Thread: Remington 700 Sako and M16 extractor conversions

Yep but as Greg Duley said if your getting the same velocity(in the same length barrel) then you must be achieving the same pressure.

Originally Posted by veitnamcam

Yep but as Greg Duley said if your getting the same velocity(in the same length barrel) then you must be achieving the same pressure.

Correct, For example, I shot a remmy 7-08 SPS today, ADI 2208 for 140 BTips, books say about 42gn for 2820-2850fps

At 42gn I was only getting 2680fps out of this rifle, so worked up to 44gn for 2800fps with no pressure signs, will try 44.5, 45 next time. I'm picking 45gn will be about a safe working max, 3gn over the Nosler book.

Originally Posted by veitnamcam

Yep but as Greg Duley said if your getting the same velocity(in the same length barrel) then you must be achieving the same pressure.

I see where you're coming from....But hang on a minute- thinking about the physics, that may not be a perfect rule:

If a barrel is "tighter" or "rougher" it will place more friction on the projectile trying to pass down it.
As a result, more pressure will be required behind that projectile to create the same speed.

-So I wouldn't think pressure vs. speed is a straightforward relationship. Sure, there will be a correlation. But I'm not sure it'd be a safe assumption to make at the upper end of the range???

Originally Posted by James

I see where you're coming from....But hang on a minute- thinking about the physics, that may not be a perfect rule:

If a barrel is "tighter" or "rougher" it will place more friction on the projectile trying to pass down it.
As a result, more pressure will be required behind that projectile to create the same speed.

-So I wouldn't think pressure vs. speed is a straightforward relationship. Sure, there will be a correlation. But I'm not sure it'd be a safe assumption to make at the upper end of the range???

True but then how tight/rough/smooth was the test barrel? how accurate is your crony? how accurate was thiers? how well calibrated was their pressure test gear? and you can guarantee you are using different components to the test data so its a moot point really.
Let common sense prevail (even if its not that common)

Originally Posted by veitnamcam

True but then how tight/rough/smooth was the test barrel? how accurate is your crony? how accurate was thiers? how well calibrated was their pressure test gear? and you can guarantee you are using different components to the test data so its a moot point really.
Let common sense prevail (even if its not that common)

Again I can see where you're coming from- but as you've just pointed out: that's even more variables that can lead things to things going astray.

-Common sense is a great cure for most problems (Just don't try telling a girlfriend that in the middle of an argument- I did, didn't work out well for me).
And I'm certainly not disagreeing with the fact that within normal scenarios most reloaders will be absolutley fine with the "load up till you get the same velocity" approach.

-What I'm disagreeing with is the statement that: same velocity = same pressure. Cos it's not correct.