What is going on here???

[JRWALLSIII]

Well to my new GAP out today for some load development. I used Nosler 280 Ackley cases/CCI benchrest primers/180 Berger VLD. All loads were 56.5 grains of RL 22. The only diffrence in between loads was the seating depth of the bullet. After I picked the best load out the bunch(1/4 MOA at 100 5 shot). I went back and loaded 20 more and decided to run some the the coronograph. Here is where the problem starts. The velocity readings that I was getting was a spread of 110 fps. And the velocity that I was getting was way higher than expected. There was absolutly NO PRESSURE SIGNS. The velocity ranged between 2963 t0 3075. I have never seen a spread this big. Any ideas? Bad Chrono?

 

[Victor N TN]

Re: What is going on here???

What brand / model of chronograph are you using?

 

[LSUbeatUby40]

Re: What is going on here???

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: .257</div><div class="ubbcode-body">Well to my new GAP out today for some load development. I used Nosler 280 Ackley cases/CCI benchrest primers/180 Berger VLD. All loads were 56.5 grains of RL 22. The only diffrence in between loads was the seating depth of the bullet. After I picked the best load out the bunch(1/4 MOA at 100 5 shot). I went back and loaded 20 more and decided to run some the the coronograph. Here is where the problem starts. The velocity readings that I was getting was a spread of 110 fps. And the velocity that I was getting was way higher than expected. There was absolutly NO PRESSURE SIGNS. The velocity ranged between 2963 t0 3075. I have never seen a spread this big. Any ideas? Bad Chrono? </div></div>

were they still grouping a .25" at 100 yards? If so then sounds like a bad chrono to me..

 

[JRWALLSIII]

Re: What is going on here???

chrony is a F-1 Shooting Chrony.

 

[LSUbeatUby40]

Re: What is going on here???

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: .257</div><div class="ubbcode-body">chrony is a F-1 Shooting Chrony. </div></div>but were you still shooting 1/4 MOA? I find it hard to believe you could still get 1/4 MOA with 110 fps variations..

 

[JRWALLSIII]

Re: What is going on here???

The rifle has a 26 inch 1/8 twist tube. I was using Nosler load data for a 175 grain bullet which they used a 24 inch barrel and were gettin 2808 fps. Heck I was hoping for 2850fps. 2963 being on the low scale of what I read is alot higher than expected.

 

[JRWALLSIII]

Re: What is going on here???

Go figure. I backed it out to 200 and was stillshot a 1/2 group (5 shot). It really makes me think the Chrony is telling a lie.

 

[JRWALLSIII]

Re: What is going on here???

Have you ever seen a spread so large?? The charge wait was exact on my end.

 

[LSUbeatUby40]

Re: What is going on here???

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: .257</div><div class="ubbcode-body">Go figure. I backed it out to 200 and was stillshot a 1/2 group (5 shot). It really makes me think the Chrony is telling a lie. </div></div>

okay so you still shot 1/4 MOA.. I'de say your chrony is having a bad day cause theres no way you shoot 1/4 MOA with velocity spreads of 110fps..

 

[JRWALLSIII]

Re: What is going on here???

I agree. the spread is crazy and the velocity is way to high.

 

[Victor N TN]

Re: What is going on here???

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: .257</div><div class="ubbcode-body">chrony is a F-1 Shooting Chrony. </div></div>

In my opinion part of the problem. That particular brand will give you a general idea to go by. But accuracy and repeatability isn't their strong suit.

What are the pressure signs showing? How did the ammo group? Treat it like you don't have a chronograph. If it groups well and doesn't have any high pressure signs, go with it.

 

[JRWALLSIII]

Re: What is going on here???

Thanks, I will load some more up and shoot it with the same load again soon.

 

[skeetlee]

Re: What is going on here???

My f1 gets a little goofy when the sun is really shining, even with the shades installed.

 

[knockemdown]

Re: What is going on here???

Sounds like inconsistent ambient light to the screens is skewing your #s...

 

[johngfoster]

Re: What is going on here???

At shorter distances variance in MV will not show on paper that dramatically. If this load still shoots 1/4 MOA at 500+ yd, then you are onto something there.

 

[lanwickum]

Re: What is going on here???

Been through 3 chonos now. I now have a Oheler 35p because of that problem. At least it give me 2 reading in 1 shoot as a proof. Only way I trust em. Other wise, just a tool. The target is the only thing that tells the truth.

 

[Greg Langelius *]

Re: What is going on here???

Velocities can read high and erratic if the screens are too close to the rifle. It may help to move the screens out to around 20ft from the muzzle, otherwise the muzzle blast can interfere with an otherwise reliable reading.

Greg

 

[MagMan]

Re: What is going on here???

FWIW my F-1 reads 112 fps faster than my CED M2. It has always given me consistent readings, though they were fast.