Boat tailed bullets

[Jack 45acp]

I love boat tailed bullets for their flight characteristics but...
Can someone help me to understand why, due to their shape, that they don't excellerate throat erosion. It would seem to me that flat based bullets would seal better and boat tailed ones would cause a "blow torch" effect upon firing. Someone please help me to see how this is not true. This is not a joke.

 

[Mikecr]

The bullets obturate under pressure to seal the grooves.
So there is little if any gasses flowing around bullets -until muzzle release.

 

[Steelflight]

The bullets obturate under pressure to seal the grooves.
So there is little if any gasses flowing around bullets -until muzzle release.

Agreed that is until your barrel is already worn out from normal use. It is then that flat Spitzer bullets are best.they will expand and seal just that tiny bit more to grab worn out rifling. A common observation with those that own old war guns.

 

[257Tony]

Agreed that is until your barrel is already worn out from normal use. It is then that flat Spitzer bullets are best.they will expand and seal just that tiny bit more to grab worn out rifling. A common observation with those that own old war guns.

I found this to be true with my 257 Weatherby towards the end of it's useful barrel life, would only shoot flat base bullets accurately for the last 200 or so rounds.

 

[Deleted member 118572]

For big game unless you shoot over 600 yards BTs have no advantage. If you don't shoot beyond 300 Spitzers have no advantage.

 

[Mikecr]

I personally believe FB bullets are inherently more accurate to ~500yds.
That is, until BT BC becomes a higher contributor to accuracy -over cleaner releasing higher stability FB attributes.

 

[Murph1951]

I personally believe FB bullets are inherently more accurate to ~500yds.
That is, until BT BC becomes a higher contributor to accuracy -over cleaner releasing higher stability FB attributes.

I have seen way too many BT bullets squirt out of the jacket when dressing out game. IMHO they belong on the range but never use for hunting. Hunters like hound dog men see something new and pretty and they go head over heels for it not knowing it will cost them in the long run.

 

[Eric Alexander]

I love boat tailed bullets for their flight characteristics but...
Can someone help me to understand why, due to their shape, that they don't excellerate throat erosion. It would seem to me that flat based bullets would seal better and boat tailed ones would cause a "blow torch" effect upon firing. Someone please help me to see how this is not true. This is not a joke.

An amazing range of responses you arr getting. But bullets don't seal from the rear, they seal from the side so it's the walls of the bullet that are actually pushed into the grooves and lands to seal. Boat tails actually offer slightly more surface area than a flate base at the rear to absorb the heat of the combustion's flame front, tranferring heat into the bullet and away from the barrel. So, if anything, the BT design would delay erosion, not accelerate it.
But, truthfully, this very slight difference would be hard to measure, a de minimus experience.

This LR group is a different lot. 98% of rifle owners will not go through 6 boxes of ammo for their rifle. 1+% will. Only the remaining fraction of 1% will ever shoot out a barrel.

If you are a LR hunter, high BC bullets (all boattails) are important cuz they carry more energy further with less drop. Personally, I appreciate them because we can do more with less when it comes to LR hunting. Under 200 yds everything works.

 

[Coldfinger]

I love boat tailed bullets for their flight characteristics but...
Can someone help me to understand why, due to their shape, that they don't excellerate throat erosion. It would seem to me that flat based bullets would seal better and boat tailed ones would cause a "blow torch" effect upon firing. Someone please help me to see how this is not true. This is not a joke.

I think it was Guns&Ammo that did a very very interesting article with high speed pictures and detailed data about the difference between boat tail bullets and flat based bullets. The differences in muzzle blast, pre bullet powder escape (before boat tail sealed the bore) and other info was a real eye opener. Just the pics of the muzzle blast and powder speeds were really interesting. I'll try to find the magazine and article to post the date so it can be looked up on internet. At first I didn't really care till the muzzle pics caught my eye and I decided to read the article!

 

[HRM Johnny]

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[bullet man]

I saw a video on u tube one time, the question was what would happen if you loaded a spitzer bullet backward. Well, it wasn't pretty I don't think he tried it but twice. That's why it's a compromise you'll never see a long pointed boat tail for that reason, they make them so you get added flight benefits without the damage to your rifle. For an average shooter nothing to worry about.

 

[Lefty7mmstw]

I don't sit and dwell about fb vs. boat tail. Most rifles have tight enough bores to seal rather well (with obduration) with either bullet. I also don't really worry about how far out I'm using a flat base bullet. My farthest kill right now is at about the 1/2 mile mark with a flat base. I usually hunt spot and stalk with a big enough rifle to reach out if needed. Some of my rifles are set up a bit more for lr (a 300rum I own is running a 225 hdy hpbt and my 7rum tosses 175 eld-x) and some run mid weight fb pills . My 7rum killed last year at 500yds with a high cross wind and my kid got his doe last year at 405 yards with a 140 sierra fb from a 7rem using (gasp) rl22.

 

[Mikecr]

I saw a video on u tube one time, the question was what would happen if you loaded a spitzer bullet backward. Well, it wasn't pretty I don't think he tried it but twice. That's why it's a compromise you'll never see a long pointed boat tail for that reason, they make them so you get added flight benefits without the damage to your rifle. For an average shooter nothing to worry about.

Bullets can be fired backwards without issue.
It's just that anyone doing it would need the common sense to back off the load, given more bullet area inside the case.

Boat tail angle and length are designed to produce lowest drag through optimum laminar to turbulent transition/release.
And it happens that a long pointy boat tail is not optimum.
Nothing to do with barrel life

 

[1mechanic]

I have often wondered if the boat tailed bullets were not completely
symmetrical or one side of the tail was off a little bit if the muzzle flash at the crown would negatively affect their performance.