Variance in Double Rifle Regulation?

[Ray B]

Suppose I order a high quality double in 500 NE and the maker regulates the barrels to hit at point of aim with one brand of bullets. I get the rifle, fire that brand of bullets in it and both barrels print exactly on target. So I book a trip and when I get there, the rifle arrives but no ammo & the local stores do not have the regulated brand in stock. What sort of variance will occur in the printing on the target of a different brand bullet of similar construction but possibly a few grains difference in weight, both bullets being approximately the same velocity? I'm not asking for an answer detailed in thousandths of an inch - Generally, would the different ammo be expected to be accurate enough for reliable use on something the size of Cape Buffalo at 75 yards? Naturally, I would have shot it at paper first.

 

[PHOENIX PHIL]

I don't know for sure, but I think your question is impossible to answer till you find out the hard way. And I believe the point of your post is to avoid finding out the hard way.

From what little DR knowledge I have, what I've come to believe is that it's a total crap shoot. You may pick up a box and it will be close enough that you can continue on. Or you may pick up a box that'll leave you asking what rifles does the camp have to rent?

@AZDAVE, have I got this correct?

 

[CAustin]

Suppose I order a high quality double in 500 NE and the maker regulates the barrels to hit at point of aim with one brand of bullets. I get the rifle, fire that brand of bullets in it and both barrels print exactly on target. So I book a trip and when I get there, the rifle arrives but no ammo & the local stores do not have the regulated brand in stock. What sort of variance will occur in the printing on the target of a different brand bullet of similar construction but possibly a few grains difference in weight, both bullets being approximately the same velocity? I'm not asking for an answer detailed in thousandths of an inch - Generally, would the different ammo be expected to be accurate enough for reliable use on something the size of Cape Buffalo at 75 yards? Naturally, I would have shot it at paper first.

Difficult to to say! I find myself wondering the same thing. My newly acquired double was built in 2003. At the time Merkel was regulating their rifles with Federal Premium Trophy Bonded Sledgehammer rounds.
I am going to try a couple of different brands over the next few trips to the range. So I tried Hornady this past Sunday morning and I was satisfied that they will work.

The two to the left are off hand at 50 yards and the 9 ring was on sticks just firing the right barrel. Open sights. The top black dot was also the right barrel. So it looks like the elevation is good. Now to work on operator error....strumming both triggers!
Next up will be federal premium with Swift A frames. Then I plan to try some Barnes.

 

[MMAL]

I own two double rifles. Kreighoff 500/416 and Blaser 500ne. I can tell you from load development for both it can be as much as 6-8 inches at 50 meters. I have had some other issues but that is my delta with different bullets and loads.

 

[Red Leg]

If using a factory load, and you find one that works, then I would stock up with a "lifetime" supply. Just the variations between different production lots (noted on the box) can vary tremendously from the original regulated load - both accuracy of the individual barrels (true of any rifle) and regulation between them. Anything you pick up off the shelf as a stand-in for the regulated load - regardless of bullet weight - will be a crap shoot.

A lot of rifle cranks finally take the double rifle plunge, and all too soon find themselves trading it away or consigning it to the back of a gun safe. "Accuracy" as most riflemen in this country appreciate the term is a fairly rare thing in doubles. I have a friend who recently sold a .500 complaining that his 8k investment was no more accurate than an 870 slug gun. Well, yes, that is probably correct. It typically takes an enormous amount of time and effort to find or create a load which will give you a 4-inch LxR/LxR at fifty yards. When it comes down to actually taking something afield with that sort of accuracy (normally not nearly that good) ...... with the exception of elephant, they tend not to get employed very often - even if they made the trip over.

There are doubles that are exceptions to this rule - my Blaser S2 - is one. I have taken game out to 200 yards with it. I have a little German 9.3x74R which is another. Both of those have adequate supplies of their favorite loads to see me through.

 

[CTDolan]

A double rifle's place is being able to reliably punch two holes in a target the size of a grapefruit, in rapid succession, inside of 25 meters, with open sights. Asking it to do something else is asking for disappointment. You might get lucky, but then again you might not.

They're fight stoppers, plain and simple. When a bull elephant is bearing down in thick brush there's nothing better to have in the hand. But to ask it to group a tight left and right, at 50 meters (or more), with varying loads, is asking a lot of such a contraption.

 

[AZDAVE]

Double are my favourite hunting rifle! Each one can have kinda a mind of it's own. I have worked up loads for 11 that have come through my hands over the last 10 of so years. and helped with 10 or 15 others. I Have been able to work up a good load (3in or better at 50Meters) and most shot different factory loads to with in 5 in that will get you minute of cranky Kritter. Except the 45/70's. There is so much variation in the different 45/70 loads. For trapdoor pressures, for older rifles, for lever guns and for ruger #1's. So as long as you aren't talking the 45/70. I will go out on a small limb and say that a High quality double shooting standard factory fodder in the 500 you should be good. I would get several different brands and try them in YOUR rifle and see how they perform. Look for bullets that have the same shape as the rounds your rifle is regulated for. Then if you have to substitute for baggage handler mishaps look for a similar profile. all else if you have to shoot bubbas pretty good 500NE. take the rifle to the range at the outfitters and figure where the first barrel your shoot prints and use Kentucky windage and Tennn elevevation so you know where to hold for 50 and 75. then shoot straight. and the second barrel is the being charged and shoot at 15 meters instinctive shot.

 

[Tokoloshe Safaris]

Agree 100%, if in doubt get closer @ 20 meter grouping won't make much difference. Only the experience will be better!

 

[8 x 60]

Hi Ray

Very interesting question.

I believe above posts cover it pretty well. All I would add is if you are using a "Stopper rifle" up close and personal as it were,, (inside 20 yrds or so?) what sort of group would be needed? If not...

If you are talking about a "smaller" calibre (say 8mm etc like use) and you are hunting "non-dangerous game" (they can all be dangerous by way!) - plains game, and you have lost your ammo en-route but replacements are available and you only have your one gun - a double rifle..

This is what I would do ...

Zero one barrel with the replacement ammo. (You may be surprised by the grouping with both barrels of course)

All is not lost. You are now hunting with a single shot (many people do) Choose your shot well and crack on.

I would rather be hunting with a double rifle with only one trustable shot than not hunting!!
(After all one of the often rightly quoted reasons for a double rifle (assuming double triggers) is the redundancy issue. ie two separate locks and barrels, so if one fails you are still good to go..)

Just my tuppence worth.

 

[8 x 60]

.577 Single shot . Cape Buff

 

[Dr Ray]

Suppose I order a high quality double in 500 NE and the maker regulates the barrels to hit at point of aim with one brand of bullets. I get the rifle, fire that brand of bullets in it and both barrels print exactly on target. So I book a trip and when I get there, the rifle arrives but no ammo & the local stores do not have the regulated brand in stock. What sort of variance will occur in the printing on the target of a different brand bullet of similar construction but possibly a few grains difference in weight, both bullets being approximately the same velocity? I'm not asking for an answer detailed in thousandths of an inch - Generally, would the different ammo be expected to be accurate enough for reliable use on something the size of Cape Buffalo at 75 yards? Naturally, I would have shot it at paper first.

I suggest something like 1.5 inches at around 40-50 yards/m.

For buffalo at 75 yards I doubt whether it will be a big problem.

 

[HWL]

Suppose I order a high quality double in 500 NE and the maker regulates the barrels to hit at point of aim with one brand of bullets. I get the rifle, fire that brand of bullets in it and both barrels print exactly on target. So I book a trip and when I get there, the rifle arrives but no ammo & the local stores do not have the regulated brand in stock. What sort of variance will occur in the printing on the target of a different brand bullet of similar construction but possibly a few grains difference in weight, both bullets being approximately the same velocity? I'm not asking for an answer detailed in thousandths of an inch - Generally, would the different ammo be expected to be accurate enough for reliable use on something the size of Cape Buffalo at 75 yards? Naturally, I would have shot it at paper first.

Check it out, as long as you are at home, every brand of ammunition you can get your hands on....

HWL

 

[Philip Glass]

Suppose I order a high quality double in 500 NE and the maker regulates the barrels to hit at point of aim with one brand of bullets. I get the rifle, fire that brand of bullets in it and both barrels print exactly on target. So I book a trip and when I get there, the rifle arrives but no ammo & the local stores do not have the regulated brand in stock. What sort of variance will occur in the printing on the target of a different brand bullet of similar construction but possibly a few grains difference in weight, both bullets being approximately the same velocity? I'm not asking for an answer detailed in thousandths of an inch - Generally, would the different ammo be expected to be accurate enough for reliable use on something the size of Cape Buffalo at 75 yards? Naturally, I would have shot it at paper first.

I think too much time and effort is spent worrying about ammo not arriving and what to do. Actually if I his is a big concern Then you must buy a .470 instead of the .500.
I think Eveyone should buy whatever gun and caliber they really like and go for it!
My .416 Ruger performed flawlessly for me but if I was worried about ammo not making it I’d been frazzled preparing for my safari!
Philip