How do you compensate for the reduced pressure?
my understanding is that the reduced pressure is caused by the reduced bearing surface of the bullet. Does this mean that the fps is greater or less?
Does less pressure mean less fps, or because of the reduced friction it is allowed to travel faster down the barrel.
Or does reduced pressure mean a slower burning rate?

regards
griff

In my limited experience with TSX (.300 Win Mag, .270 Win, .257 Wby, .270 Wby), you can expect to be able to load up to normal max loads and achieve comparable speeds to what manuals list. That was not always the case with the original Barnes X.

- mike

I seem to be getting 100 FPS faster at max for my rifle.I've only used them in my 338-06 with 185 gr-3000 and 210 gr-2800.

Personally I wouldn't count on them being ANY FASTER than normal bullets of the same weight at EQUAL pressure.
I would love to see a comparison of velocity with pressure testing equipment. It would be my best "guess" that if you took an old barnes xbt, xlc, and tsx and chrono'd WITH PRESSURE TESTING EQUIPMENT you would see almost equal pressure and velocity between the three....but it might take more powder to get there with the tsx and xlc. Maybe, just maybe, there might be a 75 fps diff but I would "guess" that would be a best case scenario.

I'm getting 3250fps with 140 bal tips and 3400fps with 140 barnes tsx in my 7mm wsm with 68 grns rel 19 and a 28 inch barrel

In Quickload, the default start pressure of the TSX is between regular "cup" bullets and the old "X's". Based on that, I'm using regular bullet data less a grain or so. FWIW, Dutch.

quote:

Does less pressure mean less fps,

It can, but it does not necesarily mean less speed. For example, in my .30/40 Ruger No. 3, I worked up a load using IMR 4350 that gave a certain velocity. I then tried some of the old H205 in the exact same weight with the same bullets, cases, and primers. The H205 load gave the same MV as the IMR 4350 load, but at considerably lower pressurte.

I have shot the 150 gr TSX in my 300 Win Mag and could not use the same amount of powder with the same weight bullet in a Sierra Game King. I had to go to the recommended starting charge with the TSX anything above that and it started showing pressure (a sticky bolt is not good). It may be only my rifle that does this, but they are a lot more accurate than a 150gr Nosler Partition at least in my rifle.

I really wanted to shoot the Nosler Partition but 4.5" 100 yard groups are not acceptable.