TWIST (from a riflemans perspective) 

I’m not understanding how mark & sam don’t have half a million subscribers. Even for the non elr guys everything in these videos is applicable. Thanks guys, keep the great videos coming.

Never owned a fire arm, maybe never will, but absolutely enjoy these videos. The engineering, science and trial and error that goes in to great shooting and making components, be it for ELR or otherwise, is just insane. Genuinely educational, love it. It's top stuff, thank you.

I'm not sure who would give this a thumbs down or why ? There's no misinformation here . Thanks for doing your thang your way guys .

Thank you for the outstanding presentation. As an aviator, I can attest that all you have said is 100% correct. After all, it is aerodynamics, which is a subset of physics.

These last few videos were just what I was looking for when I started reloading. Now that they are out there I can recommend them to friends. This is an awesome resource you guys are building and I thank you for it. Keep up the great work!

Beautifully explained Mark.

Your series of technical/theory/science videos are always very interesting. I'm extremely impressed with your knowledge and delivery. It's impressive that you can take a somewhat complicated concept and explain it in a way the layman can understand. 👍👍👍

Thanks Mark. Not sure how I missed this one. The topic is one I’ve been interested in for a long time, and you explained it better than most.

I can’t tell you how many of your videos I have referred too and recommend people to watch. Mechanical minds think a like. Great video.

Thanks Mark,,I injoy all of yours and Sam's videos,,,

20:30 - I remember hearing someone *adamant* they had a setup that would shoot 1/4 inch at 100yds, 2-3 inch at 200yds, 1 inch at 300 yds !! Yep, they put it down to over-stabilisation. Seems like it could be a real thing. Thanks for your video, well presented.

Thanks Mark, You and Sam have bin helpful. I often consider your point of view to my benefit. At 63 years old with a lifetime of shooting and reloading under my belt. Good information can be hard to find thanks again.

Love this kind of explanation, always interested in learning. 👍 thanks guys, stay safe

Brilliant presentation, Sir! Wishing you and your dear ones a Happy Christmas.

I recommend Bryan Litz's book "Modern Advancements in Long Range Shooting", he goes in great detail on rifles, sights, bullet design, construction, rifling twist, internal ballistics, and external ballistics. Mr. Litz does math until he's blue in the face, and then he goes out in the real world with real projectiles in various ways to test the theories. He, unfortunately, doesn't go into extreme and ultra long range shooting. It's an amazing wealth of knowledge regardless, as are you, Mark. I'd love to get your opinion on Litz's work.

Excellent explanation and great content as always. It is amazing how much science is involved in firearms and projectiles. Another interesting topic would be the various types of rifling and which seems best for ELR and barrel life.

Best explanation possible..ithink the gyroscopic top is great illustration too! Thank you!

Great info and presentation! Thank you!

Thank you Mark very well explained Steve.

You did a great job explaining it, I kind of wondered about overspend, , thanks for sharing

Thanks for the video. Great information.

Great explanation, useful information for all really puts things in perspective.... Especially when it's spinning at 200-300,000 rpms.

Great informational video, explained it well, thanks for posting 👍

This was a great video. Thanks.

Wow - that orbit theory is pretty interesting. I would imagine that if there is ANY imbalance through the rotary axis - that could be very possible. I bet there's some truth to that. Another great video that had me glued to the monitor.

Smart guy..Covered the topic well.

Well worth watching

I think that the "orbit" aspect of the bullet spin comes from friction between the surface of the bullet and the air. Air grabs the surface and creates that orbital flight. This would also get into the depth of groove cuts from the rifling. As you say there is lots to learn about....all fun. Great video by the way. And for those in the US...think of throwing a football with the "spiral". Not 180000 rpm but it gives you the idea. hahaha

Very well explained !

Very good, been shooting for 60 years very good job

The early M16's had a slow twist. Because they WANTED the bullet to stop spinning and start tumbling end over end. This is like a punter in football who is said to "turn it over" because if he can impart a bit of spin on the ball as it is going upward, it will go further. Then the ball will stop spinning and start tumbling end over end, and take longer to come back down. This was done in the M16 to cause the bullet to tumble and do more damage to make up for the smaller bullet. However the Geneva Convention stepped in and made them stop doing it as a violation of something akin to using a soft nose bullet rather than a full metal jacket.

Nailed that description with the spinning top. Now we just need to come up with a ratio of length, diameter, needed spin, fps. Kind of like bc that way it can be applied to any weight of pay load.

Great video....need couple Panadol after that one & a lie down!!

I had an interesting experience with my 7mm 08. It would shoot heavier bullets best, 140 gr and 150 gr even better. 120 gr bullets not so well. But also, I bought some high performance fast 140 gr with a long tapered ogive and they did not shoot as well. I can't really say whether it was a bullet jump thing or the fact that the heavier bullets with a more round ogive had more contact with the rifling. On the other hand have a 308 and it shoots 150 gr to 180 pretty well, I have had groups in the range of half inch to one inch with different brands, different velocities, different weights, all copper, lead tipped, etc. (Don't expect me to shoot better than a half inch, I'm not that good). I realize there are many variables, I have heard that even boat tails make a difference, powder loads etc. As a commoner, I just experiment and go with what works for me. Many thanks for the great videos!

Thanks Mark. Had to watch the speed of my 220 swift. I get gray puffs at about 3850 FPS. ( cheap bulk 55grn bullets) I could push 50 grn solids to 4100 FPS

I'm disappointed that The Curiosity Show didn't cover this when I was a kid.

If you haven't, have a look at Jim Boatright's paper on hyper-stabilization by way of "over spinning" of monolithic bullets, and the application at the trans-sonic threshold.

Great information thanks Mark. Currently trying to find the best weight/length bullets for my 1 in 8 twist 223. 77 grain (Berger) bullets = a single ragged hole, 57 grain bullets = 1/4 inch, 55 and 53 grain bullets = 3/4 inch. Was hoping to be able to get under 1/4 inch from lighter bullets as well, but looking at the data so far, I think its only going to be 60 grains and above for any real accuracy. Can't always have your cake and be able to eat it too!!

Brilliant, thanks! So, to summarize... It's how fast the bullet spins per-time, not how many times it spins per-distance. The longer bullet, not necessarily the heavier bullet needs more RPM. So, if you had total control over velocity, you could overcome a lack of barrel twist with higher velocity? Such as, and arbitrarily, a 1/9 barrel twist at 2,450fps yeilds the same RPM as a 1/10.5 twist at 2,850fps ... ?So you don't need as much barrel twist in your SAUM as you need in your Creedmoor to stabilize the same length of bullet, for example, I realize this is maybe an over-generalization. I've heard 100 men fumble over how to explain what bullets do on their descent, when you explained gyroscopic yaw, it made perfect sense. Thanks again!

👍 video sir.

good job. thanks.

Very informal video! Thank you Mark & Sam. I shoot a .300 Rum Reminder Sendero SFII. Recently ordered a Krieger barrel in varmint contour and the the barrel TR is 1:10" . I want to start getting into 1500 - 2000 yrs shooting what weight bullet do you recommend? I been purchasing Noslers 210 gr. Match in 690 BC. Is this twist rate suitable for this bullet at this range?

Well done

The thumbs down shows that no matter how excellent something is, there is always some asshole that will complain.

@MarkandSam AfterWork Now that you've covered twist and centrifugal force, (maybe I've missed the video) how about talking about adjustments for "spin drift". Thanks for any replies or future video.

Mark, I suspect the 'orbit' you speak of may be due to the center of mass of the bullet is slightly off the center axis of the bullet. Also in such a case as the bullet travels down the bore, it will impart a force radially on the barrel and cause the barrel to vibrate. All very interesting. An advancing twist make sense to me for two reasons. 1) the initial acceleration is less of an impulse: so you are not "spinning your wheels so to speak" starting a bullet with no rotational velocity to rotate instantly,... 2) the energy bandwidth that is developed as the bullet proceeds down the bore is spread out and less likely to impart energy at a barrel resonance.

Is it also possible for too much twist to cause more of a spin drift affect???? Just something that I've wondered about...

That was very interesting.

I have seen the yah watching slow motion tank rounds. I was led to believe that the projectile not only has a center of gravity but also a center of pressure. Since the force of the projectile passing through the air is affected by that air 80 times more than the force of gravity the projectile may yah because the center of pressure is not identical all the way around the projectile. So rpm would certainly have an affect.

I’m surprised he didn’t mention the Greenhill formula for determining the twist rate for a particular bullet.

Hi Mark. Great video. I have a Ruger America 30-06 1:10 twist. The bullet I shoot is the Hornady ELD Match. Box says 1:12 twist. Will this bullet be unstable in my 30-06

Great info and discussion - but what about the variance in barrel length with the same twist (guess it is more stable with increased length given the same twist ?? ) - btw - thx for sharing :)

What app do yall use to measure distance to target I've seen on some of yalls vids? The one u click on then go to shooting position and click again to show distance?

Mark, did you machine that top just for this video? It's cool

So how long till we see you running smooth bore fin stabilised rounds guys 🤣

Kind of sounds to me like Ballistic Coefficient and needed spin are related.

338 RUM как хороший калибор

If I were a betting man I'd bet Mark machined that top...

K. maind u god wlorlotrwltr .hahahahahahahaha god✌