Barrels & Twist Rates | AB101 Pt.6

[@DrPsychlops]

This was an extremely clear and concise explanation of spin stabilization and the potential problems with over-stabilization that occur and it even applies well to powder guns at long range.

[@64dexta]

Well after the second viewing I think I have about grasped the majority of it. I am pleased that you have taken your time to do this work Matt, it is nice to have an understanding of what happens when we use our rifles. Thanks again and good luck.

[@toms8818]

Matt, thank you for tackling such hard topics with such clarity. You contribute tremendously to this hobby, God bless.

[@rlbadger1698]

I am a machinist. Old school manual. A common mistake in machining crowns is to indicate off the outside of the barrel. A crown should be machined in the chuck not hanging out. It should be indicated on the lands AND grooves. With of course care to be taken in not induce internal compression.

[@erichaskell]

Rl Badger please explain "machined in the chuck and not hanging out". If you indicate on the lands and the groves and these two are different how do you reconcile? Thanks.

[@etiredevill7834]

@Eric H. The Goal, as I understand, is for the crown relief machining to be concentric with the inside of the barrel. Two parts Badger indicates. 1. "Indicate off the lands and grooves" Process where you measure the concentricity of the cutting tool with respect to the inside of the barrel. 2. Minimize the flexure of the barrel during high cutting forces, by holding the barrel in the chuck close to the crown, and not protruding. Last point - Badger indicated, don't squeeze the chuck excessively tight around the crown, as this may also damage it.

[@raysimon1368]

The only reason so called machinists indicate of the od is because it is easier you are 100% correct seen lots of barrels ruined by idiots that call themselves a gunsmith had one of mine done that way you could see the run out on the crown with your eye

[@WilliamParmley]

Very interesting and I will definitely watch again to absorb everything. I am enjoying this series tremendously.

[@jamesmarriott9972]

we have ben taylor to thank for the smooth twist barrel, FX bought the rights to it. sorry for being a pedant, but he's the real genius. love your video's by the way, please don't think me rude, you happen to be one of the best channels for information regarding air rifles and enjoy your content greatly. keep up the good work and again sorry for if i came across as a twat, just love me a genius englishman. love from cornwall

[@azz187]

James Marriott exactly what I was about to say

[@andychapman9687]

Knew Ben Taylor, Dave Theobald from Theoben well when I worked at Airgun World mag for many years. Fx Boss and Royale are really descended from the Rapid 7 because of Ben but obviously with redesign. Excellent work Matt, love the videos.

[@robertqueberg4612]

From what I have read about the “smooth twist” rifling method, it seems to be a derivative of the gain twist rifling used by several companies during the earliest years of the American Civil War. The best known firearms using gain twist were the Colt Army and Navy revolvers. Another time for the saying about nothing new under the sun.

[@tomgranberg5651]

Very informative and correct information my friend. Another thing to consider talking about spin rates is that the actual speed of the spin induced on the pellet is not linear in relationship to it's exit speed. Let's say you have a relatively fast spinrate 1:12 shooting at 650fps. Then you tune your gun to shoot the same pellet at 850fps , the spin rate induced isn't just 30% faster (increase in speed). But spins much faster, I don't have the accurate math in front of me, but it is a exponential curve. Also the faster something spins going trough the air, you have to account for spin drift. As well as Magnus effect, which occurs even if the head of the pellet is aligned with the trajectory, especially in windy condition.

[@fmh357]

I happened upon your website by accident but I just wanted to say it's been very educational as well as entertaining. In other words "you done good".

[@julian-vm5ec]

I subscribe to many air gun You Tube channels for entertainment, but you entertain and educate as well, thanks for all your hard work , keep it up .

[@JM10344]

Thanks Matt it's crazy how much I've learned from you. Just put the stock valve return spring back in the Fx Impact with a 600mm barrel and your slugger kit. The kit is great but like you said if you're running low reg pressure and a 600mm the stronger spring is were the magic is. Yes instantly I was able to literally hear myself power tuning the Impact right to the point were the DB level drops and the gun smooths out. Feels great I'll find out how it groups later. Thank you Matt.

[@regsparkes6507]

Good instructions. I did have to watch it twice,..but I found that there a few questions answered here. Now I know why my rifle had a couple of minor problems. Thanks for this.

[@waltereliamusic8071]

Congrats from Sao Paulo Brazil. Very import topic and deep subjects with always great explanations from an expert. Learning so much from you! Thank you so much!

[@the.original.throwback]

What a great educational video series for all airgun enthusiasts, beginner and veteran alike. Thanks, Matt. Jess

[@richard17771]

Amazing video thank you for a great lesson. I know so much more about rifling and twist rates now. This will definitely help me with future purchases. And shooting longer distances.

[@joedejesus6363]

Great video, I really learn an enormous amount of information from watching your channel. I never knew about the ratio on a rifle barrel, and pellet trajectory, but you hit the mark by your easy to follow and simple way to understand. Thanks.

[@vansantsam]

Deep rifling or more grove rifling also helps to reduce spin in flight.. They create sort of paddle like fins on the side of the pellet and these fins grab air that is passing by and causes the rotation to slow..

[@SickMeds]

Glad you back with the topic, its been months since last part ...

[@ghostrec04]

The guy has followed has passion... Thanks bro...informative video.

[@bluegray8503]

Great explanation of the minute dynamics of speed and twist rates. A third dimension seems very important weight specific pellets matched to specific barrel is as important as barrel dynamics as well.

[@dougdunlap6638]

An extremely difficult topic however you do an excellent job of explaining it. I do understand much more now. Thank You. I enjoy all of your video's .

[@Ferrari250GTO1962]

Excellent accurate thorough information. Very very well done.

[@kmom777]

Best videos ever it's like playing airgun university with some of his videos you are the best airgun channel so far with tons of knowledge. Can you do something about slug =pellet swaying and how to create your own tools and then different tests with each different pellet and then slug compare penetration on 100 yards

[@joescuderisr6663]

Great video, I am starting to understand just how much is involved in airguns, thank you so much, --Joe

[@SquirrelHunter]

Very informative, Matt ;-)

[@lianthawmte1041]

everytime i saw your notification it overwhelms me...keep posting bro. nice work

[@lelandadcock3871]

Thanks for such a nice video! I am new to Air guns and got my 1st one last week. It is a Huntsman Regal XL and I love it. This Video put much light on a lot of questions I had about barrels and pellet fight, thank you!

[@iandixon8587]

Great video Matt, really interesting. You mentioned the fact that the skirted pellet design is around a 100 years old and was originally made for smooth bore barrels! I have been saying for a long time that as we see airgun design becoming more and more sophisticated nothing seems to have changed in pellet design! Can't help thinking that there is enormous room for improvement in this area of our sport.

[@AirArmsHuntingSA]

+Ian Dixon Agreed! Pellets have horrible BCs!

[@openfieldtarget]

Excellent information. Thank you Sir. 💕 From India 🇮🇳

[@sfdsa6063]

Excellent explanation! Thank you! It would be great if you could give an explanation heap rates for different types of bullets at a different step rifling (twist), such as full-bodied pellets JSB Beast 1.05 g / H&N piledriver 1.36 g, depending on the speed. This will allow some shooters understand that there are no bad bullets and barrel there are used different speeds.

[@owenmcghee8837]

Great stuff Matt keep it up. you get the message out there instead of keeping it to yourself.

[@SpinMeneer]

I really learned a lot of this. I'm a new person in the airgun world so this is very helpfull

[@philippefrater2000]

The Steevie Wonder Crown! You made my day!!! Thanks! Regards from France, (Yes, we also have guns!)... 🇫🇷🎯🇫🇷 I shoot 22lr, 222 Rem and 243 Winchester but since i watch your channel i've planned to add a nice airgun in my collection, thanks for your time and infos. Philippe.

[@fintech112]

Wonderful series and lots of effort behind learning it and explaining it to ppl like us stay blessed buddy

[@JM10344]

Hi Matt, would ever consider doing a start to finish set of video like this on center fire and rim fire cartridges. Teach us about Throat's, neck, free boar ???, carbon rings, ojive...ect average pressure. You brought us great info on dynamic/ bolistics. Can you do the same for center fire. Everyone just shoots and teaches us many things, but I want the nerdy stuff. Thank you

[@dunkanmccleud5613]

sumamente interesantes los conceptos que expones sobre los factores previps a la balistica interna, intermedia y terminal felicidades y espero que hagas mas vodeos con aspectos tecnicos y tecnologicos saludos desde MEXICO

[@james1795]

Thanks for the very informative video. And I had no idea of Stevie Wonder having any interest in air gunning. It's good to learn at least one new piece of information every day. Seriously, I do enjoy all of your videos. Keep up the good work.

[@stolen630]

Well instead of seeing guns, barrels, bullets, pellets and being awww.. Its much satisfactory to learn about some technical terms involved in it... 👌nice video

[@richarduk679]

Matt, that's an excellent video. Thanks for that. Just a minor point. The inventor of the smooth twist barrel is actually a guy from the UK called Ben Taylor. But no less credit to Fredrik Axelsson who understood the potential of the design around which he now designs and builds his rifles. I guess those Swedish folk know a good thing when they see one.

[@AirArmsHuntingSA]

+Richard UK Ben Taylor played a huge role, but he was only brought into the process after FX had had the idea for a very long time. FX had been trying to twist the barrels from the inside, but Ben came up with the idea to remove a layer and then twist from the outside. So I'm not sure you could call him the "inventor", but you're right - without him it would never have worked.

[@richarduk679]

AirArmsHuntingSA Interesting.

[@freetommyrobinson]

Just watched this. Bit late to the game but Hay ho the explanation and detail in this video is still great. 👌

[@senatorjosephmccarthy2720]

3: 29, Ok, I got it. A bullet is like a Corvair- unsafe at any speed unless you know full well it's going to roll. HA! Thanks for the great information, Matt, presented plainly and in order.

[@RorySeanWainer]

Thank you for making a very informative & well-described series

[@তালগাছআমার]

Thank you very much sir for the detailed discussion

[@RolandDerUnverbesserliche]

Yes! Also, a smooth barrel will make it easier for the pellet to pick up velocity, especially if the lubing is right, according to the technology used. A springer tends to have more of the problem of deforming the pellet inside of the barrel, but at the muzzle the pressure behind the pellet is low, and it is more silent, and also does not tend to ruin the accuracy there.. There is also the aspect, that you should not push a pure lead pellet too far beyond its limits. Generally, about 240m/s or 800fps, starts to become more and more questionable for soft lead bullets. You'll need a harder bullet coating, if you want to go beyond. PCPs, which tend to cool down the propellant as it is released, can go some faster without causing the problem. Springers and Gas-Rams should stay lower, to avoid these problems. So, a good barrel should use a good part of its length with about constant pressure behind the Projectile, to accelerate it.. at first linearly, then exponentially slowly entering the correct twist, from the very beginning (rifling)... Next Aspect: Also, every bit of shape change of the Projectile matters very much. You'll need to experiment with conventional and polygonal rifling... Next Aspect: And then, the pressure behind the Projectile should drop off fast enough when approaching the muzzle. Next Aspect: In the ideal case, the lubing will also avoid the lead-contamination of the barrel, and instead make it more clean with each shot..

[@michaelbogdovitz2157]

Great informational videos. Thank you.

[@machobunny1]

I'd love to see some of the math. I'm a Ph. D. Mechanical Engineer---retired, and I am planning to start making my own PCP air guns, or modifying the work of others. I know, the math would get really, really heavy, real fast, but...hell. Guess I need to see if there are text books on the subject. This is a remarkable job of explaining with minimal math.

[@normkeller2405]

The world's list of Ph. D. Mechanical Engineers is very short. I've only met one. An impressive qualification.

[@salehal-ghamdi1329]

Great video and fruitful information... I think it is not complicated or you have explained it well.... thank you very much and waiting the cal. Sellection video...

[@kangmashakim3998]

Well now i am sinking by your knowledge, deep knowledge , perfect dude. Thanks so much Time to note again.

[@donrsanders4772]

Hey Matt, thanks for what you do. I am really thankful for the info you put out here and the entertainment I get watching you hunt. I bought my first PCP last April. Bought it from the same guy I bought my 1st air rifle from, 1st was an HW 97K 20cal. I moved up to an HW100, 22 cal. It is the most amazing gun I have ever owned or shot. I have had some excellent training and instructors over the years and done a bit of shooting. Question is can the HW 100 have the hammer adjusted to prevent the rebound and save air and be more consistant? Thanks for your time, Don sanders ,

[@tommanfs6843]

thank you so much for this series ........ learning a lot!

[@joachimschumann6069]

clear and understandable , thanks a lot for this amazing explaination 👍👍👍

[@wayneclarke9291]

Some very good points there well laid out and informative video, nice 1.

[@rfgon3727]

Hello, I need some help, I'm producing a pipe for caliber 5.5mm, I need to rake the pipe, but there are 2 doubts, the first is the number of lanes, I have 2 options: 6 lanes and 12 lanes, remembering that the pipe has 24 inches, the second question is, should I use the 5.5 gauge tool or would it be better to use the 5.56 gauge, because after that measure already jumps to 6mm, if you can help I will be grateful.

[@tomgranberg5651]

When it comes to crowns, they should be as you correctly pointed out square to the bore in shape, but you don't want an acute angle as it re introduce the problems you are trying to fix, uneven gas expulsion. An angle around 11 degrees, or a combined angle between 150 and 180 is good (180 forming a flat plane to the bore). The biggest reason to not use the optimal 180 flat plane is it's really hard to remove the burrs forming on the inside of the bore during the operation.

[@jonykakaut2302]

Sir please make h video on defects of a barrel (inside barrel) like ring, Bulge,bent, chromium plating flaking off etc

[@howdydoody30204b]

What a great series. Thanks!

[@Mirkuzzo636]

Hi Matt, I love your videos that you post on youtube. I have seen the entire playlist of ballistic 101. I have a question to ask, since I have not found anything specific about it on internet. The pitch of rifling is ok, but I wanted to know the difference between more or less grooves. For a PCP, how many grooves are suitable and how much do they affect the bullet, do they have different behaviors on slug balls and pellets? I was intrigued about the difference between 6 grooves and 12 grooves. Thanks a lot in advance and congratulations again for your videos and valuable advice. :)

[@heksogen4788]

First you said that the air pushed from the barrel can rotate the pellet, that's why rifling is needed, but then said that bad crown can spin the pellet, but wouldn't the pellet spin prevent that, as with the first problem with air pushing from barrel?

[@anthonyrstrawbridge]

Wow! Finally, all of these lingering nagging questions which have prevented me from selecting my first barrel entry into the discipline of precision air rifle shooting have been answered. The answers aren't dreadfully pain full now that I understand what needs to be accomplished when balancing the abrupt forces observed through the transfer of compressed gas into ( is it vector quantity?). Most interesting to me is when this cupped pelleted projectile goes happily on its way without being influenced by the propellent and I believe I now have a solid understanding as to how to accomplish this. One last thing I'll need to do first, is select a pellet to determine desired barrel criteria. I know very little about these things but have noticed people buy heaps of different types.

[@hunter100t]

You will still need to experiment with pellets to find the one that suits your barrel as no two barrels are the same. on the plus side if you choose a choked barrel some of the problems can be alleviated as the barrel is designed to size each and every pellet !

[@AirArmsHuntingSA]

+Anthony Strawbridge Most good barrels (LW, ST, CZ) are designed completely around JSB Diabolo pellets. So you know where to start!

[@hunter100t]

AirArmsHuntingSA Yes a good pellet to start with, but I did not know JSB had been going that long seeing as how LW HW CZ BSA have been making barrels with no change for decades, I can imagine FX using the best pellet for their new barrels, but not the others.

[@makerofmanythings8447]

Is the barrel on a Hatsan hercules bully. 25cal any good? And do you know what the twist rate is? VERY INFORMATIVE VIDEO. GREAT JOB.

[@richardcosta1565]

Thank you for this education. I enjoyed this video.

[@johnnyvonline1862]

I would love to see more content like this out of Airgun channels. Just sayin

[@arieldietz8574]

Great info man. Excellent videos.

[@ShinyHappyDemon]

Wouldn't you want the anti-node at the end of the barrel? At nodes in the barrel, positional displacement is 0, but angular displacement is significant. At anti-nodes, positional displacement may be a mm or two, but the angle of the barrel is always constant. Sending a pellet at the right angle from a slightly wrong height is much preferable to sending a pellet at the wrong angle from the right height.

[@ziptab]

The smooth twist barrel is not twisted at the muzzle. The barre is impressed with the rifling on the outside.

[@lilchirp4846]

would be interesting to experiment with barrels that have tiny vent holes some distance before the crown or before the pellet exits the barrel..

[@lixv2432]

For instance l use a an FX smooth twist and he mention from the video usually all the groove runs till the end of the barrel, now my question is, what if l use a choke at the end of the groove (twist) to avoid escaping the air from the barrel

[@meinok3662]

I'm thinking that if you get tired of shooting you could have a career as a physics teacher, very informative and easy to follow.

[@AndreasdeV308]

Thanks for all the info, will help a lot.

[@theg-man7868]

Awesome in depth analysis Matt, really enjoying this series. Thanks for improving our knowledge and understanding.

[@kevinjones2088]

And i would like to see a video talking about decently priced scopes that are cheaper but work just as well as some expensive ones and what to look for when wanting to get one that is cheaper but looking for high end quality.

[@BirdWhisperer46]

Any American instinctively knows what twist on a flying object does. We grow up with it, in baseball and football and even basketball, but the scientific explanation is helpful. :o)

[@heathhalfhill6401]

I’m curious to know if FX takes into consideration harmonic effects on those drinking straws they made into barrels. Like you, I come from the powder burning world and the effectiveness of a Bull or Fluted barrel. All barrels “whip” so to speak as a projectile is driven down it. In my mind the thicker the barrel the more stable the harmonics are. I find that pellets aren’t meant to be pushed past 900 FPS and slugs are basically whatever speed you can find that stabilizes them in regards to spin rate, weight, and length of the slug. I think your spot on with this video. My only question is the thickness of the barrel that the ammo is used in. Does the barrel thickness make as big of difference with harmonics that I perceive?

[@leandrobaluyotiii8193]

its nice to know bro. please make another one.

[@oliverclaffey5186]

Don’t shoot air guns, only .22lr. What a great explanation on rifle barrels. Would love to hear your opinions on rifling od .22s. Thanks for a great video. Slainte.

[@benjaminvanteunenbroek8369]

Hi Matt very informative video! Not to many videos on the subject. Why didn't you mention polygonal barrels these are my favourite.

[@oralski]

Thanx for the info,, very informative!!

[@jackcook93]

Great series, I'd like to learn more about barrel length though.. Can you have a barrel too long? Will different power settings and pellets effect an optimum barrel length? Is there an algorithm for that 😂

[@ChiefLightning9]

What if you had a smooth bore barrel that was ported at the end? Than would greatly reduce the amount of air behind it to be caught by the skirt....

[@tonybrock5288]

I thinking the same thing: A muzzle brake or port on a smooth or rifled barrel would surely help to minimise the air catching the skirt of the pellet?

[@milesm1465]

A useful addition to the understanding of barrel twist rates but there are a couple of things I would take issue with. The first is the comments on smooth bore barrels. Smooth bores are not intrinsically inaccurate it all depends on what is being fired and if it is designed for a smoothbore. After all, most tank guns are also smooth bore. Pellets just are not the best design as the aerodynamic stability is marginal. Next, the diagram of the forces acting on the pellet misses the most important aerodynamic components out. Stability is dependent on moments not forces and the most important moments in stability are from lift, not drag, and act at right angles to the center line. Pellets are not drag stabilised, they are flare stabilised. Flares stabilise by producing lift in the same way that fins do. The drag at best only produces a tiny fraction of the total stabilising moment about the center of gravity. Also the explanation for why some spin is needed is erroneous. Spin is needed because of projectile asymmetries not because of the muzzle blast since any yaw produced by this effect will be damped out on a stable design. The problem is that without spin any asymmetry on the pellet will be facing the same direction throughout the pellet flight which will produce a curved trajectory. With some spin the direction in which the asymmetry is pointing will be constantly changing and so will not produce the same gross error. Only a small amount of spin is required, much less than is necessary for gyroscopic stability. The amount of spin needed will depend on the individual pellet design. In the section on the maximum spin rate, the down range over stability talked about is extremely unlikely to occur as the amount of gyroscopic stability for this effect at sea level is much too high. At long ranges you will get excessive drift to the left or right due to the natural variation in the yaw of repose (which is not the vertical angle as suggested in the video) which may lead to the assumption that it is due to over stability. It is only at very high angles in a thin atmosphere (at high altitude, much too high for an airgun) that there will be enough over stability to produce significant Magnus forces. While on Magnus, Magnus does not cause pellets to move up or down in a crosswind, it is just part of the normal gyroscopic response of the pellet to the crosswind causing an initial yaw angle which in turn produces a vertical yaw of repose. I would agree with the comments in the video about the lack of research in twist rate choice and the video as a whole gives a good idea on the use of rifling.

[@jayjieyuan6951]

Great comment. You have supplemented/corrected the content of the video. I learned a lot, and I thanks you a lot!

[@AirArmsHuntingSA]

Thanks for your input!

[@gasconader1150]

Great explanation! Thank you.

[@sidneyeaston6927]

Very long and technical reason to rifle a bore the reason that rifling is more accurate than smooth bore is that projectiles are made on mass and no two act the same when fired out of a barrel. Spinning the projectile out of a rifle stops imperfections dragging the projectile in one direction basically pellets and lead bullets spiral towards the target the better made pellets having less of a spiral ever noticed that really cheap pellets tend to form a ring around the point of aim good pellets if off will give a group in one place according to how the weight and speed matches the spin. If I can hit a match box at 35 yards with my 30 year old under lever that is fine I have no wish to put four out of five pellets through the same hole or strike matches at 20 yards. only the insanely addicted would go in as deep as you have. The reason they do not make air rifles to that high of a standard is that the final product would only be slightly more accurate than what they sell now but would be two or three times the price. and no pellet manufacturer would make the guaranteed perfect pellets wrapped individually to prevent damage.Keep the aim straight have fun and be safe.

[@Ferdinand78gu]

Hello man, great channel and great video!. I have some doubts with the Twist Rate and the Strelok Pro App. I have a FX Impact MKII PP, I am using a .22 STX Liner A 600mm, with a Twist Rate of 1:16 (according to the FX official rates for Smooth Twist X barrels). I hope you can help me. What number do I put in Twistt Rate (inches) in the Strelok App?. How do I find that number from the 1:X relationship?. How does that translate to inches?. So I learn to find it when I change size or caliber barrel. Is it Right or Left Hand Twist? Thank you very much and greetings from Spain.

[@billiebleach7889]

JA...that was complicated. Especially the JA cracked me up 😂😂😂😂

[@markflowers1953]

I must say this was a very informative video but I wish you would include "bullets" fired from a big bore air rifle in say .45 caliber where the flight characteristics are much different from a diablo pellet.

[@Dontmakemereregister]

Nearly wet myself with the crown made by Stevie Wonder caption!!

[@randallwickus9883]

Great information! Thanks!

[@Bad-eb1dv]

The public does not touch the crown the crown is at the very end of the Mozel it is machine to a certain way so that when the barrel makes contact with anything the rifling is not touched so it is not damaged orSabotaged by dirt or debris

[@ironMan-qm6hp]

Matt, how much should the barrel exit be reduced? What is the proper length of the narrowing part of the barrel exit?

[@godisgreatallthetime2352]

What is the difference between .22 slugs of air rifle and fire arm rifle

[@Smoke-is7tq]

thank you

[@fred9532]

What twist rates do we need for slugs ?

[@bahubalbaba7886]

You are doing good Professor 😮Matt😅.

[@TPVPRO]

What about slug shooting air rifles without a choke.?

[@TheArtofBoxing101]

So with my tuned marauder pistol, at around anywhere between 22-27 fpe with 21 grain baracuda pellets COMPLETELY clean barrel the accuracy was going everywhere, the fps spread was very good with a deviation of 30, but pellets going everywhere, when I tuned it down to 18 fpe I had amazing accuracy again, so I'm guessing the barrel's twist rate wasn't meant for that kind of speed?

[@chientranvan2207]

Thanks

[@chrisfigueroa3361]

Thanks Matt your the man

[@aroeirasnipersniper6725]

Hello, how are you!! I live in Brazil and I would like to know a lot of your information about who manufactures fx guns?

[@dingachawngthu1091]

Can you please tell me what is the barrel hole size ang grooves size in .22 and air rifle

[@amink9436]

There is nothing wrong with fast twist rates(I mean 16-18),when you find the right pellet with right 《weight》,its done,problems arise when you shoot light weight pellets for twist rate

[@carsmax]

Hi Matt. what about you shooting a pellet in a complete lands and grove less barrel? like an air rifle for round lead projectiles we had in the old East Germany?? I did it at a Hänel 301 in .177 cal and it does it well at 30 yds. but just at 550 fps!!

[@johnpinder8121]

You did not mention polygone rifling. How do you rate these barrels ?. Regards John

[@jibranhussain1565]

Matt I appreciate your effort but I need to know about how can I collect twist rate from a barrel if you can help me in this particular mathed if you know it'll probably very very informative to us.