alan gordon
Inactive
Which barrel twist will work better for these two rounds on a rra 24 in stainless barrel- the 1-8 or the 1-12.
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50gr vmax and 55gr sp
- Thread starter alan gordon
- Start date
Kevin Rohrer
New member
1/12 when the bullet weight is no more than 60gr.
I have found that a 1:12 twist stabilizes real nice with 50gr. bullets in my 222. I understand that 223s usually have faster twist so I would guess that the 60gr. bullet would stabilize better with the slower twist of 1:8.
Do we have a better twist out there for the 60gr. bullets.
Do we have a better twist out there for the 60gr. bullets.
I'd pick the 1/8 barrel for an AR. Even the 50 V-Max should shoot great with that twist but if you want to ever load heavier bullets you don't want the 1/12. The 50 grain V-max won't come apart with the faster twist. Now thin skinned varmint bullets might. Only other option would be to buy another upper for heavier bullets?? Don't know what chamber the RRA 1/12 has and it may be too short throated to shoot rounds like the military 62 fmj's or even 55 military fmj's. The 1/8 twist such as the Wylde chamber is a compromise and is for 5.56 and .223 Rem loads and will have a long enough throat for up to 77 grain bullets but is long for smaller bullets. RRA has quality barrels and their standard twist for Varmint and Predator rifles has the 1/8 Wylde chamber and that would be my choice.
Last edited:
JeepHammer
Moderator
The guys are more or less correct...
The military started with 1:14", with 52 grain bullets, then wanted more energy at the target,
Went to a heavier bullet, 55 grains, which took a 1:12" barrel to stabilize.
As bullets got heavier, barrel twist rates got faster...
62 grain bullets took 1:10" or 1:9" to stabilize, 68 grain took 1:7" or 1:8" to stableize.
Continuing along those lines, I have, or have had, many of the 'Super .22' center fire rifles since about 1970...
Some have 1:16" barrels and shoot 35-40 grain bullets with astounding accuracy, but won't shoot a 50-55 grain bullet worth crap, just not what they were intended to shoot.
The old timers got it right!
I almost exclusively varmint hunt these days, coyotes, ground hogs, feral house cats...
I shoot a crap load of 'Light' bullets, mostly Hornady Vmax,
50-55 grain through 1:10 twist barrels, the 'Average' 10 shot group @100 yards you can cover with a nickel, some barrels producing 10 shot groups you can cover with a dime.
When I run that very same load through a 1:8" barrel, I'm lucky to do under a MOA.
My hog rifle (I have accurate rifles, not lead slinging 'Guns'),
Has 1:8" barrel, and shoots 60-65 grain 'Amax' or soft points quite well.
I was looking for a reasonable priced 1:10" barrel for an AR, couldn't find one, so I 'Settled for 1:8" and while not quite as accurate as my 1:10" bolt rifle with 60-65 grain loads, the 1:8" does a very respectable job.
I WOULDN'T take it to a bench rifle shoot, but it will put bacon on the table every time!
The military started with 1:14", with 52 grain bullets, then wanted more energy at the target,
Went to a heavier bullet, 55 grains, which took a 1:12" barrel to stabilize.
As bullets got heavier, barrel twist rates got faster...
62 grain bullets took 1:10" or 1:9" to stabilize, 68 grain took 1:7" or 1:8" to stableize.
Continuing along those lines, I have, or have had, many of the 'Super .22' center fire rifles since about 1970...
Some have 1:16" barrels and shoot 35-40 grain bullets with astounding accuracy, but won't shoot a 50-55 grain bullet worth crap, just not what they were intended to shoot.
The old timers got it right!
I almost exclusively varmint hunt these days, coyotes, ground hogs, feral house cats...
I shoot a crap load of 'Light' bullets, mostly Hornady Vmax,
50-55 grain through 1:10 twist barrels, the 'Average' 10 shot group @100 yards you can cover with a nickel, some barrels producing 10 shot groups you can cover with a dime.
When I run that very same load through a 1:8" barrel, I'm lucky to do under a MOA.
My hog rifle (I have accurate rifles, not lead slinging 'Guns'),
Has 1:8" barrel, and shoots 60-65 grain 'Amax' or soft points quite well.
I was looking for a reasonable priced 1:10" barrel for an AR, couldn't find one, so I 'Settled for 1:8" and while not quite as accurate as my 1:10" bolt rifle with 60-65 grain loads, the 1:8" does a very respectable job.
I WOULDN'T take it to a bench rifle shoot, but it will put bacon on the table every time!
alan gordon
Inactive
50gr vmax and 55sp
Thank you for your insight.i had a dpms ar varmint rifle with a 1-9 twist 24 in barrel.unfortunately my home was broken into and the rifle was stolen along with three pistols.that rifle loved fiocchi ammo,anything from 40gr vmax to 55gr sp.after 10 years i narrowed it down to the 50gr and 55sp because those rounds worked the best with my zeiss 6/5-20 rapid z varmint scope with the bdc.
I am going to replace the dpms with a rra rifle,but they only offer a 1-8 or 1-12 twist.i have no interest in shooting anything larger then a 55gr round.this is a purpose built rifle for target shooting and taking varmints out to 500 yards.which will serve me better the 1-8 or the 1-12 twist.
Thank you for your insight.i had a dpms ar varmint rifle with a 1-9 twist 24 in barrel.unfortunately my home was broken into and the rifle was stolen along with three pistols.that rifle loved fiocchi ammo,anything from 40gr vmax to 55gr sp.after 10 years i narrowed it down to the 50gr and 55sp because those rounds worked the best with my zeiss 6/5-20 rapid z varmint scope with the bdc.
I am going to replace the dpms with a rra rifle,but they only offer a 1-8 or 1-12 twist.i have no interest in shooting anything larger then a 55gr round.this is a purpose built rifle for target shooting and taking varmints out to 500 yards.which will serve me better the 1-8 or the 1-12 twist.
I drilled many a cloverleaf with my .222 Remington with 14" twist firing flat base 50 grain bullets. 55 grain boattails opened up to about one inch. It's bullet length that most affects how fast the twist has to be. The military 7 inch twist is used because it has to stabilize the 1.15" long M856 tracer round. The 0.906" M855 62 grain bullet it traces for is stabilized just fine with a 9" twist. The 8" twists are popular with target shooters running 80 grain MatchKings.
The reason for not using a faster twist than is required by your bullets and expected shooting conditions is dependent on bullet quality. The faster you spin a bullet the more drift away from the barrel line will be introduced by any small asymmetry in its mass around the spin axis. It also causes eccentric spin around the mean trajectory (wobble) in flight. In other words, it makes groups bigger. This is why shorter range benchrest chamberings generally use stubby bullets. They are stabilized by the slowest possible twist, which introduces the least possible level of these effects.
The reason for not using a faster twist than is required by your bullets and expected shooting conditions is dependent on bullet quality. The faster you spin a bullet the more drift away from the barrel line will be introduced by any small asymmetry in its mass around the spin axis. It also causes eccentric spin around the mean trajectory (wobble) in flight. In other words, it makes groups bigger. This is why shorter range benchrest chamberings generally use stubby bullets. They are stabilized by the slowest possible twist, which introduces the least possible level of these effects.