Range Report How do you build dope for your rifle?

[ReaperDriver]

Sorry, I originally posted this in Fieldcraft but struggled which subforum was most appropriate. But since I'm talking about ballistics, I thought I'd at least post the link to my question hoping to get some more traffic. Thanks in advance for any help.

Question on how you build dope for your rifle

 

[Rob01]

Re: How do you build dope for your rifle?

I run my ammo over a chrono and then take the data and drop it into a ballistic program, I use JBM. I find that when you put the right data in you get pretty damn close. I've only been .2 mils off at 1000 yards. That's about 7.2" which isn't bad.

Obviously shooting the ammo on the range is the best way but only having 400 yards it doesn't help me much when I need to shoot to 1000+.

Another thing to check is that your scope tracks properly because you might be getting the right data from the ballistic program but if the scope isn't tracking correctly them it's not going to matter.

 

[ReaperDriver]

Re: How do you build dope for your rifle?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rob01</div><div class="ubbcode-body">I run my ammo over a chrono and then take the data and drop it into a ballistic program, I use JBM. I find that when you put the right data in you get pretty damn close. I've only been .2 mils off at 1000 yards. That's about 7.2" which isn't bad.

Obviously shooting the ammo on the range is the best way but only having 400 yards it doesn't help me much when I need to shoot to 1000+.

Another thing to check is that your scope tracks properly because you might be getting the right data from the ballistic program but if the scope isn't tracking correctly them it's not going to matter. </div></div>

I have access to a 550 yd (500m) range and can go unlimited if I go out in the desert and just laser my target for exact range.

How do you verify scope tracking? Box test? I also use ballistic programs and have usually been within .2 mils at the ranges I've tried with other ammo. I'm mainly looking for what you guys consider is the correct number of rounds to shoot to verify the drop? Is one 5 shot group sufficent? or do you need more to verify repeatablility? DO I need to shoot at every 100 yd increments to have good dope? Or can I go say every 200 or 300 yards and interpolate the in between ranges?

 

[Rob01]

Re: How do you build dope for your rifle?

Box test and a tracking test going up from zero point about 10 mils or 35 MOA. I put a mark every mil or every 5 MOA. If there is a problem you will see it.

I run my charts in 10 yard increments. I obviously don't shoot all those. If you shoot every hundred yards for a few shots that should give you a good idea if you are on or not.

 

[jwp6114]

Re: How do you build dope for your rifle?

+1 on what Rob01 said, i take my velocity, via vrono, and use a ballistics calculator on my windows mobile phone and it will give me computer gennerated data out as far as i want to go in whatever incraments i want. factor in wind corections auto weather corection ect... verry usefull data.

Rob01 what is the box test, i am still not convinced my scope is tracking/mounted properly, (using Millett LRT 6-25x56 35mm tube mil-dot) i leveled the verticle reticle line by means of plumb, (long weighted rope hanging from tree @100 yds, but as i lay in the prone with the receiver level, the reticle looks like its twisted to the right a bit. i have access to a 700 yard steel range with targets at 1,2,3,4,5,6,&700 yards with unknown distance targets all over the range for Milling preactice.

I would love to try a solid simple test to check for straight and proper tracking...

any help???

 

[Pete E]

Re: How do you build dope for your rifle?

Shoot a group with your present zero.

Adjust elevation turret say 3 Mil up, then shoot second group.

Adjust windage turret 3 Mil right then shoot a third group.

Adjust elevation turret 3mil down and shoot a fourth group.

Finally adjust your windage turret 3 mil left and shoot a fifth groups.

If your scope is tracking correctly, the groups should form a square on the target, and the first and fifth groups should be in the same place.

There are a few variations on this method which involves more tracking, but the principle is the same, ie the final adjustments should return the scope to its original zero and the first and last groups should over lap.

 

[Rob01]

Re: How do you build dope for your rifle?

What Pete said but I go atleast 5 MOA and better at 10 MOA just to use more MOA to see if there is any problem.

For elevation tracking place marks every 5 MOA, which is 5.25" at 100 yards, out to about 35-40 MOA and keep your aiming point at the bottom. I do this at 100 yards like the box test. If you have a level or can keep the rifle level then you will see if the scope is off as when you dial up you will see the impacts going right or left.

I have a pic of my chart i use but can't get to it now at work. Will pist it tomorrow.

 

[Cigarcop]

Re: How do you build dope for your rifle?

Heres a link

Tracking

 

[Pete E]

Re: How do you build dope for your rifle?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rob01</div><div class="ubbcode-body">What Pete said but I go atleast 5 MOA and better at 10 MOA just to use more MOA to see if there is any problem.
</div></div>

A 3 Mil square at 100m will be approx 12"x12" which is a touch larger than 10MOA at the same distance??? But agree that if practial, the more Mil/MOA used the better..

 

[popeye089]

Re: How do you build dope for your rifle?

In order to effectively gather DOPE (Data On Previous Engagements) you shoot at multiple distances under different conditions. You record your ammo lot number, temperature, light conditions along with the direction of light, wind speed and direction,in a notes column record misc bullets how you felt that day (were you sick, were you overly hot, sweating, dehydrated, hungry, anything you can think of) Again I repeat "Always reshoot these same distances under different conditions, not just enviromental but personal conditions" the reason why is because you may not always be able to rezero your rifle for the weather conditions in battlefield conditions, you must know not only how your round and rifle react under these conditions but how your body and mind respond so that you may better prepare yourself for the conditions that you must operate in. Also after you get good dope and you know where your round is hitting practice, practice practice alternate firing positions. Any sniper worth his weight will tell you , real world experience most shots are not shot in the prone supportive position. You must practice your alternate firing positions and know your limitations with each. Why take a shot and know your going to miss and compromise your position. The rule of sniping is always patience, weight for it and deliver, accomplish your primary mission of delivering long range precision fire on key targets and targets of opportunity. Always remember anyone can pull a trigger but can you achieve a one shot one kill under any and all circumstances? In order to do that you must know your equipment and your most important piece is your mind & the knowledge it stores

 

[Rob01]

Re: How do you build dope for your rifle?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Pete E</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rob01</div><div class="ubbcode-body">What Pete said but I go atleast 5 MOA and better at 10 MOA just to use more MOA to see if there is any problem.
</div></div>

A 3 Mil square at 100m will be approx 12"x12" which is a touch larger than 10MOA at the same distance??? But agree that if practial, the more Mil/MOA used the better..</div></div>

Read it quick and thought you wrote MOA. Sorry. 3 Mils will work just fine.

 

[Rob01]

Re: How do you build dope for your rifle?

Here's the straight up elevation check target i use on the right and I also check the mil spacing and make sure the reticle is perfectly vertical.

 

[Millett]

Re: How do you build dope for your rifle?

Hello guys

If you would allow me it put my two cents in here.

first off there are slight variations that will come up in the cross hairs in relationship to the knobs. In other words the level on the knobs of the scope may not be exact in relationship of the cross hairs. This will be a very small amount but its possible. I recommend level the rifle, and then use a vertical line at a distance to align the vertical line. or the horzonal can be used.

As to testing the scope by the box method. the larger the movement within the range of the scopes adjustments is better than using a small amount of adjustment. Remeber the last of the adjustments in the scope may not be accurate. The spring tension gets so low at the end of the travel that the scope will not hold zero. This is normal, you are just at the end of travel and the scope adjustment tube is not being held stable.

Note. if the scope is not aligned with the barrel as far as the center of the scope to the bore is off, when you adjust the turrets it will move the point of impact in both axis. In simple terms, if you adjust the elevation the windage impact point will move too. Test this by taking large target paper at 200 yrds and have aiming point at the top or bottom, fire a group at the aiming point. then adjust the elevation so the impact is at the other end of the target, if you did everything right the second group will be above or below the first group. if the scope is off it will not be inline as far as windage. Hope I explained this properly.

good shooting

Steve
Millett/Bushnell