Home Forums Reloading Big Game Rifles Downloading a 416 Rigby?

Can a 416 Rigby be downloaded so that it shoots a 400 grain bullet at ~2,100 to 2,200 fps? I haven�t seen any recipes for that. Could it cause low pressure problems?

Well there is low pressure and then there is low velocity...which can be achieved, without causing low pressure by using faster burning powders..

I'd start out with SR 4759...or IMR 4198...

check out some cast load data..

according to an Accurate Arms load data manual I have, you can look at 5744... in the 49 to 55 grain range..

from that, I can recommend Rl 7, IMR 4198 within that range and just work up until your chronie tells you you are where you want to be...

Speer suggested using 4895 to develop a reduced recipe. (This was before Hodgdon came out with their recommendation that one might use H4895 at 2/3 of max.) In any case, that's how I've done slowed-down loads in the 416 Rigby I've loaded for. As I recall they said I could use 75 grains with the 350 Hot-Cor which is one grain more than max in the Rem Mag with the IMR version. (That isn't a recommendation BTW, as it is only from memory.) I'm sure you'd have no trouble using the book max of IMR 4895 for the Rem Mag (which is 73 or 75 grains for 2227 fps or 2314 fps respectively for the solid or Grand Slam respectively.) The larger case may not even reach 2100 fps, but it would be a place to start.

The XMP 5744 data works.

H or I 4198 works very well too.

Lyman #48 lists a number of loads near your velocity range - between 2200 and 2300 fps - as starting loads. They eschew the faster powders due to the huge case capacity and massive air space when using them - even full power loads don't fill the case.

Lyman, etc. prefer powders in the IMR4350 to IMR7828 burning range so the case is more nearly full. This is a huge case, and from my limited work with the similar-sized .378 Wby you don't want a lot of air space - this isn't a .30-06 or a .300WSM...you are likely to have occasional hang fires with the faster, less bulky propellants unless you tip the muzzle skywards before each shot...except that I never tried BlueDot. Hmmm, I wonder.



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Good point by DoubleRadius on the possible hang fire with low load density. I believe there are some loads that involve putting some sort of wad and inert filler over the powder charge to ensure proper ignition. I am a new Rigby owner myself and would be curious about such reduced loads. You may get more feedback over in the Big Bore section.

Dacron is your friend, if you are comfortable with fillers.


I'd be more wary of low pressure/bottom edge slow-bulky powder loads.

Thank you, gentlemen.


HawkI, would you mind expounding on that? I'm here to learn...

If you find pressures listed for starting loads, they are with very slow powders and pressures are very low for magnum powders in the Rigby. I personally would not reduce a starting load any further, especially with that size of case.

DoubleRadius pointed out even these loads have considerable air space.

Hang fires are never good, but particularly those with slow powders, which have a history of ruining property and persons when used in smaller doses and not filling enough of the case. Something about a primary ignition down the barrel that can happen.

Too little of a slow powder for a given case can be hazardous, just like filling the whole case with Bullseye.

I have never had anything like this happen to me, but most reloading manuals do not advise lowering slow powders from the starting points.

As DR stated, keep the case full or close to it with the slow fuel.

Powders like IMR or H4198, the 4895's and XMP 5744 are all used in large capacity, low pressure loads (under 30,000 psi) with lots of airspace and their efficiency when reduced allows them to function at lower pressures as well. It is possible they would not work well, but I have found they work great with a filler. Ross Seyfried had a formula I used for my Rigby and it uses Dacron filler.

The Accurate listed XMP data is safe, even without a filler.

You could go to an even slower fuel, like H50 BMG, and fill the case with it and may get the speed you are looking for, which is what DR might have been saying.

TrailBoss? Hodgdon might have a recommendation. Just a thought.

Contact Johan, the senior ballistician at Accurate Powders. He's very helpful, and I'm sure will give you some reliable data on using AA5744. You won't need a filler with that powder.

+1

The Hodgdon Load Center cautions against using H4895 in a case where they don't recommend its use, and it's not listed. I would take that to mean that the case is too big. With TrailBoss, however, you can get into the 1100 fps range.

I would leave this one for the pro's.

A belated thank you, gentlemen.

As for Johan, the senior ballistician at Accurate Powders, yes I've spoken with him a couple of times. He's really cool - very responsive and helpful.

Johan was very helpful. I was looking for smaller game downloads in my .404 Jeffery and went with .035 jacket 300 grain Hawk bullets using AA 5744. Keep density 50% or more and you can launch that puppy form 1800fps through 2800fps with decent accuracy. No filler needed. A 416 Rigby should be even more of a good thing. Just let your shoulder be your guide.