OK...thanks...My buddy got a lab radar recently.  I'll chrony my loads again to see where I'm at these days.

What primers are you guys using? Seeing a jump like that makes me wonder if it's the primer causing the increased velocity. Never done a test myself, but with burning so little powder, I would think a difference in primer brisance could have more of an effect on powder burn and velocities.

Just a guess after I noticed neither of you posted which primer you're using.

What I have on hand winchester and CCI small pistol. I am at about 770 feet elevation and the temp was around 60-70*

I use Gordons reloading tool to see how my recipes are affected by all sorts of changes like seating depth or brass case volume.

According to GRT, small seating depth changes do affect pressure and thus velocity. Well duh but by how much?
If you are comparing recipes, The spec that matters would be case volume once bullet is seated.

I want to change my projectile type on one of my recipes. Same weight.
I am going from a JHP to a round nose bullet.
I opened my recipe in GRT, changed the bullet setting and set the effective seating depth to the same as my JHP recipe.
The seating depth measurement changed from 1.10 to 1.15".
And the pressure and velocity are more or less the same.
So according to GRT, I can use the same charge with the new bullet if seating to 1.15".
I will build a ladder anyway.  But the data is useful to me.


Point is, the case volume and effective seating depth of the recipe are important to the result.
As well as barrel length.  


eta.
I do not rely on GRT for safe loadings.  I use GRT for relational information.
When creating a new load, I utilize multiple sources of load data to determine a range and then load a ladder.


I run a Combat armory 8" barrel and a YHM BCG.

Labradar:

80*F

*147gr Blue Bullet RN
3.3gr Titegroup

G19 PMM barrel and comp
Av 946
Es 40
Sd 10.6

Stock G19.4
Av 940
Es 26
Sd 8.2

M&P 2.0
Av 950
Es 39
Sd 11.9

12” XCaliber blowback PCC
Av 1072
Es 54
Sd 20.9

I didn’t write down the primer. Blue Bullets tend to run a bit faster for any given powder charge weight than jacketed.

^^^^^^^^
Thans for posting that info...
I gonna get a garmin xero so I can start getting FPS data.
Its long past due.