ok here it is. I am shooting a 308 rem700 kreiger barrel choate stock. the round is a 168 smk over 43.9 grains of varget, tull primer and winchester case. it leaves my 26 inch barrel at 2670. this gives me really good accuracy out to 600 but at my 850 target these rounds are keyholeing and my accuracy is gone. are these bullets going transonic and will more speed stablize them or should i go to 175 smk and what muzzle speed do i need to look for to keep them stable at that distance? I know the 175 have a better bc.
Range Report really need some help
- Thread starter 308mike
- Start date
Re: really need some help
You're gonna have to go with the 175s if you want to go farther. Its my understanding that the slope of the boat tail is sharp on the 168 smk and causes it to keyhole out past 800. Someone else will chime in with more details I'm sure.
You're gonna have to go with the 175s if you want to go farther. Its my understanding that the slope of the boat tail is sharp on the 168 smk and causes it to keyhole out past 800. Someone else will chime in with more details I'm sure.
Re: really need some help
Yes, they are going thru sound barrier. The 168SMK has a sh*tty boat-tail - too steep, too short - that screws it all up going subsonic. Why don't you try some of the 155's and that will solve your problem - Lapau Scenars 155s the best, but Berger and SMK will also do the trick nicely.
Yes, they are going thru sound barrier. The 168SMK has a sh*tty boat-tail - too steep, too short - that screws it all up going subsonic. Why don't you try some of the 155's and that will solve your problem - Lapau Scenars 155s the best, but Berger and SMK will also do the trick nicely.
Re: really need some help
If shooting past 500 on a regular basis switch to the 175s. They handle things much better at distance.
If shooting past 500 on a regular basis switch to the 175s. They handle things much better at distance.
Re: really need some help
I routinely use the 168 AMAX to 1000 yards. Never have that keyhole issue in a rifle with a factory barrel over 20" long. (an LTR had grouping issues on the Sacramento range approx 700' asl.)
Just out of curiosity why did you stop at 43.9 grains? Just seems an odd amount. I use 44 grains and many see that as a light load. Guys wanting the last fps out of the load use 46 grains so you have room to increase the powder charge.
Change from SMK to AMAX. Boost the powder charge. I haven't spoken to my friend who chronied the load through his custom Surgeon, I want to say it ran 2770fps.
Good Luck
I routinely use the 168 AMAX to 1000 yards. Never have that keyhole issue in a rifle with a factory barrel over 20" long. (an LTR had grouping issues on the Sacramento range approx 700' asl.)
Just out of curiosity why did you stop at 43.9 grains? Just seems an odd amount. I use 44 grains and many see that as a light load. Guys wanting the last fps out of the load use 46 grains so you have room to increase the powder charge.
Change from SMK to AMAX. Boost the powder charge. I haven't spoken to my friend who chronied the load through his custom Surgeon, I want to say it ran 2770fps.
Good Luck
Re: really need some help
thanks for the info. the reason for the for the powder charge is this charge seems to be my most accurate at 100 to 500 just drives tacks at 300 but i will try the 155s in amax and some 175 smks but i do think i need to get my speed up. thanks for the info
thanks for the info. the reason for the for the powder charge is this charge seems to be my most accurate at 100 to 500 just drives tacks at 300 but i will try the 155s in amax and some 175 smks but i do think i need to get my speed up. thanks for the info
Re: really need some help
A) yes, they are going transonic
B) more powder would help (absent pressure signs)
C) better bullets will help (155 scenar, Berger, 155 (2156) SMK, 175 SMK)
D) faster twist in barrel will help
E) higher altitude will help
F) high humidity will help
A) yes, they are going transonic
B) more powder would help (absent pressure signs)
C) better bullets will help (155 scenar, Berger, 155 (2156) SMK, 175 SMK)
D) faster twist in barrel will help
E) higher altitude will help
F) high humidity will help
Re: really need some help
Your results past 500 are probably worsened due to the MV. Although it's understandable why it might give you great results inside 300 yd, 2670 fps for a 168 SMK out of a 26" pipe is a little on the slow side, which will cause the performance at longer distances to fall off even faster. I often shoot FGMM 168s out to 600 from a 22" barrel with an MV of ~2730, and they work very well. Much further and the performance falls off pretty quickly.
Your results past 500 are probably worsened due to the MV. Although it's understandable why it might give you great results inside 300 yd, 2670 fps for a 168 SMK out of a 26" pipe is a little on the slow side, which will cause the performance at longer distances to fall off even faster. I often shoot FGMM 168s out to 600 from a 22" barrel with an MV of ~2730, and they work very well. Much further and the performance falls off pretty quickly.
Re: really need some help
good info thanks. is a quicker or slower powder going to affect the long distance of any given bullet?
good info thanks. is a quicker or slower powder going to affect the long distance of any given bullet?
Re: really need some help
witch of these bullets cut the wind better 155s or 175s should be the 175s but would be nice to know
witch of these bullets cut the wind better 155s or 175s should be the 175s but would be nice to know
Re: really need some help
I am shooting a 10 twist can i shoot the 155s
I am shooting a 10 twist can i shoot the 155s
Re: really need some help
you can shoot the 155 and the 175 just fine
Varget is a great powder to stick with
with the 175 smk and Winchester brass you will probably find a good hotter load around 44.5 to 44.7 grains but work your way up to it.
you can shoot the 155 and the 175 just fine
Varget is a great powder to stick with
with the 175 smk and Winchester brass you will probably find a good hotter load around 44.5 to 44.7 grains but work your way up to it.
Re: really need some help
well thanks mister cooper i had just loaded some up at 44 thats were i thought i should start ...I have shot this before at 100 yards it was not a real good porformer but will take it out to 850 and see what happens
well thanks mister cooper i had just loaded some up at 44 thats were i thought i should start ...I have shot this before at 100 yards it was not a real good porformer but will take it out to 850 and see what happens
Re: really need some help
ok so i loaded up some 175 smks and 44 grains of varget cronied a couple of shots at 2680 to 2690 and took them out to 850 and they are also keyholeing. do i need more speed on these 175s
ok so i loaded up some 175 smks and 44 grains of varget cronied a couple of shots at 2680 to 2690 and took them out to 850 and they are also keyholeing. do i need more speed on these 175s
