Light bullets in a fast twist barrel?

[Wind River]

I recently acquired a Tikka 22-250 with an 8" twist. Light bullets shoot poorly and even my go-to load of 39 gr. H380 and a Berger 52 gr. Is mediocre. Accuracy comes in starting about 60 gr up.
Anyone else experienced this?
If this is common I don't care for the trade-off.

 

[Tiny Tim]

Others will likely have more to offer. Usually "over stabilizing" bullets isn't drastically detrimental to accuracy.

Rpm may work against you,. You didn't give velocity. A fast twist or rough barrel may wreak havoc with thin jacketed bullets, causing accuracy to fall off.

 

[FEENIX]

I recently acquired a Tikka 22-250 with an 8" twist. Light bullets shoot poorly and even my go-to load of 39 gr. H380 and a Berger 52 gr. Is mediocre. Accuracy comes in starting about 60 gr up.
Anyone else experienced this?
If this is common I don't care for the trade-off.

As with anything else, you will have to find the right powder, bullet, primer, and seating that your rifle shoots. What works with i.e., 1:14" does not automatically shoot with the 1:8" twist. Not in 22-250, but I have a few fast twist barrels without any issues.

"IF" you want to stay with the Berger bullet line, you must step up in weight, i.e., 70+g, which is more compatible with your rifle's twist.

 

[Barrelnut]

This is very common. Best accuracy "match" type accuracy is usually achieved with the minimum twist to stabilize the bullet. Any out of balance the bullet has due to jacket inconsistency etc. will start to show up the faster it spins. Also a rough barrel and thin jackets can cause the bullet to come apart once it exits the barrel.
Slowing the bullets down by lowering the charge weight will probably improve the accuracy quite a bit. There's a formula to calculate bullet RPM. Use the formula and lower the charge to get the bullets RPM below 300,000 RPM and accuracy should improve.
Formula: MV X 720/Twist Rate = RPM

 

[Wind River]

Adl-SPS hinged floor plate?

threaded?

This is very common. Best accuracy "match" type accuracy is usually achieved with the minimum twist to stabilize the bullet. Any out of balance the bullet has due to jacket inconsistency etc. will start to show up the faster it spins. Also a rough barrel and thin jackets can cause the bullet to come apart once it exits the barrel.
Slowing the bullets down by lowering the charge weight will probably improve the accuracy quite a bit. There's a formula to calculate bullet RPM. Use the formula and lower the charge to get the bullets RPM below 300,000 RPM and accuracy should improve.
Formula: MV X 720/Twist Rate = RPM

Thanks! Great tip & formula. I suspected as much. The Bergers were at 3650 fps and shot 1-1 1/4". This load shoots 1/2 moa in my 14" twist guns. I did not chrono the 40-45 grain bullets but they were in the 3900-4000 range.

 

[MagnumManiac]

Honestly, this must be a barrel thing because my 7" twist 22-250AI with 32" 4 groove barrel gets phenomenal accuracy with anything I put in it.
It loves Sierra 69g bullets, whereas my 7" twist 3 groove would rip them apart every time.
Have used 52g MK in the 4 groove without issue, 3 groove doesn't like anything under 77g, so I have retired it for now.
All my barrels above were Brux and Bartlein.

Cheers.

 

[ARlife4me]

Don't forget about having high revs! Get to high with twist and velocity the cup-n-core will come apart! Get a 4t if you want, but watch the velocity! The thinner the worse it can be on jackets?

 

[ARlife4me]

Bullet Spin Rate Calculator - Calculator Academy

Calculate bullet spin rate, muzzle velocity, or barrel twist rate by entering any two known values with fps, m/s, inches/cm per turn, RPM, or RPS units.

calculator.academy

Don't recall the possible max rpm.

 

[FEENIX]

This is very common. Best accuracy "match" type accuracy is usually achieved with the minimum twist to stabilize the bullet. Any out of balance the bullet has due to jacket inconsistency etc. will start to show up the faster it spins. Also a rough barrel and thin jackets can cause the bullet to come apart once it exits the barrel.
Slowing the bullets down by lowering the charge weight will probably improve the accuracy quite a bit. There's a formula to calculate bullet RPM. Use the formula and lower the charge to get the bullets RPM below 300,000 RPM and accuracy should improve.
Formula: MV X 720/Twist Rate = RPM

This! Many people have experimented with fast barrels and high RPMs. Most of the ones I've seen concluded that you cannot over-stabilize, but can over RPM (which is NOT the same as the fast twist) for the type of bullet construction and design. Keith is a bit corny, but he explains the concept. As we all know, the recommended SG is 1.5 or higher. With my fast twist barrels, my SG is near 3. I am heavy bullet for caliber, so over RPM is not an issue.

 

[VLD Pilot]

I recently acquired a Tikka 22-250 with an 8" twist. Light bullets shoot poorly and even my go-to load of 39 gr. H380 and a Berger 52 gr. Is mediocre. Accuracy comes in starting about 60 gr up.
Anyone else experienced this?
If this is common I don't care for the trade-off.

I've got an I twist 22-250 AI and it shoots the 53 Vmax into very little groups. I don't push the bullets tho. I think I'm shooting them around 3650 fps.

 

[Huntaddict]

This! Many people have experimented with fast barrels and high RPMs. Most of the ones I've seen concluded that you cannot over-stabilize, but can over RPM (which is NOT the same as the fast twist) for the type of bullet construction and design. Keith is a bit corny, but he explains the concept. As we all know, the recommended SG is 1.5 or higher. With my fast twist barrels, my SG is near 3. I am heavy bullet for caliber, so over RPM is not an issue.

Agree with much of this...adding that over-spinning a well constructed bullet to the point of failure or negative affect is pretty hard these days. I personally have never seen it but I am sure it is possible.

I have a 22-250 ai and I run 75 grain bergers with H380 at 3355 fps. SG is 1.6. I had to use an 8 twist to get SG >1.5
I am also a heavy bullet person. I also like my stuff to go vary fast for hunting. Built this as a LR coyote rifle and it is devastating. I see no issues in accuracy at 800-1000. Target shoot well past that but really don't hunt past that unless it is a special environmental circumstance. I am now on my second barrel it is runs great both times.

I also built a 30 nosler in 2014 with 82.4 grains RTMBO an 8.44 twist BBL to run 210s with SG of 2.4 - at the time not a lot of magnum guys were "over twisting" bullets. There is a trade of and with a 24" barrel, I wanted more spin and a better powder burn by keeping the bullet in the barrel just a bit longer. Interesting outcome. I thought I made a mistake with it when it would not shoot any tighter than a .6 group at 100 - and then it shot .6 at 200, .6 at 300 and .6 at 400. Sometimes the combo will tell you the story you want to hear differently than you thought and still give you the outcome you want.

 

[VinceMule]

Tikka, jump to the lands is an issue. With the bullet jump and speed, consider the 60g Nosler ballistic tip as a start.

Intended use is? Coyotes/P. dogs/Chucks?

Bore dia is also an issue.

 

[19elkhunter51]

I have a 22-250 1:8 twist and it shoots everything from 45 grain all the way to 80 grain bullets into less than a half inch at a 100. Best part is the POI does not change.
I don't have an answer as to why your gun doesn't do the same.

 

[Hugnot]

Try the 62 grain Hornady ELDVT in the 8 twist. I have a 7.7 twist .22-.250 and that bullet shoots great. I can shoot hand size groups at 400 yards with it with minimal drop. Velocities are close to 3,600.

I use some other bullets - the Hornady 75 grain ELDM and Berger 75 VLD with great results.

Some info:



Your 8 twist should work with all of these bullets. Hornady has 8 twist on the 62 ELDVT box.

Another consideration is form factor - the ratio of sectional density / G7 BC





This indicates how well a bullet will perform independent of mass. Berger is really into this and lists Form Factor for all of their bullets. The 62 ELDVT has the lowest FF of all .224 bullets. Lighter bullets can be driven faster than heavier bullets of same caliber.

Post # 3, center of pressure vs center of mass. The 62 H ELDVT has a relatively large separation of both and requires a faster twist than would be expected for a bullet of equal length. This bullet is a failure out of a 9 twist .223 but the same rifle shoots the 73 H ELDM bullets well.