Sierra Matchking 77gs .224 for reloads of .223 rem 1in9 twist ?
- Thread starter dr.fire
- Start date
Oh yeah I get under 1/2” or better in my Savage LRPV. 24.2gr of Varget seated at 2.405”
It’s a single shot and it’s a pretty hot load so I would recommend Sierra,s data for a starting load and go from there.
My Savage was ok with 75’s and 69’s and even Berger 80’s won’t touch these 77gr Sierra’s.
It’s a single shot and it’s a pretty hot load so I would recommend Sierra,s data for a starting load and go from there.
My Savage was ok with 75’s and 69’s and even Berger 80’s won’t touch these 77gr Sierra’s.
You will probably get similar or better groups the the 75gr BTHP, but a 1-9" twist is not optimal.
https://bergerbullets.com/twist-rate-calculator/
You will be marginal, with a depressed BC. To maximize, you need a 1-7/1-8 twist for 70gr bullets in a 223.
I have shot both in my 223, including the 77gr SMK and TMK versions. Load data and performance were comparable, with the slight edge to the Sierra's. But I have a 1-7" twist.
https://bergerbullets.com/twist-rate-calculator/
You will be marginal, with a depressed BC. To maximize, you need a 1-7/1-8 twist for 70gr bullets in a 223.
I have shot both in my 223, including the 77gr SMK and TMK versions. Load data and performance were comparable, with the slight edge to the Sierra's. But I have a 1-7" twist.
Ganderite, did some consulting for Savage in 1993 concerning twist rates.
He was encouraging them to go to the 1-8 twist rate and they sent him a barrel with a 1-9 twist rate, to shoot 80 grain bullets.
His subsequent tests proved the 1-9 twist rate was adequate to stabilize the 80 grain bullets, so Savage produced their barrels with 1-9 twist rates. He says Savage was the first in the industry to do so.
I got this info from him because I came across a few thousand 77 grain SMK bullets and needed some info on velocities needed to stabilize them in my rifle, which also has a 1-9 twist barrel.
His tests showed that if you load hot enough to achieve 2850+fps, that the bullets stabilized.
He was right.. My load gets just over 2900fps out of my rifle and the bullets stabilize very well out the the 300 yards I've tested them at.
He was encouraging them to go to the 1-8 twist rate and they sent him a barrel with a 1-9 twist rate, to shoot 80 grain bullets.
His subsequent tests proved the 1-9 twist rate was adequate to stabilize the 80 grain bullets, so Savage produced their barrels with 1-9 twist rates. He says Savage was the first in the industry to do so.
I got this info from him because I came across a few thousand 77 grain SMK bullets and needed some info on velocities needed to stabilize them in my rifle, which also has a 1-9 twist barrel.
His tests showed that if you load hot enough to achieve 2850+fps, that the bullets stabilized.
He was right.. My load gets just over 2900fps out of my rifle and the bullets stabilize very well out the the 300 yards I've tested them at.
littlehughey
Regular
- Location
- Central Alberta
Mind sharing your 77SMK load and barrel length?
Twist rate for the most part will be a good indicator to what weight projectile a barrel will like but is not gospel.
My Remington 700 in 243 has a 9-1/8” twist rate so should like 85gr and up but it loves 55gr Sierra Blitzkings that have to jump 80 thou gap before it gets to the rifling and it shoots sub moa and under.
Some guns can shoot almost everything well but some are just picky and can be quite maddening at times.
To 300yds,you could load & shoot 77gr backwards in a 1:9" twist 223.
Shoot the 77gr to 600yds & they'll be key holeing.
My rifle is a Mossberg MVP, with a 24 inch bbl x 1-9 twist.
This is Ganderites reply to my query, I sincerely hope he doesn't mind me posting it.
"I was doing some consulting witn Savage and was urging them to change from 1:12 to 1:8 so we cld shoot the 80 gr bullet.
They made up a prototype rifle with a 1:9 and sent it to me.
I tested in in feb of 1993. Looking at the log book now.
24.5 gr of 748 got 2885 fps (24" barrel) and grouped .98" and .715" (10 shot groups)
Savage concluded that if it stabilized in cold, dense air, 1:9 would be adequate. They were one of the first to do it.
I would say that anything over 2850 should do the job. easy to do. My favourite powders were n140 and N150. Varget would be abut right, too. Or RL15."
The load I settled on, after trying out his loads, which worked well, was 25.5 grains of BLC2, over CCI 450 small rifle magnum primers, in Remington cases.
This load works well for both the 77grn Berger ELD and the 77grn SMK.
As for the bullets keyholing at 600yds, I don't shoot that far out anymore. 450yds would be about maximum for me at this stage of my life.
If I want to shoot further, I recently finished a Remington 700, chambered in 6.5x55 x 1-8 twist, with a 1 1/4 diameter barrel, 30 inches long, wearing a Zeiss Diavari Victory, 6 -24 x 56, with a Horus reticle. I've shot it at paper targets out to 700 yards and it still needs some load development. Hopefully it will come around.
coleman1495
CGN Ultra frequent flyer
- Location
- Whitecourt
It would be interesting to see if a 1-9 twist is still sufficient in -20.
A bullet gains stability as it moves down range. Stability is a function of bullet length, air density and RPM. Length is a constant and RPM is almost constant. Air density is a a function of velocity and compression, so it drops as the bullet slows.
If it is not keyholing at 100, you are good to go to 1500 yards.
Ganderite
Totally respect your experience on threads like these
Stability is a function of bullet length
OAL?
Stability is a function of bullet length
Length contacting the lands?
