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Ogive Designs – Tangent, Secant, Hybrid

In Blog by Rich3 Comments

If you’ve heard discussion with the terms tangent, secant, and hybrid ogive thrown around you’ve been listening to people discuss bullet profiles. Today we’re going to discuss them a bit here so if you hear a similar discussion you’re a little better informed as to the subject matter. Bullet profiles, specifically, the leading edge of the bullet is where these differences are found. Differences in the ogive profile can have a range of effects on the flight characteristics of the bullet and even on how finicky they are during load development. So there are multiple facets of precision shooting that tangent, secant, and hybrid ogive designs can participate in!

Tangent, Secant, Hybrid Ogives

Tangent ogive shapes are what you typically think of when you picture a rifle bullet. The nose has a gently sloping curve from the bearing surface out to the nose. The bearing surface is the part of the bullet that rides along the bore and which interacts with the rifling. Ahead of the bearing surface, at the point where the bullet curves down to the tip is the ogive. A tangent ogive shape is a gentle curve down to the point. That gentle slope means there’s a smooth transition when the bullet slides into the rifling as it’s fired.

Secant ogive shapes are sharper and straighter angles between the bearing surface and the nose of the bullet. A popular example of a secant profile is the VLD (Very Low Drag) line of Berger bullets. The secant ogive shape lends itself to ballistically superior flight characteristics. The downside, as anybody who’s put a load together with a VLD knows, is they are sensitive to seating depth. I’ve seen many people state they start their VLD bullets jammed and engaging the rifling. That sharper profile from bearing surface to nose means they don’t obturate (David Tubb gets the nod on that term, hadn’t heard it before) very quickly. They don’t self align in the bore as efficiently.

Is there a middle ground? Yes! Hybrid ogive shapes combine the best of both worlds. Again Berger’s line of Hybrid bullets are famous for this. These bullets have a tangent ogive shape between the bearing surface and the first part of the nose so the bullet centers itself efficiently when fired from the case and jumping to the rifling. Then ahead of the tangent ogive shape it tapers down to a sharper secant ogive shape to give the same bullet a higher ballistic coefficient and better flight characteristics!

ogive shapes

L-R: Lapua 123gr Scenar, Berger 6.5 130gr Hybrid, Sierra 115gr DTAC, Berger 105gr Hybrid, Hornady 285gr HPBT, Hornady 178gr HPBT, Sierra 155gr HPBT – Note the steeper ogive angles toward the nose on the Berger and DTAC offerings

Does Ogive Shape Matter?

Yes. Yes, it does! This is just like picking a bullet, caliber, or scope for your specific needs. Pick and use what works for you. If the smallest group and maximum ballistic efficiency is key then a Secant ogive profile is what you want. On the other hand if accuracy is a little less important than being able to load higher volumes of ammo that perform very consistently a Tangent ogive profile might be better. For me in the year 2017 I don’t see why anybody shooting a tactical rifle wouldn’t be looking at a Hybrid profile bullet. Those bullets tend to be expensive but man are they worth their weight in gold!

I mentioned how a tangent ogive profile self centers (obturates) with less hassle than a secant profile. Well, I tested this when I worked up a load for 105gr Berger Hybrid bullets for my 6×47 Lapua match gun. It was my first dedicated match rifle and I figured I would leave nothing to chance. So I did a bullet seating depth test where I used the same powder charge but seated the bullet at different depths in the case. This mean the bullet would have a varying degree of “jump” between when it left the case and hit the rifling. The results were expected, but I was surprised by how tight every group of rounds were regardless of seating depth.

seating depth

The old seating depth test for the 105gr Berger Hybrids I did when I put my match gun together

You can see there is some variance and some groups were tighter than others but none were earth shatteringly different. The worst of them still grouped in the .6s! That’s really impressive! For a guy who primarily shoots recreationally and competitively in a tactical rifle style a hybrid profile bullet makes perfect sense. You get the highest ballistic coefficient bullet available on the market without setting up a lot of extra work during load development. There are secant profile bullets with higher ballistic coefficients than their hybrid counterparts. The question is whether it’s worth the extra work in the form of seating depth tests to justify the advantage in BC? For me, it isn’t, but to each their own!

Wrapping Up

When I first started loading my own ammo I was trying to do it as cheaply as possible. I was buying Sierra or Hornady bullets and having a good time loading and shooting the ammunition. When you’re first loading ammunition that’s a great way to gain experience without breaking the bank. However, as your hand loading prowess increases and especially if you have competitive aspirations it’s better to buy the expensive stuff. I promise you the guys at the top of the scoreboards are not using cheap bullets. The bullet is one area where saving money can cost you. That cost could be in wind fighting ability during flight or in hassle on the reloading bench!

Bullet production is getting better every year. Berger produces some of the nicest bullets with the best ogive designs, ballistic coefficients, and jackets you’ll see anywhere. Other companies aren’t slouching either. David Tubb’s DTACs are produced by Sierra and his new 6mm 115gr bullets are really nice! They have very small meplats and are pointed at the factory. Hornady is doing a lot of cutting edge ballistics work these days and modifying their designs accordingly. We’re really in a renaissance of long range shooting technology. So out with the old and in with the new, I say! Get the best bullet you can afford and save the time for the range instead of the bench!

Owner and Proprietor of AccuracyTech, LLC. Rich is a Firearms Enthusiast, Precision Rifle Competitor, and Writer. He is committed to bringing readers quality reviews and articles related to the Precision Shooting Sports. If you have any questions for him, please use the contact form on the site.

Comments

  1. Hi Rich,
    Curious about anyones thoughts on Lapua Scenar 6.5 139gn, if it is a full secant or variation of Hybrid? Looking at the bullet its nose slants much greater than say a Nosler Custom Competition 6.5 140gn which I’m sure is a full Tangent but not as much as a Berger VLD and looks more similar to the Berger Hybrid in nose slant. The Lapua 139gn Scenar works better with the Redding Custom Competition VLD Seating Stem than the Regular Seating Stem.

    1. Author

      Some of them make it hard to tell, for sure! I suspect hybrid designs are quite common.

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