6.5 PRC Ballistics - drops don’t match ballistics chart

[Mram10us]

Your POI shouldn't change if you change bags, bi pods, etc etc. If it changes with bi pods then you have to much flex in your stock and it's touching somewhere. Anything else is poor fundamentals and poor recoil management. Are you using the TMOA reticle as hold overs? If so are you on the correct magnification? When you dial, are you sure you are using the center cross hair? Is all your data entered in the solver correct?

I have tested this and it will change. At some point I'll post a video to show what I experience.

 

[Mram10us]

For the drop testing I used a tripod with a ball head. This is a fairly stable setup and I can get .5 to .75 MOA groups. For the 600y shots using the scope turret I went prone on a bipod and shot a 3 shot group. The group size at 600y was .75 MOA.

I wanted to use a setup that I might use while hunting.

For testing, I would not use a tripod setup. I have a tripod setup and it is nowhere near stable as a front rest or bipod. Easy to get "soft butt" and throw rounds high with those setups. Just my experience. Good luck and hope you get a monster

 

[Canhunter35]

How did you arrive at your current muzzle velocity? It sounds like you mv is simply off.
Also, depending on what lot of 143eldx you have their can be big swings in bc.
My first batch I used .303g7 and confirmed to 1200. Next batch I'm around .312-.314 and I've shot it in the 1200-1400 yd range

 

[John Spadaro]

How did you arrive at your current muzzle velocity? It sounds like you mv is simply off.
Also, depending on what lot of 143eldx you have their can be big swings in bc.
My first batch I used .303g7 and confirmed to 1200. Next batch I'm around .312-.314 and I've shot it in the 1200-1400 yd range

I used a Magnetospeed V3 for MV at Sea Level and 85F. ES is about 10.

 

[Canhunter35]

I used a Magnetospeed V3 for MV at Sea Level and 85F. ES is about 10.

Well I would be suspicious of your scopes tracking? Or the magneto speed could be wrong, but 3100 seems more realistic number from a prc so recheck your 100yd zero then perhaps do a tall target test to check your scopes tracking

 

[X47guy]

I have tested this and it will change. At some point I'll post a video to show what I experience.

it changes because you have poor fundamentals. POI should not change moving from prone, standing, kneeling, off a bench, off a tripod, off a bi pod etc. If you change a bi pod then you can create a different flex on the stock. In a properly bedded stock, it will not change.

 

[WiscGunner]

How close are your scope rings mounted to the turret? The ring clamping too close to the turret is a common cause of turret problems.

Have you accurately input all the parameters into the apps? Scope height exact?

You MV will be slower now that it isn't 85*. You mentioned using RL26 which can get pretty erratic over 80* and now you are shooting 45* cooler. Even if the RL26 wasn't spiking at 85* you still have at least sever fps per degree change.

I prefer to save a new profile for my rifle in 3 temps (90*, 50*, 20*) commonly seem in my shooting. If you are assuming the same muzzle velocity this is likely one of your major errors in data input.

 

[L.Sherm]

O.P you said in one paragraph you tested from 200-600 and only the 200 and 600 were correct but in another paragraph you said you dont have access to a 600 yard range so how did you test from 200 -600?
Theres only one way to confirm your drops and that's physically to do it on paper. An app should only be used to get you on paper. I would test your scope to make sure its tracking correct if it is then you gotta do it on paper.
Even if you had to drive a few hours to a range.

 

[LongBomber]

In the first post it looks like you actually shot a tall target and have those drops measured at each distance. Those are your drops, and you would true you ballistic calculator to that.

To me it seems like you have a data entry issue, the scope issue is eliminated at the momment by shooting the target the way that you did. So are you sure that all of your environmental data was entered correctly and the settings are right in the hornady calc? I have used the hornady app but I am not super familiar with it, I still get better results using isnipe as I have used it since it came out.

Since you only have 100y I would also do a tall target test on the scope. Dot at the bottom and step
Up in 5moa steps to 20 or 25 moa. Would not surprise me to see a vx6 go more like .27moa per click- say that as I have one that does.

 

[LongBomber]

What was your air pressure at 2700'?

Running isnipe and the 143 eldx from my rifle settings the measured drops are not that far off. Would be able to give a better answer with your pressure number.

 

[dfanonymous]

I tried a drop test of my 6.5 PRC. I handloaded 56.1 gn. of RL26 pushing 143gn. ELD-X bullets. MV 3105 FPS at 85F Sea Level. First problem I encountered was that my 100 yard zero was 1.5 MOA low in conditions of 2700' MSL at 40F. I re-Zeroed at 100y in the current
At 600y at 2700' msl, 40F, zero wind

.

You another pilot?

 

[LongBomber]

Also 59" of drop you measured, if shot again at with the same conditions would be 9.3moa of correction to dial in.

I would check your ballistic app first, then test the scope. And test the scope anyways..

 

[LongBomber]

Last question - how much vertical do your groups at 100 yards have? Normally when I do a tall target I put a couple shots at each distance. much easier to true apps if you put a couple shots at each distance and don't have much vertical in your groups.

 

[John Spadaro]

O.P you said in one paragraph you tested from 200-600 and only the 200 and 600 were correct but in another paragraph you said you dont have access to a 600 yard range so how did you test from 200 -600?
Theres only one way to confirm your drops and that's physically to do it on paper. An app should only be used to get you on paper. I would test your scope to make sure its tracking correct if it is then you gotta do it on paper.
Even if you had to drive a few hours to a range.

I have to fly 2500 miles to get to a range. My next opportunity is when I go to Montana for an Elk Hunt.