70 grain RDF in the .223

[pharmseller]

I recently bought a Tikka T3 Superlite in .223 Rem. It's twisted 1-8. I have another T3 that's twisted 1-10", it shoots 50 grain BT and TTSX into little bitty groups.

So I'm working on the Superlite as a long range shooter using Nosler's new 70 grain RDF bullet. Benchmark didn't work out so well so I'm trying Varget. I loaded several at three different charge weights and shot them over a chrony today.

Here's the results:

First up, T3 Superlite, 1-8"

25.0 grains, average 2824, high 2827, low 2823, ES 4

25.5 grains, average 2908, high 2929, low 2891, ES 38

26.0 grains, average 2924, high 2927, low 2920, ES 7

All brass looked great, no pressure signs.

Next, T3, 1-10"

25.0 grains, average 2851, high 2865, low 2838, ES 27

25.5 grains, average 2911, high 2934, low 2879, ES 55

26.0 grains, average 2969, high 2996, low 2937, ES 59

All brass looked great, no pressure signs.

25 grains was a little crunchy, 26 was really crunchy. I'm interested in the bullet for the Superlite, so I think I'll try a depth test with 25.5 grains and see how they shoot.




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[DizzyJ]

Pictures of the groups?

 

[pharmseller]

"I loaded several at three different charge weights and shot them over a chrony today."

Just a speed test so far.




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[DizzyJ]

"I loaded several at three different charge weights and shot them over a chrony today."

Just a speed test so far.




P

Supposedly the flat spots in velocity will show you where your accuracy node is.

 

[pharmseller]

No accuracy. Three different bullets, three powders, four seating depths, no luck. I'm abandoning the heavies and going back to 50 NBT at 3400 fps and sub-MOA accuracy.




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[Greenbug]

I have not tried the 70 grain RDF's but my T3 Superlite really loves the 69 grain custom competition bullets.
First target is 26 grains of Varget with Remington 7 1/2 primer seated 2.296" over all length 2983 FPS. .234" group.
Second target is 25 grains of H4895 same primer and seating depth 3033 FPS. .312" group.
Third target is 26 grains of H4895 same primer and seating depth 3135 FPS. .356" group.
All targets shot at 100 yards from a rest 3 shot groups.


This is the same exact gun as yours with the 1:8 twist, loaded rounds just barely fit in the magazine, but they feed and eject flawlessly. Keep at it, don't give up!

 

[pharmseller]

I am intrigued...

Is the Varget load compressed?

 

[Greenbug]

I wouldn't say compressed, but there is not any sound when you hold it to your ear and give it a shake.
My idea of compressed is when you hear the powder kernels crunching while you seat the bullet.

Kind of setting this rifle up to show a buddy that you don't have to have a big heavy barrel with massive optics to have accuracy. I think I should be able to ring steel out to maybe 800 yards or so with the 3135 FPS load of H4895. It looks like it will stay supersonic out to 850 yards at that speed.

 

[Greenbug]

I am using HSM headstamp brass that I have fully prepped for consistency. Cases trimmed to uniform length, case mouth deburred inside and out, flash hole deburred, and the primer pockets uniformed.

I slowly pour the charge into the case to let the powder settle more tightly, if you just dump the charge you will get some crunching when you seat the bullet.

I noticed my velocity was a little higher than yours, it could be the brass or I just have a barrel that shoots faster... Most likely though I am at a much higher altitude than you are down in the valley there. I did my load testing at about 4000 feet elevation. Air is thinner, bullets fly faster due to less air friction I guess.

 

[pharmseller]

I'd be plenty happy with 3,000 fps. I need to see if I have any H4895.

 

[DizzyJ]

No accuracy. Three different bullets, three powders, four seating depths, no luck. I'm abandoning the heavies and going back to 50 NBT at 3400 fps and sub-MOA accuracy.




P

That sucks. With a 1:8 twist you should be able to go up to 80gr as long as you're pushing it fast enough.

 

[American123]

I am using HSM headstamp brass that I have fully prepped for consistency. Cases trimmed to uniform length, case mouth deburred inside and out, flash hole deburred, and the primer pockets uniformed.

I slowly pour the charge into the case to let the powder settle more tightly, if you just dump the charge you will get some crunching when you seat the bullet.

I noticed my velocity was a little higher than yours, it could be the brass or I just have a barrel that shoots faster... Most likely though I am at a much higher altitude than you are down in the valley there. I did my load testing at about 4000 feet elevation. Air is thinner, bullets fly faster due to less air friction I guess.

No guess, you are spot on. I load developed in Seattle, maybe 100-200 feet above sea level, was shooting in Missoula Montana and saw over 200 FPS increase in velocity with the exact same ammo. Air friction coefficient is real. Edit to also say, same rifle too and relatively same temperature. Only difference was altitude.

 

[pharmseller]

I found some H4895, a box of 69 gr CC, and a brick of 7 1/2s. I'll load a few in the morning and chrono them in the back yard before I hit the range.

If I get close to 3k and accuracy like yours, the beer is on me.

If I don't, I know a guy who knows a guy.




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[v0lcom13sn0w]

its a tikka. u could shoot groops like that with tulammo!!




all kiddin aside,
i use IMR 4320 for .223 with good results

good luck!!

 

[Greenbug]

I found some H4895, a box of 69 gr CC, and a brick of 7 1/2s. I'll load a few in the morning and chrono them in the back yard before I hit the range.

If I get close to 3k and accuracy like yours, the beer is on me.

If I don't, I know a guy who knows a guy.




P

Sounds like you are ready to go, seat those bullets as far out as the magazine will allow them too!

 

[pharmseller]

No guess, you are spot on. I load developed in Seattle, maybe 100-200 feet above sea level, was shooting in Missoula Montana and saw over 200 FPS increase in velocity with the exact same ammo. Air friction coefficient is real. Edit to also say, same rifle too and relatively same temperature. Only difference was altitude.

I understand downrange velocities changing due to air pressure, but not muzzle velocity. Help me understand how elevation affects MV to a significant extent.



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[DizzyJ]

I understand downrange velocities changing due to air pressure, but not muzzle velocity. Help me understand how elevation affects MV to a significant extent.



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That doesn't make sense to me. Your velocity at the muzzle should stay the same. Sure, you're pushing out a column of air from the barrel that may be more or less dense, but my understanding is that it's the atmosphere the bullet is flying through to get to the target that makes the difference in drop.

 

[Greenbug]

I guess the altitude difference would not and should not have any thing to do with the difference in muzzle velocity.
Pharmseller reported a muzzle velocity of 2924-2927 with 26.0 grains of Varget and 70 grain RDF bullets in his gun. My rifle (same make, model, caliber & twist) averaged 2983 FPS with 26.0 grains of Varget and a 69 grain custom competition. I guess the 60 FPS improvement in muzzle velocity should be attributed to the 1 grain lighter bullet, less bearing surface on the bullet than he was testing with and the differences dimensionally in the barrels of the two different rifles. Some difference could be attributed to the Remington 7 1/2 primer I am using vs. the primer Pharmseller was using (don't know what that was). You are correct, the muzzle velocity shouldn't have anything to do with the altitude. The downrange performance of the bullet will be affected by the difference in altitude however.

 

[American123]

I understand downrange velocities changing due to air pressure, but not muzzle velocity. Help me understand how elevation affects MV to a significant extent.



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Huh... You know. You are right! why would that have affected my muzzle velocity? Thanks for pointing that out. There must have been more happening than I thought. Now I am confused what that might have been.

 

[Goosebrown]

Berger 70 VLD in lake city brass with cci benchrest primers with 25.0 - 25.2 gr varget. Bullet jammed in the lands.

.2" consistently at 100. 5 shot groups.

In a 1/8 varmint contour barrel.

I got the same groups you did with H4895 and thought they were ok till I tried varget. I think you should give varget a good spin