Poor accuracy at 300y, great at 400

[Mr. Magoo]

Hornady has a fantastic podcast regarding twist rates in rifle barrels. Highly recommend this podcast. In the podcast they mention bullet stability will INCREASE as it travels down range. I'm guessing this is what you are witnessing. The ELD bullets are very long and need fast twist barrels like the 7 PRC has. I suggest you go to a lighter bullet in the same make/model or try a more traditional bullet shape in that rifle. I'm guessing you'll have more consistent results at varying distances.



Also, stop trying to determine bullet drop without a chronograph. You're wasting your time. Output data is only as good as the inputted data.

Very good info..that's kinda what i was wondering as you'll see arrows in slow motion yawing all over the place on the way to a dead center hit. I know arrows aren't bullets, but it proves at leas long, fletched projectiles do yaw but eventually stabilize to hit where they aim.

I dont know if I agree with your 2nd paragraph tho...I used 24 rounds of my good ammo over the course of 2 afternoons to do this testing and got dead on out to 500 (with the exception of 300 being wonky). Eyeball bore sighted a freshly installed scope then got it on paper initially with cheap stuff.

I used an app simply to get me on paper at each range, quicker than trial and error. It worked. Seeing where it really hits in real life is what i was doing at the range, so that I could know without a doubt where to aim.

 

[Chadp82]

I can only speak to my experience. I have loads be great at 100 and fall apart further out.

I started doing load development at 200. I have found if things are good at 200 I am in good shape further out.

 

[Stk]

There is no rifle that shoots tighter groups at 200 yards than it does at 100, or better at 500 than it does at 400. There are shooters that do. Shoot some ten round groups and I expect you'll see it go away. If it doesn't, it's either you or something is very wrong with your scope.

 

[Mr. Magoo]

I'm going with parallax as well.

That makes the most sense

There is no rifle that shoots tighter groups at 200 yards than it does at 100, or better at 500 than it does at 400. There are shooters that do. Shoot some ten round groups and I expect you'll see it go away. If it doesn't, it's either you or something is very wrong with your scope.

More testing is needed for sure. Ill get to the bottom of it.

 

[lancetkenyon]

^^Repeated it twice. Yesterday and today. 2 different ranges, both calm days. It hits within 2" of poa at 400 every time, but i would be afraid to miss the vitals on an elk at 300.

2MOA @ 300 is 6". Plenty for elk as long as no other cariables come into play.

"Within 2" of POA @ 400" is 1MOA. Or 4". Again, plenty for elk.

I have never seen, nor heard of a 2MOA rifle at 300 becoming a 1MOA rifle at 400. I have heard of vice versa however.

Unless you had an unlucky 3 shot group with the worst 3 rounds of ammo in the box at 300 each time. And the best 3 shot group with the 3 best rounds of ammo in the box at 400. Twice. More testing is needed.

Could be a parallax issue too.

Possibly the nut behind the bolt coming into play.

 

[sndmn11]

Are you holding over inside of 300 yards, and dialing at 400 yards?

You mentioned point blank range to 300, figuring out where to aim, etc.

 

[Short Round]

What targets are you shooting at? Stupid question and probably stupid suggestion but sometimes I just shoot at a target taped to a cardboard box or something. Is it at all possible your 300 yard target is moving around and your 400 isn't?

Again, very stupid suggestion I know…except I've done this…discovering that, even in a slight wind, it doesn't matter how steady I can hold IF THE DANG TARGET ISNT HOLDING STILL

tangent to your thought.......sometimes using the wrong target at a range will let you shoot worse groups than the right target or even thart shame target at the right range.

too big, crosshairs lost in the center
too small and you cover a dot and wander behind the crosshair
a shape that cause the shooter to err like a diamond or square not set plumb and you cant the gun to be "straight" on the target.

 

[Calvin45]

tangent to your thought.......sometimes using the wrong target at a range will let you shoot worse groups than the right target or even thart shame target at the right range.

too big, crosshairs lost in the center
too small and you cover a dot and wander behind the crosshair
a shape that cause the shooter to err like a diamond or square not set plumb and you cant the gun to be "straight" on the target.

Very true! I have indeed experienced that.

Also is your user name by chances an Indiana jones reference? Because as soon as I saw it I heard that kids voice

"You listen to short round, you live longer" !

 

[Mr. Magoo]

Are you holding over inside of 300 yards, and dialing at 400 yards?

You mentioned point blank range to 300, figuring out where to aim, etc.

Yep. 300 yards and under the plan initially was to hold dead on since its about 2.5 above or below poa at any range in that window. Past that I can either hold or dial depending on conditions/ time frame, since my scope is ffp and has hash marks in moa i can use for holdover.

The inaccuracy I got at 300 makes me wish I wasnt strapped for time and had more ammo to throw at testing.

 

[Mr. Magoo]

2MOA @ 300 is 6". Plenty for elk as long as no other cariables come into play.

"Within 2" of POA @ 400" is 1MOA. Or 4". Again, plenty for elk.

I have never seen, nor heard of a 2MOA rifle at 300 becoming a 1MOA rifle at 400. I have heard of vice versa however.

Unless you had an unlucky 3 shot group with the worst 3 rounds of ammo in the box at 300 each time. And the best 3 shot group with the 3 best rounds of ammo in the box at 400. Twice. More testing is needed.

Possibly the nut behind the bolt coming into play.

Oh it's always been the "nut behind the bolt" that causes my troubles, whether it be fast cars, fast projectiles, or fast wom... oh nevermind

Anyway, I like to have a little wiggle room in my rifles accuracy - more than i need in otherwords, so I dont miss due to what we refer to 'tolerance stacking' in the machining world.

 

[sndmn11]

Yep. 300 yards and under the plan initially was to hold dead on since its about 2.5 above or below poa at any range in that window. Past that I can either hold or dial depending on conditions/ time frame, since my scope is ffp and has hash marks in moa i can use for holdover.

There isn't any sense in applying the same standard of accuracy and precision when approximating a holdover in one instance and centering the crosshair in the other.

Bullets don't veer off course and then move back, the issue is your variable aiming method.

 

[2buffalo]

How do you set you parallax?

 

[Mr. Magoo]

There isn't any sense in applying the same standard of accuracy and precision when approximating a holdover in one instance and centering the crosshair in the other.

Bullets don't veer off course and then move back, the issue is your variable aiming method.

I see that I wasnt clear enough again. I'm not sure its possible to be clear enough in something thats not 10 pages for a mere mortal like me to explain this.

When putting it on paper out to 300, I hold dead on. At 400, I dialed. Why? A few reasons, but one of them was to save time because i didn't know exactly what the bullets were going to do. I was doing this after work, trying to get it done before the sun went down. In either instance, had a really nice square to aim at, at each range. There's no holdover while doing my target shooting. I wanted to see where my point blank range was so that in a rushed scenario, i could know at what range i would need to start compensating for bullet drop.. the lack of accuracy had nothing to do with my aiming method.

To expand on this a little more, my scope has hash marks every 1 moa. If i do have to hold over, I don't have to approximate anything.. becaue of those marks I still have a corsshair.

 

[Mr. Magoo]

How do you set you parallax?

Move my eye around while looking thru the scope and the rifle is on the bench and scope is on target. When I find the place where the crosshairs don't move, when moving my eye, I have found my setting. They don't necessarily correspond to the marks on the scope. Ive found most scopes are that way.