Small and fast or big and slow?

[Schaapen]

Hatcher's theory is big and slower is it not? But shot placement is a major factor. After all Bell shot elephant with a 6.5mmX54 Mannlicher. But apart from anything else larger calibres making a larger primary wound channel tend to provide a larger blood trail to follow in the unfortunate event that an animal is not dropped cleanly. But if you are a meat hunter and can place your shots a slower more modest and smaller projectile is surely preferable as it does far less meat damage?

 

[Flewis]

Well I agree with Safari Dave. I’ve used 308, 300win and 375H&H on pg. my next trip will be with the 378 wby shooting 270 grain Barnes. It shoots as flat as the 300s but hits much harder. Go ahead and start throwing stuff, I’ll put my helmet back on.

 

[sgt_zim]

Randy Garrett did a penetration test back in 2003 with 4 different caliber 458 cartridges, using 500 gr solids.

• 45-70 @1500-ish fps
• 458 WM @2100
• 458 Lott @2250
• 460 Wby mag @2500

Test medium was water-saturated newspaper.

Depth of penetration was inversely proportional to impact speed - 45-70 penetrated the deepest, 460 Wby mag the shallowest. We assume flesh and blood/water provides consistent resistance to projectiles, meaning faster penetrates deeper, but it doesn't as Garrett's experiment demonstrates rather dramatically.

Quite obviously, too slow means no penetration at all, but there's a Goldilocks impact speed where the best penetration depth is achieved, and it generally isn't with the blazing fast bullets.

For small animals like white tails, impala, and blesbok, it doesn't really matter a lot, pretty much anything will come out the far side at reasonable shooting distances.

If speed were what really mattered, I'd hunt cape buffalo with a 204 Ruger.

 

[Flewis]

I don’t think you are trying to tell us to swap our 458lott for DG hunting for the 45/70 at 800fps slower or are you?

 

[sgt_zim]

I don’t think you are trying to tell us to swap our 458lott for DG hunting for the 45/70 at 800fps slower or are you?

No (and Garrett says as much in his write up), but it seems to be fairly well established that more speed doesn't mean deeper penetration, at least not for solids. The sweet spot seems to be around 1500 fps impact speed, though.

The results in Garrett's test were pretty stunning. Keep in mind - he did this test back in 2003, the data have been out there for a VERY long time.

45-70 got about 72" of penetration
458 WM about 48"
458 Lott about 40"
460 Wby mag less than 40. I'd assume 450 Rigby would be about the same.

The reason this happens is counter-intuitive - water's resistance to a projectile increases exponentially as impact speeds exceed about 1600 fps, or there abouts.

I have long believed that speed only means lethality at distance. At distances where slower works well, faster doesn't work better.

If you and your buddy come to a 3' wide ditch and need to jump it, and you can jump 4' while your buddy can jump 6', it doesn't really matter much. If you need to jump a 5' ditch, you've got a problem and your buddy doesn't.

DG hunting should always be that 3' ditch.

 

[Flewis]

I read and heard that number was 2400fps or there about. Some say a little bit less but not much. I think someone will be along to give us the answer.

 

[BTP-KennethWRoyce]

To paraphrase Jeff Cooper, velocity is evanescent but bullet weight is forever.

I'll almost always prefer a second-heaviest/heavy-for-caliber bullet impacting between 2100-2400fps. I'll stalk closer if necessary, vs. sending a 2900+fps from 300+yds.

 

[BTP-KennethWRoyce]

The whole point of the Spomer article was to show 7mm rifles are very capable of killing the biggest plains game animals. And shooting lighter recoiling rifles resulted in better shot placement, quick kills, and no lost game. Making for a better experience for those going to Africa. But if you want to use a 416 rigby because that is what Harry Selby used, go ahead. Just be prepaired to pay trophy fees for wounded animals.

I independently came to the same conclusion as Boddington that a 7mm is a bit too light for African PG, and prefer a .30 caliber (-06 is just fine, as is a .308, with 180-200gr at 2500-2700fps). They are light enough recoiling for nearly anybody.

Whoever here used a 7-08 on 340yd Gemsbok got somewhat lucky that day. There was very little margin of power for such a tough animal.

Just because something can be done doesn't mean that it should be done.

A guy back from a single RSA hunt, one of three hunters over a week, taking a total of 13 animals.
How dare any of us question a man with such depth of experience!
If he claims the .223 is an acceptable DG caliber, how can we argue with such knowledge?

 

[BTP-KennethWRoyce]

But the underlying insight — that pure kinetic energy undersells what a big, heavy, slow bullet does compared to a small fast one — is exactly why the .458 Win Mag crowd and double-rifle guys don’t put much stock in foot-pounds as the final word. Sectional density and momentum are doing more of the real work for penetration than energy is.

Concur. Even though I don't use a .458 Win Mag or NE calibers, I do not deny their success on DG. I simply want at least 2350fps MV (with no compression) vs. 2150fps.

 

[Schaapen]

Concur. Even though I don't use a .458 Win Mag or NE calibers, I do not deny their success on DG. I simply want at least 2350fps MV (with no compression) vs. 2150fps.

I have positive experience with the .458 Win Mag and agree fully that SD and momentum are key. The DG don't read the same ballistic tables as some of us do.