Home Forums Reloading Big Game Rifles 7_08 Velocity

Would be willing to bet he's using a Shooting Chrony. Have seen one of them jump 10% in velocity due to a change in the light.

The magic new velocities (which amount to maybe 100 fps) in the .243 with Enduron powders are most likely due to using more accurate piezo-electronic pressure-test equipment, rather than older copper-crusher equipment. If you look at Hodgdon's data on their website, it shows the pressure for the Enduron powder in PSI (electronic) rather than CUP (copper crusher. Hodgdon has not made any claims about higher velocity levels with the Endurons.

If your load of CFE223 is at 48.9 and your getting those speeds then, I'd say you've got a real fast barrel...don't know what else to say. If it was me, I'd see if someone would let me run that load over their chrony, just to see what a different chrony would tell you.

Your varget load seems about right IMO, based on your 22" barrel, etc.

Apparently you don't have the iq to understand that velocity DOES NOT EQUAL pressure. It can be an indicator, but only when variables don't change.
PRESSURE OVER TIME minus whatever resistance the bullet encounters, blowby, etc. Determines velocity.

slim' if the 120 TTSX blew up on your doe in 2012, why are you back again pimping the same load?

Edit: if pressure does not equal velocity, what pushes the bullet through the barrel, CFE 'pixie dust?

You are a prize.

I just looked at the Hodgdon 100-grain data for the .243 and the ONLY pressures in PSI are for the Enduron powders.

I know companies improve powder, because they send me samples all the time to test. BUT, as I stated already, Hodgdon isn't making at claims that the Enduron powders get any "extra" velocity than other powders. All the improvements are in other areas, such as temperature-resistance, a decoppering agent, and "green" ingredients, so they can sell them in Europe.

Not quite. The work done by an expanding gas is pressure as a function of volume, integrated over volume.

w = ∫p(v)d
fine then, area under the curve, which I mentioned previously. if you get what I am saying, why bring calculus into it?
Thanks for trying to explain it to RDW though.

This can be parameterized using time t, but the pressure-time curve by itself doesn't tell the story.

yes...sorry I don't know how that got crossed.

slim' if the 120 TTSX blew up on your doe in 2012, why are you back again pimping the same load?

Edit: if pressure does not equal velocity, what pushes the bullet through the barrel, CFE 'pixie dust?

Slim,

That's because they switched to piezo equipment within the past few years, so started testing every new product (whether bullets or powder) in PSI.

They didn't run nearly as many powders with the 85 TSX as they have with older bullets, particularly in the slower burn-rate range where IMR4451 stands out. Check out their .243 data for the 90-grain Speer bullet: the velocities for 4451 lag behind such "new" powders as H4831 and H414/W760.

Have you ever actually done any work with pressure-testing equipment, whether strain gauge or piezo-electronic?

Please put your comments outside of the quote box, or color them, so I can follow them better.

It's area under the curve all right, but you still haven't latched on to the fact you're talking about the wrong curve. Work done, and hence velocity, is through the area under the p-v curve, not the p-t curve.

Calculus was brought in precisely because that's how area under curves is described in other than simple situations.

Well, this is a simple situation where i was trying to keep an explanation simple. what am i missing? pressure times the area is force. simply put, the average force (however you want to arrive at that) exerted over the time the bullet is in the barrel will give velocity when bullet weight acceleration are figured. BTW The area under a curve with pressure in the y axis and time in the x-axis will give the work done on the bullet. what is it you think I am not latching on to? - how to open up my physics book and write some equations? Thanks for your "help"