Simple tuning for acceptable vertical spread?

[Carole Baskins]

Hello all. I am getting my feet wet in ELR. I have an AXSR with an 8.5 Twist Brux in 300 Norma. My current load with the 250 A-tip checks all of the boxes at 100 and 300 yards, but I've had it on paper at 820 yards three times on different days and it's resulting in about 5" of vertical at this range.

The days I've shot this rifle have been roughly two months apart with about a 25 degree temp difference. Velocity hasn't changed and the load has consistently given me this result.

Would a simple seating depth at range be my next step for trying to cut down on the vertical dispersion?

Thanks!

 

[kthomas]

What's your SD/ES of that load?

 

[Carole Baskins]

The worst ES has ever been on a five shot string is 22 fps. SD is 5-7. Thanks!

 

[Bandit320]

Hello all. I am getting my feet wet in ELR. I have an AXSR with an 8.5 Twist Brux in 300 Norma. My current load with the 250 A-tip checks all of the boxes at 100 and 300 yards, but I've had it on paper at 820 yards three times on different days and it's resulting in about 5" of vertical at this range.

The days I've shot this rifle have been roughly two months apart with about a 25 degree temp difference. Velocity hasn't changed and the load has consistently given me this result.

Would a simple seating depth at range be my next step for trying to cut down on the vertical dispersion?

Thanks!

Isn’t 5” at 820 yards like 0.6 MOA? That could easily be to mirage, sighting error, etc. doesn’t sound to bad to me.

 

[Jareth Cutestory]

whats the horizontal spread in comparison?


work on getting the ES as tight as you can manage, same with how you brace, can make a big diff

 

[kthomas]

For vertical, things to focus on would be tightening ES, breathing control and your discipline in handling the rear bag.

22 ES is not horrible. I aim for sub 20 fps ES. There's no secret to getting there, use good quality reloading components and equipment and a repeatable consistent process.

 

[Carole Baskins]

I work on as consistent of cheek weld and grip pressure as I can manage, but the rear of the rifle and the bag are something I hadn't considered. Maybe it's time for a bag rider.

Horizontal was about 4" the last time I shot it. But the shots were spread out over about five minutes and the wind was switching.

 

[Bandit320]

Your ES of 22 fps is something like 2.6” vertical spread at 820 yards; about half of your error. Seems to me a 4” x 5” group at that range with wind, mirage, etc is very good. I’d just work on your loads and technique. Any photos of your groups?

 

[Sandow the Heretic]

Can you tell us more specifics about your load? Have you shot a ladder?

-Alex

 

[Carole Baskins]

I did my ladder at 300. It shot under 1.5" (three shots) twice with the load I decided on so I moved to 810 yd to see what it was doing. I didn't get a picture of the first two tries at 810 yds, but here is a 5-shot group that was about 5.25" of vertical spread.

This was yesterday (only four shots) with the seating depth reduced by 0.015".

And another four shots with the seating depth reduced by 0.030" from the original load. I'm not sure what to make of these groups.

 

[Jareth Cutestory]

looks like you need to do more shots in your groups, seems about normal... .75moa


do you have any anti cant devices? looks like you need one.

 

[GIXXER2000]

When shooting at 1000 yard matches I work on the basics. rifle level, grip and trigger pressure and fire at the bottom of my exhale. My last group was about 7 inch vertical dispersion. But you can do all that and the wind and other factors still play a major part.

 

[camotoe]

Reloader 33.?

 

[Carole Baskins]

Reloader 33.?

I've been using Retumbo.

 

[BuildingConceptsllc]

The worst ES has ever been on a five shot string is 22 fps. SD is 5-7. Thanks!

In my experience, a 5 shot string is almost meaningless for ES.

 

[Carole Baskins]

In my experience, a 5 shot string is almost meaningless for ES.

I've recorded the velocity of every shot. I'll go back and see what it is across all of the shots I've made at distance. Thanks!

 

[BuildingConceptsllc]

I've recorded the velocity of every shot. I'll go back and see what it is across all of the shots I've made at distance. Thanks!

You may be a better reloader than I am, that's very possible but I've found that unless I shoot 20 shots I really don't have a good idea of ES. I don't just shoot a 20 shot string, I generally do sets of 5 shots with a break in between but I went on for a while doing 5 shot groups and then the next time the same and it didn't produce the same ES as if I do 20 shots in the same trip. There's several factors in there that can have an effect on that of course.

 

[secondofangle2]

shoot with a labradar and a good spotting scope on a target where you can see the individual shots (one of those shoot-n-see or a piece of painted steel, or a target cam) and see if the highs and lows correlate with high and low velocities

Also, seating depth is usually done for accuracy after you've already found a node with acceptable velocity and velocity SD

 

[camotoe]

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[camotoe]

I'm also convinced powder company's are putting out subpar lots of powder trying to keep up with demand, New rl33 is garbage compared to older lots

 

[badassgunworks]

Rear bag to hard or may be bipod extension both can cause vertical

 

[Carole Baskins]

I was finally able to take it out and shoot it again. I am becoming convinced it's shooter error. I was able to shoot a ~ 3.76", 5-shot group at 820 yds. I really focused on breaking the shot at the same time during my breathing and lowered the front bipod (Elite Iron Revolution) a bit so the rear of the rifle sat in the bag a little better. Everything felt more stable. I think I'm good with this load.

I really appreciate the advice!