Muzzle flip

Has the amount of muzzle flip in a BE .45 been measured? That is, the amount of upward angle of the barrel during firing.

And where along that angle is the bullet leaving the muzzle?

Too many factors here. Even if you take the physical attributes of the shooter out of the equation, there is the potential of early unlock (if you are talking about barrel tilt). Your pistol will do different things in a random rest, which is why most test off sandbags at the wrist with a specific bullet. Bullet PF, spring weight, arm strength, muscle composition, grip strength, firearm balance, on and on forever. It's what makes the sport so intriguing. Theoretically it's not supposed to unlock before it leaves the barrel but under certain circumstances it can. Then you would have to know PF etc.

Depends how you grip it, especially for revolvers, but I think it’s irrelevant for autos because the flip force is absorbed by the slide motion and the bullet is gone before the slide has moved much. Revolvers are gonna roll up…

The barrel angle is pretty close to the same at rest initially and at firing completion

Your motion dominates impact points 

I was writing this as CL above was writing but yeah on that too

I would be surprised if there were any muzzle flip before the bullet leaves the barrel

https://www.youtube.com/watch?v=7y9apnbI6GA

JHHolliday wrote:I would be surprised if there were any muzzle flip before the bullet leaves the barrel

https://www.youtube.com/watch?v=7y9apnbI6GA

I would agree in most cases but I have encountered very vertical stringing with light springs which was solved with heavier springs. In our sport, if you tune for short line functionality and then add a heavier long line load/bullet, there is a possibility of having more of a chance of early unlock. Just my observations but certainly can be scientifically tested if a person were so inclined. I've satisfied my own curiosity to be aware of the possibility.

Thinking some more, there must be some vertical movement of the barrel before the bullet leaves - though probably not significant.

When the powder gasses expand they are pushing in all directions, forward on the bullet, lateral along the barrel walls, and rearward on the brass case captive in the chamber.  Forces on the barrel walls would cause the walls to expand slightly but in any case cancel out.  However the force on the bullet is equal to the force straight back on the captive case along the bore axis.  

If the gun was clamped at the level of the bore the force on the gun would be straight back along the barrel axis (assuming a perfectly straight barrel and no lateral moment of the bullet, which isn't exactly true).  And if this barrel clamp was elastic the gun would move straight back in recoil without jumping vertically.  However in reality a pistol is "clamped" by one (or more) hand below the bore axis, and since the hand-clamp is elastic the rearward force on the barrel would cause the gun to rotate and the barrel tip up.

The question is how much (I think very little) and whether it would result in vertical stringing.

This recent video has even higher speed footage, zoomed in on the muzzle, of a variety of guns including a 1911 in 10mm and a SIG 220 in .45.

https://www.youtube.com/watch?v=e-R-D_v0udk

It looks to me like with all the Browning tilting-barrel designs, the bullet leaves the barrel after the slide and barrel have retracted about a millimeter or two. Muzzle rise at this point is very little if any. The recoil is mostly moving the slide+barrel assembly straight back along the frame rails and not rotating the whole gun around the fulcrum point in the shooter's hand yet.

This is definitely long before the barrel unlocks from the slide, and likely before the link has even *begun* to pull the rear of the barrel down. Although the latter is harder to be sure about and could vary depending on how the barrel, slide stop, and link were fit.

With the revolvers you can see the muzzle climbing from the moment of ignition and it definitely has moved at least equal to a few clicks of elevation by the time the bullet exits.

Anecdotally I have not noticed much difference in POI at 25y between 185, 200, and 230gr bullets in my 1911 or Glock 21, but I can easily see a difference in my .45 revolver and have to adjust sights for it (heavier hits higher).

Great video RSP.  Off topic, some of the shots show lots of particulate debris leaving the barrel after the bullet (especially .380 and Taurus revolver).  Is that unburned propellant? And if so, why?

Yes, unburnt powder. Barrel is too short to get complete ignition before bullet exit. Can also see that on the short-barreled .223 they had. Far less with the longer barreled rifles.

Wow. The conclusion, for semi autos anyway, is muzzle flip is not a factor in determining POI.
Thanks all!

jwax wrote:Wow. The conclusion, for semi autos anyway, is muzzle flip is not a factor in determining POI.
Thanks all!

There isn’t a BIG effect but pistol recoil while in your hand does have an effect that is measurable.  If you load ammo with a light bullet to a higher velocity your impact in a fixed sight revolver is often lower than a heavier bullet at a lower velocity.  There isn’t enough difference in trajectory to account for the difference.  That all said, a 5 inch difference at 25 yards doesn’t require much movement, about .005 which is hard to measure in a movie.

Fascinating Wobbley! I suspect a single-axis accelerometer on the muzzle could yield actual displacement of the revolvers muzzle.

jwax wrote:Fascinating Wobbley! I suspect a single-axis accelerometer on the muzzle could yield actual displacement of the revolvers muzzle.

Or we could just make a sight adjustment!

To add a little more on this topic.

Here are two targets shot side by side, same ammo, same gun, same chamber, same zero on the optic. The only change is that the target on the left was shot with this broad-base grip resting on soft foam giving it freedom to recoil, and the target on the right was shot with hard wood-on-wood contact between the grip base and a plywood sheet. I repeated this POI shift across many groups, not just these two.

Although the 25 yard centers were used for a smaller aiming reference, both these targets were at 50 yards.

This illustrates how if the recoil of a revolver is constrained, the POI changes. I believe neither of these groups represents the actual accuracy of the gun+ammo. Both are affected by variations in how the gun recoiled depending on my grip pressure and amount of downward force on the base. After all if a difference in rest material can create a 4" POI shift comparing the two groups, it would follow that a difference in grip or pressure downwards into the rest can easily create create a 1-2" variations in individual shots within a single group.

If you've had the experience of loosening your grip pressure while shooting a wheelgun in SA, trying to control the trigger more finely, only to have an uncalled high shot... maybe think about it.

Just one of the reasons why testing off a bench is inversely correlated with sanity.

I love this ^^^^. Bravo and thanks for showing these targets.

jwax wrote:Has the amount of muzzle flip in a BE .45 been measured? That is, the amount of upward angle of the barrel during firing.

And where along that angle is the bullet leaving the muzzle?

A quick answer is… Yes
The bullet is around 15 to 20 feet out of the barrel before any “ muzzle flip “ is noted.

Danehogle wrote:

jwax wrote:Has the amount of muzzle flip in a BE .45 been measured? That is, the amount of upward angle of the barrel during firing.

And where along that angle is the bullet leaving the muzzle?

A quick answer is… Yes
The bullet is around 15 to 20 feet out of the barrel before any “ muzzle flip “ is noted.

You are talking a semiauto, and not a revolver correct?

Both

How then do we explain a heavier, slower bullet hitting higher than a lighter, faster bullet? All else being equal.

Nothing is ever equal. 
And a slower, heavier bullet will cause more anticipation which causes bullets to hit higher.