Weather can also affect the gyroscopic stability of your accurate bullet in your 14 twist barrel.
The previous projection where your gyroscopic stability factor was 2.91 was with normal weather conditions.

Caliber      0.375      Inches            
Bullet Weight      310      Grains            
Bullet Length      1.16      Inches            
Barrel Twist      14      Inches/turn            
muzzle velocity      1250      fps            
Temperature      100      degrees Fahrenheit (59 is standard)            
Pressure      29.92      inches of mercury (29.92 is standard)            
                       
Sg =      3.19            

Caliber      0.375      Inches            
Bullet Weight      310      Grains            
Bullet Length      1.16      Inches            
Barrel Twist      14      Inches/turn            
muzzle velocity      1250      fps            
Temperature      50      degrees Fahrenheit (59 is standard)            
Pressure      28      inches of mercury (29.92 is standard)            
                       
Sg =      3.11                  

Caliber      0.375      Inches            
Bullet Weight      310      Grains            
Bullet Length      1.16      Inches            
Barrel Twist      14      Inches/turn            
muzzle velocity      1250      fps            
Temperature      100      degrees Fahrenheit (59 is standard)            
Pressure      28      inches of mercury (29.92 is standard)            
                       
Sg =      3.41                  


So the bullet spins even faster under higher temperatures and lower pressure systems. 
Sometimes a person overspins a bullet and still gets fair accuracy under low temperatures and high pressure systems. 

But the bullets may key hole when the weather changes.      

But Joe It is all dependent on the rifle twist and bullet length.

Do you have a 14:1 twist .38 caliber barrel? And the length of the bullet was?

The temperature and atmospheric pressure when you shot it?

People saying any barrel twist will shoot any bullet have not shot many different bullets or different rifle twists under a variety of weather conditions. 
Ballistics programs provide some answers to prevent you going too far astray. 

It requires more information than just a target Joe to verify your point.

I like to pass on the scientific way of making an assessment as opposed to the seat of the pants approach others are recommending.

To duplicate your success Joe works good if I have the same rifle and bullet and shoot in the same weather conditions.

Joe you still have not said what twist and bullet length and bullet speed you were using.

If you were using a 20:1 or 18:1 barrel it does not relate to the fellow with a query with a 14:1 twist.

I am not posting pictures of tight groups from my .38 since it is a 18:1 twist and the rate of spin is entirely different than the 14:1 twist posted in this query.

My 25 RKS:

Caliber      0.258      Inches            
Bullet Weight      122      Grains            
Bullet Length      1.052      Inches            
Barrel Twist      9      Inches/turn            
muzzle velocity      1600      fps            
Temperature      50      degrees Fahrenheit (59 is standard)            
Pressure      29.92      inches of mercury (29.92 is standard)            
                       
Sg =      1.99                  


Your 25:


Caliber      0.258      Inches            
Bullet Weight      108      Grains            
Bullet Length      0.93      Inches            
Barrel Twist      10      Inches/turn            
muzzle velocity      1600      fps            
Temperature      50      degrees Fahrenheit (59 is standard)            
Pressure      29.92      inches of mercury (29.92 is standard)            
                       
Sg =      2.03                  


Yes the Bullet length is good for your twist. Just on the borderline for overspinning.

Check your velocities with a chronograph since everyone is getting tight groups with their quarterbores when they bump the velocities up to 1,600 fps.

And do you have a breech seater that centers the bullet without any runout. 
Remember the problem I had with my Miller until I switched to a Weber seater.

I projected your bullet weight; but if it is actually 120 grains:

Caliber      0.258      Inches            
Bullet Weight      120      Grains            
Bullet Length      0.93      Inches            
Barrel Twist      10      Inches/turn            
muzzle velocity      1600      fps            
Temperature      50      degrees Fahrenheit (59 is standard)            
Pressure      29.92      inches of mercury (29.92 is standard)            
                       
Sg =      2.26                  

It is into the overspin range.

westerner wrote on Oct 13^th, 2017 at 2:20pm:


Joe,
I know what you mean about reading them big books. This is mine, it will be a couple of days before I'm done

If you feel the ground shake up there, it may be my head exploding. I'm not sure there is enough space to hold them, there pages 

Frank

Schuetzendave wrote on Oct 13^th, 2017 at 1:57pm:


In order to really see any of that, you're talking really long ranges where the bullet arrives at a pretty steep angle on order for it to be visible ) and there's another distinction too - the bullet is still stable, and can be very accurate indeed.  It will just make a sslightly different bullet hole.  But we're really talking massive overspin here.