Donation

All Springer/NP/PCP Air Gun Discussion General > Big Bore AirGun Gate

Tricks for getting chrony readings?

<< < (3/6) > >>

rkr:

--- Quote from: ballisticboy on January 09, 2023, 07:59:14 PM ---I personally would never dream of using a radar chrono indoors. Over the last 20 years or more, muzzle velocity radars have caused more problems on our trials than anything else. There are just too many things indoors which can give spurious signals and false readings, many of which you will be unaware of with only one unit operating for each shot. Even the professional instrumentation engineers were surprised at the differences in readings between multiple units when we insisted in having two radars for each shot.

To reduce the blast problem, I would suggest firing through a hole in a plate to strip most of the air away. Some will still follow the bullet and may still interfere with the chrono, but the amount of air will be reduced.

--- End quote ---

Aha, plexiglas with a hole would allow aiming and strip most of the blast away. Thanks Miles!

sb327:
Just make sure that plexiglass is secured very well. You are essentially creating a very large muzzle brake which are designed to transfer all the energy of the blast into the barrel to reduce recoil, essentially giving the gun a jerk forward.

I would consider as small a piece as necessary to block the sensors.

Do you have a thread here on the build? Sounds like a fun one!

Dave

rkr:

--- Quote from: sb327 on January 10, 2023, 08:39:16 AM ---Just make sure that plexiglass is secured very well. You are essentially creating a very large muzzle brake which are designed to transfer all the energy of the blast into the barrel to reduce recoil, essentially giving the gun a jerk forward.

I would consider as small a piece as necessary to block the sensors.

Do you have a thread here on the build? Sounds like a fun one!

Dave

--- End quote ---

Good points Dave, thanks!

It's this X2 Sniper I'm working with https://www.gatewaytoairguns.org/GTA/index.php?topic=110075.0

I made a 2mm stem for the valve and it's getting crazy dwell and thus pushing out loads of air. It would be fun if I could get that valve to seal, I think I need to change the seat geometry or valve face to make it self centering as the next step. I'll update that thread when I get it sorted out.

Tusker:
Mr. Seller,

How does the chronograph you linked working out for you? I'm happy to see you list that. I got one a couple of weeks ago and haven't been able to get out to the range to test it yet. Any tricks you apply to make it work best?

I got it off of Amazon for about $30 during Christmas, after reading this: 

https://hardairmagazine.com/reviews/doug-wall-tests-a-low-cost-chronograph-its-pretty-good/

I like his idea of placing a block so not to shoot off the led plus the shrink wrap on the u-bolt to save the barrel from scratches seems nice too. 👍

If you have the time and don't mind sharing, would love to know your experience with yours. I'm really hoping to be able to get out to the range sometime thjs month! 🤞🙏

*edited to add: for about $30 I'm pleasantly surprised how many good reviews it's getting,!*

mackeral5:
Using Caldwell and Competition chronographs I never had any problems with muzzle blast causing errors, even when testing a 4500psi .457 extreme.  But I was always able to maintain at least 6-8 feet of distance from muzzle to chrony.   Any closer and the muzzle blast could make a mess of the chrony/light kit.

My biggest problem was wrecking my infrared light kit on multiple when testing various configurations of a balanced valve in a gun equipped with .300 porting, some of which resulted in machine-gunning tank dumps.  My lights still work, thankfully.  However they have been pieced back together multiple times. 

The idea of using some type of blast shield  sounds like a practical solution assuming you do not have enough room to create space between the muzzle and chrony.

Navigation

[0] Message Index

[#] Next page

[*] Previous page