Cronograph's ??

FEENIX

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Ouch. Oweeee.

Poor FEENIX. Poor, poor soul. More than three hours of stewing and brewing, and that's your best shot?
Been 10 hours since your last Post so here, let me hep ya along; go ahead and type "Did not." Then I type "Did so."

Bowing.gif


Are you the "post watch-er"?

Sorry it took me that long, my friend and I helped a rancher friend thin down the gophers! After a quick break when I got home, I took my dog for a hike then to the dog park for some quality time with my 4-legged buddy.

Yes, I am poor but not my soul ... I am not the one that belittle people if it does not meet your self imposed standard.
 

kcebcj

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West Central Idaho
Original Poster
I dont want to spend a lot of $$ ..............What is your experiance with Cronograph's .....are they accurate and consistent, what problems have you had.
It would be nice to know what my exact velocity is.....................

Thanks
There are 3 chronos I would consider owning. Ohler 35, CED Millenium II and CE ProChrono Digital – the best value by far being the last one though the IR sky screens that are optional for the CED Millenium II are nice if you like to keep shooting as it is getting dark. I don’t like anything hanging on the gun barrel as the added weight will shift point of impact and “tune” accuracy to make it better or worse.

My best chrono trick - use a boresite laser to align it. Point your rifle at the target and insert a boresite laser. Put clear plastic targets in each sky screen that are marked with a grid. When the laser hits the grid in both screens in the same place it is aligned. Do this and it will be aligned in both the pitch and yaw axis and will read as accurate as it can. Don’t do this and it usually will be misaligned which will cause it to read low in proportion to the misalignment. Also, measure the distance from muzzle to the center of the chrono. I always put mine at 4 yards. After shooting, correct velocities back to the muzzle using bullet BC and you ballistics program.

For alignment I do almost exactly what Engineering 101 states above. I have a permanent shooting bench with a mount for the chrono that is 20 feet exactly in front of the bench set in concrete. On the stand pipe for the chrono I installed a adjustment mechanism so I can adjust up and down and side to side. I have two center marks on the plastic inserts and after the rifle is set in the bags on the bench and on target I simply look back at the rifle through the inserts and align the chrono dead nuts with the muzzle so the bullet passes through the center of the chrono perfectly. I used a laser boresite when building the mount to get it located properly but now only sight back to align.

The chrono is a CED M 2. I don't know how accurate it is but sense setting everything up I have taken the velocity numbers ran them in Exbal and put the bullet on the paper at my 800 yard target many many times. Once that is done I know the velocity is somewhat close then I can fool with the BC and velocity to prove the load.

So yeah I think a chrono is a good investment and set up properly it will do as designed. Exact velocities I doubt it but gets you in the ball game and speeds up the process.
 

FEENIX

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Trickymissfit

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at one time I had two steel rods that would clamp onto the chrongraph's nounting plate (light bar). Each one had a small round ball threaded onto the end. Simple and crude but it worked for aligning the chronograph. Later on I used the same method I use for bucking in a laser, and this actually took longer to do than the older method. The idea of printing out a grid setup on clear acetate (you need a laser printer) sounds like a much easier idea todo. I like for the bore center to be about 6" above the cells during travel as the bullet will climb as it travels thru the chronograph, and not down. At the range I drove gutter spikes into the ground out front of the bench. (I think I have five of them out there now on five different lanes. This makes the distance thing easier to measure as your already there. I carry to torpedo levels with me in the box, and this makes things go much quicker.

I rarely get a no read on a shot (maybe six or eight total as long as I've had the unit). My ES is more often very tight (often around seven to eight). The idea of using a laser bore sighter is probably as good of an idea as I've heard over the years.

I have an idea on how to find out if said chronograph is accurate (it it will read low enough) using one of the few constants that never changes. But have not tried it out, let alone took the time to figure the correct velocity before checking it out.
gary
 

FEENIX

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Gary,

I know you and I had this discussion before ... once your idea is materialized, can you make it affordable for poor guys like. :D

Ed
 

Trickymissfit

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Gary,

I know you and I had this discussion before ... once your idea is materialized, can you make it affordable for poor guys like. :D

Ed

I think the total cost would be well under ten dollars! And zero if you had access to some junk parts in an auto repair shop. I have to dig out one of my physics books to figure the actual velocity, but the rest is kinda easy.
gary
 

phorwath

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If you where limited to the pistol range (200-) for load development, then you would have no choice but to use a chrono, but if that is the case: you have no business hunting at long range if you can't train at those ranges.

Never said anything about not being able to shoot and develop field measured dope at long range. I'm saying it's not a readily available option for me and others to shoot rocks at 1000 +yards at the variety of elevations and temperatures we plan to hunt.

Of course a person has to shoot at long range. It's part of the load development process for any serious long range hunter. It's nice if a person can shoot and measure long range drops at the same location, under the same environmental conditions, where the trophy game animal presents. As mentioned earlier, it's even nicer if I can set a target up and practice where the animal will be standing sometime after taking the practice shots and taking the target down. For many of us, that's not as convenient as it is for others. I don't often get the opportunity to target practice in the mountains where I hunt in Alaska.

Your methods may work well out to 7-800 yards under the conditions you practice and hunt. But the intrinsic errors of guesstimated MV and BC will become more troublesome at longer yardages and under variable elevations and environmental conditions.
 

D.ID

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Never said anything about not being able to shoot and develop field measured dope at long range. I'm saying it's not a readily available option for me and others to shoot rocks at 1000 +yards at the variety of elevations and temperatures we plan to hunt.

Of course a person has to shoot at long range. It's part of the load development process for any serious long range hunter. It's nice if a person can shoot and measure long range drops at the same location, under the same environmental conditions, where the trophy game animal presents. As mentioned earlier, it's even nicer if I can set a target up and practice where the animal will be standing sometime after taking the practice shots and taking the target down. For many of us, that's not as convenient as it is for others. I don't often get the opportunity to target practice in the mountains where I hunt in Alaska.

Your methods may work well out to 7-800 yards under the conditions you practice and hunt. But the intrinsic errors of guesstimated MV and BC will become more troublesome at longer yardages and under variable elevations and environmental conditions.

I was not saying you had said anything about only shooting close range, I was just saying.
Now for the rest, You are assuming my bc is off......ok I have bean trusting Brian's data on that and have no reason to doubt it or method to research it beyond what he has done, since apparently you do, I would love hear how that is done .
.
And your assuming my velocity is off " intrinsic errors of guesstimated MV" Who said anything about guesstimating?
I am running my data threw the same software everyone else is using and trusting, there is no guess work involved.
I am using gravity tested in reality and filtered threw the same software, your using the read out on the chronograph and filtering it threw the same software. How could you possibly conclude that yours is any more accurate than mine?
In fact mine has already bean proven when I run my solutions threw that same software.
 

D.ID

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It just occurred to me that perhaps my system was not elaborated on adequately.
I am using ballistic software, I am dependent on pre established bc numbers just like everyone else.
I am not running on just drops and expecting that to work in a variety of conditions. I am just using known conditions and gravity instead of known conditions and a chronograph for my initial base line.
Both limited by and dependent on ballistic software to develop firing salutations for what ever conditions we are in.
The only difference is an led screen or gravity to establish initial base line. NO GEUSS WORK.
 

phorwath

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You're presuming your measured drops based at various yardages run backwards through a ballistics program provides you with a MV as accurate as my measured velocity over triplicate chronographs. This involves at least three immediate sources of potential error.
1) Shooter error at long ranges. You may be dead nutz on or you may not be. Could be a 12:00 or 6:00 wind. At long ranges like 1000 yds, if you're not including coriolis drift for an eastward or westward shot, you could automatically have several inches of error built into your measurement. An error in your drops for these or any other reasons will lead to an errant MV from a ballistics program, even if the BC of your bullet is exactly correct.
2) Your bullet BC out of your rifle may not be the same as it was out of Bryan Litz's rifle. There's a scholarly fellow that occasionally posts on this Forum that does a lot of research for a living, and he's documented significant differences in BC from the same bullet out of different rifles. First name is Michael. Seems he does some work under contract for the military.
3) Error in the ballistic program. No all ballistic programs are built equally. Dunno which one you use. Some don't even incorporate coriolis.

So you can fudge BC and MV with any ballistics program and come up with a match for your measured drops at any single yardage. Doesn't mean the BC and MV are accurate. Just means you tweaked two input variables in a mathematical equation to got the drops you measured. Take faulty (yours may be perfect every time and good for you) MV and BC values and re-apply them with a ballistics program under different environmental conditions, and bad data input will result in bad data output.

I contend measured MV from a decent chronograph, properly operated, with a proof channel to detect bad velocity data, is a more accurate method of determining MV than back calculating MV through a ballistics program based on measured drops. If you want to disagree, that's fine and your option.

On a second topic, there's a good reason Ken Oehler designed the proof channel into his 35P chronograph. He learned early on that every chronograph, even those of his own manufacture, will occasionally record and provide a faulty velocity. The proof channel or a second chronograph run in tandem, allows these faulty data to be identified and discarded. I experienced this problem and learned this lesson myself, as soon as I started running two chronographs in duplicate. Since I use chronographs to identify loads with acceptable low ES and SD during my load development, it's important to me to be able to identify ES and SD accurately. Otherwise I throw out a potentially good load, based on a faulty chronograph velocity, wasting time and money in the process. This is the primary reason I say anyone that makes claims about the quality, accuracy, and precision of their chronograph based solely on the singular velocity data their chronograph records, is operating semi-blind, and possibly, without knowing it. And FEENIX, if you don't accept this premise, or care about it, good for you. It is important to me, the way I use my chronographs. You dismissing the significance doesn't negate the facts. Just means it's not important to you, or for whatever other reason, you could care less.
 

D.ID

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Once I have my base line established, I shoot all over with positive results. ES is obvious at distance. Groups fired repetitively can eliminate shooter error and needs done anyway to develop a load, test it's consistency and stay in practice.
Agree that not all software is equal and the bc discrepancy exists no matter how you measure your speed.
I am limited to a few long range rifles and about 1300yrds (the limit of my range finder) but my numbers match my scope with my rifle and my set up, using the software I use. My numbers are solid and you can't beat them because they are solid.
You can spend more, put more rounds down range, have more stuff in your range bag but you can't beat the math because it adds up.
A 1/4moa remington is not better than my 1/4moa savage. They are two different means of doing the same thing, but in all likelihood one costs more than the other. Same results and same limitations.
 

Wachsmann

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The best inexpensive chronograph for me has been the Pro Chrono Digital which I am still using. Had one of the Chrony masters beta series and I could only get it to work about a third of the time. I was very sore displeased with it. The Pro Chrono Digital worked the first time out of the box. Could get simialr results between the two within 10fps but for every good reading on the Chrony I probablly had 15 good on the Pro Chrono Digital. I used it to set up my 6.5x284 turret and it has been on out to 600yrds. For as my shooting i'm about .75 to .7 moa at 600 so I'm shooting around a 4inch group with the turret out to 600yrds. I also for a test ran the turret to 850 yards and pinged the metal target but not exactually sure how close to center...I was just testing to see if I could hit it with the come ups. So for ar the Pro Chrono Digital I like it alot. Also read the review at Midway USA's web sight. Several reviews with almost all of them being positive. I set mine up about 10 to 15 feet away from the rifle and it seem to work great. Hope this helps.
 

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