14 replies to this topic

[zippy1970]

Now what do I do with it ? I got a tripod & went a shooting . Ran 10rds of some of my guns through it , recording the speeds that came up .

Ironically a few of the loads came in where they should have been .

But how do I figure out the " Average " FPS ? SD ? And whatever fancy talk these are supposed to do .

I am thankful for all help .

I should be going up to Angeles Thrs if anyone can help me , has the remote button for my basic unit , a printer , can show me what all of this means and would like to have their day paid for : ) Just looking for help . Also can do it other days if need be .

The BIGGEST reason I brokedown and bought it was due to the fact I found a " Ballistics " programe that I can insert " needed data " & it gives me drop , rise , etc from 100-1k yards .


Andy

[Air Rifle Hunter]

What brand did you purchase and what model?

I own a Chrony brand chronograph and it is the Alpha model (red one). If you own a Chrony brand chronograph you push the function button on the top left of the Chrony face and it will cycle through the Low FPS, High FPS, Average FPS, Extreme Spread and Standard Deviation and then if you keep pressing it, it should show you the velocity for each individual shot.

If you own another brand, you'll need to pull out the manual and give it a once over.

[zippy1970]

Its a Chrony F1 . It is the " basic " one that Chrony sells . I think . If I bought the " remote " ( which from what most people state is PVC with a button & cable ) I can get all of that info . There is also a " cheap " homemade version that includes buying a " RCA " jack , some cable & a button .to make the remote .

But with all of that info , aside from the Ballistics program , what is it for ? 1 load had a " spread " of 42 ( took highest FPS , - lowest FPS ) others were 90 , 91 , 66 .

Does it mean I need to make all of my brass more uniform to " lower " that # or ?????? I know that having " consistant " loading data / FPS , I can rely on my shots doing the same thing, be it the 93rd , 54th or 1st shot . Is that correct ?

Honestly , I was glad I did not shoot it on the 1st day : )

Andy

[Loopdog]

Which ballistic program do you have? At some point you will need to true your MV

[zippy1970]

Right now its " Bullet Drop " , I think . Its free on Ipads or phones . It does not use elevation or air temp / humidity . You input bullet grain , B.C , FPS your running , scope to bore (1.5" is standard ) and what you zero it at .

The 1 load that I did all of the math with , the program showed I was 1/10th of an inch off . Published was +1.8 , I showed +1.7 .

But i do want to use another one , don't remember the name but my GF has it on the phone and it takes weather / temp / elevation into consideration . . its 10.00 just dont care for it at the moment .

Andy

[Loopdog]

I use "shooter" on my Droid and i like it alot..

[Air Rifle Hunter]

Its a Chrony F1 . It is the " basic " one that Chrony sells . I think . If I bought the " remote " ( which from what most people state is PVC with a button & cable ) I can get all of that info . There is also a " cheap " homemade version that includes buying a " RCA " jack , some cable & a button .to make the remote .

But with all of that info , aside from the Ballistics program , what is it for ? 1 load had a " spread " of 42 ( took highest FPS , - lowest FPS ) others were 90 , 91 , 66 .

Does it mean I need to make all of my brass more uniform to " lower " that # or ?????? I know that having " consistant " loading data / FPS , I can rely on my shots doing the same thing, be it the 93rd , 54th or 1st shot . Is that correct ?

Honestly , I was glad I did not shoot it on the 1st day : )

Andy

That is a bummer that they don't include the function button on the F1 model. It doesn't make much sense to me.

I don't know all that much about loading, but I would think that if the bullets are all the same weight, shape, size and you are using the same measurement of powder with the same brass, your numbers should come out more consistant than that. I typically use my Chrony for tuning my air guns and for knowing what velocity they shoot at because their trajectory is so much more arced than a powder burner's. However, I have shot my .22 Marlin 81-DL-S-L-LR over it using Remington Golden rounds and most of the velocities were very consistant (around 1270 to 1277) and didn't vary much from shot to shot.

Perhaps someone with more loading experience and knowledge will be able to provide a better and more informative response from their personal experience.

[ratassassin]

I've seen variations of as much as 80-100 fps in some of the same handloads so don't make yourself too crazy. Just try to find a load that is both accurate and consistent in velocity with the lowest extreme spread possible. Then take the average muzzle velocity and go with that.

In my experience, ballistics programs can fail to accurately predict the actual trajectory for your particular ammo. Even after running the program, you'll want to confirm your actual trajectory at various distances to see if the program's chart is accurate. Ultimately, there's no substitute for knowing the actual trajectory of your particular ammo in your particular rifle. Once you know some of the actual trajectory data, play with the program's parameters until it reflects those known data points. Then the program should be able to accurately predict your trajectory at the rest of the ranges.

[zippy1970]

What do I do , if the Chronograh gives me FPS that are slower than the published data ?

My .243 load , Winch brass , WLR primer , IMR 4064 at 34.9 grains , Sierra 85grn BTHP with a COAL of 2.675" .

Chrony says that it has an Average FPS of 2700FPS (10 shots , 2675 slowest , 2744 highest ) . Sierra shows 33.7 of IMR 4064 as Min at 2800 FPS .

Is that what they mean when its said " load data for test gun only , your gun / load / data may differ ??????

I still need to shoot my .308 loads tto . Wonder whats going to happen there . I use FederalGM & Lapua brass , everything else dup . But the Lapua seems to groups better .



Ratassassin , I don't / won't rely on the " data " from the site until I comfirm it either .

Andy

[Frank]

Andy, as mention many times, ALL &/or ANY reloading manuals are guidelines ONLY. With that in mind, I have seen as much as 300 fps variances from not only "book" velocities, but also from one rifle to the next with the same load & barrel lengths. EVERY rifle is different and can, but not always, produce w i d e velocity differences. Seen it too numerous of times. Along with accuracy results. IE; one rifle loves a certain load, while your partner's rifle hates it.

And yes, I have to agree that your 4064 load is slower than "book" speeds. Which, again, may or may not mean a thing. Semi-normal in other words... whether below or above book listing.

A couple questions... 1). Where did you get your 2.675" O.A.L. from? Industry standard is 2.710", with many rifles likely accepting a round longer than that with the 85 gr bullet. Unless it is too long for the magazine or chamber of course. Also, a longer round, MIGHT produce higher velocity.

2). What is the length of your barrel? If shorter than 24", that would also produce less velocity. Many manuals use a 24" barrel for their load tests. All my bolt action center fires wear 26" barrels... being a speed junkie that I am!

As far as what to do about it goes... You've only just begun, so of course more load development and testing for starters. Increase the OAL, IF your chamber and magazine allow it. Make sure your chrony is set up right.

After a bit more testing & you are still getting the slower than expected or wanted results, only 2 things can be done. First is, Nothing... 2nd, (which is what I would do, but most folks wouldn't) is sell it and buy another rifle or replace the barrel with a custom one. Either selling or replacing may, or may not, resolve your velocity problem though, but may improve accuracy... at least consistently wise, along with potentially liking a wider variety of loads.

Anyway, hang in there, it will come, and Good Luck

[tawnoper]

What do I do , if the Chronograh gives me FPS that are slower than the published data ?

Smile and realize your Chronograph is doing it's job.

If it's not showing pressure signs I'd bump up the powder charge a bit and try again.

[zippy1970]

Frank : Sierra calls for a 2.650" coal . I do not have all of my orig data as this was my 1st reloading experiance more than 10 years ago . I may have used my Chamber gauge , measuring out until it was just off the lands . It is accurate as heck , when I do my part . And I single shoot it .

As far as speed goes , I ran it up to 35.8 , maybe 36.0(?) and the groups got larger . So I said screw it , left it alone .

Trying to postpics but " too large " . Not my grouping . I can cover it with a dime . Will have my GF try later .

Andy

[Divernhunter]

Those little electronic boxes will really open your eyes. You will often get lower speeds. You need to test a min of 5 rounds and 10 is better to get results that mean much. I was testing some loads for my Africa hunt yesterday and the low end and middle 338win mag loads gave tight groups of 5 shots but the hot load opened up. This sometimes happens. In another rifle chamberd for a different cartridge(25-06) the hottest load printed best. Often the load with the lowest SD will be most accurate but I have loads that do not have the lowest SD which are more accurate than the lowest ones. Every rifle is different. As long as the speed is enough for the bullet to do its job you will be ok. The first time I tested my all-time favorite 30-6 load I was shocked to see how slow it was compared to "the book". I started to scramble to get a hotter load untill I realized it was a load that had killed several pronghorns and well over 100 deer with no wounded animals and all but one of them were one shot kills. The more you use it the more you will understand it and what your loads are doing. It can also tell you some reasons why a rifle all of a sudden starts shooting like a shotgun when it use to be very accurate. I have this problem with a 223 that I have shot for many years. I tested the old, new and newer loads over the chrno Sunday and found the problem Old load still shoots, Newer load has a higher ES and SD and the newest load had a very high ES and SD. Time to futher test the loads and tweek them until I can get good results with the faster newer loads or just go back to the tried and proven load which is slower and slower than the book ----3200 vrs 3400fps

[Frank]

Well, I'll try this again... PC trouble.... again! Ugh!

Andy, often times when someone "ran up" a load, they usually just ran it up to the mid range level of a particular load. 35-36 grs is mid level in some "manuals" in that caliber & bullet weight. But of course, proof is always in the pudding.

Anyway, what typically (but not always) happens when a load is worked up to that mid level, groups often times do in fact get larger, and I believe is what happened in your case. It is not until we get close to, or at, or even above so called "book" max, that the groups get smaller again. Just a matter if someone wants to go through all that or not. I suspect most do not, and is perfectly fine of course. Especially if they are already getting great accuracy with the lighter loads.

Hang in there and Good Luck

[GSH]

When I first loaded for my 300 Win Mag, I started near the max., just happen to get a load that produced less than moa with no signs of over pressure and that is where I quit. Sometimes your lucky.