Range Report Conflicting data - please assist

[bottom_gun]

All,

Could use a little help on this one. I am developing a load for my 223 using the 75g AMAX. I did the ladder test and had best results for 25.0 grains of Varget. After that, I experimented with seating depth from 2.40" to 2.43" COL and have conflicting data. The best vertical spread has a higher ES and SD. Please advise, thank you in advance.

All loads were with 75g AMAX over 25.0g Varget in Win brass and Rem 7 1/2 primers. All groups were shot at 400 yds with very little wind. Targets and measurements shown below.

 

[TEAMSENDIT]

Re: Conflicting data - please assist

how do you measure the powder charges? that alone could give you that much inconsistency?

 

[Bigwheels]

Re: Conflicting data - please assist

What chrony are you using? I have 2 shooting chrony's, & set them up in line, & ignore any readings that aren't the same. Otherwise I don't trust them. As they say, the bullets don't lie, but chrony's do.

 

[mjh30]

Re: Conflicting data - please assist

Bottomgun, I like target two, low es/sd, vertical isn't that much, but as Jeff says chronos sometimes lie, but thats an extreme difference 8.46/3.31 to 50.15/20.71 to 114.3/45.92. The last match I was at some of old timers stated that they were loading 15-20 of each when testing, to eliminate our error. Seems to make sense, but you have some promising results there.

 

[doc76251]

Re: Conflicting data - please assist

I'd say catch up with Rob down at the fire station and have him check you form and technique. You won't find a nicer guy and you work in the same place.

I'd hazard a guess you are having breathing issues or butt stock position issues. The butt stock issues will give you a disparity in ES and the breathing will give you the vertical you are looking at. Of course all this goes out the window if you are using iron sights in which case, ROCK ON!!!

Cheers,

Doc

 

[DrGiggles]

Re: Conflicting data - please assist

I would reload it the same and re shoot the entire string.

 

[bottom_gun]

Re: Conflicting data - please assist

Thank you all, and if anyone has any other advice, please share.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TeamSendIt!!!</div><div class="ubbcode-body">how do you measure the powder charges? that alone could give you that much inconsistency? </div></div>
Powder measured using RCBS 750.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bigwheels</div><div class="ubbcode-body">What chrony are you using? I have 2 shooting chrony's, & set them up in line, & ignore any readings that aren't the same. Otherwise I don't trust them. As they say, the bullets don't lie, but chrony's do. </div></div>
Data from Chrony Master Beta.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: doc76251</div><div class="ubbcode-body">I'd say catch up with Rob down at the fire station and have him check you form and technique. You won't find a nicer guy and you work in the same place.

I'd hazard a guess you are having breathing issues or butt stock position issues. The butt stock issues will give you a disparity in ES and the breathing will give you the vertical you are looking at. Of course all this goes out the window if you are using iron sights in which case, ROCK ON!!!

Cheers,

Doc </div></div>
All shots were from bipod with rear sandbag. I tried to minimize my inputs to that part of the equation.

Rob is one good dude. He showed me the range out here, assisted in fast-tracking my membership, and took me to Black Hat last weekend for my first tactical competition. I can't thank him enough for all his help. My time here is running short, but I will definitely try to get to the range with him again before I leave and learn as much as I can.

 

[jbailey]

Re: Conflicting data - please assist

Is this for a bolt gun or gasser?

Gassers are tougher to get good ES out of.

Also, how much time between shots? If you are quickly putting rounds down, ES will go to hell.

I don't trust Shooting Chrony, so you might want to borrow another one and redo the test.

Sounds like you are deploying - if so, thanks for your service and stay safe out there!

 

[bottom_gun]

Re: Conflicting data - please assist

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JamesBailey</div><div class="ubbcode-body">Is this for a bolt gun or gasser?

Gassers are tougher to get good ES out of.

Also, how much time between shots? If you are quickly putting rounds down, ES will go to hell.

I don't trust Shooting Chrony, so you might want to borrow another one and redo the test.

Sounds like you are deploying - if so, thanks for your service and stay safe out there!

</div></div>

It's a bolt gun, Savage model 12 BVSS in a McRee's stock. Time between shots was not slow, but also not rapid fire, and I waited several minutes between each string. What chrono do you recommend? I will be back on a sub soon, should be my last sea tour before retirement. I appreciate the opportunity to serve.

 

[jbailey]

Re: Conflicting data - please assist

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bottomgun</div><div class="ubbcode-body">
What chrono do you recommend? </div></div>

I don't know, just not the Shooting Chrony. I have stacked them before and I never get similar results. I guess I would repeat what was said above "Chronographs lied; paper doesn't"

 

[Killshot44]

Re: Conflicting data - please assist

For $200 the CED Millenium II is very nice. Wired remote with lots of display features and a simple USB connect to keep your data in Excel for tracking development.
Damn thing will even announce shot velocity audibly if you want it too.

Haven't had any problems (yet) with weird numbers mid-string or noticeable fluctuations over the course of a few hours with daylight changing from sun to shade.
The rack and screens are sturdy but this means you need a good, solid tripod, especially if it's windy.

Captain Obvious says to be sure you measure and set up your muzzle to 1st screen distance <span style="font-style: italic">exactly </span>the same from session to session, otherwise.............no bueno.

 

[ctressler]

Re: Conflicting data - please assist

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bigwheels</div><div class="ubbcode-body">the bullets don't lie, but chrony's do. </div></div>

I like that