My Labradar muzzle velocities are getting pretty consistent now

[Mysterious Stranger]

I have patiently been working the issues out of both my recently delivered Dillon XL750 and my own setup, to improve the consistency of my 357 Magnum CAS handload that I use in both my CAS rifle and my CAS revolvers.

 

Today, I was at the range to fire some groups to see how far out my Uberti 1873 rifle's sight settings were off after installing a different front sight that I could see much better. As it turned out, I only needed to fire 3 groups of 5 shots each to get consistent data for both elevation and windage errors.

 

I noticed that the Labradar muzzle velocities being reported seemed more consistent than I had been getting before. After the range session, I examined the Labradar shot log, and found a really nice set of statistics for this short 15 shot batch of shots:

 

Stats - Average		1129
Stats - Highest		1144
Stats - Lowest		1120
Stats - Ext. Spread		24
Stats - Std. Dev		6.86

 

Finally! 

[Happy Jack, SASS #20451]

That is very good S.D.   However it is illegal for SASS revolvers.  The limit on velocity is 1000fps for revolvers and 1400 fps for rifles. It is probably also illegal for rifles.  

 

The drive to a lower power factor has led to some very light loads and resulting very bad S.D.s  But to hit big targets at 5yds you don't need good ammo.

[Mysterious Stranger]

2 hours ago, Happy Jack, SASS #20451 said:

That is very good S.D.   However it is illegal for SASS revolvers.  The limit on velocity is 1000fps for revolvers and 1400 fps for rifles. It is probably also illegal for rifles.  

 

The drive to a lower power factor has led to some very light loads and resulting very bad S.D.s  But to hit big targets at 5yds you don't need good ammo.

 

These statistics were obtained firing my CAS RIFLE, not a CAS revolver. The revolvers shoot the same handload at about 910 fps. Also, the SASS speed limit for main match rifles is 1400 fps. There is nO speed limit for the long range side matches. So, the load is legal for SASS.

 

And the CAS target distance here in Alberta, Canada are longer than what you U.S. shooters apparently shoot at. Handgun targets at our last club match a few days ago started at about 10 yards and went to 15 or 17 yards. Rifle targets went from 15 yards to 45 yards.

 

Many U.S. CAS shooters have told me that a PF of about 100 is sufficient for their knockdown targets, but at our club a .38 Special or 357 Mag load with a PF of 110 will NOT reliably take down the plates on our non-adjustable knockdown rack (You have to hit the plates right near the top rim to do so).  My 910 x 158 / 1000 = 144 PF handload does take them down.