Why do we need slow twist barrels again?
 

I was shooting 40gr Ballistic Tips in an 8 twist 223 yesterday. Once again, light bullets seemed to do just fine in a quicker twist barrel. Is there a good reason why manufacturers continue to use slow twist barrels in many of their offerings?

https://i.imgur.com/oF1pS0q.jpg

https://i.imgur.com/QcmsOlf.jpg

Good question Chuck. Not sure what the purpose of slow twist barrels is. I would like to be able to shoot 80gr bullets in my 22-250. Kind of tough with a 1-14 twist.

I just purchased a lefty Tikka in 22-250. Kind of disappointing its a 1-14 twist.

Especially when they are producing 8 twist .224 barrels.

I always thought
 

it was so the fast twist did not destroy the fragile "varmint" bullets leaving the barrel. Every 22-250 I have owned has been 1-12 or 1-14. come to think of it I believe my BRNO 223 is 1-12 as well

When buying a barrel, I prefer to get the slowest twist that will stabilize the bullet I plan to shoot.

twist rate article
 

another chuck

http://www.chuckhawks.com/rifling_twist_rate.htm

i shoot 55's very well out of a 7 twist

Anecdotal evidence is not evidence.

Manufacturers would be basing their decisions on a much larger sample size than an individual shooter could ever come up with.

If your chasing velocity a fast twist will hinder you in cartridges like the 22-250 im learning this the hard way put a 9 twist on a 22-250 wishing i went 12 or 14 i was on the same mindset shoot all weights instead of 55g and under but the reality is i dont want to shoot anything heavier than 55g in it

It does shoot 50g bullets very well but not fast

Usually a few things when people purchase a tikka that can be a concern.

Care to elaborate?

He can’t and won’t.

Because manufacturers and lawyers stick with antiquated SAAMI twist rates, and "shooters" who don't shoot other than their keyboards think that fast twist rates have downsides.

Question for the OP. What's the distance you were at when you shot those groups?

You might know where I'm going with this question.

100 yds

Maybe
 

Maybe a better question is why would you want to force a light bullett into a fast spin, exerting forces that slow it down in the pipe?

Twist rate has a negligible effect on bullet speed, under 10fps. As stated earlier, slower twist rates prevent thin-jacketed bullets from spinning apart under excessive centrifugal force.

Quoted for truth. Similar to chuck's example, my 1-8 223 shoots 50s-75s awesome. Light projectiles can shoot very well out of a fast twist, but no slow twist I know of can shoot the heavies.

Haven't done too much experimenting with my T3 in 223 with the fast twist but so far it shoots the lighter bullets better then the heavyweights. But being a t3 it shot not only the first thing but everything I tried well enough any more experimenting is probably not needed.

It is a lot more than two groups from me that says there is evidence in support of this.

Well
 

Where did you arrive at 10 fps? Or did you mean 10%? There are a lot of variables to consider to have been able to arrive @ 10 FPS. For instance, the differenace in a 1:8 vs 1:14 will not be the same. Putting a projectile into a forced tight spin is detrimental to bullet skins, speed and barrels, and lighter projectiles in a good barrel don't require it, in my opinion, so what would be the positive trade off? I can't think of one really, but there may be
.
Twist rate has a negligible effect on bullet speed, under 10fps. As stated earlier, slower twist rates prevent thin-jacketed bullets from spinning apart under excessive centrifugal force.[/QUOTE]

Where are you getting your information?

I’ve run light bullets in fast twist barrels at over 4000 FPS with ZERO problems. Am I just lucky?

All I know is my fast twist factory rifle will shoot light bullets “under 1/2” all day”. :sHa_sarcasticlol:

https://i.imgur.com/34pFTKr.jpg

Hows your speed on that load ive done 2 243 win one 1/8 one 1/8.5 both shot all weights very well but could not find an acceptable load at upper ends of their pressure limits with 58g vmax
Same with the 22-250 1/9 i mentioned ealier.
All three fell short of the velocity id like by 150-200fps with light weights
All three acheived velocity and accuracy i was looking for with bullets on the heavy end of the spectrum
Many other factors may contribute to my results but im becoming more apt to rethink my thoughts of fast twist on everything.
I do have a 1/7.5 twist 6.5 barrel ill be chambering in 6.5x284 soon i will see how it likes the lightweights just for fun

My last three fast-twist barrels shot light bullets very well, and velocities were where they were supposed to be.

An 8T 22-250AI Benchmark was set up for 75 A-Maxes, but did fine with 40 grain V-Maxes and B Tips.

An 8T 6mm Rem Krieger set up for 105 Hdy A-Maxes was a one-holer with 58 Hdy's at over 4000 fps.

And my latest 8T 243AI MacLennan on a 84M does the same with 105s and 58s.


Earlier in the thread, it was asked why someone would subject bullets to faster twists. Three reasons that come to mind immediately are, more goo on gophers with light-weight bullets, optimzing BC with pointier target bullets, and more positive effects on big game with monometal / bonded bullets. Bill Steigers with his old BBC line was an early proponent of that.

My understanding is that physics says there is no such thing as “overstabilization” so suggesting that spinning a bullet faster than necessary impacts on accuracy (espescially at 100yds) has little merit. Also of limited merit is predicting consistency based on a couple of three shot groups.

No doubt two groups don’t a story make. But I have found it extremely difficult to fluke a pair of sub 1/2” groups also. This outing was just to get a close zero and I was actually shooting handloads for another rifle.

Lol
 

From science. Lol
I never said a rifle with a fast rate wouldn't shoot, of course it can. What was asked was why are there still slow twist barrels on the market.
To prove any formula, we'd have to swap out your barrel for a slower twist chambered exactly as your last, but lets be honest, that's not reasonable.
But if we did, do you also believe as someone else posted, that if we put on a 1:14 that you'd only be shooting 4010 FPS? Tighter twist, more friction is imparted on the barrel and projectile. What's it mean on paper? Maybe nothing, but maybe something.

Did you change your zero between groups?