do we really need a chronograph to tune a barrel?

[Cassidy]

I went to the range yesterday with my tuning plan and cases prepped and loaded accordingly. Set up my chronograph (an inexpensive $150 or so unit I bought 3 years ago). Sighted then started the test load sequence recording the muzzle velocity for each round. Before I finished the sighting rounds, the chronograph started reading "err" intermittently, then for every round, so I got no muzzle velocity readings during the tune test. The chronograph was a full length phone cord away from the muzzle - maybe 8 yards or so. I figure I need a new, different and better more reliable chronograph - one that doesn't attach to the barrel and foul-up the harmonics. Then I searched this site and started reading other threads re chronographs for tuning, and there seemed to be those who think muzzle velocity reading are important to tuning, and those who relied on group size and don't use a chronograph (for tuning). The answer to this question is important because if I'm going to move up to a more reliable chronograph, I think it might cost about $720 or so. And if I really don't need one, no sense in spending the money and having to go to all the trouble to set the thing up every time I tune (which seems often).

Do I need to get a chronograph for barrel tuning, and if so, which one do you think I should get?

 

[jonbearman]

I would think 15 feet might be better and were you using your sunshades on the sensors.

 

[Judd]

If you have very easy access to the ranges you'll be shooting, no you don't have to have a chrono. But it could help you eliminate issues before they become apparent on a target board.

My 2 cents...

 

[spclark]

No they're not required as such but having access to one & using it properly can not only shorten the process but also provide useful information that can come in handy later on.

As for which one? Do a search here for 'chronograph' & you'll find lots of info. Magnetospeed is a new one & seems well spoken-of. Oehler used to be the go-to brand but may be hard to find now. There's a new one slated for introduction soon that's radar-based & is supposed also to provide all kinds of interesting statistics but we'll have to wait & see on that whether promises turn out to reflect reality.

 

[6BRinNZ]

If you are load developing at short range with the intended use being long range then you will need to use a chrony. You need to know what your ES/SD numbers are as it is more than possible to have a load that shoots small at 100 but with large ES numbers so won't shoot further out.

 

[artbosco]

Actually the barrel is tuning the load by telling you what it likes in order to put bullets through the same hole. You Never need or use a chronograph to tune a load!

You tune a load with the right primer, brass, powder, and bullet combination and then fine tune with neck tension [using a bushing(s) in a F/L bushing die] and seating depth.

The results of the proper combination and fine tuning are seen down range on the target, not on a printout from a chronograph.

 

[DennisH]

You could get by without one, but . . . I found You need to know what your ES/SD numbers are, plus and mainly FPS, JMO

 

[BoydAllen]

Before I did anything, I would try to figure out why my chronograph had a problem, and if there was a relatively easy fix. It might be something like putting a diffuser over the top. I would call the manufacturer and get some help. Friends have used Chronys for years without too much of an issue.

 

[RDavies]

If you are load developing at short range with the intended use being long range then you will need to use a chrony. You need to know what your ES/SD numbers are as it is more than possible to have a load that shoots small at 100 but with large ES numbers so won't shoot further out.

Exactly right. If you are tuning at short/mid range, then competing at long range, you need a crono. If you can get to tune at long range, a crono will still help to diagnose problems. If all of your shooting is short range, you probably wont need one.

 

[LHSmith]

The best use of a chronograph in Short Range is determining the difference in burn rates when switching powder lots.

 

[Scott Harris]

having a poor chrono is not useful. Having a good chrono is very useful. I don't subscribe to the "something attached to the barrel gives me bad data" school. I happily use a Magnetospeed and get great results. Does barrel-attached chrono change your zero?...yes it does. Does it change your load development results? Not in my experience. I used to own a German PVM-21, arguably the best consumer-grade chrono or the market. I tested the Magnetospeed and the PVM simultaneously and the ES/SD results were identical over many test groups. Sold the PVM and never looked back. The Magnetospeed is priced very reasonably, produces accurate data, never misses a shot, and is a pleasure to use. Get one and you won't regret it.

 

[Cassidy]

Scothar - I don't understand how attaching a magnetospeed to the rifle barrel does not influence ES or SD. I'm not saying it doesn't, only that it flies in the face of what we think we understand regarding barrel harmonics, and therefore seems counterintuitive - I don't understand it. Would be nice to see some data if available, with and without the magnetospeed.

 

[Nomad47]

Barrel harmonics and ES/SD have no relationship. +1 for the MagnetoSpeed.

 

[savage10shooter]

Barrel harmonics and ES/SD have no relationship. +1 for the MagnetoSpeed.

+1
I have a Magneto Speed and I love it. It is reliable, easy to use and I personally like saving the data on an excel spreadsheet.

 

[Patch700]

If you're using a "Shooting Chrony" then it's quite probable you are setting it up too far away from the muzzle... I realize the manufacturer says to set it up approx 10' away but in all honesty I've had the best luck with as little as 24-36" away so long as they were'nt boomers with a lot of muzzle blast.

A properly working chronograph that you can trust is a handy piece indeed .... Working and trust being the key words lol. One piece of advice i could lend if you're doubting the repeatability of your chronograph is to take along an air rifle of known velocity , if it keeps giving you errors then get your rig setup proper using the air rifle and not popping off your meticulously prepped rifle ammo.

Good luck.

 

[Hoier]

I never use a chrono for load developement. I let the target tell me how much vertical I have. Sometimes I can tell you how fast my loads are running but most the time not. My current 6br barrel has about 1100 rounds on it and I couldn't begin to tell you how fast it's going. And I've won a lot of fake wood with it.

 

[normmatzen]

It's a shame that people believe anecdotal evidence when evaluating a new product like the MagnetoSpeed.

One shouldn't make guesses about a complex system unless you understand the science behind it.

I and a friend both went with MagnetoSpeed and haven't looked back! My friend leaves his on for competition and records every shot for extended statistics.

We both are into barrel tuning and have found no effective change in tuning when attaching the MagnetoSpeed. We have, as have others, found that point of impact moves around 0.5 to 1.0 MOA with the MagnetoSpeed on the barrel. This shift in POI is due to the physics of the system and is caused by our old friend the Eddy current! When the bullet goes past the two inductor sensors on the device, it goes through a small inductive field due to DC current flowing in the inductors. This causes an impulse of force against the bullet similar to a small puff of wind from the bottom. As this force is consistent, it is just a constant and does not effect your accuracy once the scope is adjusted for the shift.

And, the weight of the BAYO of the MagnetoSpeed is small compared to both barrel and tuner weight so doesn't cause a first order error in tuning.

Simple!

By the way, neither I nor my friend have any connection to MagnetoSpeed, we are both just electronic engineers that appreciate science based toys like the MagnetoSpeed!

 

[madderg]

I have found that they are OK to use, but the target will tell you whats going on. Some people state that the accuracy is between a and b and again c and d speed. Hell, you can see that on the target and the primer. as far as SD goes, I've seen some winning rifles with what some would consider bad SD's...and they still win. If you are so concerned about SD, shot a 10 shot group...that will tell you a lot more than paper numbers. I have, and use a crony, but my load depends on the target and the primer. There is so much written material on loads for a given cartridge most of the leg work has been done for you. I have designed and shot a wildcat round, and of course you take an educated guess and work from there. Good shooting, Gary.

 

[338 Mollett]

We did an experiment between the magneto,ced and chrony,in that order.The Magneto registered the fastest,the CED the slowest and the Chrony in the middle.There was a difference of 75 fps between the high and the low.The crony's were lined up in a row for each shot on multiple rifles and these spreads were consistent.There is a plus or minus factor on all machines.There fore I don't put much stock in es or sd on load development.But the info helps out come ups when you are fooling with a new cartridge.Shoot ten at three hundred yards and you'll know what you got!

 

[Alex Wheeler]

I had a barrel with a tuner on it. I could change the size of the groups with the slightest turn of the tuner ring. No way I would hang something on my barrel that can move around. I like to shoot groups at the distance I want to compete. I have shot great groups with bad ES and I have shot bad groups with good ES.