My stainless #1 really liked Benchmark and TAC. Hodgdon data for the 300 Hdy FP shows that 59gn Benchmark gives 2404fps with 42,200PSI.
If you want to go heavier, I found that the Woodleigh 400gn (.411") bullet was very accurate. Oddly enough, the 400gn Hornady (.400") bullets made sideways holes in the 100yd target when they hit the target at all.
Having hotrod ambitions, I had a reamer made and lengthened the chamber throat by .28”. This allowed 300 TSX to be seated at 3.500” and 400 Woodleigh to be seated at 3.520” overall length and still leave .020” of clearance before the bullets touched the rifling. Using “The Rules” by John Barsness, I calculated the potential velocity increase over the loads in the Hodgdon Manual.
The 300 TSX went up to 2500 fps using Benchmark or 8208XBR. Recoil was quite sharp and verging on unpleasant.
The 400 gn Woodleigh (.411”) went to 2150 fps using 8208XBR, TAC or Reloder 15. Recoil was more of a push and not at all unpleasant.
No indications of excessive pressure were found. Accuracy was excellent and loads of normal length shot as well as they did before the surgery.
True Shot .41 caliber 265 gn cast bullets loaded to 3.09” overall length over 12 gn of Unique made cloverleaf groups.
The reamer is now in the custody of gunsmith Doug Wells in Huson, Montana. If he is terribly busy he might just rent you the reamer. His number is (406)626-4152
Enjoy your .405.
Cheers,
Walt
