muzzle exit pressures

[chop house]

i do not own quickload, and have not yet loaded up grt, so i ask, generally speaking, do ...

1. heavier bullets show more or less muzzle exit pressure than light bullets
2. do slower powders show more or less muzzle exit pressure than faster powders
3. what are typical numbers and/or pressure traces comparing, say, M193 and M855 in 16.1" bbl

generally speaking, all things equal, apples to apples, equivalent energy, etc, etc. ?

thanks

 

[joshb]

By my wild a— guess, they would all have about the same pressure if charged to max loads. Now.....velocity?

 

[chop house]

By my wild a— guess, they would all have about the same pressure if charged to max loads. Now.....velocity?

ah ha, peak pressure likely equal. i am curious about pressures at the time the bullet exits the muzzle, however.

 

[3Sigma]

I have the ultimate engineering answer... it depends

 

[chop house]

it depends

and hence 'generally speaking', is there a trend?

 

[Adam in WI]

I quick did a sim with my .25-06 in grt. With 75 grain bullets at 3800+ fps and 115s around 3300 the exit pressures are within ~2% around 16,000 psi

 

[chop house]

I quick did a sim with my .25-06 in grt. With 75 grain bullets at 3800+ fps and 115s around 3300 the exit pressures are within ~2% around 16,000 psi

thanks. do you also have info on one or other bullet with a couple powders on opposite ends of burn rate?

 

[Adam in WI]

I just did another quick one with my 7x57 and 120 grain bullets. Using imr 4198 for a reduced recoil load figuring 63,000 psi maximum pressure gives a muzzle pressure of ~10,000 psi, while the same bullet with a max charge of RL-16 yields ~16,500 psi.

 

[chop house]

great info. thanks again @Adam in WI

 

[wwbrown]

I have the ultimate engineering answer... it depends

I always used: I need more data

 

[granite1]

Why?

 

[3Sigma]

I always used: I need more data

That's the next step after they understand it is not a trivial question.

 

[wwbrown]

That's the next step after they understand it is not a trivial question.

... and after that is the ask for an estimate (time and money) of the task.

 

[Ggmac]

I would think barrel length has a MAJOR influence. Also bullet makeup, bore diam , bore condition, type of steel , coated or uncoated bore . Etc

 

[chop house]

I would think barrel length has a MAJOR influence. Also bullet makeup, bore diam , bore condition, type of steel , coated or uncoated bore . Etc

yes, of course. my question was pertaining to different loads of equivalent bullet kinetic energy from the same firearm.

 

[chop house]

Why?

inquiring minds want to know.... and i suppose you could counter with, "inquiring minds want to know why you are inquiring"

 

[dantiff2]

Someone got a suppressor