Effectiveness of Flat base vs Boattail on game animals

[nate45]

Why is it that flat base rifle bullets have such seemingly greater anchoring ability than boattails do?

Example you shoot a deer with a .30-06 150gr spitzer boattail @ 2900fps at 150 yds you hit right behind the point of the shoulder on a broadside shot deer runs a short distance you find it dead.

Same identical circumstance only with a 150gr spizer flat base deer instantly falls or runs a much shorter distance.

I from my own experience have seen this effect many times and have talked to many other hunters who have noted it as well.

None of them knew exacly why though and I don't either.

Does anyone have an explanation as to why this occurs?

[Smokey Joe]

Nate 45--There are so many variables that go into a deer falling DRT when shot, as opposed to staggering 20, or 50, or 100 yards and being DRT, as opposed to scampering off into the next county, that I for one can't see the base of the bullet being a major factor in any case.

If the deer was shot at long range, say > 200yd, the boattail will contribute to a more accurately placed shot. Closer than that, the boattail won't have an appreciable effect on accuracy.

Now, you state

I from my own experience have seen this effect many times and have talked to many other hunters who have noted it as well.

Well, what is "many times?" And exactly how "many other hunters" have noted this in any sort of scientific comparison. Have you been keeping careful records on this over the years?

Forgive my saying so, but that sounds like belief talking, not scientifically valid comparison.

Now, I have no problem with belief. If you BELIEVE that flat bases are going to do the job, then use the flat bases in which you have more confidence. And at normal deer-shooting ranges, it won't make any difference in accuracy. But you'll get better results because you believe you will.

For me, I use boattails. I get one-shot DRT kills when I place the bullet where I should. And I don't when I don't. But I started using boattails when I started reloading, because they slip into the necks of the cases easier!

To each his own.

[nate45]

I said seemingly has that effect.

The question was directed at others who had heard of or seen the effect themselves.

My father for one has noted it when he went from a 117 gr spitzer boattail to a 117 gr spitzer flat base in his .25-06

I don't know how many people I've asked about it in the last 20 years or so but quite a few very expierienced hunters.

I never claimed it was scientific just an observation.

If the deer was shot at long range, say > 200yd, the boattail will contribute to a more accurately placed shot.

How exactly would a boattail accomplish that?

There may be no scientific validity to my observation but I know the science and reason behind the boatail design and thats not it.

[rantingredneck]

Boat tail bullets = less drag = more stable flight at longer range = better long range accuracy.

Lethality difference between boat tail and flat base?

[nate45]

Lethality difference between boat tail and flat base?

It's not a question of lethalness dead is dead.

That was not he question.

Boat tail bullets = less drag = more stable flight at longer range = better long range accuracy

The boattail does not take effect till the bullet speed falls below the speed of sound.

At speeds above the speed of sound the nose shape has a greater effect than that of the base on retarding drag.

How many deer are shot at those kind of ranges.

[JohnKSa]

At speeds above the speed of sound the nose shape has a greater effect than that of the base on retarding drag.

Sounds right.

The boattail does not take effect till the bullet speed falls below the speed of sound.

But this doesn't.

The reduced drag is "in effect" from the time that the bullet leaves the barrel. The effect may be GREATER at subsonic velocities, but it's not as if it "switches on" when the bullet transitions from super- to sub-sonic. In fact, one of the main criteria for caliber selection in the extreme range shooting sports is making sure you pick a caliber that remains super-sonic to the target. And yet these folks invariably use boat-tails in spite of the fact that their bullets will never be subsonic before hitting the target.

That said, I can't imagine why flat-base bullets would be more effective than boat-tail bullets on game. ...unless the boat-tail bullets are match bullets and the flat-base bullets are game bullets.

[2rugers]

Could be other design features of the bullet?

Bonded vs. not bonded,
jacket thickness,
lead softness etc???

I have never really compared the two in hunting situations to notice a difference.

Could be though.

[nate45]

The boattail does not take effect till the bullet speed falls below the speed of sound.

No it dosen't I should have said "does not take the greater effect"

unless the boat-tail bullets are match bullets and the flat-base bullets are game bullets.

No I'm only refering to properly structred hunting bullets.

[nate45]

Bonded vs. not bonded,
jacket thickness,
lead softness etc???

Here's a good actually example: my Dad's favorite rifle cartridge is .25-06 he for years he used the 117gr Serria SBT Gameking he shot 100+ deer with it all ran an average of 40 to 50 yds before falling.

When I told him about my switch to the flat base after hearing of their increased effect and noting it myself.

He switched to a 117gr Serria spitzer Prohunter since then he has shot 30+ deer with that combo all have either dropped or ran less than 25yds.

I have noticed the same thing with a .30-06,.270,7mm mag and a .300 Win mag. all animals have either dropped or ran less distance with various flat base bullets from different makers.

Like I said in the OP I don't know what exactly is going on here but something is.

[Trapper L]

Your spitzer flat based bullets will tumble on impact creating a wider wound channel. The BT bullets also tumble but not to same degree as there is not as much rearward weight. If you want to punch a hole straight thru, use a round nose bullet for penetration like the BIG guns use on large dangerous game.

[nate45]

Your spitzer flat based bullets will tumble on impact creating a wider wound channel.

Interesting that could very well be the reason.

[castnblast]

The tumble theory is just that...a theory. soft point bullets are designed to mushroom and do not tumble. If they did, you would not have a mushroom... I swear by boat tails, and use them in all the rifles I shoot. they are simply more accurate. I have killed deer with 22 cal boat tails, 25-06 117 btsp, .270 130 btsp, 7mm rem mag 139 btsp, 7mm mag 160 btsp, and 300 win mag 150 btsp, & 165 btsp. The deer I shot last year w/ the 22-250 55gr btsp cockroached with a shot directly to the shoulder. I've had em run w/ 270, and had em drop in their tracks. I've had em run w/ the 300, and had em cockroach in their tracks. My theory is it depends on the amount of shock the spinal cord gets from the placement of the bullet, and if it causes enough trauma to cockroach em. There are other biological issues as well, but careful inspection of the deer I have cockroached seemed to have quit a bit of contusion to the upper spine above the shoulder blades. (I shoot my deer square in the shoulder...) I hate getting intestine matter on my meat...I'd rather ruin a little chili meat than get feco coliform in my meat...

[nate45]

I swear by boat tails, and use them in all the rifles I shoot. they are simply more accurate.

Boattail bullets are not more accurate than flat base.

Flat base bullets are proven to be more consistently accurate.

The tumble theory is just that...a theory.

Tumble is not a theory it is a fact.

soft point bullets are designed to mushroom and do not tumble

Yes they are designed to mushroom.

I'm researching right now to see if they also tumble like full jacketed bullets do.

[FirstFreedom]

Your and your friends' observing seems to be a strong anecdotal bit of evidence for this....

First, I think castnblast is right - they do not tumble - either type of bullet is designed to penetrate in a straight line and mushroom. UNLESS it hits heavy bone, then all bets are off - it may tumble; it may not.

My SWAG would be, that IF this is a valid actual phenomenon, as it seems to possibly be, then it is likely due to extra hydrostatic shock (wound channel) cause by the rear of the bullet being wider and causing a wider "trail" for the hydrostatic shock, than a boattail that more easily "slips through" the flesh, with a smaller "tail" or "trail" of hydrostatic shock. But again, just a SWAG....

Boattail bullets are not more accurate. They have a bit longer PBR, due to having a better BC. They also may leave a smidge less copper in your barrel.

[taylorce1]

I use Sierra SBT 130 grain bullets out of my .270, and haven't ever noticed a lack in lethality. None of the deer I've ever shot have made more than 20 yards after being hit with proper shot placement. I've had such good performance I've never needed to try a different bullet on deer.

Boat tail bullets are not more accurate than flat base.

Flat base bullets are proven to be more consistently accurate.

If flat base bullets are more accurate then why do match grade bullets known for accuracy come in boat tail designs? I didn't check every manufactures bullets just Sierra, Berger, Hornady, and Nosler and I didn't see a single flat base bullet in their match grades. I might be wrong but I think they have put quite a bit of research into these bullets.

[FirstFreedom]

Because target shooters happen to want good BCs in addition to accurate, consistent bullets, so target bullets have both features (consistency & good BCs).

I don't think that either is more intrinsically accurate - they are the same in a vacuum - accuracy is a function of consistency / uniformity, and lack of eccentricity / asymmetry; not really a function of base design.

All of above: IINM.... I could be wrong. It's possible that boattails are more accurate instrinsically - so take my "pronouncements" with a grain of salt.

[JohnKSa]

FF,

Unless the benchrest competitors are confused about accuracy, then you're right about flat-based bullets being more accurate.

Strictly speaking it's not so much that the bullets themselves are more accurate, it's just easier to get a flat-based bullet to depart the bore in a more stable fashion due to (of all things ) the flat base.

A good many match bullets are boat-tailed because they offer better wind resistance & flatter trajectory which are important to match shooters. But the extreme accuracy nuts (benchrest shooters) are using flat-base bullets.

[nate45]

"To tell the truth, boat-tails are oversold. They fly flatter because they set up less drag than flat-base bullets, but you won't see much if any difference in trajectory for the first 300 yards."-Hornady ballistician Dave Emary

"As for accuracy, my tests show that flat-base bullets, on average, turn in tighter groups. Making a tapered heel is tricky; you have two angles instead of one, and both must be perfect. Unlike the bullet's nose, which can take a lot of abuse without affecting accuracy, the heel must be cleanly shaped and any taper concentric. Irregularities result in tipping when the bullet leaves the muzzle. Then you kiss accuracy good-bye. On the other hand, match bullets are mostly boat-tails, and some of them print one-hole groups. It's dangerous to generalize," he said.-Dave Emary

"My favorite saying is the records speak for its self. Show me a national benchrest record shot with a boat-tail bullet. One thing that clouds the issue is that no high powermatch bullets are made with a flat base so they can only be compared with custom match bullets made with flat bases of which there are few.I will say that the small amount of loss of accuracy is off set by theability to overcome conditions due to decreased flight time at ranges of 600 and beyond."-Gale McMillan

[FirstFreedom]

Actually, nate said that flat-based bullets are more accurate. I said that they were intrinsically the same / depends on the consistency. I was mostly wrong. Yes it depends on consistency, but it's EASIER to make an accurate flat-based bullet from you you describe, sounds like. Cool, learned something new.

[Wildalaska]

What John said.

Boattails are better at longer ranges.

All things being equal a properly constructed bullet of either shape will kill critters equally dead

WildusethebestbulletsyoucanAlaska

[nate45]

Cool, learned something new.

So have I Freedom.

I know more about projectiles than I did before,but I still can't find anything to support or deny my observations.

All things being equal a properly constructed bullet of either shape will kill critters equally dead

Yes maybe it does just come down to construction and once you place a good shot in the kill zone FB or BT there's no predicting how the animal will react or how far it will goes before it dies but die it will.

Altough I just came upon some information about BT shedding their jackets more readily than the FB I'm looking into it.

[taylorce1]

JohnKSa, thanks that cleared some things up.

Altough I just came upon some information about BT shedding their jackets more readily than the FB I'm looking into it.

I've heard this as well, I've never seen it though. I've never had a boat tail bullet fail to the job yet as long as I'm on top of my game.

[Trapper L]

nate45, here's an out of context comment in regards to bullets tumbling. An example could be that as the bullet impacts, it deforms and mushrooms. Now it acts just like an 18 wheeller with front brakes only on wet streets. The back end wants to pass the front end and starts swapping ends or tumble. The BT bullets will shed the core quicker as there is not much a manufacturer can do to get the core to bond to a cone (the boat tail) that has forces on it that are trying to eject the core. Here's the commentary:

In the 1960s we all thought bullet tumbling on impact was a unique and wonderful effect of 1:14 rifling and there was much controversy when the Army adopted the "inferior" 1:12 rifling.

Since that time Army medical research in 1988, confirmed by later ballistic research, has confirmed that (1) all bullets longer then their diameter will tumble in animal tissue, (2) tumbling bullets cause only small additional wounds, much like hollow points, and (3) the massive wounds caused by M193 and M855 Ball are caused by bullet fragmentation tearing the walls of the temporary cavity resulting in 150mm wounds. Temporary cavity requires rifle velocity target strikes (pistol bullets have very minor temporary cavities if at all) and the fragmentation of these rounds does not occur below 2500fps, or about 150 meters.

Hope this has value for you.

[Art Eatman]

I've never seen any DRT difference between flat-based and boat-tails. I've used both for some forty+ years. ,243 and .30-'06.

I've never seen any notable difference in group sizes, either. That's with hunting rifles which mostly shoot somewhere between 1/2 and 7/8 MOA. I used to have an old Ruger 77 heavy-barrel .220 Swift. I used exclusively the Sierra 52-grain HPBTs. Five-shot groups of 3/8 MOA, darned near every time I checked. Dangfino.

Art

[nate45]

I've never seen any notable difference in group sizes, either.

I have not either.

I'm not much of a target shooter and didn't even know benchrest shooters primarily used FB bullets till I started this thread.

Years ago my Dad used to shoot 1/2 in groups with his Douglas barreled custom 1909 Mauser .25-06 and he used exclusively BT back then.

Maybe there is nothing to it and it's all circumstantial.

Perhaps if there really is something to it the secret might lie in the structural diffrences of BT and FB.

As far as DRT goes last year my Dad dropped one in it's tracks with his Tenpoint crossbow so maybe you never can tell.