Long Range 101 Part 36 - Bore Axis Shifts Due to Internal Rifle Vibration Issues

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11 жыл бұрын

Bore axis shifts can present a challenge to the long range shooter. One of the primary mechanisms for bore axis shifts are harmonic and vibratory inconsistencies due to problems with rifle system rigidity. Inconsistent whip action can occur when the movement of the projectile experiences frictional changes on its way down the bore due to various affects. Rifle rigidity dynamics also play an important role in ensuring the harmonic consistency of a vibrating rifle. In this video Rex addresses the issues related to barrel / stock contact points, stock warp, lockup of bolt lugs, chamber dimensions and headspace.
All the music, animations, and photography in this video were created by TiborasaurusRex, and unsigned artist.
Song Title: Wadi Watir
Music and Lyrics by: TiborasaurusRex
Instrumentation and Vocals by: TiborasaurusRex
Recorded by: TiborasaurusRex

Пікірлер: 77

@TiborasaurusRex 5 жыл бұрын

Come train with Rex - in person!!! rexdefense.com/

@wayneparker9331 5 жыл бұрын

I know it's been six years since you posted this video but this was very, very informative. Thank you for sharing your knowledge of internal ballistics!!

@todd3dot5 9 жыл бұрын

Hi Rex. I've been studying your videos for a few months now, got me off the couch and back in the field-thinking again. Thanks man, hope you are doing well. The wife is grateful to see me moving as well.

@TiborasaurusRex 11 жыл бұрын

The vid is coming right around the corner, but it shouldn't be a big issue in a .308 barrel. Basically, it can throw off your bore axis causing POI shift IF you have poor rifle deployment. More coming soon. If you are shooting well right now, then your deployment must be alright :-)

@MrGman9999 10 жыл бұрын

Love this series. Learning a lot. Best compliment I can give you is that I bought a smart TV box so I could watch your series on the big HD TV, and see all the details better.

@TiborasaurusRex 11 жыл бұрын

Yup, still on the list. Muzzle brake pull-off will be in this internal ballistics portion of the series. Hang in there! Those goofy things can actually work pretty good, but the trick will be to get consistent placement if you choose to use one. You won't want it sliding around after you get everything sorted out. The better way to go may be to accurize your rifle. Bed the action, lap the lugs, float the barrel, etc... That will produce more conistent results in the long run. :-)

@GunsNGills 11 жыл бұрын

Amazing Videos man. Put them on DVD!!! Thanks so much!

@TiborasaurusRex 11 жыл бұрын

They are both top-notch. If you wanted to try to beat down a brick wall with your stock or drive it over with your truck, the McMillan A5 would actually hold up better. Solid fiberglass of that thickness is very very tough. The Aluminum chassis will be impervious to temp and humidity changes just like the A5, but it may not be able to smash a brick wall or get driven on w/o compromising its integrity and experiencing serious deformation.

@lylesmith6304 4 жыл бұрын

Very thorough explanation and oh so true. Thanks so much !

@TiborasaurusRex 11 жыл бұрын

Great question. Its true that shortening any barrel will increase it proportional stoutness and thus increase its rigidity. However, its still possible to tune your harmonic whip action, even on a long thin contoured barrel, by load development. I would advise this before shiortening the barrel as 22" is needed by that cartridge get the proper and most efficient burn dynamics. If you tune a load to that barel, it should shoot VERY VERY well.

@JimFleming1953 10 жыл бұрын

Another good one, Rex, this is great material!

@jodelboy 11 жыл бұрын

This topic is so much exciting. You rock!

@Cogzed 11 жыл бұрын

Another excellent video!

@TiborasaurusRex 11 жыл бұрын

Good question. Although the harmonic wave does reverberate back and forth, resulting in less amplitude at the muzzle at times, the end of any long skinny vibrating object will always be an antinode region. Although vibration will generally be worse at the muzzle, if we time it just right, we can have the bullet exit the muzzle as the MAIN part of the harmonic wave has reverberated as far as the muzzle as possible. It’s somewhat complex and difficult to explain verbally - but I hope this helps

@dragonusmc0311 11 жыл бұрын

keep um coming rex thumbs up ....

@TiborasaurusRex 11 жыл бұрын

Great question. Its true that you will have differential expansion between aluminum vand steel, however, the effects will be minimal and much much less than the expansion differences between wood or plastic vs steel. Overall, aluminum bedding really helps out to minimize POI shifts caused by harmonically enduced bore axis shifts :-)

@shooter77us 11 жыл бұрын

Definitely solid info. My Savage 10FP injection molded stock was about as rigid as a grilled cheese sandwich. Before replacing it the rifle would do no better then 1 MOA, with the joy of random shifts in POI from weekend to weekend. Replaced it with a B&C varmint stock, now if I do my job I can get 3/8 minute groups. Keep 'em coming brother.

@jomat270 11 жыл бұрын

Ok thanks. Looking forward to the next instalment.

@TheGuitarmaniac10 11 жыл бұрын

Thanks I'll have to check them out.

@TiborasaurusRex 11 жыл бұрын

Yes, sir. These will cause POI shift which will be measurable even at close range. These harmonically induced POI shifts are usually on the order of 1 moa or less, unless something is really out of whack in which case it could shift the POI even more. If you are shooting prairie dogs at 200 or 300m this will be a problem, if you are shooting at deer at 300m, it might not be a big problem.

@TiborasaurusRex 11 жыл бұрын

Thanks, bro. You'll really like the next couple videos as well.

@TiborasaurusRex 11 жыл бұрын

Yeah, those are a great choice for the money. My buddy uses one on his custom Surgeon 6mmBR and it shoots great!

@TiborasaurusRex 11 жыл бұрын

Great commentary.

@TheGuitarmaniac10 11 жыл бұрын

Thanks I'll check it out.

@TiborasaurusRex 11 жыл бұрын

Yes, sir. There are certain time-windows where the main harmonic reverbertion is away from the muzzle. Thats the point we are ttrying to find when we develope good loads.

@TiborasaurusRex 11 жыл бұрын

Although they are really goofy, they actually do work. However, there are better ways to actually fix your harmonic problems so I don't suggest using these devices which are sort of a temporary band-aid type fix.

@matthewcopeland1032 11 жыл бұрын

Awesome! thank you :)

@TiborasaurusRex 11 жыл бұрын

Coming very soon. We are almost there. It will be right after we finish the advanced ballistics section.

@moomoomlik99 11 жыл бұрын

your videos have been very helpful I cant wait for more also I am in the military so I get a good amount of shooting there keeps my trigger finger happy lol

@TiborasaurusRex 11 жыл бұрын

I got my Kestrel at Ambient Air, if I remember correctly.

@TiborasaurusRex 11 жыл бұрын

As long as you can determine you MVs, that all we'll need :-)

@TiborasaurusRex 11 жыл бұрын

It actually looks like it should work pretty good. Aluminum bedding is usually very helpful.

@nickscape75 10 жыл бұрын

Rex, would free floating work on semi-auto systems like m14 models, or ar models?

@TiborasaurusRex 10 жыл бұрын

nickscape75 Its easy to do with an AR platform, but rifles like the M14s have the gas system set up in such a way that true 'free floating' is not an option. Usually the best option on those platforms is getting the operating rod and the gas lock system to mate up uniformly and consistently from shot to shot - this may require custom fitting by a veteran M14 armorer who knows his stuff.

@nickscape75 10 жыл бұрын

TiborasaurusRex thanks for the response rex!

@theclaymore5150 11 жыл бұрын

Dig it!

@mikebyers7019 7 жыл бұрын

as far as tuning the harmonics, is there a good dampener system? I have seen some installed in the stock and on the barrel.

@TiborasaurusRex 11 жыл бұрын

Magpul has a LR rifle series? Right on, I'll have to check that out. RELOADING - Yes, sir. I will discuss LR reloading tips in pretty good detail in this Advanced Internal Ballistics portion. I'll probably use my .338 as the example.

@TiborasaurusRex 11 жыл бұрын

That should work fine I would imagine. You don't need accuracy down to 9 significant figures, you just need to see where the pressure is at.

@shawnhenderson2968 9 жыл бұрын

ok i have a few questions, 1) on rifle harmonics if i put a bipod would that help with harmonics because it will put a contact point with the barrel and the ground. and 2) rex was talking about one of the older weapons that the military used that had the spring between the stock and the barrel could that possibly help i know some people are going to tell me to throw the gun away and buy a different one but i have a remeington 770 300 win mag i love the gun i have no issues that others have had.so im trying to make it even better. so i can shoot long range. i dont mind doing the work myself. to make it better.but i was wanting someones elses thoughts on the matter. if it would help or hurt the rifle system.

@REDNECKROOTS 7 ай бұрын

What about full length action & barrel bedding? Would having full contact all the way make it more rigid?

@eluitmoose 8 жыл бұрын

Do you have the stats on your .243 posted anywhere? Thinking about getting a .243 and would like to see how yours is built thanks.

@TitaniumBallz 11 жыл бұрын

Yeah, that definitely does help. Just so I can get this right, your saying that as the muzzle-end is vibrating up in down in a violent yet harmonic motion (which is inevitable) we are aiming to have the bullet arrive at the muzzle at a specific point in time in its harmonic cycle?

@rajoshusse 7 жыл бұрын

Hi. Im live in Sweden. We have not so many stocks to choose on depending of export rules from USA. I need a new stock to my Remington 700 SA 308 SPS Varmint. Do you have any experience of GRS Stocks? I think about GRS Berserk or GRS Hybrid. Thank you for sharing.

@ryanrosser8520 9 жыл бұрын

Off the wall question but what CAD software do you use for your animation?

@bahrm4 11 жыл бұрын

I have very much enjoyed this series and I'm learning so much! I wonder what your thoughts are on shortening a 'thin' free floating barrel on a 30-06. It's already 22 inches long. My thinking is, with less torque against the last point of contact with the receiver, wouldn't that cause significantly less vibration? Is all that I would sacrifice is muzzle velocity? Why not first shorten to 21 inches and then 20, etc, until grouping is tighter at say 100 or 200 yards? All in regards to accuracy.

@Noremac1557 11 жыл бұрын

can the aluminum bedding block play a role in POI change in cold temps due to the metal shrinking, or is it more of the effects of the MV and air density changes?

@Pilottoproperties 9 жыл бұрын

Rex! First off thanks for all of the video's. I am thoroughly enjoying them. I was wondering with everything you said in this video. Did I understand correctly when you said you still free float your precision rifles that you free floated the Mc A5 stock? been thinking about picking one of these stocks up and wanted your opinion? Thanks

@xmachine7003 5 жыл бұрын

Good stock. The action need pillars and bedding and free floated. Help?

@matthewcopeland1032 11 жыл бұрын

Hi Rex. Will these inconsistensies (primarily rifle dynamics like bore axis, barrel/stock contact points, stock warp etc.) be much of a cause for concern regarding accuracy at shorter ranges between about 100 and 300 meters? Thanks!

@therabbit50 11 жыл бұрын

Rex, would you recommend a Bell & Carlson stock for accuracy improvement ? I plan on replacing my Rem 700 sps stock for hopefully a sturdy stock. Can you tell me if that would be a good choice?

@jimmyforester8492 11 жыл бұрын

none of this really seems to apply to a semi automatic. Is there anything that can be done to help accuracy of an AR style rifle besides having a free floated hand guard?

@TheGuitarmaniac10 11 жыл бұрын

Thanks for your opinion :)

@larryalexander7796 11 жыл бұрын

Do you have a comment or advice on ballistic chronometer's ? I am leaning toward the Bayonet type. Thanks again for the series.

@killcancer6499 6 жыл бұрын

What do you think about bedding the action all the way up through the shank of the barrel leaving the rest free floated?

@xmachine7003 5 жыл бұрын

Recoil lug back bedding is best. Full free float. Pillars also desirable. Help?

@darcypotter2732 11 жыл бұрын

I hand load for all my rifles and have allways neck sized only. But I allso watch my OAL and on hunting loads I run the loaded rounds through my rifle before they leav the loading room . I keep close records of my brass and I do not use brass for defence or hunting loads that have more than 3 trips into the chamber . After fireing more than 3 times the brass is still used but only onthe range . I spent many years guideing in Alberta and Yukon and have watched rifles fail to feed

@TheGuitarmaniac10 11 жыл бұрын

Have you ever used limbsavers barrel de-resonator? I was wondering if they actually work? haven't seen any reviews on them.

@matthewcopeland1032 11 жыл бұрын

so for me with my hunting rifle it shouldnt be too much of an issue with medium sized game at shorter range? (like white tail size)

@jomat270 11 жыл бұрын

I'm searching your videos for the part where you explain how to build your range cards using all the points you have discussed. Can you tell me where to find this. Really useful information by the way.

@TitaniumBallz 11 жыл бұрын

Does the antinode always occur at the muzzle?

@JourneytoAdventure 10 жыл бұрын

What are your thoughts on the Savage Accustock? is it any good?

@TiborasaurusRex 10 жыл бұрын

It is mechanically and harmonically sound... much better than the cheap injection molded units without sound bedding.

@myron666mosley666 8 жыл бұрын

+TiborasaurusRex this is off topic but is there any way to get this series on audio files? I would love to listen to these when I don't have access to youtube.

@TheGuitarmaniac10 11 жыл бұрын

where did you find your alt/temp/bar indicator?

@Yelladog78 10 жыл бұрын

I fill up the but stock on all my syn Stocks with automotive fiberglass. Never seen one it didn't help.

@kevluv93 11 жыл бұрын

So...I think I might know why my mosin nagant doesn't shoot sub-MOA with surplus ammo.

@AFWoodFloors 10 жыл бұрын

I'm looking at Tikka T3s. They advertise glass fiber reinforced copolymer polypropylene stock. Is this just another word for plastic, or does this sound like fiberglass?

@TiborasaurusRex 10 жыл бұрын

A. F. Wood Floors Yeah, that's plastic, but it sounds like a pretty good plastic design with a little glass reinforcement. Most of the factory T3s I've seen shot really well, so they must be doing it right.

@NickFrom1228 10 жыл бұрын

I own a couple T3s and am pleased with them. They are pretty sturdy. Their plastic magazines are stronger than you think too. I plan to get a spare mag but its more because I'm afraid of losing one than breaking one.

@gravityprone 10 жыл бұрын

I just bought a Weatherby vanguard series II in .308, with a 24" Right 1 in 10 twist barrel. it is the #2 contour, (thinner), and Weatherby does not recommend free floating it. They say it has better rigidity as is with the factory stock. I'm not sure which stock it is. Its from the WBY X line. I don't know it has any aluminum in the fore end. I haven't shot it yet but they guarantee .99 MOA with premium ammo. Will this be good for long range shooting, or should I have bought one with a thicker barrel? I was thinking of weight savings. Your videos are great, and I'm learning a bunch. Thanks. Oh yeah, would putting a bipod on it, and even installing a second swivel stud have a POI effect?

@rwesnitzer 10 жыл бұрын

I have a question on stocks. I really prefer the look of wood, but understand its potential problems. I understand the advantage of the HS or McMillan, but just do like the look -- yeah perhaps silly I know. So the question is, how about laminates? At least I still have a "traditional" look of wood, but how about warping, etc -- do laminates minimize this problem?

@TiborasaurusRex 10 жыл бұрын

Laminates are usually pretty structurally sound in that they offer less suceptability to warp than solid pieces of newly harvested hardwood in some cases - however - quality will vary between different pieces of wood. Properly aged walnut is usually very solid, but its getting harder an harder to find lately.

@davidfishburn4735 5 жыл бұрын

It may be a long shot, no pun intended, but I was wondering if you could possibly post this in text format. For some reason this video and the next both will not play...keeps saying unplayable/something went wrong. I am at the point of breaking in a factory barrel and can’t figure out how to properly “cooper” a barrel. I may as well add I’m brand new to long range shooting. Haha.

@moomoomlik99 11 жыл бұрын

I reload for my browning blr I shoot the 53 gr v max. I have shot every thing from 45 gr to 60 gr and the 45 shoot the best out of it. but I can not get i to shot very well so i bought a stevens 200 hoping to build it up slowly. I would like to start to shoot at longer ranges I am a good shooter i have shot sub moa groups with my dads 30-06 consistently. but where i live you cant take 30-06 or any lager rifle cartridges unless your hunting big game and the longest range around is 100meaters