I bought the little chrony off aliexpress pictured below. I think I paid $28 shipped. I set it up inside the sensors on my Pro Chrony Digital and fired about 50 shots. The readings were, amazingly dead on. The farthest descrepency was an astounding 1 fps! Since the sino-chrony reads in tenths of fps, it was normally less than 0.5 fps difference. I was amazed at the precision. I was a little apprehensive about shooting thru the small opening, but at around 18" - 24" or so, it was no big deal at all. If you group shoot while chrony'ing you'd need to readjust between groups.
I had bought one before and it was real flaky from day one, but after emailing the this seller back and forth, I decided to give this one a try. I was also told that if I contacted the original seller they would refund my money, but I should have done it a long time ago when I got it, so that's on me. Glad I tried again. I tried to video the shots but messes it up.
Here's pics of the two chrony I used.
I had bought one before and it was real flaky from day one, but after emailing the this seller back and forth, I decided to give this one a try. I was also told that if I contacted the original seller they would refund my money, but I should have done it a long time ago when I got it, so that's on me. Glad I tried again. I tried to video the shots but messes it up.
Here's pics of the two chrony I used.