Just got my 416 Taylor on a Savage action with Adams & Bennett barrel together a week ago. Since then I set out with 400 grain Interlocks and Re-15 to establish max. load before going on to developing a useable load for this rifle.

I started out by shooting a few loads with 15 grains of Unique just to fire form some of the 458 Win. brass and,,, Well, this was my first conversion and I just wanted to be sure things were right before dumping in the Re-15!

I started with 66 grains of Re-15 working my way up to 70 1 grain at a time. Once I got to 70 I then worked up from there a half grain at a time. 74 grains showed 1/1,000 of stretching in the belt and though the primer was not "flattend" it had definately changed shape a little and lost some of its oval shape around the outside. Even though 73.5 showes no sign of pressure problems I decided to set my max at 73. I will not have a chrony for 2 weeks {sure would have been handy to have during this developement process) but even though I'm a little disappointed at not being able to get 74 grains of powder in I beleive that 73 grains of Re-15 behind a 400 grain Interlock should be plenty good for trajectory and what ever finds it way onto the receiving end of the projectile.

All loads were shot in the coarse of a week in my back yard for a couple of reasons. It has been very cold so I figured by loading up the rounds in the house one at a time and then holding them in my hip pocket with my hand over them for the couple of minutes they were outside should more closely resemble shooting them in warmer weather and it gave me a chance to take my time cleaning my barrel between shots as part of the break in procedure inside the house were it was warm!

Now I guess it's time to do some shooting from the bench, arggg!

I have the same barrel on mine. Thank you, you just saved half my load development time. Until now I've only shot 350gr. MagTips and was going to try 400gr Hornadys and now know were to start without wasting rounds. Does your chanber let you seat long? mine leaves me all kinds of space to keep the bullet up in the neck. FYI 75.5gr of Rel 15 and the 350gr Speer worked great.

Heavy Varmit,
I have a .416 Taylor. Mine is throated for 400 gr Interlocks seated to an overall lenght of 3.420. This gives me 80gr water capacity under the bullet.
My max load with Rx 15 is 72.0gr. I am getting 2305fps chronographed.
I have also used 77.5gr of H4350 extreme for 2280fps.
Both loads using Federal 215s and Winchester cases. Both are very consistent.
Incidentally, I had my chamber cut with a longer neck, so my brass length is 2.600". All other dimensions are the same and I can use .458 brass necked down, too.
I make cases out of .300 Win Mag. I remove the die decapping pin. Form a shoulder on the .300 Win mag case that causes the bolt to close hard. I insert a large rifle primer, charge with 17.0gr of Unique, insert a wad of tissue paper in the end to hold things together and fire form.
I trim the cases to 2.600, full length resize and load.
This cartridge is a hoot to shoot.
Hope this helps
The Bearman out in the "Big Sky Country"

NBHunter, I have seated all bullets to the crimp groove so far but by seating them with the rifle the OAL is 3.475 so yes, there is plenty of room there to experiment with.