Nosler 6.5mm 130 gr RDFs

[Sticks]

I set my loads .3 grains apart. For 123gr pills I see 25 +/- fps spread per .3 grain charge, then when I get a velocity node, that drops to single digit velocity spread between .3gr increments. Same theory should apply here, different speed spread.

So, I have 2 nodes in that first run, and all the case heads looked fine after closer inspection, so with the seating longer, I may run up to 33+ grains of CFE. Still worried about temp sensitivity. Though, the 2450 is my target speed. Would like to see a bit more, but that is running a touch slower than Hornady Black in the same rifle.

[AustinTom]

I set my loads .3 grains apart. For 123gr pills I see 25 +/- fps spread per .3 grain charge, then when I get a velocity node, that drops to single digit velocity spread between .3gr increments. Same theory should apply here, different speed spread.

So, I have 2 nodes in that first run, and all the case heads looked fine after closer inspection, so with the seating longer, I may run up to 33+ grains of CFE. Still worried about temp sensitivity. Though, the 2450 is my target speed. Would like to see a bit more, but that is running a touch slower than Hornady Black in the same rifle.

That's kinda what I figured you were doing. But but it goes straight from 29.8 to 31.1 instead of 30.1. Was that intentional or just data left out of the post?

[Sticks]

I'm with you now. Yup, typo, math error, can't count...

I started at 32gr and worked my way down. I think even my notes represent that error, but I know i did not skip a full grain.

[AustinTom]

Hit the range today. It was cold and windy so I didn't shoot for groups just over the magnetospeed.

Ar-15 20" proof research barrel.
Leverevolution powder
Cci450 primers

48 degrees 25 mph wind.

29.2
Ave. 2391
Hi 2412
Lo 2373
SD 16
ES 39

29.5
Ave. 2419
Hi 2446
Lo 2378
SD 25
ES 68

29.8
No data. Didn't properly reset chrono.

30.2
Ave. 2449
Hi 2477
Lo 2427
SD 21
ES 50

30.5 only 4 of the 5 shots registered.
Ave. 2461
Hi 2466
Lo 2458
SD 5
ES 11

30.8
Ave 2445
Hi 2458
Lo 2428
SD 13
ES 30

31.1
Ave 2489
Hi 2510
Lo 2453
SD 25
ES 57

Before you guys give me any hell about 48 degrees being cold, it's been averaging the mid to upper 80's here already and I'm used to that.

[Sticks]

Weird pressure drop at 30.8.

[AustinTom]

Yeah I saw that too. I wasn't shooting all that fast, but the barrel was pretty warm, definitely not too hot to touch. The range called a ceasefire between 30.5 and 30.8 and the gun really cooled off. Not sure if temperature sensitivity of the powder can the reason for that though.

Single digit SD at 30.5 is probably what I'm going to focus on for now though

[Sticks]

Temp sensitivity as I understand it requires the majority of the powder to be warm/cold to have the effect.

70* ammo temp on a 30* day will shoot just as fast as a 70* ammo on a 70* day. The heat transfer I don't think is all that fast (would need to be sitting in the chamber for a few minutes).

Primers and case head?

I am guessing you loaded at case length of 2.26?

[AustinTom]

Well we'll find out later today. Gonna head back to the range this afternoon. It's going to be 68 and sunny so I'll be able to see pretty directly the effects on the loads. I had made 10 rounds of each but only shot 5 yesterday.

There were no pressure signs on any of the loads. But from what I understand that doesn't mean all that much in the Grendel for a gas gun. I had intended to go up to 31.4 to duplicate loads that I'd seen others on here do with 130 grain bullets and leverevolution but decided against it with the amount of compression at 31.1. I don't intend to fire the remaining 31.1 today.

I had all of that loaded to 2.275. These bullets are way off the lands and I could go out to 2.295 and still feed from my mags.

[Crusty]

In my tests with them (using AR-Comp) I've found that the longest bullet sets have delivered the best groups. My rounds just barely fit into the mag when my bullet ogive is still .130" off the lands. I'm also dealing with heavy powder compression to the point that I sometimes can't feel the neck hit the die when seating a bullet and I continue pulling resulting in an inverted shoulder and a ruined case and bullet. I have had some mitigation by holding the covered charged trays on top of my vibratory cleaner for a couple of minutes so that it settles the charges in the cases a bit.

[AustinTom]

Today's results. Same loads as yesterday. 64 degrees and sunny. Have group sizes. Groups were shot with the magnetospeed on the barrel. All groups and speeds are 5 shots at 100 yards

29.2- 2.405"
Ave 2406
Hi 2418
Lo 2393
SD 9
ES 25

29.5- 2.060"
Ave 2422
Hi 2434
Lo 2409
SD 10
ES 25

29.8- 1.395"
Ave 2430
Hi 2446
Lo 2412
SD 13
ES 34

30.2- 1.031"
Ave 2464
Hi 2474
Lo 2449
SD 11
ES 25

30.5- 1.780"
Ave 2471
Hi 2492
Lo 2455
SD 15
ES 37

30.8- 1.645"
Ave 2497
Hi 2525
Lo 2485
SD 16
ES 40


Yesterday the 30.5 load looked really good at least from the SD. I got a little ahead of myself and loaded up some at longer seating depths. 5 shots each didn't chrono these.

2.280- .805"
2.285- 1.36"
2.290- .942"
2.295- 1.89"

Based on today's results I may try adjusting seating depth on some 30.2 loads. Not sure yet. May also try some H4895 too.

[Sticks]

Thanks Austin Tom

[Crusty]

Sticks, per your request in the other thread, here's what I know about loading 130 RDFs so far.

I'm currently using AR-Comp and I previously identified two OCW nodes at 26.6gr and 26.8gr (in my barrel), so my target charge is 26.7gr of AR-Comp (2448 fps avg), individually trickled on a beam scale. As I previously mentioned, I have to load the RDFs ogive to .130" off the lands in my rifle to even fit them in the mag. At this seating depth, the bullet's ogive is almost to the neck, so pulling bullets after seating normally ruins them due to my collet puller having to be really tight to hopefully get enough of a grip. Also at this seating depth, my charge is well compressed, to the point that if there's additional friction when going in there's a high probability of folding the shoulder inward and ruining the case.

To control that I've turned my Hornady brass so that when I neck size with a bushing die the neck ID is .262", for an interference of .002" for bullet seating. I follow up the neck sizing with an expander to size the neck ID to .2620-.2625". I also coat the RDFs with hBN to reduce friction. Then, when I seat the bullets, I have to be sensitive to the force and STOP when I feel the bullet experiencing unusual resistance before the neck hits the die, and I have to carefully work them down around .010" deeper on each stroke until the bullet arrives at my target base to ogive length of 1.613" ( a seating depth which showed the best groups previously).

It's time consuming and I'm having second thoughts about these bullets just because of the difficulty of loading them, and if they don't improve (most groups were MOA+ but a couple were cloverleafs - variable neck tension was likely the difference I guess) I may end this experiment soon because I'm nearly out of things to try to make them load more consistently. I ruined 15% of my cases in the last session (which is my lowest failure rate for them so far) and I'll go shoot them tomorrow. The cost is high because with each failed load I loose a case and an expensive bullet and can only salvage the powder and primer.

[IescapedCali]

Crusty, couldn’t you pull those bullets with the hammer-type puller, when the shoulder gets scrunched? I realize you’re still losing the case, but you could at least salvage that bullet.

[Crusty]

Nope, only the ogive portion is outside the case. Nothing will grip onto that inward curving surface.

[Sticks]

He is talking about an inertia tool - as LR1955 stated, "A tool specifically made to convince people to buy a collet puller"

b3c0e7e4-af38-4cf2-8a44-ad38f17ea049._SL300__.jpg

Thank you for updating with your findings.

I don't understand how you are folding the shoulder in. Something would have to be contacting the brass to cause that other than the bullet.