Why not pick the boat tail? (Hornady Interlocks)

[melanie]

Hi guys,

Riddle me this...

Hornady make these three of their "Interlock" bullets. All 180gr weight and all same construction and features and blah blah blah.

Hornady Interlocks

180gr-hornady-interlock.gif (12.75 KiB) Viewed 6145 times

One tipped boat tail, one round nose flat bottomed and 1 tipped flat bottomed.

Boat tails are supposed to be the best, right? So why would you pick either of the other two when everything else is the same?

[Jack V]

The spire point bullet would be more suitable to longer range than the round nose.

The Round nose better at scrub penetration and bone penetration at shorter range.

The Boat tail would be better BC at longer range and good in a new tight barrel.

The flat base would be better once the barrel starts to wear out and the BT looses accuracy.

Both BT and FB would shoot about the same up to about 400 to 500 metres until the barrel starts to wear out , then the flat base takes over for a while until nothing shoots well. Over 500 meters the BT would hold more velocity and shoot a bit flatter and potentially tighter due to better wind bucking than a flat base.

As long as everything stays supersonic. Once the bullet drops into the transonic zone then the BT can be more upset than a flat base.

If you gun barrel is in good new condition with adequate twist rate then there is no reason not to use a boat tail on average game in open terrain.

A 180 grain 308 will pretty much nail anything in Australia.

[BBJ]

Boat tails are supposed to be the best, right? So why would you pick either of the other two when everything else is the same?

No such thing as "best", only most suited.

A boat tail, as a general rule, will have less drag so will go further and lose velocity and energy at a slower rate. Both generally desirable things.

Further range obviously a requirement for long distance shooting. Also higher velocity mean less flight time, so less time to be effected by wind drift. Making them suited to long range target shooting.

Round nose will handle debris in the way a little better as jack said. They also expand better at lower velocities which make them perfect for lobbing big calibre, heavy pills which are lower velocity. Look up African game hunting rifles and cartridges and you'll see plenty of them. They're not bullet for long range, hair splitting accuracy but a heavy round nose bullet creates a devastating wound channel through hide, muscle, bone and all.

I'll leave one of the benchrest boys to cover the flat base spitzers, not something I've had much hands on with but that's where they live normally AFAIK.

[Tiiger]

A 180 grain 308 will pretty much nail anything in Australia.

A spire point boat tail is pretty all purpose, Melanie. Especially for a new shooter like yourself.

If in doubt, grab a box of those.

[sbd3927]

Round noses are more intended for tubular magazines, Noone wants a sharp projectile sitting on the primer of the next cartridge.

I question that round noses are better at penetrating bone. I think they expand sooner, which doesn't equal penetration.
I shot a 5yo bull with a 30/30 a few months ago, which failed to drop the animal. Looking at the skull recently, shot placement was perfect, but the projectile disintegrate at the back of the nose, about 2 inches in, never reached the brain cavity. Part of my motivation for getting the .308

[Warrigul]

Round noses are more intended for tubular magazines, Noone wants a sharp projectile sitting on the primer of the next cartridge.

I question that round noses are better at penetrating bone. I think they expand sooner, which doesn't equal penetration.
I shot a 5yo bull with a 30/30 a few months ago, which failed to drop the animal. Looking at the skull recently, shot placement was perfect, but the projectile disintegrate at the back of the nose, about 2 inches in, never reached the brain cavity. Part of my motivation for getting the .308

Round noses give same weight for a shorter projectile and they fit in magazines better(I have this issue in my .300 WM).

Protected round noses generally feed better and are less subject to magazine deformation (I have this issue in my .300WM)

Round nose definately thump better and stay together better (this may be more to do with composition)

Bugger all difference in accuracy over 300m(most people aren't capable of shooting past this distance)

Flat base round noses have better bearing surface and obdurate better(expand to fill the bore grooves)

Round nose bullets look tough

[Jack V]

Round noses are more intended for tubular magazines, Noone wants a sharp projectile sitting on the primer of the next cartridge.

I question that round noses are better at penetrating bone. I think they expand sooner, which doesn't equal penetration.
I shot a 5yo bull with a 30/30 a few months ago, which failed to drop the animal. Looking at the skull recently, shot placement was perfect, but the projectile disintegrate at the back of the nose, about 2 inches in, never reached the brain cavity. Part of my motivation for getting the .308

That is one of those situations where some extra velocity and a better bullet design helps a lot. The 30-30 is a great cartridge but it is lacking in penetration on a hard target . I have found that a six calibre ogive bullet in a 308W is a nice compromise between good penetration and reasonable BC down range.

Long high calibre ogives tend to be weak and can just bend or collapse on hard bone which can cause the bullet to change direction or fragment and miss the vitals .

The round nose has higher sectional density and tends to push through even if it does expand or at least keeps on the same track .

Core bonding in it's many forms does help to make higher calibre ogives more useful as larger game bullets as it makes the whole bullet stay together better which is what Interlocks are some form of chemical bonding I suspect .

[The Brass]

I question that round noses are better at penetrating bone. I think they expand sooner, which doesn't equal penetration.

Got a wire crossed there with non-expanding flat nose bullets me thinks.

Look up the Nosler Solid bullet. The flat nose is to reduce deflection off of bone, no lead in them and no perforation or whatever it's called like in the Barnes TSX. They're a 1 piece metal body designed to penetrate without expansion.

Designed for Buffalo, Elephant etc.

Jacketed lead will expand regardless of the bullet shape (as you know).

[Vati]

I'll leave one of the benchrest boys to cover the flat base spitzers, not something I've had much hands on with but that's where they live normally AFAIK.

The greater bearing surface on the rifling lends itself to stability and accuracy.

300m is where the flat base really thrive from memory. Further than that the advantage starts swinging back to boat tails.

[Jack V]

The greater bearing surface on the rifling lends itself to stability and accuracy.

300m is where the flat base really thrive from memory. Further than that the advantage starts swinging back to boat tails.

Yes but then a guy goes and breaks the World 1000 yard group record using flat base bullets ????

Bearing surface alone is not the whole issue it's way more complicated than that.

The low BC round nose bullet will never be the accepted long range accuracy performer because it can't hold velocity as well and will be more affected by wind and need more elevation which also exacerbates wind problems .

[Vati]

Bearing surface alone is not the whole issue it's way more complicated than that.

I did just say 'lends itself to accuracy', didn't claim it was the be all and end all.

Just talking rule of thumb stuff.

[tripletwo]

Look up the Nosler Solid bullet.

Daaaamn they're some big buffalo in the Nosler photos for that bullet.

[headspace]

Melanie if I'm right you're loading for a 308. I'm using 165gn Interlock boattails in mine and it shoots extremely well.

Ballistically the 165 is a better hunting bullet because you can get more velocity out of it, it maintains velocity better and has better terminal velocity, particularly over a longer range.

For hunting the 180 is probably a good bet at closer range, like in thick scrub, but it loses velocity very quickly once it get past 200m.

Most long range comp shooters favour the 175gn bullet over the 180.

For hunting at sensible ranges I find it hard to pass up the 165. I chronographed my loads and they are going at an average of 2,740fps.

JD

[melanie]

Melanie if I'm right you're loading for a 308.

That's the plan

[Jack V]

Melanie if I'm right you're loading for a 308. I'm using 165gn Interlock boattails in mine and it shoots extremely well.

Ballistically the 165 is a better hunting bullet because you can get more velocity out of it, it maintains velocity better and has better terminal velocity, particularly over a longer range.

For hunting the 180 is probably a good bet at closer range, like in thick scrub, but it loses velocity very quickly once it get past 200m.

Most long range comp shooters favour the 175gn bullet over the 180.

For hunting at sensible ranges I find it hard to pass up the 165. I chronographed my loads and they are going at an average of 2,740fps.

JD

+1 on what headspace says. 180 grain is a bit too heavy for the smaller 308 case for general hunting. In a 30-06 or 300 Win Mag it would be different.

I have a ballistic program that models two bullets side by side and the mid weight bullets are better overall.

[Westy]

Round nose definately thump better and stay together better !!I wouldn't use anything else in a 308 if I had one !!!!I use these( Speer 70 Grns semi spitzer) in a 223 and haven't had a Pig or Goat that has remained standing after 1 shot so IMHO they work Bloody well for me

[melanie]

+1 on what headspace says. 180 grain is a bit too heavy for the smaller 308 case for general hunting. In a 30-06 or 300 Win Mag it would be different.

It's cool, I just used the 180gr as an example for the question.

Same applies across a bunch of lower bullet weights though so info still all applies.