6.5 PRC .5moa at 100 to 4 at 200?

[Txcowboy50]

I did load development for 6.5 PRC with 140 gr Berger elite hunters over 59gr of MagPro. 5 shots at 100yds yielded <.6 inch groups. I thought this would be a good hunting load. Shot the exact same load at 200 yds and got a shot gun pattern the size of a 4" saucer. The only thing different was adjusting my NF NX8 to 200yds. Puzzled? Could it be the scope?

 

[Varmint Hunter]

That's a pretty dramatic increase in moa. How many shots or groups did you shoot at 100yds to determine accuracy at that distance? Sometimes I can shoot an unbelievably small group only to determine, later, that it wasn't repeatable.

 

[Txcowboy50]

That's a pretty dramatic increase in moa. How many shots or groups did you shoot at 100yds to determine accuracy at that distance? Sometimes I can shoot an unbelievably small group only to determine, later, that it wasn't repeatable.

One group of 3 and one group of 5.

 

[Dmagna]

I got the same scope, the parallax is pretty touchy. Also mag pro is pretty temp sensitive, anytime I shoot i. The summer I leave my ammo in my truck with the ac on. Keeps it consistent, also I let the barrel cook to ambient every shot to make sure I am consistent.

I have had a couple of rifle with barrels that would dramatically change POI after 1 shot. There must have been issues with the barrels, I ended up changing the barrels and it didn't happen anymore.

 

[wasskeet]

If your NF scope is like mine - pay no attention to the distance markings on parallax adjustment. Just adjust until the crosshairs/dot/etc stays on target while moving your eye around. Also - it may not be the clearest when you get it still. This could be your issue?

 

[L.Sherm]

I've seen this to many times stuff at 100 falls apart further down range, maybe not as much as yours. On my LR stuff I dont waste my time after my scope is were I want it, go straight to atleast 500 for load development and test at 700.

 

[Rick Richard]

Did you shoot it again at 100 yds after you shot the 200 yard group? If not see if it repeats the tight group at 100 yards then we can go from here. If it stays opened up at 100, then the first thing I would do is check all fasteners especially the Action screws.

 

[Txcowboy50]

If your NF scope is like mine - pay no attention to the distance markings on parallax adjustment. Just adjust until the crosshairs/dot/etc stays on target while moving your eye around. Also - it may not be the clearest when you get it still. This could be your issue?

This could be a possibility. It was a hot day over 100 degrees...I cool the barrel between shots with a barrel cooler fan. At 200 yards target was still fuzzy with parallax adjustment from heat. May have to shoot this load again..thanks

 

[Txcowboy50]

Did you shoot it again at 100 yds after you shot the 200 yard group? If not see if it repeats the tight group at 100 yards then we can go from here. If it stays opened up at 100, then the first thing I would do is check all fasteners especially the Action screws.

No, these were the last 5 shots of the day but will try tomorrow. I did check all screws. Action, scope base and rings

 

[lancetkenyon]

100*F? Mirage can wreak havoc on actual POA. So can parallax that is off. Combine those two, and my bet....you were aiming for a 4" target. At 200 yards, that is 2MOA. With light winds, those big rolling mirage waves can EASILY move the appearance of the target POA 2".

 

[blackburbot]

Crank down the magnification as much as you can to eliminate as much mirage as possible. You can still shoot small groups on low power, even at distance. Then try reshooting. Try going back and forth on the 2 distances and even try others. Eliminate as much as possible. Keep ammo cool in the shade or AC in truck. Make sure everything is tight and your fundamentals are solid. Don't worry about numbers for parallax, or distance. Sometimes you get a mental block on shooting a particular distance. Let things cool down between strings.

Yeah, I know its lots to think about but relax on the range and you will shoot betrer

 

[lancetkenyon]

Crank down the magnification as much as you can to eliminate as much mirage as possible. You can still shoot small groups on low power, even at distance. Then try reshooting. Try going back and forth on the 2 distances and even try others. Eliminate as much as possible. Keep ammo cool in the shade or AC in truck. Make sure everything is tight and your fundamentals are solid. Don't worry about numbers for parallax, or distance. Sometimes you get a mental block on shooting a particular distance. Let things cool down between strings.

Yeah, I know its lots to think about but relax on the range and you will shoot betrer

I have not found that reducing magnification reduces mirage at all. Just can't see how much it is moving POA when you are at 5X vs. 15X. Mirage looks smaller, because your target is smaller. Just because you can't see it does not mean it is not there.

I agree with the rest of your points.

 

[Varmint Hunter]

I have not found that reducing magnification reduces mirage at all. Just can't see how much it is moving POA when you are at 5X vs. 15X. Mirage looks smaller, because your target is smaller. Just because you can't see it does not mean it is not there.

My experience dealing with mirage has been different. Mirage doesn't affect POI, it effects my ability to see a stationary target. Once the mirage gets to the point where the bullseye appears to be dancing all over the backboard, I turn the magnification down. Reducing the magnification minimizes the amount that the bullseye appears to be moving.

I've had very good results with reducing the magnification and maintaining a better hold when the mirage makes life difficult. Mirage is one of the reasons that I shoot at 8am, which is when our firing line opens. Even on a hot day, we'll get a few hours to shoot before the mirage is problematic.

 

[Andrew Massi]

2 moa load or shooter. 8 rounds under moa isn't much for a data point.