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u guys seen this vid?

5K views 25 replies 16 participants last post by  antifederalist22 
#1 ·
thought it was kinda cool

 
#10 ·
I disagree. I can't see much of it but I think the barrel starts to flex before the round gets all the way down the tube. It's not flexing much but my guess is as the hot energy gas ball is going down the tube it's already expanding and bending the barrel. It's most obvious after it leaves but you can't flex the barrel that much and NOT have it swelling the barrel and stressing it.

It only takes a small amount of flex to change the point of impact. When Ruger changed to the fatter barrel there is no doubt the same ammo became much more accurate and the reason why is, much less flex. kwg
 
#11 ·
I disagree. I'll admit that one's take on the video is subjective, but I "accurized" my 185 series by glass-bedding the action, smoothing the sear, and feeding it the right handload. 1"/100 yds with 4X scope. I I would guess it flexed as much as the one in the video.

From what I've read here, the so-called "heavy barrel" mini isn't much more accurate with factory ammo than the old ones. Some folks are lucky, however.

You HAVE to handload with almost any rifle to get 1 MOA.
 
#12 ·
All barrels flex to a certain extent as the bullet travels down the barrel. The point of building consistent handloads is to have the barrel at the same spot in it's oscillation each time a bullet leaves it so they will hit the target in roughly the same spot as the previous bullet. All that whipping around after the bullet leaves is of no consequence. That sure is a bitchin video, though!
 
#14 ·
I'll ask my question another way.

Using consistent hand loads, on a bench rest:

1. Barrel at 70 degrees F, fire a single shot, let barrel cool to 70 F. Repeat for 9 more shots.

2. Dump however many rounds it takes to bring barrel to, say, 200 F. Fire 10 more shots.

Would the expectation be that the second 10 shot group has a larger spread than the first 10 shot group? Would that second group show more vertical spread than the first one?
 
#16 ·
I've done a wee bit of scientific data collection on the Mini and how it shoots (;)), so thought I'd share...

Yes, there are (at least) 2 error modes involved with the Mini, one is the harmonics of the thin barrel, the other is thermal stringing. The effects must be separated out for proper experimentation and accurizing.

Thermal stringing is a problem for most thin-barrel minis. Cryoing always solved the problem for us, and it got to the point where we would automatically have the barrel cryo-treated before accuracy tests. I am not sure how much of a problem it is for the newer thick barrel. I also don't know if group size changes with a hotter barrel. Intuition says it will, but I have not run those particular experiments (better to simply solve the problem!)

The thin barrel of the earlier Mini is indeed a source of accuracy-killing harmonics. In fact, it is a concern for any barrel size, it's just much more pronounced for a thinner barrel. Can this really be a question, as common knowledge indicates accuracy and barrel diameter tend to be directly related? Sniper rifles tend to have heavy barrels, competition barrels thicker still. I don't think they would build them this way for nothing, considering the weight a heavy barrel adds. Current history is replete with experimental and anecdotal evidence that the newer 5/8" barrels are roughly twice as accurate as the older 9/16" Minis.

I have often heard the opinion that the bullet leaves the muzzle long before a barrel vibration, and have always wondered how this could be. Thinking in terms of acoustics, a barrel vibration is basically a sound wave. Sound travels through steel at approximately 17x the speed of sound through air, so over 19,000 fps. A .223 bullet leaves the barrel at only around 3000 fps (and must be accelerated first). By definition something must reach the muzzle before the bullet does, maybe it's too hard to see the initial movement even with time lapse.
 
#18 ·
If open page up and watch full screen then start /stop the video around the 40-45 sec frames you will the whip go up and then the whole gun will start rising before you see the flash. I watched it about 20x. There is movement before the bullet leaves the barrel.
 
#22 ·
You still got a bunch of cool points! I like it! I watched it 20x trying to find the frame were the bullet left the barrel, I think it was right before the big flash and after the small flash. It spurred some good conversation!
 
#23 ·
I keep coming back to this video because it helps me understand the operation of the mini. I was always under the impression that the force of the spigot on the gas block blowing the operating rod back raised the barrel before the bullet left was the cause of some of the inherant inaccuracy of the mini 14 platform. Not the case! Thanks for posting the video, Whofarted. By the way, he who smelt it, delt it.
 
#25 ·
I think someone needs to do this test on a mini with a high speed camera. The military did some testing on sniper rifles some years ago, and showed the barrel torque and slap when firing a 7.62 from different types of barrels.

They also did a gas expansion test. They made longer and longer barrels for a universal receiver to find out at what point the length no longer helped velocity. They got close to 10 feet before the bullet speed maxed out...at a ridiculous muzzle velocity....LOL.
 
#26 ·
I would like to see this test run against the various modern Mini-14 barrel lengths with and without the various strut systems (Accu-Strut - all models respective to the barrel length they are intended for), and for other struts if necessary.

I have a 16.15" Tactical 14/20GBPR model and I added the Accu-strut SOCOM to mine. I have an HD GoPro960 that might be able to be slowed down using my video editing software. If I can get to the range in the next week or two, I will film it with the strut on and off and see if I can slow-it down to observe that flex. I will make sure I film from the same position/angle/distance and maybe we can measure differences in it. I added the strut for looks, so I have no comparison on grouping, but I will try do that too after a full mag or two is expended.
 
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