Nosler 6.5mm 130 gr RDFs

[Sticks]

Thank you again Austin.

[Crusty]

Which were you seeing at the high charges: extractor wipes, ejector indents, or both?

How much neck interference (tension) did you have for bullet seating?.

What's in those attachments that won't open?

[bj139]

AustinTom,
Your attachments are invalid for me as well.

[AustinTom]

Here are the attachments again. Just pictures of the good groups. IMG_0939.jpgIMG_0938.jpgIMG_0937.jpgIMG_0936.jpg

[AustinTom]

Which were you seeing at the high charges: extractor wipes, ejector indents, or both?

How much neck interference (tension) did you have for bullet seating?.

What's in those attachments that won't open?

I don't know how much neck tension they had, I don't measure it. I also don't keep track of how many time this set of cases has been fired, but it's over five. They were getting marks from the ejectors. The primers looked good but that doesn't mean much in my mind.

[Crusty]

Agree about the primers - I've seen high charge rounds that didn't show abnormal flattening. Ejector imprints though are in my mind evidence of excessive pressure. Worn primer pockets can cause flattened primers with a safe load.

I also found the AR-Comp node at 26.2gr (actually 26.7gr for me because I'm using hBN coated bullets which require a 2% charge increase because of the reduced bullet friction). My necks are turned and I'm using an expander die to final size to .261" ID before seating for consistent neck tension and that's resulted in decreases in SD(8) and ES(28), but I'm still having an occasional flier to MOA+ that's ruining most 5 shot groups and I'm not sure where to go next to eliminate them.

My next batch of cases has been SST pin wet tumbled, which removes residual neck carbon for more seating friction and higher pressures, so I'll see if that has a positive effect. My MV avg was 2312 in an 18" barrel and it's low compared to yours, corrected for the different barrel length. I'm also going to sneak up on the final seating depth because profile variations on some bullets resulted in them being seated .005" deeper than my target seating depth.

[Sticks]

Is it the ammo, or the shooter that is getting the Stonehendge?

[grayfox]

Yeah, I was going to vote for shooter (no offense intended), if you're anything like me... I've been working on my technique and have reduced the nbr of those... not all the way however. I've stopped using a bipod on the bench in favor of a rest, finding rear bags that match up better to the stock (AR vs boyd's, etc) and practicing cheek weld, trigger controls and eye focus. IMO the rifle and the round are pretty much mechanical so I should be able to expect some kind of (more or less) "pattern" from them -- anyway gives me a rationale to practice more!

[StoneHendge]

Is it the ammo, or the shooter that is getting the Stonehendge?

I particularly like the 3rd one. A perfectly executed StoneHendge followed by a perfectly executed counter StoneHendge.

[bj139]

I see the attachments in post #154.
What power scope?

[AustinTom]

Is it the ammo, or the shooter that is getting the Stonehendge?

I think it was me. I think I'd do better prone, but that's not allowed at ranges around here.

[AustinTom]

I see the attachments in post #154.
What power scope?

It's a Leupold 4.5-14x

[Sticks]

I think it was me. I think I'd do better prone, but that's not allowed at ranges around here.

This is why I prefer 5-10 shot groups. A 4 shot .4 ragged hole and a StoneHendge .75 up and left, I don't have a problem with a person eliminating that from the data. I do it, and if I am developing a load, and I have one of those strays, yet my SDs are in the single digits, the FPS is in my target range, and everything else is great. Go with it. The charge above and below that 1.2 MOA was a solid .8. I am going with the StoneHendge group.

Don't forget target fixation affecting groups either.

I have two good examples that I will dig up tomorrow (I need to get on the road). One is an Up/Down exercise of 25 shots. Fire one, get up, get back down in position and fire. Each shot went to a different target, 5 total targets (on a single 8.5x11 sheet), ....25 shots. I have sub MOA groups, and 1.5 groups. Same ammo, not StoneHendged...those targets flat out got a crappy groups.

Second one is verification of zero on the Youngest Daughter's Howa. 5 shots 1+ inches low, +MOA group. Adjust the scope, and it turned into a .7 or less.

[AustinTom]

The Stonehenge was strong today. Ongoing battle to make these 130 RDF's shoot well. 5 round groups at 100 yards. No chronograph data today. After today, going to load up 50 or so with 26.9 gr AR Comp, at 2.285 to see how they do at distance.

IMG_0951.jpg

[Crusty]

I'm starting to make some headway with these bullets too. Here's my best 100y 5 shot group. The lone flier was definitely a pulled shot because I knew it when it went off. Center square is 1". Paying attention to consistent neck friction is making my groups smaller.

26.7gr AR-Comp, .130" off lands, necks turned to .010" wall thickness and accurately sized to .261" ID with expander die, hBN coated bullets
05.10.18.jpg

I've determined that I can seat these bullets .120" off the lands and still have .010" clearance in my mag so my next batch will have some set at that depth.