FAST TWIST BARREL QUESTION

[22BRGUY]

The fastest twist barrels I've had so far are 8's. I see and hear about guys having those 7 1/2's, 7's and even
6's. to stabilize those heavy long slugs with high BC's.
In my mind I imagine some place where the twist becomes Too Fast and bullet jackets start getting
stripped off unevenly affecting accuracy.
Would appreciate any comments from any of you who have experienced and used 7 1/2 or faster
twist barrels and ask if they gave you the performance and accuracy you hoped for with those long
heavy pills.
Thanks Much!

 

[Nealm66]

I haven’t had any issues with 7 twist criterion 26” with 90 bergers and 88 Hornady’s at around 3150. The bergers shot very well, hoping to finish tuning the 88’s tomorrow. Only switched because I can’t find 90 bergers.

 

[Fast14riot]

My service rifle (NMA2) has a 1:7 barrel for shooting 80+ gr bullets. Does great with those, I've also shot 50gr bullets out of it pretty fast and accuracy was still there. Light jacket bullets over spun is usually the issue. I will say that on game, light bullets in a fast twist are pretty explosive!

 

[Bill Norris]

I have a 7.5 twist barrel on my 243AI and have shot up to the 115 gr. Bergers 115 gr. Noslers and 115 gr. JLKs with no issues at all. Groups are very good as well.

 

[Walt Krafft]

I have made a lot of 5 twist 300 Blackout barrels.

 

[22BRGUY]

I have a 7.5 twist barrel on my 243AI and have shot up to the 115 gr. Bergers 115 gr. Noslers and 115 gr. JLKs with no issues at all. Groups are very good as well.

NICE!!

 

[jelenko]

twist becomes Too Fast and bullet jackets start getting
stripped off unevenly affecting accuracy.

Absolutely. => we should choose the barrel twist based on the bullet we're going to use. The longer, heavier ones are going to have less muzzle velocity => less rpms.

Bullet rpm = [MV] x [720]/Twist rate

 

[gunsandgunsmithing]

Frankly, it amazes me that a lead core copper jacketed bullet ever reaches the target. An 8 twist at 3000fps is the bullet spinning at 270,000RPM while the lead is bordering on becoming liquid! That's just amazing to me!

 

[22BRGUY]

I have a 7.5 twist barrel on my 243AI and have shot up to the 115 gr. Bergers 115 gr. Noslers and 115 gr. JLKs with no issues at all. Groups are very good as well.

WHO made the barrel Please?

 

[JEFFPPC]

I have used 7 and 7.5 with 6mm and 6.5 mm with appropriate bullets. In both cases I got better more consistent accuracy with 8 twist and appropriate bullets. I think I was pushing the envelope. Accuracy and tune ability trumped a bc gain for me.

 

[PhilKeil]

I have a 7 twist Kreiger in 6-06 AI with 115 Bergers at a little or 3000 with no issues.

 

[Bill Norris]

WHO made the barrel Please?

Krieger

 

[swd]

We’ve had no bullet failures with 6mm Krieger, Bartlein, Broughton and PacNor 7”-7.5” with 107SMK’s, 109 Berger’s and 110SMK’s. And they all shoot great!

Brux 7.5”, 6.5 cal with 140 Berger Hybrids, 142SMK’s, 156 Berger’s.
Krieger and Bartlein 6.5 7” with 140 Berger Hybrids and 153.5’s.

All are F Open rifles and shot hard..

 

[DR_2297]

My go to is 7.5 in 6 mm and 7 in 224. I did receive a pair of .218 x .224 6.8T 5R barrels this week though. Destined for 223 Fullbore / Palma rifles firing 90 VLD.

 

[Walt Krafft]

Many years ago I built an 8 twist 22-250AI. After 10 shots heated up the barrel, no bullets ever made the target. Spectators said it looked like ack-ack busts.

 

[K22]

I shoot both 55 and 60 grain bullets out of my Tikka's, 8" twist 223 Rem's with no adverse effects. They are moving at about 2,900 f/s with the powder I use.

The 60's shoot slightly tighter groups but the 55's are not bad either.

The 60 Vmax is specially an excellent bullet in my 223 Rem Tikka's.

 

[David Milisock]

The fastest twist barrels I've had so far are 8's. I see and hear about guys having those 7 1/2's, 7's and even
6's. to stabilize those heavy long slugs with high BC's.
In my mind I imagine some place where the twist becomes Too Fast and bullet jackets start getting
stripped off unevenly affecting accuracy.
Would appreciate any comments from any of you who have experienced and used 7 1/2 or faster
twist barrels and ask if they gave you the performance and accuracy you hoped for with those long
heavy pills.
Thanks Much!

My 7 1/2 twist is very accurate for heavy 6mm projectiles, 103 and above. It provides an ok platform for lighter projectiles.

Rifle barrels (if good accuracy is required) need to be cut to a range of weights. In 6MM for 100 grain and lower 1 in 9 works well. When I build rifles I have specific projectiles in mind and send dummy cartridges to the smith to cut the throat.

 

[wkdickinson]

I have a 7.5 twist Criterion on my 6 Dasher (2,920 fps) and it shoots Berger 105 Hybrid beautifully. I also have a 7.7 twist 4-grove Krieger on an AR and it shreds the jackets on 50gr VMAX, so only about 30% ever make it to the target. Same load in a 9 twist AR shoots great.

 

[ebb]

how could you possibly answer this question with out the caliber and chambering

 

[Clam]

I have a 1:7 twist, .221 FB. I use it on gophers. hornady 40 gr v-max. The terminal performance is spectacular. It is only accurate out to about 210 yds. My theory is that the energy gets used up spinning the bullet and it just poops out. I can’t remember my velocity #’s. I never tried it with heavier or longer bullets.