Good groups, Bad distance results with reloads?

[Sgtsideways]

Shooting 6.5 Creedmore new guy. 140g Hornady #26335 with IMR 4350 and wlrp. Lapua and Peterson brass. Groups at 100 yards at 0.5moa or less. Where the rub seems to come in is when I'm shooting at greater than 200yds. For instance, at 600 yards my groups looked great, but they were way low (2ft) and off to the right by 3ft.
I had been hitting the 13" steel plate with factory Hornady 140 g bullets with no problems at 600 yds and very close to the turret settings provided by a ballistic calculator. When I switched over to my good grouping reloads, I was way off as stated above. Roughly guessing I figure I will have to add 0.7 mils up and 1.8 left.
Understanding that different powders. bullets, primers, ect will give difference results, but should there be this much of a difference?

 

[brianf]

paging @Dthomas3523

 

[Newbie2020]

I’m not sure I understand the question. Different loads will have a different POi. The left to right variance is weird but oh well. Half moa old is good. Adjust your scope and true your Dope in your software and go shoot it.

Am I missing something?

 

[davsco]

you are plugging your reload velocity into your ballistic program? different wind when shooting factory and reloads? if you're getting good groups i'd just adjust your poa accordingly.

 

[GrumpyOleFart]

Did you chrono the reloads?

 

[KnowNothing256]

Does your POI at 100 yds shift by roughly the same amount as your 600yd POI shift?

 

[mbeavers1]

Something seems strange. Is your ballistic calc set up correctly? Is scope height correct?

 

[ditter]

better get some velocities on your handloads. But I'd venture to say it is way slower than factory.

 

[OREGUN]

Sounds like your reloads are slower than factory. Concerning left/right, is your zero good?

 

[mbeavers1]

better get some velocities on your handloads. But I'd venture to say it is way slower than factory.

Also possible. Check this by back calculating your MV using a target at 600 yds.

Paint a waterline on a 600ish (known distance) target.

Dial elevation based on ballistic calc (already done). Adjust elevation manually until you hit the waterline. Modify MV until it spits out the adjusted elevation.

This is basically like truing your ballistic calculator.

 

[TheGerman]

Reloads are slow as fuck yo.

 

[1moaoff]

Are you mixing brass also??? Do you KNOW your mv?

 

[Sgtsideways]

I'm thinking that you guys are on the right track with mv. Previously, I had used 42g of IMR4350 and chrono'd 2859fps at muzzle. With that amount of powder, I could tell it was compressing when seating the bullet. I then reduced the load to 41.8. Sorry I didn't have the chrono at the time. It's time to go back to the drawing board. Is compressing a big don't do?
At least I'm getting better results with the new brass. Neck tensions are consistent along with cbto.
Thanks.

 

[KnowNothing256]

Mildly compressing extruded (stick) powder is totally fine, and can even yield more consistent ignition under some circumstances. Compressing spherical (ball) powder isn't a good idea, and generally the faster powders are a little risky as well.

It takes a lot of MV drop to pull you down 1.1 mils at 600 yards with a 140gr 6.5mm bullet, and that doesn't really explain the 1.6 mils or so of extra windage shift you saw. It'd be one thing if you were zeroed at 100 and took that same load out to 600 and needed that much windage; that would suggest to me that you just had a brisk wind (which should be fairly obvious at the shooting position if you're out in the open).

I'm shooting the same bullet you are in a 6.5CM, and to increase my normal dope at 600 yards (2.8 mils, 2720 fps) by 1.1 mils my MV has to change to 2440 fps, or a drop of 280 fps. That seems...unlikely, unless you're WAY underloading your ammo. POI shift due to barrel harmonics or whatever seems like a plausible contributor, but I'm still wondering what the story is on the windage shift.

I asked above, but I'll repeat it here: when you change from factory to reloads at 100 yards, what is the POI shift?

 

[Sgtsideways]

Mildly compressing extruded (stick) powder is totally fine, and can even yield more consistent ignition under some circumstances. Compressing spherical (ball) powder isn't a good idea, and generally the faster powders are a little risky as well.

It takes a lot of MV drop to pull you down 1.1 mils at 600 yards with a 140gr 6.5mm bullet, and that doesn't really explain the 1.6 mils or so of extra windage shift you saw. It'd be one thing if you were zeroed at 100 and took that same load out to 600 and needed that much windage; that would suggest to me that you just had a brisk wind (which should be fairly obvious at the shooting position if you're out in the open).

I'm shooting the same bullet you are in a 6.5CM, and to increase my normal dope at 600 yards (2.8 mils, 2720 fps) by 1.1 mils my MV has to change to 2440 fps, or a drop of 280 fps. That seems...unlikely, unless you're WAY underloading your ammo. POI shift due to barrel harmonics or whatever seems like a plausible contributor, but I'm still wondering what the story is on the windage shift.

I asked above, but I'll repeat it here: when you change from factory to reloads at 100 yards, what is the POI shift?

Very little POI shift between the two. This one has me scratching my head, as I've never had such a shift and it has to be something with the reloads. My reloads have never been this far off. Next time I go out I'll check with the chrono. Thanks for the info.

 

[1moaoff]

Are you mixing brass?
What is your powder charge weight?
How are you weighing?

Basics....
Rifle specs? Home built?
Scope specs?
Have you tightened or checked everything?
Muzzle devices?

List out all specifics as a list not a paragraph. Add some pictures of overall setup a.d ammo etc.

You will find without giving us detailed info this will turn south.

 

[Mbaysinger89]

What is "very little"?

 

[Shoots 700's]

you also don't have your rifle zeroed for that bullet and load