 inch or a 20 inch barrel using 130 grain bullets

Hodgdon shows a bunch of loads at 2800 or so out of a 15" test barrel.

In my experience, it depends on the barrel.

Don’t know about the velocity, but I have a fair notion of the report, more than I want…

Enuf to kill chit at most any reasonable range.

The first thing I killed with a 17" '06 , and 180 gr factory load bullets, was a ram at 330 yards. The two important things beyond bullet construction is knowing the range and the load's trajectory. Velocity is over-rated.... JMO. Still to be considered sometimes....

Others have need for a crony- I've never owned one.

I guess I don't know what I'm missing? I'm still happy.

https://matchgrademachine.com/velocity-testing-thompson-center-barrels/

maybe around 100+/-fps, muzzle velocity is different for every barrel.

It depends on the individual barrel. Some barrels are slow, some are fast, and some are "half-fast."

It also depends on the powder, primer, etc.

I would expect a 20" barrel to have 125fps additional velocity over a 16.5" barrel. tdoyka is probably the closest with right around 100 fps.

I usually experience a 200fps difference between a 16.25" and a 26" barrel 308 win. 21" would split the difference perfectly and so 20" would normally be a touch slower. Individual barrels will vary in actual performance.

18" barrel: https://www.barnesbullets.com/wp-content/uploads/2021/05/7.62x51-18.0in-Barrel.pdf

20" barrel: https://www.barnesbullets.com/wp-content/uploads/2021/05/7.62x51-20.0in-Barrel..pdf

I found that it varied with the load and can run from 25-100 fps going from a 22" barrel to a 20" barrel. In my rifle's well-worn 20" barrel, the 130-grain TTSX lost 82 fps but was still faster than anything else at 3,003 fps.


Okie John

I compared various .308 Winchester loads, including some with the 125 grain Nosler Ballistic Tip, from 16.25" and 24" barreled rifles. The short barreled 308 impressed me with both accuracy and velocity:



I think 2905 fps is worthwhile.

I've seen that little 125 grain Nosler Ballistic Tip in action on a fat whitetail buck, and it did real well at about 120 yards. The 130 gr Barnes TTSX would also be an interesting option...

Regards, Guy

16.5" barrel? Begs the question - why?

Maybe close to legal minimum to make room for the length of a can?

If you average this all out it coms to 27.375 fps per inch. This fits what I've seen with various bullets and powders across my herd of 308 chambered rifles.

My Savage hog hunter has an 18”, kills hell out of pigs at 275 yards with a 150 grain GameKing.

Yeah, I’d expect around 25-30fps per inch.

I sent off a magnum-contour 22” .308 bolt gun not long ago for a chop/thread at 17”. Makes for a very pleasant shooter with a 7” suppressor.

One of my favorite barrels is 42” long.

Is it on a 308?

One of the interesting things about this sort of conversation is that only rarely does anymore figure out how much velocity a typical 125-130 grain .30 caliber hunting bullet loses at 100 yards--or any other range.

Most hunters have been fixated on muzzle velocity ever since the appearance of smokeless powder, even thought it's made less and less difference as powders and bullets have improved....

The only way to know is to shoot the loads from a 20" barrel, cut it to 16.5" and measure the speed at 16.5". I'd expect 50-100 fps less. BUT... you can see 100 fps difference between 2 different 20" barrels. Both of them will lose 50-100 fps when cut, but since one of them may start 100 fps faster than the other it is entirely possible to find an individual 16.5" barrel that is a bit faster than another 20" barrel. OR.... an individual 16.5" barrel may well be 200 fps slower than another individual 20" barrel.

Out of an 18” BAR MK3 I’m shooting the 150 gr Lapua Mega SP at 2730’s. This has been great whitetail medicine. Not what you asked, but some info that may help. Powder selection may make a difference by going to something on the faster side. Pretty sure that one was with CFE223 or PP2000.