To boat-tail or not to boat-tail? This is a question.

H

HighGround

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Does a .308 boat-tailed bullet offer any accuracy advantages over a flat-based bullet of the same weight at 0-300yds? Also, I heard the 1/12" twists stabalize lighter(150-165g) bullets better than the 1/10's, but with the longer driving band of a flat-base, will the 1/10's stabalize the lighter flat-based bullets better than they do a boat-tail of the same weight? I've heard alot of stuff about the 1/10's won't stabalize 150-165's as good as the 1/12's. Why? is it because the bullet's shorter or because it's lighter or both? If because it's shorter, then wouldn't the more contact area(longer driving band) of the flat-base help out to properly stabalize the lighter bullets? What do you guys think? Thanks.
 
au contraire

Actually the 1:10 stabilizes 150-165gr bullets just fine. M-1 Garands with a 1:10 twist use 150 gr (ball) and 165 gr (AP) as standard loads. 1:12 on the other hand starts going unstable in the 180 gr area and doesn't do well with 165 AP because of the bullets length. 150 and up I'd prefer the 1:10 in either .308 or 30-06.

As far as boattails below 300 yds, there's no appreciable accuracy advantage.
 
I agree with riverdog. Boattail bullets do not do better than flatbased bullets of the same weight unless you are shooting at 200-300 yards or more.
 
Go to:
http://home.sprynet.com/~frfrog/miscella.htm#boat
Also check the very good balistics overview that is offered in the site.
No advantages for SBT bullet over a spitzer up to 300 yards, in trayectory or accuracy. The lenght of the bullet (not the contact area) determines the required twist, the shorter the bullet the slower the twist, so a 1 in 12" is better for spitzers, but the difference is small.
 
The best load in My old Savage 110B was a 150 grain remington bronze point, flat flat based bullet would print 3/4 to 1/2 inch groups regularly. But that was on the bench at a 100 yard target.

My new Savage 116 Likes the boat tail bullets better, specificaly sierra 165 gr. Game king spitzer boat tails. I can regularly cover 3 holes with a dime at 100 yards.

Having shot at, and killed a bunch of antelope with both rifles, I'd say the boat tails have better long range accuracy, of course it could just be I've gotten to be a better shooter over the years. Ranges have been from 15 yards to 425 yards and probably 25 or more animals (I've lost count)

That game king is the closest bullet, ballisticly to the sierra "palma match" 168gr bthp for sectional density and ballistic coefficientsif I recall correctly.. thats why we chose to load the game king.
 
Ditto the above. :)

In the FWIW department, staying "within 300 yards", for critters dressing out in the 150-pound range or less, I don't think it matters one iota whether it's flat-based or boat-tailed--or which brand. They all work. No premium bullets needed. Bigger critters and longer distances--different story.

Occasionally, for no known reason, a given rifle can be picky about which bullet it likes best. Outside of that sort of thing, I stand by "it doesn't matter".

For longer range target shooting, the boat-tails hold velocity better--this means a lower time of flight, with less wind drift. They have a more stable "re-entry" to below-sonic velocities.

Hope this drift off-thread helps...

Art
 
No difference EXCEPT............

They hold on to their velocity better and shoot flatter requiring LESS guess work about the point of impact.

I would ask why use flat base at all?

They start easier down the case when you reload too.
icon_smile.gif
 
Zorro: From some recent reading, the flat-based bullets are less likely to blow up on bone, say at the higher velocities at short ranges. At least, that seems to be the case for the Sierra 150-grain bullets. About all this means is that there may be no exit wound.

I shot my last two mule deer with the Sierra 150-grain SPBT. The first deer was hit in the lungs. He humped up, looked insulted, and started to walk off. A heart shot finished him off. Neither shot exited, but his lungs were totally jellied from the first shot. He dressed out at 125 pounds.

The second was hit in the neck at 30 yards. (The way his neck was all swelled up, I expected a 200-lb dressed weight; he weighed only 150.) The bullet didn't exit, but he didn't move from where he was lying. Needless to say, I was startled that the bullet didn't exit.

For comparison, I shot a 110-pound whitetail buck at 350 yards with a Remington 150-grain Bronze Point. It blew a 3" exit hole as it took out a rib on the off side.

I sure agree about the BTs being easier to seat. I'm taking a break from loading up some 165 & 180 Sierra BTs for some comparative accuracy shooting against some 150s, some Federal High Energy 165s and some GI stuff...

I think that around 300 yards is the "key" to differences between the flat-based and the boat-tails. Less, it doesn't matter; more, and it does.

Regards,

Art
 
Boat tailed bullets make only modest improvement in bullet drop except for the true long range work that NO hunter should take lightly. At the ranges they offer improvement there are too many variables that affect bullet flight.


The advantage is most useful at 600+ yard target work and there its major credit is drift as drop is a constant and known.
 
Within reasonable hunting range (0-300 yards), a BT bullet is more likely to shed its jacket than a flat-based one, due to its rear body taper,which lends to a loss of weight retention and over-mushrooming. This may very well cause Art's "no exit wound" situation. For a quick and clean kill, BTs are useless within 300 yds, unless your gun really loves them and nothing else. Hope this helps.
 
Thibault: "Useless" is too strong a word :), but I tend to agree with you after what I've seen and what I've read.

I started using boat-tails when Sierra first started making them. I've noted no accuracy difference in 100-yard groups, compared to flat-base bullets.

I dunno. I'm not knocking Sierras at all, but the deer I shot with the Remington Bronze Point always had a sizable exit hole. My father always used the 150-grain Hornadys, beginning way, way back when the Spire Point was a straight taper to the tip--he never lost any deer, and had kills "way over yonder".

But if you hit 'em in the white spot it doesn't matter.

:), Art
 
Art, you are absolutely right, "useless" is too strong of a word:). Since English is my second language, I tend to oversimplify things with my choice of words... "bears no advantage whatsoever over flat-based" would be the exact wording of my thoughts...
 
Bullet weight and jacket construction aside, I recall only one ballistic advantage of the boattail design. They are more stable than flat-based bullets when decelerating through the sound barrier. The high quality of construction of a Sierra BT or a Nosler Ballistic Tip, as examples, doesn't infer anything about the ballistics of the boattail design, per se.

The boattail is a wonderful aid to starting a bullet into the case when reloading, IMHO.
 
Sensop, the effective accurate range of a given load (as defined by the US military) is defined by the range at which the bullets goes transonic, at the local environmental conditions. It is believed that any load (BT or not) can become unstable a that point, and accuracy will degrade drastically (sometimes more, sometimes less, at random).
A boat tail bullet at normal velocities does offer a trajectory advantage past 300 yards (and energy advantage past 200), making a very large difference at 500+ yards.
 
Ruben,

That makes sense to me. Any recommendations for reading material you may think of on this subject would be appreciated.
 
The only advantage of the boat tail is better ballistic coefficient. It will retain its velocity better, which will result in less bullet drop and less wind drift, all else being equal.

The flat base should, at least in theory, be more accurate at shorter distances. At longer distances, the better ballistic properties of the boat tail will give it the advantage.
 
laissezfirearm, no disrespect intnded but a combination of Sierra Bullets, The USAMU, and the Aberdeen proving grounds all did extensive work trying to either prove or disprove the erosion factor between boat tail and flat based bullets. They all decided that the difference was so miniscule that it is not worth worrying about
 
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