In looking at larger bore (40 cal and above) i wonder what are the normal expected ranges they are expected to engage at and what is the max effective range with iron sights and with scope?

I believe you're asking two completely different questions. I would venture a guess that most DR's with iron sights are going to be used at or under 300yards, with the vast majority of shots being taken significantly under that mark. As far as 'effective range', it depends on your meaning. For example, the BPCR crowd are shooting straight walled BP cartridges and sending lead VERY accurately to 1,000 yards and further. I certainly wouldn't stand down range at 1,000 knowing someone was up range sending thumping big pills in my direction! As far as relative 'killing power', for their intended use, certainly less than 1,000. You could probably tie relative velocities at points x through x+n to bullet weight and get your impact energy. As a practical suggestion, I wouldn't shoot my .500 BPE at anything living past about 200. Certainly nothing likely to take umbrage with being shot at and likely to retaliate.

The BPCR game is very interesting and the shooters are very good, but they are shooting at stationary targets that don't bleed and a bad hit is still a hit.For an open sighted double,I would say no farther than you can keep all shots on a paper plate.It would be the same with a scope, except the scope would extend the range.If the rifle/ammo is well regulated, I would guess 80-100 yds. for open sights and up to 200 with a scope.This could be significantly extended for a really well regulated, smaller caliber rifle with scope( ie 7x65R-9.3x74R).
Mike

My comment regarding BPCR was merely to emphasize the fact that despite a long range trajectory resembling a howitzer shell, these heavy lead bullets can travel quite far. I believe my second point echoes yours regarding maximum engagement distances.

PS- Paper plates don't generally move much either.

In reality, for its intended purpose, 30 to 75 yards. You don;t take longshots on dangerous game period!

Agreed.

I'd go for a double at DG at up to 100 with iron sights and up to 300yds MAX. with a scope. IF it was a GOOD SHOOTING RIFLE. Many won't be able to handle this.

Those really shine with large calibers (400 to 500 grain bullet at about 2100 to 2200fps) with two triggers at stopping charges at five to 10 paces though unlike Mauser can be defeated by grain of sand into the action. Their owners claim typical mass-produced small caliber French Chapuis is good well past 150m perhaps even past 200m. Not sure if that is so because for same coin I would rather take custom engraved bolt gun or semi-autho instead.

Rule of thumb is Arpeture sights resolve to 1 moa, scopes improve on 1 moa by their power, 2 1/2 power resolves to a bit less than 1/2 moa and so on This with good eyesight. Less than good eyes scopes can make a significant difference.

Practical use on game my 03 Sporter is as effective to 100 yards with its Lyman 48 and large Arpeture as it is with a K 2.5 mounted as long as light is good. Dark poor contrast the scope is an advantage. Easier to pick a spot on Animals with the scope too. It's a reliable 200 yard gun not needing any range estimation when scoped and zeroed properly. Flat shooting.

Thing that limits range on any big bore is trajectory. Have shot a lot of 45/70 and on game they are 100 yard rifles at best. Bullet drop gets them very soon. I shoot iron sight 40/65 & 45/70 to 500 meters and further on measured target ranges, no way to link target performance to live game in the field. Apples and oranges.

Big double rifles I have seen are 100 yard guns, little more in the smaller bores perhaps, not much. Study the drop charts for your cartridge, more important than what kind of action. Big advantage the doubles have have is fast handling a major plus.

Boats

This is one of most informative threads I've read on the subject, backed up by experience. Thanks.

There are a lot of variables, but, in my opinion, a scope-sighted, properly regulated and sighted, big-bore double rifle, in the hands of a man who shoots it a lot, and shoots it well, is at least a 300 yard rifle.

This is not conjecture on my part. In Zimbabwe, three years ago, I took my Sable at 208 yards with my self-built double in calibre .450 #2 NE. Had he been at 300 yards, I am confident that the rifle was fully capable.

Three weeks ago, in Texas, I took a Scimitar-Horned Oryx at 154 yards, with my self-built double in calibre 9.3 x 74 Rimmed. Had he been further out there, the same applies.

The key is careful and accurate regulation, and sight-in at a good distance, NOT 50 yards.

Purely an observation from me as I have only ever shot thin skinned game in Africa, these animals are not usually dangerous, but the Big Five are something else. The Professional Hunter J.A.Hunter told his clients that were hunting Elephant to get as close to the animal as humanly possible....... Then get five yards closer.

That sounds like very good advice. The graveyards of Africa are filled with tombstones inscribed with remarks like, Killed by Elephant, Buffalo, Lion etc. Don't forget either, no one knows just exactly how they feel when shooting dangerous game for the first time. It isn't unknown for Buck Fever to hit the shooter, no matter how experienced on other game they may be.
Harry.

Harry my African experience has been almost all looking not shooting. Short side trips around business with borrowed outfits. It’s hard to argue with direct experience and I won’t however when we are taking “normal effective range” consider double rifles have been built in many calibers and it’s the bullet that does the job.

500 gr 45 caliber bullet launched at 2100 fps rifle zeroed at 200 yards is going to be almost 5 inches high at 100, little over 8 inches low at 250. That’s good enough, however add the rifles normal group size and more important sighting error on a game animal 250 is stretching reasonable expectations. If the big 45 moving fast as it will go is sighted for 150 yards you can practically ignore the bullets rise and drop to 200 yards. Hold were you want to hit him. That’s why I say 200 is the practical limit for a well set up 45 caliber rifle.

The 45 at 2100 fps out to 300 yards with a 150 yard zero, drop on target is 25 inches 200 yard zero same velocity drop on target is 18 inches,however that zero makes it very likely you will overshoot shorter targets, given the other variables, most important error in range estimation, sure hit in the field on live game at 300 yards with any of the big 45’s is as much luck as anything else.

9.3 is a lot flatter shooting cartridge, drops half as much as the slower 45 caliber bullet at 300 and a much better choice for distance. If distance my personal opinion flat shooting cartridge is the way to go no matter what kind of rifle.

Boats

No argument there, however two things have changed matters in the last few years.

One: The pocket-sized, extremely accurate,laser rangefinder.
Two: Quality telescopic sights with bullet drop compensating turrets.

I'm 71 years old, my eyesight is not what it once was, and all of my double rifles now wear good scopes.

For iron sights, I agree. Not for a scoped .45-70 Ruger No. 1. My son and I have both taken many deer with Ruger .45-70s. A properly sighted in, scoped .45-70 is more than a 100 yard deer/hog rifle. With 300 gr. FNHP bullets at 2100 fps I have found it to be easily a 150 yard gun, and a good, practiced rifleman can extend that a little under the right circumstances.

Just my experience, SRH

45/70 can be Loaded two ways modern strong rifle, old weak actions. When I owned a new Marlin 1895 used that samr light bullet fast and it was a 150 yard rifle. Most of my 45/70 experience is black powder at under 1300 FPS.

Bullet drop is linked to lag time how long the bullet is in the air. Mostly velocity some ballistic coefficient. Effect is about any 2100 FPS bullet has the same drop. That means the big 45's have 30/30 Trajectory, or very close to it. Power being another thing.

Boats