pistol ammo es

[stool]

last night i loaded up a mere 15 rounds of 45acp, 230 fmj.
three groups of 5, looking for a 875 or so velocity with a new bullet maker.
the thing i did different was to use my 2 speed power trickler and my f120i really good scale with mag dampening.
using the fast speed i got close and trickled up to weight..which with this scale it is then plus or minus .02...
kind of over kill on pistol ammo, but it was quicker than using my beam.
at the range from a 1911 at 10 feet i got 815, 847, and 887 with es's of 3,5 and 3 !
i'm just not use to such small es's in pistol ammo...
actually pistol ammo is short range and accuracy is not br stuff.
i do not expect these es's when i switch to loading the ammo on a dillon 550b.....

yes its only 5 rounds..and es is based on big data sets...but even so...dang those are small!

 

[jlow]

You have to multiply those ES numbers by something like 2.5 to 3.0 to compare to the rifle stuff since the fps is less by those degree.

 

[bheadboy]

I may be wrong but I have never had a problem getting accurate es/sd with pistol and my 45acp data indicated them in th 8-12 range. with much more consistant speeds.

I question the date output from you crono

Bob

 

[stool]

behed...
those are the AVE vel for 5 shot strings,,,,,in three diff loads.....

I may be wrong but I have never had a problem getting accurate es/sd with pistol and my 45acp data indicated them in th 8-12 range. with much more consistant speeds.

I question the date output from you crono

Bob

 

[stool]

you will have to explain that to someone, but not me.
es is a number based on variation from an average..etc /etc....and has nothing to so specifically with shooting, so not related to a given speed bracket.

in real life it does require a large data set..like a 1000 or more.....we just use the math they use to generate numbers for all small data sets......which are really too small to validate the sd/es.

You have to multiply those ES numbers by something like 2.5 to 3.0 to compare to the rifle stuff since the fps is less by those degree.

 

[jlow]

It’s a percentage thing. Say if your MV is 3,000 fps, a 1% ES because of say slight difference is neck tension would be 30 fps. For a 1,000 fps round, the same 1% ES would be 10 fps. That is why the ES tends to be smaller for a lower MV round.

 

[stool]

no...

It’s a percentage thing. Say if your MV is 3,000 fps, a 1% ES because of say slight difference is neck tension would be 30 fps. For a 1,000 fps round, the same 1% ES would be 10 fps. That is why the ES tends to be smaller for a lower MV round.

 

[dan06]

You wil find that crimp and brass consistancy has more to do with Es than small powder charge variations. If you want small ES with a pistol sort brass by amount of fireings and get consistant crimps.

 

[stool]

all once fired brass from the same lot...so was sort of ahead of the game there...
people call me crazy when i trim pistol brass......

You wil find that crimp and brass consistancy has more to do with Es than small powder charge variations. If you want small ES with a pistol sort brass by amount of fireings and get consistant crimps.

 

[stool]

Extreme Spread ES is a statistical term that basically defines the difference between the highest and lowest numbers of a group. For example, 35 fps would be the extreme spread for a velocity string of 3000, 3010, 2990, and 3025.


it is a number, in statistics in a large sample it might mean something to the number cruncher, for us it is just the spread from lo to hi.


no percentage of anything

 

[JohnMill]

Please send all rounds that are too accurate to me so that I may dispose of them properly.