Newbie needs Shooting Chrony advice

[Bobarian]

I'm still fairly new to handloading. Because I'm a technogeek, I need to see the numbers, so I got the Shooting Chrony Alpha.

Learning how to use the chrony, I fired ten rounds of American Eagle 115 gr 9mm FACTORY ammo over this thing with my S&W Shield. Muzzle was about 8 feet or so from the unit. (The instructions are a little vague WRT distance from the unit for handguns.) The average velocity for the ten rounds was 1394 fps.

My question is: Why are the velocities I'm seeing with factory rounds so much higher than what the reloading tables indicate? The highest velocity on Hornady's 115 gr table is 1250 fps.

Muzzle blast? Am I just too close? Seems like the readings would be more erratic if that was the case (extreme spread was only 12 fps).

 

[cfullgraf]

There are many reasons for the discrepancy. Hornady data tends to be conservative. But you will see differences from other companies' reloading data.

Different guns, different components, different test rigs, different climatic conditions, different lawyers, different testers, different ways they held their mouths and the list could go on.

1394 out of a Shield seems a little high though so muzzle blast may be causing an effect.

Working with a chronograph is a bit art and a bit science.

Hope this helps.

 

[steve4102]

Move it out to 12-15 feet.

Make sure it is opened completely.

Make sure you used the sun shades and had them set correctly.

Make sure it was not tipped or at an angle.

 

[clutch]

I got a really high reading out of my Chrony when I touched off a .32 acp in a box of .380 magtech ammo. I'd move your Chrony out a couple more feet, suspect it is reading muzzle blast on first screen and the bullet on the second one.

 

[Bobarian]

Good advice guys, thanks.

 

[Otto]

Muzzle was about 8 feet or so from the unit.

That sounds about right...they recommend 10ft for high power rifles and 5ft for shotguns.
Remember, the further away you are from the unit the more likely you are to accidentally shoot it.
The bullet should pass 5 inches above the sensors give or take a inch. And the path should be as straight as possible.
Believe me, there's no way you're averaging 1400 fps out of a Shield with Walmart ammo.

 

[Potatohead]

Just shoot that thing if it's not acting right!

 

[ironworkerwill]

That'll teach it a lesson!

 

[murf]

as steve4102 says, make sure it is unfolded all the way. there is a, sort of, latch that locks the two pieces of the unit together. if you just unfold it, without latching the two pieces, the unit will not sit flat and give higher (but still consistent) readings.

murf

 

[spitballer]

I've had good luck with my Chrony but I have run into occasional problems related to lighting conditions. Bright sunshine from the side in the morning used to give me high readings. I solved the problem by going to Staples and getting some black poster board, the kind with foam sandwiched between two pieces of heavy black paper, and cutting pieces to fit the sides of the Chrony. Usually I only use just one, on the sunny side, and I just slip it alongside the metal rods and tape it to them with a little masking tape. Only takes a few seconds and it very effectively solves the side-lighting problem.

Low contrast, low lighting conditions are a little trickier. As a rule when it's really cloudy I'll remove the diffusers and shoot closer to the photo eyes to accentuate the bullet signature. My Chrony also demands to be lined up with the bullet path under low light conditions, too; any twist left or right will quickly give me error readings. In fact, alignment may be a much more significant issue for handgunners shooting under low-light conditions. If readings take priority over technique, consider a gun rest.

 

[Bobarian]

I went ahead and ordered a laser boresight and bench rest from the largest river in South America. That should help me get it dialed in.

Not too concerned about shooting the Chrony, but if hit Spousal Unit's camera tripod you may not be hearing from me again.

 

[steve4102]

There are two type of shooter that use a Chrony.
Those that have shot their Chrony.

Those that will shoot their Chrony.

 

[cfullgraf]

Those that have shot their Chrony.

or two--I'm a slow learner.

 

[mgmorden]

Not too concerned about shooting the Chrony, but if hit Spousal Unit's camera tripod you may not be hearing from me again.

Might be worth just getting a different one. I have a nicer tripod I use for camera work, and for my chrono I use a $20 tripod from wal-mart. Works perfectly fine, and its a good bit cheaper to replace than the chrono .

Overall though to the OP I'd say back the unit up another 2 or 3 feet and try again. ~1400 fps seems way to high for anything shot from a Shield.

 

[Rule3]

All I can say is I wish you luck. I tried and returned 2 of them. They would not work anywhere there was SUNLIGHT! I would have liked to shoot the darn thing.

Bought a different one that works, every time.

 

[Potatohead]

but if hit Spousal Unit's camera tripod you may not be hearing from me again.

Uh-oh, same deal here, I didnt even think about that. Now it's destined for destruction for sure.

 

[Rule3]

Oh heck, there have been so many threads here and on every other forum

Chrony Brand sucks. (no offense to the OP or other owners)

Read the reviews just check the forums or Midway. Nothing but problems, errors and frustrations. Sure some may get them to work sometimes. I tried every trick, different sky screens shields up shield down, card board shields. Klingon Shields forget it.

Returned one as it would not read, return the second same problem. waited for CE Pro Chrono Digital to go on sale and it has recorded every shot at High Noon down here close to the equator and bounce light off the sand at the range.

What's the sense in trying to collect data if the machine will not do it or do it accurately?

https://www.competitionelectronics....id=7&vmcchk=1&option=com_virtuemart&Itemid=79

 

[Sunray]

Reloading manuals reflect the conditions and the specific firearm (if one was used. A lot of testing is done with a universal receiver) on the day of the test. Your chronograph is giving you data for specific ammo with a particular powder lot.
However, something is wrong. Federal AE 115 grain 9mm ammo doesn't get anywhere near 1394 FPS. Fastest MV runs 1180 fps and it will not get faster after leaving the barrel.
Hornady's data accuracy will depend on the powders they use. Reloaders cannot buy the powders the manufacturers use. Anyway, Hodgdon's max loads don't go that fast either.

 

[cfullgraf]

Chrony Brand sucks. (no offense to the OP or other owners)

Over a period of 20 years, I have had three Chrony's, two expired from "lead poisoning" which was not their fault, and all three performed well.

They were a bit temperamental in some lighting conditions and required a few tricks including holding your mouth correctly to get reliable reads.

My CED M2 with the infrared lights and my Magnetospeed have been much easier to work with.

But, the CED M2 had similar issues as the Chrony's until I got the lights.

 

[dagger dog]

Can'thelp myself.

In my best mudbug-coona$$ dialect :

Chute it Bobarian !
Chute it !


Really, I own a Beta Master, when it's set up right, and the ambient light is not a problem, it gives me the service and reliability that I need, that is as a hobby shooter, reloader. I rely on it to check out all my new calibers, against factory and printed data. It has kept my back for quite a few years now.

I'll have to give Ole' Blue a decent funeral when it happens !

 

[1SOW]

I had bad experiences with Chrony.
I went with the CE Pro chrono digital and get good results when the sun is high or when it's in the shade/cloudy. Diffused lighting.

1. Manufacturers Ammo is not tested in a pistol. It's tested in a machine with pressure sensors, usually with 4 inches of "bbl".

2. Shoot some quality .22 rimfire ammo across it to give YOU a base-line comparison for days that give any strange readings. CCI is my choice as it's consistent and not too far off the stated speed using my pistol. When strange numbers come up, shoot the .22 and see if it's changed.

3. As said above, take the time and effort to set it up level, straight and for your shooting position to be aligned level with it about half way up or a little less. Always use a target to have the SAME POA and to prevent shooting the chrono out of season---the fine can be pretty costly.

JMHO, but I haven't shot mine either.

 

[rodregier]

A little trick I came up with was to put a piece of masking tape at the correct height between the second sensor diffuser supports. Makes for an easy aiming point w/o messing around with aligning a separate downrange target. If you use heavy masking tape it will even stay put after you cut thru it with your correctly aimed shots.

Of course, this works best if the Chrony is leveled wrt the shooters location.

To help with the levelling I got a cheap bubble level and installed that inside the Chrony floor.

http://www.amazon.com/Valterra-A2402-Bubble-Level/dp/B005948MO8/ref=sr_1_16?ie=UTF8&qid=1407607028&sr=8-16&keywords=bubble+level

 

[Bobarian]

Much better numbers

Good advice, gentlemen.

Backed up to 12 feet, took the time to get my bench level and aligned with the chrony, used a bubble level to get the chrony squared away, and used the laser to get dialed in 6 inches above the sensors.

String of 10 rounds from the Shield showed a low of 1034, high of 1061, and mean of 1048 fps with that crappy American Eagle 115 gr ammo (rated at 1080 fps according to the carton), so I'm confident the chrony is working well.

I had spread out a cheap tarp to catch the brass. Not the best idea, since half the rounds stuck to it and tried to melt the plastic.

New question: as far as evaluating my recipe goes, do I want to keep using my Shield (3.1" barrel) or the Glock 19 (4.02" barrel)? Or does that even matter?

 

[cfullgraf]

Good deal on getting good info from your Chrony.

Get a cotton drop cloth from the big box hardware stores for catching brass. Not expensive and cases will not stick to it.

Depending on what you are looking for in your evaluation, you probably will wnat to shoot the ammunition in both guns over the chronograph.

 

[greenmtnguy]

Good job - I figured that was your issue -- too close to the muzzle. I had my Chrony 10 feet from the muzzle of my Ruger Blackhawk (45 Colt) with Ruger Only loads, and that wasn't far enough to avoid muzzle blast-induced velocity readings.
I like my Chrony - it sometimes takes some adjusting to get it setup right, but works great for all my firearms and archery needs.