Good SDs but horrible accuracy?

[Corse]

Really, SDs of 0-1? I'm impressed... almost incredulous.

Throwing stuff at the wall: Given that the rifle and the bullets aren't the issue, maybe your charge weight is too high/low? Or your seating depth is off?

I could hardly believe the SDs either, that’s why I’m so disappointed in the accuracy, I was hoping for a great long range combo.

Not much room with the seating depth, set at max mag length. The charge weight could be adjusted, it is about .5gr under max.

[Bimmer]

The charge weight could be adjusted, it is about .5gr under max.

Sounds like there's your answer...

[Corse]

I would like to think that is it, but even if the groups ended up at half the size, which I doubt, they would still be worthless. This whole thing is perplexing.

[markm]

I would like to think that is it, but even if the groups ended up at half the size, which I doubt, they would still be worthless. This whole thing is perplexing.

I would still CRANK it up just to see. You can go over max.

[Corse]

I would still CRANK it up just to see. You can go over max.

May as well. YOLO.

[CMV]

Here's the thing....accuracy and repeatability/consistency measures how well your LOAD PERFORMS. SD measures how consistent your RELOADING PROCESS performs. They are separate metrics to measure different aspects of your handloading. Now once you are in an accuracy node, have your OAL dialed in, now the SD comes into play, but really, that's ensuring you're getting the same thing shot to shot (all else equal) so if that bullet lands somewhere other than the X, it's not your load's fault.

At least that's how I look at it. But until you're in an accuracy node and length adjusted for that rifle, it really doesn't much matter what the SD is, within reason. Obviously if you have huge velocity swings, you aren't going to be accurate.

Without knowing anything other than what you posted, but 2 different charge weights, my first thought is you are jamming the ogive into the lands - you're too long. Just a guess, but either the 2 weights you picked are way low and close to starting load and just too low velocity (just bad luck picking 2 that are horrible) or there is something very wrong with your length measured from ogive.

[mark5pt56]

My dilemma is the opposite, good accuracy, crappy spreads. Trying to narrow it down.

[Corse]

The charge weights are within .5gr of the published max. I have loaded some more, increasing the charge weight to see the results.

There is no way they are too long, since they are loaded .005” under max length, and no issues chambering or ejecting a live round. I’m starting to think the RDF is just way to sensitive, but the poor results with the TMK are perplexing.

[Corse]

My dilemma is the opposite, good accuracy, crappy spreads. Trying to narrow it down.

Are you using the same components?

[Tx_Aggie]

How many shots over the chrono at each charge weight are you using to come up with those SD numbers?

If it's only a few rounds it may not be a enough of a sample to really mean anything.

If you had a sample of 10 shots giving you an SD of 1, I'd say play with seating depth as it can have as big of an effect on how something groups as charge weight. You won't have as much room to work with is an AR as you would in a bolt gun, but it might be a place to start.

If you're going off of 3 shot strings for your chrono numbers, I'd say start over. Try loading in smaller increments (.2 or .3 grs), with a minimum of 5 rounds per charge weight, ideally over the space of a full grain or more.