SmallCaliberCentral

I've been testing a few loads with ADI Benchmark2 and 26gn VGs
Need a little help with where to go next though.
5 shot groups 100yds
27.9gn 0.85" SD 38
28.0gn 0.97" SD 20
28.1gn 1.12" SD 16
28.2gn 1.29" SD 8
(last group had 3 shots in 0.47" all at 4028fps)

Next move is to play with seating depth.
Question is - do I stick with the load that produces the tighter groups, or the lowest SD?

I would shoot that last group again to see if it still flies on you. If not go with that. The 2nd group I believe deserves another chance as well with the lower ES of the top 2.

Cheers Glen
Sounds like a good plan.
There's every chance that the larger group is due to operator error. Chrono shows good consistency, just gotta make sure I'm doing my bit right.
This is the 1st rifle I've owned. My technique would certainly be playing some part in (lack of) consistency.
None of these cases had any prep work either.
The cases for the next loads have all been trimmed, deburred, primer pockets and flash holes uniformed.

when you say sd what do you mean ? the only thing i can think of is sectional density or speed devation ? also i would use 5 shot groups . oh and what velocity with each group ? thank you. sometimes i use 28.4 benchmark.

In ballistics, SD usually refers to Standard Deviation. A very good explantion of just what that really is was posted here recently by Fred C. Dobbs.

thank you rick. am brain dead had 1.5 litiers of champain. dumb question does standard deviatoin affect point of impact ? or are there too many other factor that affect poi ? i know the more velocity between shot the greater the poi. but how much deviation does it take to low or rase the shot one caliber ? last range outting did a bug hole of .2 thank you.

Dan-- On your next range session adjust your scope 1" up & 1" right. Or somewhere else on the target so you don't shoot your main POA out of the target. And if you're already doing this just ignore this post!!

Glen wrote:Dan-- On your next range session adjust your scope 1" up & 1" right. Or somewhere else on the target so you don't shoot your main POA out of the target. And if you're already doing this just ignore this post!!

Don't get your point here Glen.
Not into unnecessarily adjusting my scope. If I wanted to shoot another spot on the target I'd just aim there

Just printed a few off - about to test that last load again. Luckily my range is just out the door and a few paces down the paddock
I'll see how that goes then come back inside and load a few more.

204cat wrote:also i would use 5 shot groups . oh and what velocity with each group ? thank you. sometimes i use 28.4 benchmark.

Yep - doing 5 shots.
28.4gn gave me 1.74" and 4037fps
I've got a 20" barrel
Average speeds:
27.9gn-3942
28.0gn-3960
28.1gn-4037
28.2gn-4028-that's weird ay. But like I said earlier, none of the cases were prepped. Are now though, and loaded, and I'm wasting time on my keyboard Better get going while the wind is slow

Not so good there.
1.49"
av 4001fps
SD 31

I did have troubles with the scales on the last case, and noticed that one other case (loaded) weighed a full grain heavier.
The 3 that I know for sure were all good had a lower spread (3992,3992,4004), but still shot a 1.19" group.

Reckon I'll try a few at 27.9gn and play with seating depth,
OR

-I reached max recommended load with CCI400 primers and no pressure signs. Could try hotter load, different primer. Never tried any other powders either Where do I stop. Can't keep testing loads until the barrels burnt out

By having your POI different from your POA you will always have a consistent POA because the bullets won't erode that away. Any good scope will move back & forth with very little if any final shift in POA. It's no different than dialing in 8 clicks up & 4 clicks left to compensate for the distance & windage.

Ah no worries. My scope's been doing that automatically for a bit. Had it zeroed for some factory rounds then when I started load testing they all shot high right.
Didn't get around to loading any more. Will have to look at that over next few days

One caveat about adjusting your scope for a different impact point is rifle cant from shot-to-shot can induce unwanted results. For me, I just add different aiming points on the target and shoot there.

Second, try to shoot your entire test under the same conditions…including gun barrel temps. For example, especially with a small cartridge like the 204, leaving a loaded round in a warm chamber heats the outer portion of the case and the powder, increasing pressure, producing unwanted results. Whether your powder is one of those heat insensitive ones or not is irrelevant. For me, I don’t chamber a round and close the bolt until I’m ready to fire.

HTH

'Dan, I say get behind the .22 for a couple hundred rounds and then see if its your form. OR, perhaps even better, if you have a buddy with a tack-driver that has some recoil, see if you can replicate his best groups. that might save you going nuts over load recipies like someone I know...

Dave (bow shot): "I hate myself "
Dave's friend: "Why is that Dave? "
Dave: "Because I spent 2 years trying to develop loads for my .204. "
Dave's friend: "So? Didn't you get what you wanted for groups "
Dave: "Yeah, but It became clear to me that I really, really, really have to have a good rest, impeccable form, and pay attention to the wind before I can group at all ".
Dave's friend: "But I bet all that shooting was fun, right? "
Dave: "For sure, Bro. but I could have been killing critters instead!! "

Printed off a couple of dartboard targets recently and had a few games with my dad, brother and his 22lr. I did as good as the old man who was a pro roo shooter for years.
There are certainly elements of my technique that need improving, but I'm confident that I'm reasonably consistent with the process.
I'm gonna mess with the seating depth for a bit and see what happens.

Thanks for the help so far.

As I load a few different seating depths, I'm noticing that (with the seating die in the same place) some OALs are different.
With a bit of fiddling I've managed to get a few different 5 load groups with OAL +/-0.001"
But as I was doing this, I was wondering - It's probably more important to keep the measurement to the ogive consistent right??
ie-Get the seater working roughly to the desired OAL then DON'T TOUCH IT??