Pressure Curve on PXT Barrel/Peak Case

[SloppyJ]

Been trying to think wholistically about this entire situation as new products have been trickling out in the past month. Has anyone seen a pressure curve for a PXT barrel? I struggled with what subforum to put this in but figured my reloading nerds would have the most interest in it. Second, I'm just a redneck nerd that works in engineering for a living but I'm no ballistician or anything close. I've been mulling this around:

All factors remaining equal, what does the pressure curve of a PXT barrel look like compared to a conventional barrel? I'd have to imagine there's not as big of a peak right at the start because we aren't jamming a bullet down the rifling and expecting it to spin up to 250k rpm as fast. I would also imagine that as the twist rate tightens up down the barrel, it would elongate that pressure curve so maybe we have the same area under the curve but the distribution is more spread out. If that's actually true, what does that mean in terms of powder choice and charge? Is there now a little more head room to bump that "spike" up?

If any part of #1 is true, how does that tie into the peak cases? We've now upped our top end pressure limit, supposedly up to an additional 18k psi, and now we need to change quite a bit to take advantage of that. Do we have a further advantage with the exponential twist barrel? To me this would come down to powder choice and adjusting the burn rate to see what works by messing with that peak pressure.

Maybe I'm retarded and need to focus on something productive? I don't have pressure testing equipment nor the means to size the cases but I'd love to test some loadings out of standard barrels and the PXT barrels in both case types to see if I could gain any insights on any of this. I can't find much information out there yet.

Anyone played with this yet?

 

[Tanner]

The more I think about it, the more that LRP Lapua brass and 140s scootin’ 2630fps appeals to me

 

[43.6N]

I am admittedly not so bullish about the peak ammo or how much benefit the gain twist actually will have on prolonging barrel life.

So far we have a lot of internet hype, and exactly 1 video of a 7prc going 4000 rounds iirc.
I think this will need to be out in the public hands for many months of high volume shooting before we see if it actually holds up.

That being said, I found a pressure curve from a howitzer barrel life study:


I’m imagining peak pressure will be higher, but the slope to peak pressure will be slightly more gradual. Total area under the curve will be higher, and exit velocity will correspondingly be higher.

Something like this: