Owner of two Sako rifles

[Dave123]

Hi

I recently purchased a new Sako 85 hunter chambered in 223 Remington. After i bought the rifle i realized that the twist rate is 1:8 and will need to shoot heavier bullets, the problem is heavier bullets above 55gr is difficult to find in my area. I surfed the net wanting to find out if a 1:8 twist rate will be able to stabilize 55gr bullets. I'm thinking to sell the rifle and go for the 1:12 twist rate. During my search for answers i stumbled on this forum and i joined, i hope all the Sako enthusiast on this site will be able to help. So my question is will the Sako 85 hunter with a 22" barrel 1:8 twist rate stabilize 55gr bullets? Dave

 

[paulsonconstruction]

There is no "need" to shoot heavier bullets because of your twist. You can't "overstabilize" a bullet. The 1:8 twist will stabilize any bullet weight made in 22 cal. It's a faster spin than needed for 40 to 63 grain bullets, but that seems to be the current fad. The faster twist will cause a slight increase in pressure, foul quicker, & could cause very thin, fragile bullet jackets to fail. I much prefer the slower 12 twist in the 22 centerfires, but they are becoming almost nonexistent in the new rifles. A 12 twist will stabilize bullets weighing up to about 63 grains in a 223 Rem. Some of the newer plastic tipped bullets are longer for weight than the old cup & core bullets, so they may change that weight limit.

 

[stonecreek]

What Paulson said.

"Fast" twist is a current fad, with many people blaming accuracy problems with bullets of conventional weight and length on "too slow twist". Hogwash.

However, your fast twist barrel should handle bullets of any weight with little, if any, problems. I always advise people who are concerned about the twist of their barrels that the only way to know how it will shoot with a particular bullet is to actually shoot that bullet in it. I suspect your Sako will shoot bullets of any weight just fine. But if it doesn't, don't immediately blame the twist since the normal accuracy issues with bedding, crown, scope, ammunition quality, etc., etc. have far more impact on accuracy than does the fast twist. In other words, check to see that your action screws are tight and your reticle isn't floating around inside your scope before you go spend many hundreds of dollars swapping barrels.

 

[Branxhunter]

Agreed.

I have read gun reviews over here where 40gn projectiles have shot tighter groups than the heavies (63gn+) in factory rifles with 1:9 barrels.

Marcus

 

[Glenn Verrall]

Agreed.

I have read gun reviews over here where 40gn projectiles have shot tighter groups than the heavies (63gn+) in factory rifles with 1:9 barrels.

Marcus

I have a mate who just bought a Browning x bolt and WILL not consider anything less than 70 grn projectiles because he wants it as a pig gun. This seems to be a trend in recent years due to the cheap nature of 223 ammo. I cannot convince him to even try the 55 grn pills. He couldn't hit the side of a barn with his current set up but won't budge and he was insistent on getting a 1.8 twist barrel for this purpose as you have stated. Sad but maybe he will come around, specially when he keeps seeing the 222 Mag knocking ferals over with ease. I tried to convince him to use 60 grn Partitions but not heavu enough for him. He is not a Sako owner so I put it down to that.(and he is a lefty).

 

[kirkbridgershooters]

There is no "need" to shoot heavier bullets because of your twist. You can't "overstabilize" a bullet.

This is not necessarily true. I have a 223 rifle with 1/7 and it won't shoot anything under a 55 grain bullet worth a damn...

 

[paulsonconstruction]

This is not necessarily true. I have a 223 rifle with 1/7 and it won't shoot anything under a 55 grain bullet worth a damn...

Just because your rifle doesn't like bullets 55 grains or less has nothing to do with my statement about there being no "need" to shoot heavier bullets, as the question was about stability not accuracy. Accuracy varies from rifle to rifle, but a bullet is either stable or it's not. Others on this thread have claimed better accuracy with 40 grain bullets in fast twist barrels than with heavies, so your rifle is just different in what it likes, but I guarantee you with an insanely fast 7 twist your bullets are gyroscopically stable.

 

[kirkbridgershooters]

Just because your rifle doesn't like bullets 55 grains or less has nothing to do with my statement about there being no "need" to shoot heavier bullets, as the question was about stability not accuracy. Accuracy varies from rifle to rifle, but a bullet is either stable or it's not. Others on this thread have claimed better accuracy with 40 grain bullets in fast twist barrels than with heavies, so your rifle is just different in what it likes, but I guarantee you with an insanely fast 7 twist your bullets are gyroscopically stable.

I suppose you are correct, but what good is an over-stabilized bullet that won't shoot?

 

[stonecreek]

There is a theory that if a bullet has a slight internal imbalance then the faster you spin it the greater the influence of the imbalance on the bullet's flight and therefore the less accurate it is. This is why many people claim that light bullets fired in fast twist barrels are less accurate.

However, the theory is flawed, in my view, when you consider that a heavy (long) bullet is just as likely to have an internal imbalance as a light (short) bullet. So why should the two act differently?

I think the logical answer is that light bullets can be driven to faster velocities than heavy bullets. The faster you push them down the barrel the faster they spin in terms of RPM's. I'll use an example: An 80 grain bullet fired through a 1-6" barrel (that twist picked for simplicity of calculation) at 2600 fps would be spinning at 312,000 RPM. A 40 grain bullet fired through the same barrel at 3800 fps would be spinning at 456,000 RPM.

Is it possible that by spinning the bullet half-again as fast that you are pushing the envelope of the bullet's structural integrity? I've seen light bullets vaporize and never reach the target when fired from a large wildcat .25 cartridge. By definition, it is not possible to "over stabilize" a bullet. But I suppose that you might negatively impact its performance by spinning it to near the limits of its structural integrity. Maybe?

But in my experience some rifles simply shoot some bullets better than conventional wisdom says they should and some bullets worse. I've seen some 1-12" .244's shoot 100 grain bullets with excellent accuracy, for example. The proof always seems to be in the shooting.

 

[kirkbridgershooters]

The debate on the value of fast twist will not end soon. It has become over valued in just what fast twist is really good for. The tendency to buy or want fast twist has been affected by all the recent hype in the gun industry to sell more rifles and ammunition.

The whole concept of fast twist is to shoot longer bullets. The longer the bullet the faster the twist needs to be to get the performance that is necessary to hit your target. Along with longer bullets, you get a higher Ballistic Coefficient and that is what makes a difference in sustained flight of a bullet at long range. With that longer bullet, you also gain weight and weight gain will also slow the velocity of the bullet, so now you have a different dynamic that needs to be considered for the shooting you do.

Most of what has come about with the recent interest in fast twist and specifically the 6.5 Creedmoor cartridge is the ability to shoot long range more consistently in regards to wind drift and trajectory. Fast twist and the 6.5 Creedmoor are specialized tools for the competitive shooters, but you won't see the records set by the 308 Winchester being destroyed anytime soon. Older less specialized cartridges have been doing wonderful things for decades.

Enter fast twist and again, the 6.5 Creedmoor and you have a large pool of people that buy these things do to the hype in the gun world through magazine articles and the uninformed buyer thinks he needs these latest advancements to shoot well and consistently.

There is a reason the most accurate cartridge in the world (6mm PPC) doesn't have fast twist. It accomplished what nothing had before, without fast twist and not shooting 1000 yards.

You need to address your particular style of shooting, then get the rifle/cartridge combination that will accomplish that goal and leave fast twist and the 6.5 Creedmoor to the long range competitors.

 

[paulsonconstruction]

There is a theory that if a bullet has a slight internal imbalance then the faster you spin it the greater the influence of the imbalance on the bullet's flight and therefore the less accurate it is. This is why many people claim that light bullets fired in fast twist barrels are less accurate.

However, the theory is flawed, in my view, when you consider that a heavy (long) bullet is just as likely to have an internal imbalance as a light (short) bullet. So why should the two act differently?

I think the logical answer is that light bullets can be driven to faster velocities than heavy bullets. The faster you push them down the barrel the faster they spin in terms of RPM's. I'll use an example: An 80 grain bullet fired through a 1-6" barrel (that twist picked for simplicity of calculation) at 2600 fps would be spinning at 312,000 RPM. A 40 grain bullet fired through the same barrel at 3800 fps would be spinning at 456,000 RPM.

Is it possible that by spinning the bullet half-again as fast that you are pushing the envelope of the bullet's structural integrity? I've seen light bullets vaporize and never reach the target when fired from a large wildcat .25 cartridge. By definition, it is not possible to "over stabilize" a bullet. But I suppose that you might negatively impact its performance by spinning it to near the limits of its structural integrity. Maybe?

But in my experience some rifles simply shoot some bullets better than conventional wisdom says they should and some bullets worse. I've seen some 1-12" .244's shoot 100 grain bullets with excellent accuracy, for example. The proof always seems to be in the shooting.

Remember the Hornady SX series of varmint bullets? They came with a piece of paper in the box warning not to shoot them over 3500 FPS because of their extremely thin, fragile jackets. Well, when your young you automatically do what you were told not to do. They turned to a puff of blue @ about 75 yards when pushed to 3800 fps as they disintegrated from centrifugal force & air friction. Target @ 100 yards looked like it had been sprayed with a 22 rat shot round from all the tiny particles. Later, I built a Swift to shoot the new (at that time) Nosler 55 gr Ballistic tip. Called Nosler & they said use a 12 twist instead of the standard Swift twist of 14 because of the extra length of the BT & that they had tested them to 4600 fps without any structural bullet failures. New technology allows us to do things that we once thought impossible. I think you are spot on that spinning a bullet too fast can cause "internal instability" that is detrimental to accuracy & there are no hard or fast rules that determine how any particular combo of barrel, twist, & bullet is going to perform. Like you said, proof is in the shooting!!

 

[paulsonconstruction]

I suppose you are correct, but what good is an over-stabilized bullet that won't shoot?

Not much good at all! But the question could be "What is a 7 twist 22 caliber barrel good for?" Just food for thought.

 

[kirkbridgershooters]

Not much good at all! But the question could be "What is a 7 twist 22 caliber barrel good for?" Just food for thought.

I don't think it is as much about what it is good for as much as what can 1/7 do. Fast twist isn't new, the 25-35 was developed in 1895 and had fast twist. It isn't new technology to need fast twist to stabilize longer bullets. It is just that magazine articles and internet chat rooms have made the fast twist phenomenon come alive.

Fast twist is wasted on 223 sized cases, as there isn't enough velocity generated in that small of a case to give a longer bullet eny distinct advantage. My brother shoots 69 grain bullets in his rifle at about 2700 FPS and I shoot 40 grain bullets at 3800 FPS. On a prairie dog field at realistic ranges (250-350 yards) his bullets are such poor performers as there isn't any velocity at those ranges for the bullet to do more than poke a hole in a prairie dog. My 40 is a different story, as a prairie dog is lifted off the ground and destroyed by the 40 grain bullet.

In a nutshell, fast twist and high BC bullets are designed for about 5% of the shooters out there and 55% or more think it will help them and they are mistaken.

 

[stonecreek]

We're taking this thread a little off course here, but hey, that's what freedom of speech is all about, right?

I've long been shooting the 40 grain tipped bullets (B. Tip, V-Max, etc.) in my .221 Fireballs and have been extremely happy with their accuracy and performance. For years I had used 52 grain HP's in my .222 Magnum, which worked well enough. But recently I tried the 40 grainers in the .222 Magnum at around 3800 fps and, wow, did those little pills shoot accurately and excommunicate prairie dogs even more effectively than the 52's. There is no question that the little 40's running 500 fps faster than the 52's have been better for me at extended ranges. True, the lighter bullets shed velocity and energy faster, but their extra muzzle velocity appears to more than make up for this -- at least out as far as I care to try to hit a prairie dog, anyway.