Ladder test powder increments

Planning on conducting load development testing using the ladder testing method of evaluating and determining the optimum powder charge for 45 auto 185 & 200 gr swc and 38 special 148 gr hbwc.  What powder charge increments do you use? .1, .2 or ?

Ladder increments in rifle are 1%.  Difficult to do do in bullseye loads as they are below .1 Gr.    So,.... what to do...?  For starters load to velocity 700-825fps.  Unlike rifle most pistols will shoot target velocity loads reasonably well and aren’t particularly fussy on precise loads.

This picture shows a couple of targets shot from a sandbag rest at 25 yards.  The pistol is a stock S&W 745 which is accurate but not as accurate as my Wadgun.  The ammo was leftover chronograph loads of 3.8Gr, 4.0 Gr, and 4.2 grains behind a 200 SWC Brazos bullet.  The outliers were called as bad shots.  So use an accurate load that is known to be a good shooting load in many guns, load up a big quantity (2000 or more) and go shoot! 

I use 0.1increments and refine as needed.

My scientific method is to use only increases or decreases as determined by the collets in my Lee powder dispenser. Thus insuring that I never have to fiddle with something trying to change powder charges by that small of an amount. Ever. My method works great for pistol load development.

Early on, I did a lot of Ransom testing over my chronograph. I assumed, that like long range Pasture rat shooting, you needed low standard deviation & extreme spread. Short answer, NO you don't. Some of my tightest groups had the greatest velocity spreads.

Don't try to reinvent the wheel. Here's the link to favorite loads for Bullseye. Just pick one. They'll shoot just fine. You can always tweek one later if another 1/4" better group is your goal.

https://www.bullseyeforum.net/t1209-pet-loads-of-top-shooters-loads-from-the-past

It's only 50 yards, don't get hung up things that aren't going to matter. Train and dry fire, dry fire, dry fire. I agree with Cecil, "the shooter needs more work than the loads or equipment."

You need a gun capable of shooting tight groups at 50 yards. You need a reliable method of testing at 50 yards. The bullet, especially the quality of the base, is a huge factor. It is hard to beat a Nosler or Zero 185 gr. JHP over an appropriate charge of powder. I always used Dave Salyer's suggestion of 4.5-4.6 grains of Alliant Bullseye with a crimp of about .470". For .38 SPL with 148 gr. HBWC, it is hard to beat the tried and true load of 2.7-2.8 grains of Alliant Bullseye or 3.0-3.1 gr. of 231 or HP-38. Bullet must be seated flush or slightly below flush for the S&W Model 52 with a taper crimp and/ or slight roll crimp.