Thread: Chronograph advice

Greetings All,
My chronograph is an Oehler 35P that was bought in 1991. It was expensive but I won't need another one. I run a 4 foot screen spacing wihch gives consistent results and the three screens measure velocity twice to alert you to a dud reading. It is still sensitive to light conditions so I pick my days for chronographing, bright overcast being the best. Two of the most important uses for it is validating load data and estimating pressure. If you are getting close to max velocity from the load data then your pressure is likely to be close to max as well.
Regards Grandpamac.

Originally Posted by grandpamac

If you are getting close to max velocity from the load data then your pressure is likely to be close to max as well.
Regards Grandpamac.

^^^^^^this^^^^^^^
I like a lot of others when I first started reloading thought I was doing great things because I could get better Velocities than book max without getting pressure signs, In reality in some cases I was flirting with disaster as velocity is a very good indication of pressure and a sign often overlooked.
just cause you don't get a sticky bolt or ejector stamp doesn't mean you aren't close to or over pressure.

Originally Posted by dannyb

^^^^^^this^^^^^^^
I like a lot of others when I first started reloading thought I was doing great things because I could get better Velocities than book max without getting pressure signs, In reality in some cases I was flirting with disaster as velocity is a very good indication of pressure and a sign often overlooked.
just cause you don't get a sticky bolt or ejector stamp doesn't mean you aren't close to or over pressure.

A friend with a 6.5-06 worked up to the old ADI book max of AR2213 (a little faster than AR2213SC) powder with the 140 grain projectile. Absolutely no pressure signs at all but not one case would hold a primer ever again. Current ADI/ Hodgdon book max is 50 grains for the 143 grain ELDX. Book velocity is 2,763 but in a different rifle of same calibre the 140 grain Hornady soft point barely reaches 2,700 fps and it took 52 grains to reach 2,780 fps. Cases last well with that load in Winchester cases, Without a chronograph I would not have known where to start.
Regards Grandpamac.

Looking at the replies, I should have mentioned another couple of things up front.

I have a self-imposed limit of 300y because the 243 shoots pretty flat to there and I'm concerned about effectiveness at longer ranges. And my shooting ability.

As I'm planning on shooting pretty flat I want a chrony for gauging pressure not so much for drop charts. I am a beginner reloader and am not confident at recognising pressure signs, I would feel more confident using a chrony I think.

Finally we're lucky to have the 110y RRGC range here in Palmy but I don't have access to a longer range. The good thing about the RRGC range is that it is covered and pretty consistent light (shade) so hopefully that will mitigate some of the issues with light effecting the chrony.

Again apologies if I'm a bit slow I'm just trying to learn how to reload and am still at the theory stage not had a go yet.

Originally Posted by Moutere

A cheap chrono will most likely give you average data anyway.

I was planning on shooting 3 shot groups and averaging the velocity is that what you mean?

Originally Posted by Micky Duck

ok I will say it.....
you using a .243 good on you.

so you are going to be shooting out to?????300-400 yards...... so what use is chronicgraph information to you???? you arent going to be likely shooting far enough to need to dial up so you arent going to need velocity to last 10fps

if you sight in 3" high at hundy...going to be point and shoot out to somewhere around 250 and spine hold at 300.... its only going to take a couple of rounds to verify your drops...which you will do anyway after using chronograph.

near enough is good enough for ballistic chart to give you your drops give or take an inch.....
but Im a bush hobbit who doesnt shoot past 350 so what would I know...

You're dead right, as I should have said at the beginning I don't want it so much for drop charts, more for gauging pressure.

Originally Posted by dannyb

Also knowing your velocity will give you a good idea on if your close to max pressure especially if you aren't seeing typical pressure signs or are too inexperienced to identify them.

This is exactly what I want one for.

Originally Posted by Grasshoppa

https://www.amazon.com/Caldwell-7200.../dp/B00HTN5DTE

cheeeeeeeep

That is cheap. Will probably go with that if I go ahead.

Originally Posted by grandpamac

Greetings All,
My chronograph is an Oehler 35P that was bought in 1991. It was expensive but I won't need another one. I run a 4 foot screen spacing wihch gives consistent results and the three screens measure velocity twice to alert you to a dud reading. It is still sensitive to light conditions so I pick my days for chronographing, bright overcast being the best. Two of the most important uses for it is validating load data and estimating pressure. If you are getting close to max velocity from the load data then your pressure is likely to be close to max as well.
Regards Grandpamac.

Originally Posted by dannyb

^^^^^^this^^^^^^^
I like a lot of others when I first started reloading thought I was doing great things because I could get better Velocities than book max without getting pressure signs, In reality in some cases I was flirting with disaster as velocity is a very good indication of pressure and a sign often overlooked.
just cause you don't get a sticky bolt or ejector stamp doesn't mean you aren't close to or over pressure.

Sums it up well.

Sounds like your on to it then, an optical chrono will be close enough to give you velocity in regards to pressure, just remember that most load data published in books is based on a 24" barrel so if yours is shorter take that into account.

Originally Posted by dannyb

Sounds like your on to it then, an optical chrono will be close enough to give you velocity in regards to pressure, just remember that most load data published in books is based on a 24" barrel so if yours is shorter take that into account.

Thanks, I'll go with an optical one then.

I haven't figured out the load data yet, am struggling to get a match for my projectiles/powder. Will cross that bridge eventually.

tell us projectiles and powder type....most of us have 3-4-5 reloading manuals plus online sources and love nothing better than to help out by finding loads that are published and pointing you towards them.
the mighty EBRG/Twoforfree does a stirling job if you stick to what its good at and know your limits.
some of us love to poke shit at it but secretly admit it would do 97.5% of anything we do shooting wise just as well......shhhhh dont let 257WEATHERBY know I said that of I will never hear the end of it.

Originally Posted by Cigar

I have an early Prochrono (before the digital model) and a Magnetospeed. The Prochrono sometimes gives some weird readings, mainly on sunny days when the light is coming from an angle, but when I used both together, two of the shots were within 1fps, if I recall correctly the third shot had a 30fps difference.
For your use, I would try to borrow one, or team up with a forum member who has one.

Further to my 3 shot test using both the Prochrono and Magnetospeed together, I have found some other data, averages of 3 or more shots from the same batches of reloads, but not the same shots, and sometimes not even on the same day.
Magnetospeed Prochrono Difference
2368 2375 +7
2987 2980 -7
3107 3094 -13
3138 3122 -16
3168 3151 -17
3187 3176 -11

None of those differences are significant if you're only shooting to 300yds

If you mount your Chrony in a box with artificial light for the Chrony sensors, you mitigate the only problem of the light detecting chronograph and get consistent readings because the light is consistent. The Chrony is so handy, so cheap, and so useful for developing loads. Best money I ever spent.

Originally Posted by Micky Duck

tell us projectiles and powder type....most of us have 3-4-5 reloading manuals plus online sources and love nothing better than to help out by finding loads that are published and pointing you towards them.
the mighty EBRG/Twoforfree does a stirling job if you stick to what its good at and know your limits.
some of us love to poke shit at it but secretly admit it would do 97.5% of anything we do shooting wise just as well......shhhhh dont let 257WEATHERBY know I said that of I will never hear the end of it.

I'm finding myself in that camp as well, realizing the 2forfree would be quite a good addition (or even replacement, gasp) for other calibers especially for teaching others, children and wives (or husband's )

Hey @cbfb I'm in Palmy as well, if you want to have a yarn about reloading I'm usually floating around.

Sorry for the late reply.

Originally Posted by Micky Duck

tell us projectiles and powder type....most of us have 3-4-5 reloading manuals plus online sources and love nothing better than to help out by finding loads that are published and pointing you towards them.
the mighty EBRG/Twoforfree does a stirling job if you stick to what its good at and know your limits.
some of us love to poke shit at it but secretly admit it would do 97.5% of anything we do shooting wise just as well......shhhhh dont let 257WEATHERBY know I said that of I will never hear the end of it.

Thanks that's good to know, I will ask because some of the powder/projectile combinations I'm struggling to find load data for.

I am happy with the 243, it's my only centrefire now but I've owned a few calibres and this is my favourite. It's cheap to run and the recoil/noise with a suppressor is minimal. As you say just need to be aware of the limitations.

Originally Posted by Cigar

Further to my 3 shot test using both the Prochrono and Magnetospeed together, I have found some other data, averages of 3 or more shots from the same batches of reloads, but not the same shots, and sometimes not even on the same day.
Magnetospeed Prochrono Difference
2368 2375 +7
2987 2980 -7
3107 3094 -13
3138 3122 -16
3168 3151 -17
3187 3176 -11

Originally Posted by 6x47

None of those differences are significant if you're only shooting to 300yds

Great to see some real-world numbers, I think for what I need the Prochrono would be fine.

Originally Posted by rupert

If you mount your Chrony in a box with artificial light for the Chrony sensors, you mitigate the only problem of the light detecting chronograph and get consistent readings because the light is consistent. The Chrony is so handy, so cheap, and so useful for developing loads. Best money I ever spent.

Good tip, I'm hoping with the range being covered and pretty shaded I should be safe but I'll bear this in mind.

Originally Posted by Rated M for Magnum

I'm finding myself in that camp as well, realizing the 2forfree would be quite a good addition (or even replacement, gasp) for other calibers especially for teaching others, children and wives (or husband's )

Ha ha it's the calibre the whole family can enjoy.

That would be good if you don't mind me running a few questions past you. I've got some more reading/watching I want to do to get my head around it but will flick you a PM.

You're shooting a .243 right? Here's a tip, contact targex on here and try some 70grain flat base projectiles. They cloverleaf at 100m in my howa when everything else ive tried gets flung all over the page.

Originally Posted by T.FOYE

You're shooting a .243 right? Here's a tip, contact targex on here and try some 70grain flat base projectiles. They cloverleaf at 100m in my howa when everything else ive tried gets flung all over the page.

Will bear in mind however I've got quite a collection of projectiles to try. Also looking at a bit heavier 85+ gn to use on deer.

Would be interested to know what 6mm/243 projectiles go well on deer for people.