Which charge? And why?

[Subwrx300]

So have found a good node with 224V and 88 ELD but I'm in bit of a debate with myself: tight groups with occasional flyer that could be me OR slightly less tight with good SD.

Here is original test target with 4 shot groups:

25-25.2 tested well so I retested 25, 25.1, and 25.2 shown below:

SDs are good across the board but 25.0 has been consistently around 5-7. The velocity changed between the two days but that's probably because I let the loaded ammo sit for an extra day in my last test, as opposed to loading and firing within a few hours.

So here's my debate: a load that will put 80% into about 1/4-1/3 moa and 20% into a .6moa vs a solid 1/2 moa load with good SD?

I really want to chase that bughole load but feel like in competition, a flyer that's 50% out of group average could give me bad info for follow up shots. If this was your rifle, which would you choose for PRS style comps in gas gun division?

 

[mdmp5]

Take it out to some distance and see how it prints. I've been burned by 100 yard wonders before. You have it narrowed down to just a couple groups so it shouldn't be too hard from here

 

[XLR308]

If your really chasing accuracy I would be looking at a powder that has less variation and swing with temp changes, especially for a match round were temps can greatly vary from morning to afternoon and one day to the next.

If chasing velocity then CFE is good for that but you may be disappointed when the mercury makes big swings and pushes you out of your node or worse causes pressure problems.

 

[Subwrx300]

If your really chasing accuracy I would be looking at a powder that has less variation and swing with temp changes, especially for a match round were temps can greatly vary from morning to afternoon and one day to the next.

If chasing velocity then CFE is good for that but you may be disappointed when the mercury makes big swings and pushes you out of your node or worse causes pressure problems.

I'm actually dropping charge from 25.8 (ragged edge of pressure at 85+ degrees). That's why I wanted to retest for lower node and find something that doesn't put me in a potentially dangerous spot if ammo gets over 100 deg.

I've tested several other powders but none of them are giving me the accuracy I need for a match (have been .7-1.2 MOA with most). Varget is one of the only super temp stable powders I've run but also have R15, R17, XBR and H4350. Just can't get the mix of speed/precision/SD with the others or at least I haven't found it yet.

I will be testing whichever load I choose with the ice bath/room temp/carheater test 10 rounds each. That will at least give me an idea of temp variation for matches.

This load is being developed for a match in southern Ohio scheduled for early Nov. I'd expect temps to be between 45-70 max.

 

[XLR308]

I kind of figured you had your bases covered on the temp stability issue but had to mention it.
If you haven't tried it yet AR-COMP might be worth a test, it's in that sweet spot of burn rate but a touch faster than what your using but has good temp stability and velocity in the cartridges I've used it in.

 

[Subwrx300]

I kind of figured you had your bases covered on the temp stability issue but had to mention it.
If you haven't tried it yet AR-COMP might be worth a test, it's in that sweet spot of burn rate but a touch faster than what your using but has good temp stability and velocity in the cartridges I've used it in.

I do have some ARComp. In past, it's been a touch fast for heavy bullets but I think I'm going to run a powder temp test to see how sensitive CFE really is.
I ran it at from 70-88 actual air temp (maybe 70-100 deg swing for ammo in the sun) at 25.8 and very similar velocities (2795 vs 2802 for 20+ rounds each.)

If it stays around .4-.5fps/deg, I'm completely fine running CFE with that. Would only be <20fps change through a 40 deg temp swing. Plus I can't find anything anywhere with an approximate CFE temperature velocity correction value so would be useful for the Hide anyway.

Assuming I get all that other crap taken care of, which would you run? Tiny groups with possible flyers or consistent groups without flyers?

 

[Deleted member 113831]

That 25 to 25.1 spot is where you need to be. POI looks good, vertical looks good. You didn't mention the ambient temp when testing. If it was colder I would go for 25g to give you room for heat. If it was 85 degrees, I'd go for the 25.1 to give you some extra room for the cold.

 

[XLR308]

ROB01 I know has done a fair amount of testing with various powders temp stability and shift per degree of increase as I have seen it listed under his name on various sites.

Maybe he has the data for CFE223 as well, might be worth sending him a message and could save you some time and components or atleast give you a base line for comparison.

 

[Subwrx300]

That 25 to 25.1 spot is where you need to be. POI looks good, vertical looks good. You didn't mention the ambient temp when testing. If it was colder I would go for 25g to give you room for heat. If it was 85 degrees, I'd go for the 25.1 to give you some extra room for the cold.

Tests were shot at 80 and 75 deg. 25, 25.1, 25.2 test shot at 75 today. I've loaded 15 of each for mid range test (400yrds) and will put both to the test. I have a gut feeling that 25 will be a better node long run. It was tested with hot dirty barrel (200 rounds dirty) and as long as it runs good from clean barrel, it's a winner.

But as temps are falling through the next three months or so, 25.2 may keep me in the node for colder matches. I agree with you on 25-25.1.

 

[mcfred]

I could live with a 'worse' group that has a consistent velocity if you're going to be shooting at extended ranges at targets larger than what the rifle will hold.

For small targets up close I'd go with a tighter group allowing for higher ESs.

Small targets at long range you pretty much have to have both accuracy and consistent velocity.

As for varying temperatures. I shoot in the desert and there's routinely a 35˚F spread between the morning and afternoon and 60-70˚F spread between seasons. In the Summer, I find that a 500ml plastic bottle of ice wrapped in a handkerchief holds the temperature in my pack at a consistent enough temperature for a few hours that the dope holds well enough. Usually the targets are generous enough that if it's hot you can aim a little lower and if cold hold a little higher. I have to keep the pack/ice/ammo out of the sun as best I can, but it's worth it to have the velocities the same over the course of a day.

 

[Precision Underground]

When you are talking .5 vs .7 you are splitting hairs. That barrel loves that combo. We all have 0.2 shooter error in us anyway. I would go with the best numbers. If it were me I would be pushing a bit higher, It looks like another node is coming. But I am a velocity whore lol.

 

[Subwrx300]

So testing went well and tried both 25 and 25.2 at 400yds. Also tested CFE223 temp stability...which was both interesting and enlightening. I compared CFE in my Valkyrie to a control of H4350 in my 6?5 bolt gun.

Top row two groups of 25.2 (top left is CB 6 shot group and right top is next 5 after 2 minute break. Ammo temp 75 deg.
Middle row is 30 deg ammo (224v on left 6.5 on right)
Bottom row is 115 deg ammo (224 on left 6.5 on right)

Here is target with 25 vs 25.2 (middle row; top and bottom row are 6.5 CM) 10 shot group for each fired 5 of each then switch.

I think it's going to be 25.0 when temps are 65-90; 25.1 when 50-70, and 25.2 when 0-60. The 25.2 charge acted EXACTLY like 25 when frozen and SD was 3.3.

Note: the 25.2 group is crazy consistent: notice each bullet has one right next to it. It literally fired the same pattern in same order twice.

Powder is definitely temp sensitivite as it had a 60fps swing over 85deg variation (2711@30deg, 2735@75deg , 2740@85deg, 2785@115deg). I really don't love having to temp tune a load but it is super consistent for a given temp (SDs around 3-10 fps).

 

[Subwrx300]

When you are talking .5 vs .7 you are splitting hairs. That barrel loves that combo. We all have 0.2 shooter error in us anyway. I would go with the best numbers. If it were me I would be pushing a bit higher, It looks like another node is coming. But I am a velocity whore lol.

Yeah I have a node that is JUST out of reach at 26.0-26.1. It's too hot to run at these temps. If spring or fall, I'd run it but not if temps are anything near 70+. It runs at 2800+ and is right about 1/2 moa.

Also going to retest Varget for high and middle node. Didn't have much luck when barrel was new but that may have changed as it's speed up a solid 60-75 fps since new.

 

[Kentucreed6]

Has anybody tried H4895 in the Valkyrie with any luck on 75-80 grain bullets?

 

[bfglowkey]

If you toyee with RL 17...try RL 16....near same but much more stable and crazy good numbers sd/es wise. Velocity is near on par with 17