Question on chrono's

[mugsie]

Well, it's time I purchased a chronograph. Up to this point I've been adjusting my MOA until I was on target at various known distances. That worked except I didn't know the speed so I couldn't calculate drops on distances which were not known (does that make sense?).

The charges, bullets were all tailored to my specific rifles and all shoot consistently to a half MOA or less. That's great if my target is posted at 300 yards, or 209 or 400 etc. now I have a target somewhere out there and I mil it to be 385 yards. I don't have a drop for 385. If I knew the speed I could plot drops for any distance.

That all being said. Which chrony do you guys recommend and why? By the same token, if you don't like a particular unit, tell me why.

Thanks for the help....

 

[rcmodel]

You must trust ballistics tables more then I do!!

Why not just shoot the load on paper in 50 yard increments out to your max range and plot the actual drop on paper??

It will prove much more accurate & reliable in the long run.

Rc

 

[mugsie]

I could do that, but with several rifles, several different types of bullets and loads, and distances going out to 1000 yards it will become very cumbersome and time consuming. Then if I change a load or powder I'd have to start all over again. A chrony would make it a lot easier and I could simply verify at a known distance easily.

 

[rcmodel]

Assuming you trust the bullet manufactures published ballistic coefficient to be right out of your rifles.

They usually aren't.

Shooting is the only fool-proof way to get reliable down-range drop tables.

There are no magic shortcuts.

But if you want to buy a chrono, far be it from me to try to dissuade you.

rc

 

[jmr40]

For what you want to do you don't need a top end chronograph. There are several in the $100 range that will be close enough. I've seen some test data showing the cheaper units are usually within 1% of what the real expensive units show. That would be no more than 20-25 fps different in most cases. Closer to 10-15 fps most of the time.

The biggest difference is that sometimes the cheaper units give nonsense readings, especially if light conditions aren't right. I've been using one of these or about 5 years.

http://www.walmart.com/ip/F1-Chronograph/4382668

Most of the time it is just fine, but in 5 years of use there have been 2-3 times when I just had to pack it up. It just wouldn't give readings that made sense because of lighting conditions. You'll know, it is not like you get inaccurate readings that are believable. I'll get 200-300 fps when I should be getting 2800 fps.

If I were buying today I'd buy this.

http://www.walmart.com/ip/Competition-Electronics-Prochrono-Digital-Chronograph/37466422

Only a little more, but from what I read is a better unit.

If you're shooting factory loads I'm not sure it is worth using. You can look up the ballistics and be close enough. As RC said you really need to shoot at the actual ranges. A chronograph and online ballistic chart will get you close. But there is nothing like actually shooting to confirm the data.

I wouldn't want to handload without one. I did for years and wouldn't think of doing it anymore. With your handloads you really have no idea how fast your loads are. You could be 100 fps faster than the manuals say you should be, or 100 fps slower.

It is really a safety issue. Some loads, in some rifles may be overloaded in certain rifles even though you are 2 gr or more below published max. Testing the loads for velocity is the only accurate way to know if you are approaching a dangerous load. Traditional pressure signs don't show up until you are 10,000-15,000 psi over the max pressure.

 

[edwardware]

I wanted one to provide more feedback on my handloads, and ended up buying a once-returned Shooting Chrony Alpha Master Chronograph for a discount on Amazon. The 15' wire and remote display is the kitten's wiskers.

I do most of my handgun chronography in the basement, and it does take a while to get the lighting right. Never had a problem under sunlight.

For rifle work with significant drop, I agree with RC (always a safe bet). The Chrony will give you an estimate, but "Trust, but Verify."

 

[WelshShooter]

Unsure of your budget but the Magneto Speed chrono's are worth a look at. They slip onto the end of your barrel (sort of look like a bayonet) and work based on a disruption in the magnetic filed (hence the name). They work in broad daylight which could be another plus for you.

For what it's worth, I chrono'd my 6.5x47 Lapua rifle while performing load development at 100m. The chrono worked great, average velocity at top load was 2,950fps (5 shot average) which was perfect for me. A couple of weeks later I headed to shoot some long range (~1,000m). Using the chrono'd velocity along with the Lapua smartphone app (I was using Lapua bullets) it told me that I should give 9.9 Milrad elevation at 1,000m. First shot was a miss due to a bad windage call, next shot nailed the target (1.0m tall, 0.5m wide) along with the rest of the magazine.

YMMV.

 

[murf]

i've been using a plain-jane shooting chrony for over 15 years now. it does what i want. that and a cheapo 15 dollar tripod is all i need to find out how fast that projectile is going.

as rc has pointed out, actual hits on target at known distances is the only way to find out the true trajectories of your bullets.

suggest you adjust your trajectory data while you are shooting your various guns at the various ranges. it doesn't have to happen all at once.

murf

 

[JimKirk]

I use an old Pact Model One ... it has worked really well for me. The "brains" sit on the bench with my gun... out of harms way. Only the sensors and wires are out "in front" of the gun in the possible danger zone. If I happen to hit one or the other ... it is only about $15 to replace ... a lot cheaper than the units that are all built together. I've personally seen four chronos shot ... two by arrows, one by a .357 Mag and another with a 7mm mag... neither survived !! I'll take my chance with the remote type any day....

 

[CB900F]

Mugsie;

Back, before the cheapie chrono's became available, I bought an Oehler 35P. When the cheapies did come out, I didn't feel cheated either. The thing's been running, accurately, for several decades now & shows no signs of age. Well, other than having to replace a print head & that was no big expense.

With the unit, you get two chrono's. One backs up the other & tells you immediately if there's a variance that is beyond a calculated norm. It allows two, four, or eight foot spacing of the screens, depending on your convenience factor and need for accuracy. Most of the time I've gone with 4 foot spacing & have been there for years.

900F

 

[mugsie]

Thanks for the input guys, it's exactly what I'm looking for. I picked up a Caldwell ballistic, on Amazon for $74, it will be perfect for my needs, thanks for all your help.

 

[taliv]

I totally disagree with all the advice in this thread except welsh.

This isn't the 1980s. Most successful precision shooters these days use a chronograph and do not try to get dope at every distance and condition

3 weeks ago I shot on a mountain in Colorado at 10,000' asl with a 11,480' DA using a rifle zeroed at 1100' asl in TN. My friend and I lased a small rock around 1080 yards away and tested our dope. My calculator said I needed 7.7 mils. My first shot was .1 high and right. I dialed down to 7.6 and held wind and hit on the second shot. .1 at that distance is about 4 inches.

The reason rcmodels and others' advice doesn't work is easily understood when you realize that my dope for 1100' density altitude is 9.0 MILs. That's a difference of 1.4 mils! I would have missed by almost 4 and a half feet!

All chronos are not equal. If you can afford it the magnetospeed is the best option on the market hands down. It works. using a magnetospeed will save you hundreds of dollars in ammo over the long term.

Before you buy search for Bryan litz article on his test results for various chronos. You will see the differences and can make an educated decision.

 

[taliv]

the other reason is that velocity changes over the life of a barrel, particularly with calibers that people use at longer ranges. for most calibers, it goes up for the first hundred or two rounds, then gradually tapers down until end of life.

so if you go to all the trouble to shoot groups at every distance, and manage not to screw that up, (by poor marksmanship, an inaccurate or variable load, missing wind calls, etc) you will spend a significant amount of your barrel life gathering data, which will be worthless a few hundred rounds later when your velocity has changed.

and of course, your ammo can change too. unless you buy in bulk, it is likely that over the life of your barrel you will see a couple of firings on your brass, changing lots of powder or bullets, etc which will change your velocity and cause you to have to gather data again.

and if you're one of those poor souls still cleaning every 20 rounds, you're pretty well screwed because you're going to spend 4 times as much ammo trying to find data for clean/cold bores at all those distances.

or... you can strap a chrono on, shoot 5 rounds, plug your new velocity into a calculator, and start hitting targets.

 

[taliv]

read this
http://appliedballisticsllc.com/Articles/ChronographChapter.pdf

 

[WelshShooter]

Thanks taliv!

It's worth mentioning that I used the Magneto Speed Sporter which is half the price of the v3 (well, for me in the UK anyway!). I'd also like to point out that the Lapua app takes temperature, incline/decline angle and air pressure into the ballistic calculation which will have the greatest effect on trajectory. The app will not give you an elevation once the bullet is subsonic, it will only work while the bullet is supersonic.

Once the bullet leaves the barrel the rest is down to Physics there's no "magic" about it. If you have the correct information for your environment and your ammunition there should be absolutely no need for guess-work.