Ladder test results, typical ?

[Rusty Scabbard]

Trying to dial in loads for a 25-06 hunting rifle, lightweight barrel.
I worked up 6 loads of 5 each, with steps of 0.5 to 1.0 grains.
Got one group with the 60 gr charge at about 0.25" at 100 yd.
All other groups were an inch or over.
Is it normal to see that much improvement at the sweet spot ?
...or did I merely demonstrate a statistical sample of 5 may not represent reality ?
Conditions were perfect today. I think this time I finally did my part as far as proper shooting goes.

[boyguan]

How long did you wait between shooting groups?

[God Bless America]

Yes there can be that much of a difference.

You also need to determine the POI for each load and plot it.

That will help you determine your next steps.

[Jta]

I didn’t know Ladder tests went shot in groups.
It almost sounds like you were running a ocw test. In that case you want to look at where the center of each group was and find the three groups in a row that all hit around the same spot. Group sizes can be adjusted a little bit by seating depth.

[Rusty Scabbard]

How long did you wait between shooting groups?

30 seconds to a few minutes.
I also mixed the shooting order- did one or two from each batch in order.
POI moved a bit with the groups but not much. I probably should've measured it too.
Jta- I'm loading Barnes 100gr TSX and seating at 3.12" COAL, longer than the 3.08" they recommend. The first (of 3) cannelures is pretty much out of the case neck already at this length, so I don't think I'll screw with seating depth. SAAMI for 25-06 shows 3.25" max. I was surprised the Barnes were designed to seat so deep.
The best group (60 gr MagPro) was 0.5 grains below the max on the Barnes table. I loaded a bunch more so hopefully will be able to repeat the best groups tomorrow.

[Whiterabbit]

Light barrel, may I guess that the first group was the 0.25?

I have a 7x57 that shoots 3 round cloverleafs at 100 on a cold barrel. After 10-20 rounds quick, I’m lucky to be at 3 inches. Raging hot barrel.

To develop a good load, I take a long long time between shots. 30 rounds would take hours.

[Whiterabbit]

I have data that shows group size can be affected a LOT by OAL! Nice thing is that velocity not so much, so I found I can tune charge by ES/SD then dial in groups with OAL.

Of course the absolute best performance was always the best ES at the longest OAL.