.223 barrel twist
- Thread starter jigger08
- Start date
roberti11 said:
Robert,
I have a Stevens 200 in 223 rechambered to 223 Ackley. It has a 1:9 twist and gets the 75 gr A-Max going more than 3000 fps. It easily stabilizes this bullet.
Wondering if you have you actually tried shooting this bullet in your 700, or just going by what others have said?
The same rifle puts Nosler 40 gr Ballistic Tips into half an inch at 3900+ fps!
Ted
Last edited:
Twist rate
No, the information I gave you was from experience.
I spent the month of August 2005 trying to get my Rem700P to shoot 75gn Amax bullets. I made 5 trips, and on each I shot multiple 5 round groups at 100 yards using 75 gn amax's and 69 gn smk's. Match brass, N540 powder and all the finicky reloading steps. I used 5 different powder charges and the best group I ever got was 1 inch at 100 yards, most were 1.5 inches. This was at 2900 fps. With the 69gn smk's on the same day I would routinely get .3 inch groups. I finally settled for 73gn Bergers until I came across the 77 gn smk's. With these I can get groups of .3-.5 inches all the time.
About a month after I gave up on the 75gn amax's I came across an excellent article in Handloader magazine that helped explain to me why I was failing (see below), in truth there are many, many ways to calculate stability, the Greenhill formula is crude, and was designed for .30 cal, many of its assumptions fall apart when you apply this to a different cal.
The formula I posted below is also only an approximation and is not as good with VLD bullets. There is an even more complicated formula on the Lija website if anyone is interested. Using the formula below, a 75gn Amax at 3000 fps has a "calculated stability" of 0.73, A 77gn SMK has a stability of 1.05 at 2900 fps. Both of these assume a 1:9 twist.
A friend of mine has a Savage 1:9 twist .223 and he shoots the Amax bullets very well, but the actual measured twist is closer to 1:8.
Finally, When I purchased my Rem700p it was one of a pair at Elwood Epps, a buddy of mine bought the other one. This last fall I had the chance to shoot some handloaded 75gn Amax's from his rifle, the result were the same as mine.
Why not? said:Robert,
I have a Stevens 200 in 223 rechambered to 223 Ackley. It has a 1:9 twist and gets the 75 gr A-Max going more than 3000 fps. It easily stabilizes this bullet.
Wondering if you have you actually tried shooting this bullet in your 700, or just going by what others have said?
The same rifle puts Nosler 40 gr Ballistic Tips into half an inch at 3900+ fps!
Ted
No, the information I gave you was from experience.
I spent the month of August 2005 trying to get my Rem700P to shoot 75gn Amax bullets. I made 5 trips, and on each I shot multiple 5 round groups at 100 yards using 75 gn amax's and 69 gn smk's. Match brass, N540 powder and all the finicky reloading steps. I used 5 different powder charges and the best group I ever got was 1 inch at 100 yards, most were 1.5 inches. This was at 2900 fps. With the 69gn smk's on the same day I would routinely get .3 inch groups. I finally settled for 73gn Bergers until I came across the 77 gn smk's. With these I can get groups of .3-.5 inches all the time.
About a month after I gave up on the 75gn amax's I came across an excellent article in Handloader magazine that helped explain to me why I was failing (see below), in truth there are many, many ways to calculate stability, the Greenhill formula is crude, and was designed for .30 cal, many of its assumptions fall apart when you apply this to a different cal.
The formula I posted below is also only an approximation and is not as good with VLD bullets. There is an even more complicated formula on the Lija website if anyone is interested. Using the formula below, a 75gn Amax at 3000 fps has a "calculated stability" of 0.73, A 77gn SMK has a stability of 1.05 at 2900 fps. Both of these assume a 1:9 twist.
A friend of mine has a Savage 1:9 twist .223 and he shoots the Amax bullets very well, but the actual measured twist is closer to 1:8.
Finally, When I purchased my Rem700p it was one of a pair at Elwood Epps, a buddy of mine bought the other one. This last fall I had the chance to shoot some handloaded 75gn Amax's from his rifle, the result were the same as mine.
Hmmm, then maybe the reason mine shoots them, is that the twist is actually faster than 1 in 9 in my rifle too. Well, that's not a bad thing at all.
As well, the 223 AI actually gets a bit over 3100 fps with some loads. What is the stability factor at that velocity?
Ted
As well, the 223 AI actually gets a bit over 3100 fps with some loads. What is the stability factor at that velocity?
Ted
