Heeman,
I called Barnes today for loading data with the 120 TSX.
H4350:
Min. 38gr./2558 fps
Max. 42gr./2780 fps.
24" barrel, Federal 210M primers.
GB
If 42 gr of H4350 is maximum with a Barnes 120 TSX, and only produces 2780 fps out of a 24" barrel -- a different powder choice is
definitely in order!
2900+ fps is very easy with Re 15 and H 414, out of a 22" barrel, without undue pressures. Each rifle is a law unto itself, and you have to work up, and all the standard caveats. But I would never trifle with H4350 in a 260 Rem if that's the best it can do.
Dennis
The only way you can empahticly say a load can be over book max and still be under pressure is with a strain guage.
Any other method is just a guess. You can mic it, look for flattened primer, shinny spots, loose primer pockets, sticky bolt lift, whatever, it is still a guess.
Whether or not another powder should be used....maybe.
GB
Hodgdon data shows a maximum load of 45.5 gr of H414 or 45.5 gr of WW 760 producing 2968 fps with 120 gr Speer bullets -- which is just a little more than my chonograph is showing me from my rifle. Their data shows 58,600 psi for those loads.
Nosler's data shows 45 gr of H 414 producing 3005 fps with 120 gr Solid Base Ballistic Tip; and 47 gr of Re 19 producing 2980 fps with 120 BT or 125 Partitions.
My loads are by and large within the limits of the loading manuals, and were fairly carefully developed watching chronograph data as well as the other signs. Certainly the concept of exceeding 2900 fps with 120 gr bullets is solidly grounded in quite a lot of reloading book data -- just not with H 4350 -- hence my suggestion to go to a powder that produces reasonable results. Nosler alone lists eight different powder types that will get you to 2900 fps, or within 5 fps of it, with 120 gr bullets.
Incidently, I have found that TSX's exit the muzzle going faster than other 120 gr bullets in my Remington, given the same (safe) powder charge. Which would seem to indicate something, though I will leave it to others to decide for themselves what that might be.
Dennis
