Dot Tracking Analysis

[robot]

Took my high-speed camera and my Open gun out for a spin yesterday to see if I can capture the difference that different ammunition loads make in my dot. This is by no means a scientific test as there were many variables like shooting from a weird position behind the camera trying to align the scope, but I do hope it makes for some interesting discussion around what you see.

Loads are :

1. 115gr Montana Gold CMJ, 11.0gr N105
   
2. 115gr Montana Gold CMJ, 11.2gr N105
   
3. 115gr Montana Gold CMJ, 11.3gr N105
   
4. 115gr Montana Gold CMJ, 11.5gr N105
   
5. 124gr Montana Gold CMJ, 10.0gr N105
   

Starline Brass, Winchester Small Rifle Primers. Ave 1.240 OAL

My key takeaway :

1. No difference in dot tracking across all loads
   
2. Slightly softer felt recoil using the 124gr vs the 115gr. Now I understand what you guys mean, but dot doesn't track any differently.
   
3. Pressures seem fine across all loads up to 11.5gr of N105.
   
4. I need to manage my trigger more effectively. Catch myself dipping the dot before the shot breaks.
   

love to hear comments and feedback.

Edited October 17, 2011 by robot

[Aircooled6racer]

Hello: Looks like alot of dot movement to me. But then again I never have used a high speed camera to film the dot on my 9mm open pistol. Just using my own eyes and a couple of others who have shot my open pistols say the dot does not leave the glass. It looks like the dot is doing a figure 8 a little bit also. That may be your grip causing that or the powder. I know when I have run the power factor up with 3N37 in 9mm it does that figure 8 motion. Good looking video Thanks, Eric

[Jon Merricks]

Is this the same thing you see when shooting normally?

[robot]

Is this the same thing you see when shooting normally?

well no, my eyes are not fast enough to see how the dot tracks when shooting for real. All I see is the dot jumping, but never notices it dipping and coming back up again. I would say that it comes back to start and I've never realize that the dot would leave the scope either.

The slow-motion video you see is captured at 420frames per second, that means almost 14x slower. Those are two-shots (what you'd call a double tap), with split-time around 0.15-0.20secs (roughly, never timed it)

[robot]

Hello: Looks like alot of dot movement to me. But then again I never have used a high speed camera to film the dot on my 9mm open pistol. Just using my own eyes and a couple of others who have shot my open pistols say the dot does not leave the glass. It looks like the dot is doing a figure 8 a little bit also. That may be your grip causing that or the powder. I know when I have run the power factor up with 3N37 in 9mm it does that figure 8 motion. Good looking video Thanks, Eric

yup. it could also be the angle with regards to the c-more and the camera. If you're holding the gun in the normal stance, you'll be looking through the sights perfectly so the dot doesn't leave the sights. When looking through the camera, I might have been holding the gun in a different position that leaves little space on the top of the sights. So what normally would be enough space for the dot to move, this time, it goes off the edge. All subjective and hard to prove unless I bolt the gun down and secure the camera behind the gun for each shot. But by bolting the gun down, you lose the capability of tracking the dot accurately.

anyway, it's a fun experiment!

[Jon Merricks]

Depending on the loads I've seen my dots do backwards C's, figure 8's, and for sure I would think you would notice such a dip on return.

[shred]

]

Hello: Looks like alot of dot movement to me. But then again I never have used a high speed camera to film the dot on my 9mm open pistol. Just using my own eyes and a couple of others who have shot my open pistols say the dot does not leave the glass. It looks like the dot is doing a figure 8 a little bit also. That may be your grip causing that or the powder. I know when I have run the power factor up with 3N37 in 9mm it does that figure 8 motion. Good looking video Thanks, Eric

I've yet to slo-mo a dot that didn't leave the scope, no matter what it looks like to the naked eye.

Figure 8's and loops and such are quite common and usually grip/stance/timing/flinch/push-related.

Here's one of me shooting a plate rack at 600 fps.

[Jaxshooter]

From what I see from the dot movement if your grip etc is good that load is really violent. I have never loaded N-105 maybe somebody here does and can tell you if they have that much dot movement. I use Silhouette with 115 and 125 JHPs and the dot never leaves the window.

[caspian guy]

]

Hello: Looks like alot of dot movement to me. But then again I never have used a high speed camera to film the dot on my 9mm open pistol. Just using my own eyes and a couple of others who have shot my open pistols say the dot does not leave the glass. It looks like the dot is doing a figure 8 a little bit also. That may be your grip causing that or the powder. I know when I have run the power factor up with 3N37 in 9mm it does that figure 8 motion. Good looking video Thanks, Eric

I've yet to slo-mo a dot that didn't leave the scope, no matter what it looks like to the naked eye.

Figure 8's and loops and such are quite common and usually grip/stance/timing/flinch/push-related.

Here's one of me shooting a plate rack at 600 fps.

Shred,

What kind of camera did you use to capture that video?

[robot]

]I've yet to slo-mo a dot that didn't leave the scope, no matter what it looks like to the naked eye.

Figure 8's and loops and such are quite common and usually grip/stance/timing/flinch/push-related.

Here's one of me shooting a plate rack at 600 fps.

awesome! I see the dip in the first two shots as well, but you still got the hit so I don't feel that bad Love that video, saw it a while back, thanks for posting. It's def one of the inspirations for making my video.

[Aircooled6racer]

Hello: The shots of the plate rack are good except you have movement to the side as you are going to the next plate A better shot would be straight shots with no side movement. That way you could see if the dot tracks straight up and down. These high speed videos are very interesting and a great testing tool for powders,comps and springs. I may have to look into one. What are you guys using? Thanks, Eric

[Sarge]

Cool! I didn't know you could use an Open gun in IDPA!

Pretty neat video. So hard to tell what is really going on when slowed down so much. Looks like the 11.5 load is climbing high AND right more than the others?

[robot]

What are you guys using? Thanks, Eric

I'm using a Casio Exlim FH100 camera. (http://www.bing.com/shopping/casio-exilim-ex-fh100-10-1-megapixel-compact-camera-black/p/D357D2E6DF8B213E5005?q=casio+exlim+fh100&lpq=casio%20exlim%20fh100&FORM=HURE) It's one of the cheaper high-speed cameras that can record at 120fps, 240fps, 420fps and 1000fps. resolution/quality drops a ton when filming in those speeds.

Cool! I didn't know you could use an Open gun in IDPA! Pretty neat video. So hard to tell what is really going on when slowed down so much. Looks like the 11.5 load is climbing high AND right more than the others?

yup! Good observation. 11.5 load is more erratic and jumps to the top-right.

[shred]

I use a Casio EX-F1. I think they're discontinued now, but they're the original big-daddy of their high-speed camera line-- 60 FPS stills, up to 1200 fps video.

My video wasn't really to look at dot movement; it was to show that as long as you can call the shot and the dot goes to where you want it, it doesn't matter a lot what else it does.

I've done enough videoing of Open guns to know that the flip happens when the slide hits the frame, and that's long after the comp does it's thing. While it may look like the dot doesn't leave the scope with some loads, it does. I have a 9x25 Dillon that would recoil down, yet it still flips when the slide hits the frame.

[pjb45]

I will try and set my camera up to emulate your method.

My sense is my dot does not track like the ones in the video. The dot stays within the C-More. I get more of a dip from the POA and less of a rise.

I run VV3n38 pushing a 125 gr Zero. I am playing with 10.+ grains to experiment with the tracking of the dot. I use a SV IMM with 8 million poppel holes.

The blast is quite bad for the RO or anyone nearby.

I am increasing my grains to around 10.6 to see if i can get the dot to level out more i.e., less muzzle flip due to more gas production.

A couple years ago, I had a phone conversation with Chris T. about muzzle flip and recoil for an article that was to be in Front Sight. I remember him stating he would rather have less muzzle flip and would put up with more recoil. He also talked about the dot tracking more vertical as a preference. He emphasized the need to experiment to get his Open gun to react the way he wanted it to react.

Edited October 18, 2011 by pjb45

[SN13]

I love my EXZR100 (Casio)

See me shooting my XDm40. When you are shooting, it looks like the gun isn't moving hardly at all, but in high-speed, you really see the recoil flip.

http://www.youtube.com/watch?v=vW-7h9FA1vM&feature=youtu.be

Edited October 18, 2011 by SN13