I have a 602 which is being converted to .500 Jeffery at this moment. I am more than a little concerned with the question of feeding, but I am expecting to be notified that the job is done any day now and as soon as I have the rifle in hand, I will be glad to furnish you with an evaluation of the conversion.

Another consideration is the expense of componants. The .458 Lott, Watts, Ackley, etc. are all cases based on the .375 H&H, and the brass is FAR cheaper than any of the more exotic British rounds. It is also far more available. Taking the case one step up to .460 Weatherby/.416 Rigby size is another possibility. Either of those cases opened up to .500 will produce velocities which will easily outperform .500 Jeffery or .505 Gibbs factory loads. The brass is more expensive than the H&H size, but still easily available and inexpensive compared to .505 Gibbs or .500 Jeffery brass.