Shortstroking method comparison

Hi guys. Like I promised, here's a quick comparison of the performance of the two shortstroking mods I tried out:
- DIY recoil buffer
- commercial extra recoil spring

Here's another look at my diy mod:

To achieve (about) the same amount of shortstroking as with the extra spring, I added an extra rubber sealing and another washer. This makes 3 washers and 2 sealings in total. This is the maximum amount I can add that still allows me to put the recoil rod back in the slide.

Above is a (admittedly blurry) picture of how far the slide goes back with the buffer method...

...and one (of better quality) of how far it goes back with the extra spring.
The spring allows you to shortstroke further, but will also allow the recoil to create more movement in the gun as the spring is compressed whereas the buffer only allows for a tiny bit of compression of the rubber sealings.

This principle is also reflected in the shooting test I performed.
I shot at a small (12cm x 12cm) target from 5m away, doing 3 times a double tap.
This I did with the DIY buffer in the gun (left) and with the AIP spring in the gun (right):

Green: primary shots - Red: secondary shots

We can safely assume the shots marked in green are the primary shots of the 3 double-taps and the shots marked in red are the secondary shots of the double-taps.

For our comparison, we can ignore the primary shots, since the shortstroke mod is not in effect at the time you are aiming. The recoil with the buffer installed seems to point the gun downward and only slightly to the left while the spring makes the gun move more to the left, making it harder to remain on-target for the secondary shot.

I've seen a couple of comparisons of buffer vs spring shortstroke mods and the internet seems to agree that a buffer is better. After doing my own testing, I agree with the internet. My DIY shortstroke buffer will remain installed in my gun.