A bullet has three distinct phases in its life cycle. Internal ballistics are the science of what is going on from the point of powder ignition to the moment the bullet leaves the muzzle. Then we have external ballistics which is what a bullet is doing as it flies through the air. Then we have terminal ballistics wich is describing what a bullet does once it hits a Target.

When I'm describing dwell what I'm talking about is how long the bullet stays in the barrel after the powder has been ignited. Measuring dwell in an engine is easy because things are going slower then a rifle bullet being fired. You have to break down the event in ten thousands of a second to truly understand what's going on inside the bore of a gun. I do not have the instruments ( no one does) to measure that but I understand exactly what's going on. A rifle and an internal combustion engine function in the exact same way, they are trying to derive mechanical work from a chemical reaction.

That would assume that the bullet had the same bearing surface or more being a heavier/longer bullet.[/quote]

Instead of assuming let’s refer to Hornady published data for the two projectiles and H 4350 being discussed here.
140 eld-m advertised max is 41.5 grains
153 A-tip advertised max is 40.3 grains

Regardless of what the true max charge for a given rifle is, considering that the 6.5 creedmoor is Hornady as are those projectiles, I would wager they have taken a more thorough approach than most of us rednecks eye f*%#’n our brass.

I can't provide any pressure curves, but any idiot would know what I said is true. Even if I did, you'd figure out a way to argue about it, and you've proven it numerous times around here.

Im not saying the loads are safe or under max. None of us have, or have used pressure testing data on these loads, nor will they likely ever be. You stated in your first post quoting mine loading longer wont change anything. There are numerous knowledgeable posters that post here that say the opposite. I guess we will never know till we all run our stuff through pressure testing. Seems like everyone always forgets it takes more than one to argue.

Idiots don't stick around in the hand loading game for a long nor do they have a good grasp of what's going on. You like many others before you have noticed a relationship between pressure and seating depth. It is an indisputable fact under every circumstance that I've ever encountered that it changes things. I was simply trying to explain why it changes things.

Edit: I can go into great detail about why it changes things if you would like for me to do so.

I could care less why it changes things, I just know that it does, and it happens every time. No need to waste your breath unless it just makes you feel better and are trying to impress us.

I highlighted what you said in case you forgot why I responded the way I did in the first place.

^^^^ When I said not necessarily true what I was talking about is that higher velocity can only be achieved by higher pressure. You can achieve higher velocity without raising peak pressure by having a slower drop in the pressure curve throughout the entire event of the bullets travel down the barrel.

You not caring why the pressure rises is willful ignorance. Evolutionary changes in technology come from people that care about why things work and dig into the details to make them work better.