Bullet Weight vs Twist Rate test
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- เผยแพร่เมื่อ 9 ม.ค. 2015
- A brief clip from the TV show "Ruger Inside and Out." They take three rifles that are identical except for barrel twist rate and test them for accuracy with three different bullet weights.
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I like these kind of video where the secondary dude ask basic questions.
Thank you :) I can see that you are clearly professional people that have a good understanding on this topic. I have debated on which grain of bullet to get. I see some that are on youtube that are like well Jokers. You have help me out a lot thank you. Keep up the good work guys.
These people are jokers too. The "bearing surface" comment completely lost them their credibility with anyone who actually knows anything about bullet stability.
Best explanation I have found yet, well done.
Found 1/8 twist WYLDE barrel is best compromise. got a 20" and works great with anything from 55gr to 77gr. found the 75 gr to be the perfect match for my rig.
4 days I was struggling between 1, 1,8 or 1,9 and I went with 1 and 9 and I'm still worried until I saw this video that oh wow I got it too slow now I know I'm pretty much good to go. thanks!
I feel much better after watching this my M&P15 has a 1:9 twist and someone had suggested I need a faster twist rate for 62 gr bullets. My Savage Axis 223 also has a 1:9 twist. I now feel much better firing heavier bullets from my AR & Savage bolt gun.
I have 1:9 AR and watch video's stating not for heavier bullets, but deer hunt with 69 grain and not shooting over 60 yards even thought u could shoot much future and would be fine. This video clarifies all the question that I had about twist rate not interested in shooting out to 300 yards and would not shoot a deer at that range with 69 grain bullet anyway...thanks u....
Don't pay any mind to this video. It's perfectly fine to shoot 69gr out of a 1/9 at distance. If you bothered to read the box of 69gr SMK you'd see that it calls for a 1/10 twist. You can shoot 75gr at distance just fine with a 1/9. These guys in the video don't know shit.
I think they should have shot more intermediate weights, like 62 and 69gr, which are also very common.
I know, LMAO....a 1 in 12'' will stabilize up to 64 gr WW Soft Point Bullet. the 1 in 12'' WILL NOT Stabilize 62 gr. Mil Spec Green Tip due to the steel insert in front of the lead core makes it as long as a 70 Gr Speer Soft nose which needs a 1 -10" or 1-9" to stabilize. So the 1-12" will stabilize 40, 45, 50, 52, 53, 55, 60, 63 and 64 gr HP and SP Bullets and 55 gr FMJs.
@@demoratdestroyer7890 - Based on my experience, the 62 grain SS-109/M855 green tip FMF-BT is closer to the Sierra 69 grain HPBT MatchKing than the Speer 70 grain SP in turns of stabilization requirement. My rifle is a 22-250 Remington 700 fitted with a Krieger match barrel with a 1-10 twist rate, and I believe 1-10 is the minimum required to stabilize this bullet. Also, the bullet needs to be driven out at a minimum muzzle velocity of 3,300 fps. Under 3,300 fps will result in target groups looking like it was made by a shotgun shooting buck shots, and some of the bullet holes are not round but slightly oval in shape.
I'm an internet expert, here to enlighten the world via TH-cam comments!
The berger bullets website has a very good bullet gyroscopic stability calculator based on the Miller stability formula. Bullet stability is affected by air density which is affected by temperature and altitude. Sg=1 or less indicates an unstable bullet that will likely tumble. Sg= 1.2 to 1.5 indicates a marginally stable bullet with increased drag due to wobble and precession. Bullets in this stability range might group well at short ranges but also might do poorly in the transonic range and subsonic range. Sg>1.5 is a fully stabilized bullet. For long range shooting at velocities below Mach 1.2 (transonic) It is best to choose a bullet that has Sg>1.5 for your twist rate and environmental conditions.
good video guys !
My Smith and Wesson M&P 15 is 1 in 9 twist.
Wow, lots of real shooters and loaders on this board.
I really appreciated this video. I noticed the Ruger trademark. I have often wondered why Ruger decided to change the barrel twist on their Mini 14 (223) from 1:7 to 1:9? I suspected it might have something to do with the more common 55 grain bullets and maybe matching bullet rotational frequency with barrel vibration (i.e. ultimately accuracy). I have also wondered if the tighter twist might magnify any bullet imperfections. I have an older 1:7 barrel, and it seems to like 62 grain better, but I haven’t been very scientific. I haven’t tried anything bigger. Don’t worry, I didn’t buy the gun to win marksmanship contests. I like shooting open sights.
Wouldn't velocity also effect the stability in a given twist rate?
So to compare different twist rates on different length/weight of bullets they would need to all be fired at the same velocity?
The breech only has so much room so longer bullet can reduce powder. Plus of course, heavier bullet goes slower with same powder charge.
So your suggestion is not practical.
Except for handloaders, using light weight bullets. If you try to crank up a lighter bullet to perform as it should, you run into more pressure with a faster twist rate. I have a 1/9 twist, an with 50/55 grain bullets I'm running into pressure way before optimal performance for those bullet weights. Can't wait to get my 1/12 twist barrel.
Is a identical ogive bullet, but with boat tail technically shorter and one way to be heavier without being longer ?
Whats the best ammo for a 7mm mag with 1 and 10 twist tc compass
Now I know why my 1940s jc higgins is 1:15, with a 28inch barrel. Because it's chambered for shorts, longs, or long rifle, and they made it a slower twist as a compromise for all 3 different grain weights in 22. Am i about right ?
Longer bullets are more unstable and therefore need faster twist. Kinda like a short fat spinning top compared to a long thin spinning top. Since the bullet diameter is fixed - heavier bullets must be longer. Look up mark and Sam for a better explanation.
let's see some groups! what about the 55gr???
yep I was really wanting to see the 1:9 results with 55 gr
Its Me again. I'm sorry i should have given more info. I play with--shoot a Savage axis with a 22" barrel 1in 9 twist. My loads are 77gr. Nosler HPBT With a C.O.L. of 2.30" LC brass and I started with BLC 2 powder and have now switched to CFE223. I worked up from min to max. powder charge all with no stability problems. I got the load data for CFE223 from the Hodgdon www.hodgdonreloading.com/data/rifle. Like I said this is a very accurate bullet in my rifle. To date my friend has kill one deer (don't know the range) and one Coyote at 250 yds. All I shoot is targets. For me the fun is in developing the rounds, testing them and shooting. Have fun guys
Twist Rate. Bullet Weight
1 in 7. 62-75gr
1 in 8. 50-77gr
1 in 9. 40-75gr
1 in 12. 40-55gr
... it can depend a lot on material, both in bullet lenght and gyroscopic stabilisation. Also a large effect does boat tail vs flatbase . So what you say is wrong. Even more it starts to differ with diffrent ogive lenghts.
and .308?
Apophis when it comes to 308 most are a 1:10 twist and the best ammo for it is 168grain.
The 1/7 can shoot heavier bullets than what you show.
@@_j.v.st._7367 It's not wrong. It's a "moving target" chart, given a lot of other factors and assumptions taken into account. It's a guide.
I had stabilization issues that started at around 700 yards with a 105 gn. Bullet in a 243 win. With a 1:9.25 twist. 1:8 fixed the problem.
Were you surprised that a stabilization issue didn’t show up before 700 yards? I’m not going to argue with success.
@katrinadarling3271 surprised, no. Impressed, kinda. It wasn't working for competition out to 1200 yards.
Have you guys did a twist rate video for .243??? I'm wondering if my 1/9.25 twist rate is enough, to stabilize the 100g bullets. From what I've read, it should be good for anything from 55-100.
You can say that about 1/10 as well, Depends on the length of the bullets bearing surface on the rifling.
Back in the early 90’s, before the assault weapons ban, I picked up a used Colt Sporter AR-15. It had a 1:7”twist, 20” barrel. I reloaded 62 gr. Speer FMJ for it. I also reloaded 36gr. varmint grenade projectiles for my TC Contender 14” 1:12” twist. Which I used for varmints (go figure 🙄).
Then I was sighting in a new scope for the AR and used the lighter 36grain bullets. After firing off about 5 rounds each at 100, 50, and 25 meters and not one round punched a hole on target. I discovered the 1:7 twist rate was to fast for the projectile. It spun so fast the bullet flew apart upon exiting the muzzle. The jacket was to thin to hold the projectile together as it was spinning at over 300,000 rpm’s. 😳
Live and learn.
So why exactly does the bullet length need to be shorter as the weight goes up (for any given twist rate), or to say it another way, why exactly won't the bullet stabilize if its length is increased ?
Gold, was trying to get my head around bullet weight and twist - you nailed it! Im getting a Tikka T3X .223 with a 1/8 twist, 20" barrel length. so it seems that the best ammo would be a bit heavier to get greater accuracy and range ? PS could you do a comparison of a 20" barrel vs 24' I am unsure it will make a difference in accuracy ( speed of bullet) at .223 ranges out to 300m?
it does make a difference in speed an accuracy.
you can shoot as light of a bullet as you want and still get just as good of accuracy. The difference will be at distance when the wind effects smaller bullets more.
Twist rates are OBVIOUSLY velocity dependent. Because twist rates are a fixed mechanical property of a bore, the faster the bullet is shoved down the barrel, the higher the bullet RPM when it leaves the muzzle. The fixed thing is the bore rifling, the dynamic thing is the amount of velocity a hand-loader can adjust by varying loads.
Ultimately a given length (bearing-surface-area) of bullet in a given caliber will require a SET twist rate at an OPTIMUM velocity (forward-speed). Since the twist rate is a fixed feature, the only variable is the bullet length and charge-volume of powder in the case.
That established, the heavy-for-caliber bullets require a flight RPM that may not be attainable in that cartridge. The velocity required to achieve that RPM may be out of reach for a heavier bullet. So the twist rate needs to be faster.
It's not about bearing surface area.
@@kn761 What's it about, enlighten us.
Basically if you had just said what you said with out including the "(bearing surface area)" in there you'd have been just fine.
@@kn761 I really would be nice if random people on the internet today would strive to be articulate and state their case, without making blanket statements of disagreement to prove some personal point.
I've articulated it enough times here. Read around.
I have a savage rifle in 223 with a twist rate of 1 in 9,what bullet weight do you think will work better for my rifle or what heaviest bullet I can shoot with more accuracy?
69gr. sierra works best in my 1:9 Rem700 20" barrel
I was really wanting to see the 1:9 results with 55 gr
Me too... wanted to see the 55gr with a 1:7. Tavor is 1:7 and the most common (cheapest) ammo is 55gr.
I can give first hand experience that my 1:9 produces almost 1 jaged hole at a 100 yards with 55
1:9" is very common as is 55gr.
I think the question is to what grain size is 1:9" adequate? 62gr, 65gr?
It's fine.
@@artsmith103 I found 69gr sierra works with my 1:9 Rem700 barrel best and increasing to 75gr the groups begin to open up @ 100yds.
I can't seem to get any accuracy from my RAR 300 blk with a 120 gr bullet keyholing every time at 100 yds. It's a little better with a 145 gr.
What about a twist rate of 1:3.141592653
I do have a question I got 6.5 creedmoor savage110 24inch barrel 1.8 twist I can knot get accurate with hornady bullets my wife's howa 6.5 creedmoor 24 inch barrel 1.8twist hers dead on is the rifling or twist same depth and width
Even if your wife had the same rifle as you they might prefer different bullets. As it is the rifling is almost certainly cut differently, the chamber on hers might be tighter than yours so she'd have higher velocity and so on. Also, one of the rifles could be better bedded in the stock or has a heavier barrel.
@@JohnSmith-nz9dn ok that makes since I really appreciate that thank you
"All the AR platforms are in that weight range" I'm planning 220 gr 30 cal., as are 4 friends. I would be happy if someone made a 1 in 4 twist for 300BO. It would definitely improve the stability, but working the powder compositions would definitely be a new challenge.
Why would you think anything would need a 1/4 twist? my 1/8 10.5" blackout shoots 220gr beautifully.
Haha. 1:4? Bullets would simply explode from spinning too rapidly.
Let's throw some hypotheticals out there, do the math:
1:4. Every 4" that projectile rotates 360º.
Assuming a median 1,780 fps, we can also say 21,360 inches per second, and 1,281,600 linear inches per minute.
Divide 1,281,600 linear inches by 4 inches (per 1 revolution). Answer is 320,400 RPM exiting muzzle.
Can your 150gr bullet withstand that sort of force?
@@exothermal.sprocket 8.6 blackout being made from the factory at 1:3 twist.
What twist rate is good for shooting 90 grain in 223 in a nef s shot
Mike Todd 7 twist will do it if the barrel is long enough and the velocity is sufficient.
1:8"
Interesting
Hi Guys. I feel like your missing something, Like maybe, barrel length. I shoot a 77 gr nosler HPBT in my Savage with a 1in 9 twist and at 100 yds. its the most accurate load I shoot. I have also worked up the same load for a friend of my with a Savage like mine with the same results. If you really care, you might want to do a little more testing.
What they are demonstrating is the effect of twist rate on stability of bullets with different weights/lengths. To do that they needed rifles that are identical except for twist rate. They weren't trying to find the most accurate loads.
@@JohnSmith-nz9dn ... after years of testing i realized that a while paired with 150grn bullet. A .308 with a 16" barrell 1/7twist rate will SPANK most other 308s with higher twist rates.
Just get all of your gun info from gunblue490 and you won't have to deal with the confusion anymore.
test it at 300 yards you will see a huge difference. i seen a 1:12 shoot 12 moa at 300
If it can't shoot are 100 I would not have high hopes the groups magically will all go into a single hole at 300. These are varmint calibers not for Deer. Need 1/2 MOA at 100 yards or toss it out.
@@Physics072 settle down bob. plenty of people use 223 for deer.
@@James28R I know I could kill one with my .204 ruger too. Its illegal to use .223 for deer where I live. Some places you can use them though. A .22 rimfire can kill one if placed well in the head.
Can anyone tell me if a tikka 30-06 with 1:11 twist rate will be fine shooting 220g bullets?
Are you sure its 1:11? I havent seen a tikka that is anything more than 1:10 unless its a very old model. 1:10 is fine for pretty much anything.
@@WayStedYou yes I am sure. All the new tikka T3X 30-06 rifles have 1:11 twist it says right on their website
It's a 3+ min video holding 45 min information for today video standard.
Thanks!
So if you shoot heavier bullets, you'd want a faster twist rate?
Which is that much harder on barrel life.
I found it mines a 1 in 9 it was hard to find because it's a stainless steel barrel I can't find any brand on the whole done either then Duffy made in Westminster Colorado thank you for answering my question though I appreciate it
*I've got a Savage 1:9 twist 22-250 and if you try to shoot anything below 50 grain bullets in it, they will never make it to the target. You can literally see the POOF as the bullet flies apart at the 50 yard mark. Contrary to what's not discussed here, velocity does play a role* 💥💥
OK im sorry but heres what it is 40gr to 55gr is 1:9 twist preferably
60gr to 70gr is 1:8 but that twist likes all of them evenly and loves the 62 or 64 gr and the m855 stuff A LOT
71gr and up to 80gr is 1:7 like mk 262 otm 77gr ammo loves heavy bullets and can do 62 but its a little low
1:12 has no place but 40 gr and its in my opinion stupid and obsolete twist rate why bother
Agreed. Yet you can jump on a lot of rifle manufacturer's sites and select a .22-250 in a given rifle, and the listed twist rate is 1:12. That's great if you want to limit yourself to 50gr bullets being accurate.
You do realize that the 69gr SMK calls for a 1/10 twist right? And the 75gr Hornady match BTHP calls for a 1/9. When you spout bullshit like you did in your comment it only hurts the newbs by misinforming them. Do some research and test things for yourself before acting like you know anything.
how about 1:8
Go get hornady America. Gunner 55gr hp these shoot remarkably accurate out of my 1:8
Great do-it-all twist rate for a carbine - stabilizes everything from 55-grains on up to 75-80-grains. Good-to-go...
The service rifle competitors shooting heavy .224-cal. pills at 600 and 1000 yards - are using 1:6.5 or 1:6 twist rate barrels for those stages. For a 90-grain SMK, you need something that fast.
This guy says it's about the "bearing surface length" that determines the twist required. This is not true. Stability is an externally ballistic event that is a result of internally ballistic events. You can create a 75gr bullet that has the same bearing surface as a 55gr bullet. This would not mean that the twist rate to stabilize it would be less than the twist rate required to stabilize a "typical" 75gr bullet.
The bearing surface is the only available means of any bullet to engage rifling. Yes that surface area in mm² or in² changes relative to the TYPE of bullet shape per a given volume of material; ie. flat base or boat tail, ogive shape, hollow point, polymer tipped, partition, even how the jacket is distributed all affects the amount of bearing surface in a given caliber with a given bullet mass.
For sake of discussion in the video, he has to start somewhere.
@@exothermal.sprocket I understand, but he literally just gave all these newbies the impression that it's all about bearing surface. Now when somebody says "the length of a bullet has more to do with stability than weight", one of these impressionable newbies is gunna chime in saying "no actually bearing surface is the determining factor, not length". I know because I have been "corrected" by such a person in a thread. I couldn't imagine what could give them such a preposterous idea like that until I found this disgrace of a video. The truth is it's not even about length from tip to tail, but rather about the moment arm between the center of mass and the center of pressure. With most bullet design profiles the arm lengthens with bullet length, but not always. Bullets like round nose flat base projectiles have relatively short moment arms for their length compared to boat tail spitzer deigns.
@@kn761 Well I'm not sure the video was designed for the "newbies" honestly. And I understand what you mean. My career is mechanical engineering.
@@exothermal.sprocket nice. I'm in school for my BSME right now part time. My first BS was in physics.
I went to a 2 year technical college. Never went 4. Been working in various related jobs for about 15 years. Don't get yourself sunk in debt. :)
Spent all that money and time building 3 rifles, buying ammunition (not cheap) range time sighting them in only to give like 3 basic details, where is all the data from this test?
are the twist rates marked anywhere on the barrel?
Sometimes. They can be in pretty small print so good light will help you find them. If they aren't there try Google for your make and model of rifle to see if you can find it.
Don't gunsmiths have a mechanical gauge they use to determine what a given barrel twist is?
Look in your owners manual, or measure it yourself, with a ruler, and a light. It's not that hard to do.
True. A bore brush, a piece of tape, and a measure.
What about 1in10???
What is the longest bullet that a 1in10 will shoot accurately?
That is what the Savage 110e is.
U mean what. Bullet weight fits that TR? Probably 48 gr and lower
@@sigspearthumb8856 lol the 69gr SMK calls for a 1/10 minimum. Try again.
K N lol what was I thinking? Yeah... slow twist, heavier round.. oops
@@sigspearthumb8856 Length is actually what effects the stability not weight.
You can have a lighter projectile that is all copper that is longer than a heavier copper/lead projectile.
I call bullshit. Longer barrels and high powder loads can make up for lack of twist. It is also based on bullet geometry.
1:10?
Will handle bullets with a ballistic coefficiency up to a 68 to 69 HPBT match bullet. But velocity is also a factor on how well the bullet stabilizes. In general, the 1-10 twist rate for a high velocity .224 caliber cartridge is ideal for shooting bullets in the 55 grain to 64 grain weight with a (G1) ballistic coefficiency of 0.255 to 0.305.
I had a Howa 1500 with a 1:10 twist and the damn thing could barely keep rounds on a 3ft diameter target at a 100 yards, I had to handload with a 52g bullet to get any reasonable accuracy, I finally sold the rifle, beautifully made but far too fussy
Caliber?
Wheres the data? Results and conclusions? What's the point here???
Bearing surface...? WTF he has not idea about actual external ballistics. Ok stability is 1 , optimum stability stability is 1,5 . There are TONS of units taking part in needed twist rate. Projectile Material (lead, copper/brass, steel, tin, aluminium, polymer, tungsten) Ogive Lenght, Bearing lenght, Boattail lenght vs Flatbase. At wich place certain material is like a heavy front but light back or the other way around, also if the outer diameter material is lighweight or heavy for gyroscopic effect.
The bearing surface should be atleast ~one caliber (5,7mm for 5.56). Otherwise it has not even the slightest such an effect as the other main variables.
Would you please stop babbling on you are making no sense. People just want a gun that shoots well out of the box. Look at all the time and ammo wasted on this dud of gun.
When you increase projectile weight and no other factors what happens?
The projectile body, the part that makes contact with the barrel, gets longer.
More surface area to make contact with the rifle barrel makes a difference.
Therefore different rifling twist rate is required to spin the projectiles to balance them in flight.
calls it a misinformed myth then proceeds to explain how the test results confirm it to be true. who's the one misinformed?
Watch it again. What Ken says is "...I'm trying to decide whether it's a myth or not...."
joemrp05 velocities change stability as well. a heavy bullet at screaming velocity will stabilize better than the same projectile traveling at slower velocity in the same twist rate.
as far as grain weight to twist rate. typically the heavier the bullet the longer the bullet because more material is needed to make up the weight.
some specialty bullets have extremely long ogaves and short bearing surfaces. these typically require less twist rate than traditional bullet but require single round feed because the bullet is now too long to fit in the magazine.
Kyle, what is your physics behind your statement saying bullets with long ogives and short bearing surface require less twist than traditional? Just wondering because it's totally wrong.
Heavier and longer always needs higher RPM, regardless of bearing surface. I think the guy in the video was simply saying, in general, the heavier bullets will HAVE longer bearing surfaces. It's a general statement. One could say "heavier" or one could say "longer" or one could say "greater bearing surface." Without going into exact math, these are general ways of communicating bullet shapes and the relationship to weight. It's geometry and density.
I have a 1/12 .308 with 22" barrel. Thing would not shoot 150gr worth a shit. It shoots 168gr very very well which seems to be the opposite of what I just heard.
A 1:12 - in a bolt-gun especially - is a suitable twist rate for 168-175 grain loads, easy. There are some general guidelines about what should work regarding barrel twist and specific bullet weights/types/lengths, but every barrel is different and only empirical testing can determine what loads it "likes" to fire. Many bolt-actions are somewhat forgiving of heavier and longer than recommended bullets for caliber and twist, thanks to the fact that the barrel length allows sufficient velocity for adequate stability. The go-to source for rigorously done testing on bullets and twist rate is Bryan Litz of Applied Ballistics. Bryan is an aeronautical engineer and chief ballistician for Berger Bullets. His books are a great resource.
@@GeorgiaBoy1961 I'll have to check that out. Thanks
You bet !
It's the length of the projectile not the weight.
Projectile weight makes a difference in external ballistics so... not sure what in the hell you're on about here about the bearing surface being the sole deciding factor... WHat a truly pointless video. No target's, just some marketing managers talking out of their asses.
"Bearing surface". Dude you've just embarassed yourself. Take this video down.
S Userman no he is right.
When a projectile has more weight, what do they do to the projectile to increase its weight?
They make it longer.
The tip doesn't get longer but the body inside the case gets longer.
So that means you now have more projectile surface area touching the barrel and rifling.
you just embarrassed yourself! look up "bearing surface" for definition. the surface of a moving object against a stationary surface. In terms you may understand, the skin on the palm of your hand is a bearing surface against your penis. which you would know if you educated yourself instead of just skinning the flute. lol
It's a thing called math and geometry. The relationship between the diameter and length of an object. Cubic area is [pi X radius² X length]. When you change the tip shape and base shape of a given bullet, the "cylinder bore" BEARING SURFACE length will also change. All of it affects, ultimately, the gyroscopic stability of a given object, where the CG of that object is located relative to the central axis, and how much RPM is required to stabilize that object at a given forward velocity.
@@exothermal.sprocket man you guys are some thick headed fucks. Picture this if you can manage a simple thought. You have a bullet that has a shape resembling a football meaning it has no straight section. It's just curved from meplat to boat tail. then picture that it is enclosed in a sabot and fired from a gun. No bearing surface whatsoever. The bullet still needs to be stabilized. Are you seriously trying to tell me that bearing surface determines how much twist it needs to stabilize? Yeah that's what I thought. It's about length. Bearing surface is irrelevant. God you guys are fucking dumb.
I'm inclined to agree with you. A wadcutter, flat base bullet has a lot of bearing surface but doesn't require a fast twist to stabilize.