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Forum Index > Rifles general discussion > using a chrinograph

using a chrinograph

22 Sep 2015
@ 08:10 pm (GMT)

Brendon Greig

I know I have put a bit of this in another post but!! I am only new to reloading and I'm finding it a fascinating hobby / learning curve and are looking forward to getting Nathans book about it, my mate that is guiding me through it has a chroney, reading the instructions it suggests to get an accurate reading you should fire 10 shots through it for an average with my rifle and powder it appeared to get good groupings 1/2 inch @ 100 yard with 45 grain but at 200 yards was about 2 1/2 to 3 inches when we tested it with the chroney it was only doing about 2800 fps but worse was that it had a variance of over 100 fps so we worked the loads up to 46 grains and ended up with 3028 fps and a variance of 45 fps and my 200 yard group came down to about 3/4 inch and then going up another .3 grain my variance increased again to about 75 fps. so what I were wondering was how many people only fire a few shots over there chroney to save money on shells but end up with a very false reading either fast or slow I personally needed the range time to help my shooting and using a target at 200 yards served two purposes as well as getting my scope bang on and giving me a lot more confidence in my shooting and my gun
any thoughts on this should be of interest Cheers

Replies

23 Sep 2015
@ 01:00 am (GMT)

Eloy Vilavella

Re: using a chrinograph
In my opinion chronographs have always an error so I can shoot more for the spreads but when we move to another chronograph I might get a different answer with the same rifle, load and conditions.
So if I am working a load up a 10 shot average might not give me a lot more than a 3 shot average just to have a reference point. In then end I are going to stick with the loads that can keep tight groups and I can consistently reproduce (repeat-ability).
Of course I could spend more funds and time in getting super accurate measures but is it really that important?

In the end once I get my average or a reference number that I feel it is close enough and satisfactory still I will have to find out if all other variables are true as well, like the kestrel readings for pressure in front of me or the ballistics coefficient of the bullet that sometimes needs a correction and the wind, the darn wind.

Where I am going with this is that at some-point the actual trajectories in the different conditions are the final and only truth.

IMO adjusting my variables and math to map what is on paper whit the results on the field and keeping a detailed log is far more important than small variations in speed.
A small mistake in reading the wind or other variable has often far more impact than small variations in the speeds off the bore so I have to decide how much time I want (or have) to spend in one thing vs. another.

I use the chronys all the time for wildcat development and had several brands including one I shot myself. Right now I am using mainly the RCBS because it is compact and light and carry in my car all the time and don't worry too much if it is the best or more accurate. It just works.

I hope this helps.

23 Sep 2015
@ 09:10 pm (GMT)

Martin Taylor

Re: using a chrinograph
Well written Eloy, your advice is spot on!

Chrono's can change readings with light conditions ie sunny then cloudy during testing. I also shoot my preferred, accurate nodes across it then use the average to assist with building my charts. This is my "Fps start point" to which l then field test manipulating along with Bc just the same as Eloy.

You must confirm YOUR set up under field condition as we have discussed on other posts, any given projectile will perform to an average, but as l love to tell people "your rifle & load combination is as Individual as you are".

I find my F1 chrono to be very accurate and still an affordable bit of kit but l don't tune my loads with it, only getting it out at the end of my development as the rifle & load have the final say.
Get Nathan's reloading book and work at getting your reloading technique sorted Brendon. Lowering your ES and run out will help you heaps in the accuracy department.
23 Sep 2015
@ 09:10 pm (GMT)

Martin Taylor

Re: using a chrinograph
Well written Eloy, your advice is spot on!

Chrono's can change readings with light conditions ie sunny then cloudy during testing. I also shoot my preferred, accurate nodes across it then use the average to assist with building my charts. This is my "Fps start point" to which l then field test manipulating along with Bc just the same as Eloy.

You must confirm YOUR set up under field condition as we have discussed on other posts, any given projectile will perform to an average, but as l love to tell people "your rifle & load combination is as Individual as you are".

I find my F1 chrono to be very accurate and still an affordable bit of kit but l don't tune my loads with it, only getting it out at the end of my development as the rifle & load have the final say.
Get Nathan's reloading book and work at getting your reloading technique sorted Brendon. Lowering your ES and run out will help you heaps in the accuracy department.
24 Sep 2015
@ 01:13 am (GMT)

Warwick Marflitt

Re: using a chrinograph
Every SHOOTING CHRONY® measures the speed of bullets, arrows, shotgun & airgun pellets, paintballs, et cetera, from 30/fps. to 7000/fps. and with better than 99.5% accuracy.

So .5% at 2800fps = 14fps
24 Sep 2015
@ 01:53 am (GMT)

Mike Neeson

Re: using a chrinograph
Here's a good article on Chronographs - very technical. It also checks the accuracy of the different models. I had to read it a few times to get it into my head, but worthwhile info.
https://www.dropbox.com/s/lwvuj6llluv3kca/ChronographChapter.pdf?dl=0
24 Sep 2015
@ 02:00 am (GMT)

Mike Neeson

Re: using a chrinograph
FYI When you click on the link, Dropbox suggests you might want to sign in or register, but you don't have to - just click cancel and it should go to the article.
24 Sep 2015
@ 06:24 am (GMT)

Warwick Marflitt

Re: using a chrinograph
Mike How did you get a picture for your member profile thumb picture??? Sorry for the post Hijack guys.
25 Sep 2015
@ 12:00 am (GMT)

Mike Neeson

Re: using a chrinograph
Warwick, it tracked me down from my Battlefield 3 days. I must say I forgot how or why it worked and it took me a while to track the bloody thing down. (Battlefield 3 is sooo 2011) Turns out I set up an Avatar account on www.gravatar.com This service manages your global presence in the cyber world... for free and it tracked me down to this site! Oh well, I guess my dirty little secret is out.
25 Sep 2015
@ 12:54 am (GMT)

Warwick Marflitt

Re: using a chrinograph
Heck! Talk about Big brother watching and tracking your every cyber move! Thanks for the reply. Again sorry for the thread hijack guys.
25 Sep 2015
@ 01:22 am (GMT)

Mike Neeson

Re: using a chrinograph
There, that's better.
 

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