3 Gun Optic

[00bullitt]

Using 2905fps for muzzle velocity, .240BC(.269 is inaccurate), a Density Altitude of 0, and a sight height of 2.75", the following should be your holds:

Center dot zeroed at 100 yards

1st small dot below center dot(200yd)is 1.1moa - 195yds

2nd dot below center(300yd) is 3.3moa - 280yds

1st line below center dot(400yd) is 6.1moa - 360yds

2nd line below center dot(500yd) is 9.5moa - 440yds

3rd line below center dot(600yd) is 13.6moa - 515yds

4th line below center dot(700yd) is 18.4moa - 590yds

See attached reticle pic

[Onagoth]

Those variances don't correspond with my actual results.

[00bullitt]

Those variances don't correspond with my actual results.

Then your MV is more in line with 2710fps.

Center dot zeroed at 100 yards

1st small dot below center dot(200yd)is 1.1moa - 180yds

2nd dot below center(300yd) is 3.3moa - 255yds

1st line below center dot(400yd) is 6.1moa - 330yds

2nd line below center dot(500yd) is 9.5moa - 400yds

3rd line below center dot(600yd) is 13.6moa - 475yds

4th line below center dot(700yd) is 18.4moa - 545yds

[co-exprs]

I agree. There is something else wrong besides reticle choice. I know tons of guys who use Burris scopes very effectively. My shooting buddy runs about 2700fps with 55gr FMJs out of his 16" barrel and Burris scope. He has to use the 400yd mark for 300yd targets as well, which coincides well with the math. If you were pushing the velocity claimed and a 100yd zero, you would only be an inch or so low at 300 with a proper 300yd hold. A new scope will cost you $$$ and won't solve your problem.

Edited May 17, 2012 by co-exprs

[Lead-Head]

My Tac-30 is zeroed at 100 and as far as I can tell it's pre-determined dots are "on enough" out to 500 yrds w/55 grain ammo.

At Texas Multigun I had only shot the thing out to 400 in practice, so when I got to the 500 yard plates it was a bit of a leap of faith using the reticle. Turn out the 500 yard dot is "on enough" to hit a big 24 inch gong at 500 yrds. Where did the rounds impact the gong? On the front of it facing the spotters who were calling hits, that's all that matters to me.

Edited May 18, 2012 by Lead-Head

[Onagoth]

Those variances don't correspond with my actual results.

Then your MV is more in line with 2710fps.

Center dot zeroed at 100 yards

1st small dot below center dot(200yd)is 1.1moa - 180yds

2nd dot below center(300yd) is 3.3moa - 255yds

1st line below center dot(400yd) is 6.1moa - 330yds

2nd line below center dot(500yd) is 9.5moa - 400yds

3rd line below center dot(600yd) is 13.6moa - 475yds

4th line below center dot(700yd) is 18.4moa - 545yds

Muzzle velocity of 2905 was 10 shot average measured through a chornograph

Its not my belief that a different reticle would solve this problem, only that perhaps a bullet drop reticle is of little use to me.

Edited May 18, 2012 by Onagoth

[00bullitt]

So now we know that your muzzle velocity is not correct based on your drop at distance.

It is not uncommon for chronographs to read 10% in error based on lighting conditions.

You can make this BDC work for you by doing as I suggested. If that is not acceptable and you want it to match perfectly, you need to construct a load that matches it and now you know that you can't trust your chronograph. For accurate velocity, you need to be able to true at distance.

[waktasz]

Has anyone used the Strelok Android app? I like it because it has the Burris reticle in it and it will show me my hold for any distance I input assuming I input the correct data for my load. I'm shooting 55gr PMC that I chrono'd at 2930 fps. I don't really know what to use for BC though.

For example, if I enter in my load data, zero'd at 100, this shows a 300 yard hold.

Edited May 18, 2012 by waktasz

[outerlimits]

Has anyone used the Strelok Android app? I like it because it has the Burris reticle in it and it will show me my hold for any distance I input assuming I input the correct data for my load. I'm shooting 55gr PMC that I chrono'd at 2930 fps. I don't really know what to use for BC though.

For example, if I enter in my load data, zero'd at 100, this shows a 300 yard hold.

Cool app...gay reticle.

[Onagoth]

So now we know that your muzzle velocity is not correct based on your drop at distance.

It is not uncommon for chronographs to read 10% in error based on lighting conditions.

You can make this BDC work for you by doing as I suggested. If that is not acceptable and you want it to match perfectly, you need to construct a load that matches it and now you know that you can't trust your chronograph. For accurate velocity, you need to be able to true at distance.

Interesting, I think there are two other possibilities though. The reticle is out or the BC of the cartridge is different.

I have a shooting Chrony chronograph and they are manufactured not far from where I live if I'm not mistaken. I'll have it calibrated and round some rounds through a friends chrony as well.

I don't need the reticle to make perfectly, it would just be nice if it was closer.

[Onagoth]

Has anyone used the Strelok Android app? I like it because it has the Burris reticle in it and it will show me my hold for any distance I input assuming I input the correct data for my load. I'm shooting 55gr PMC that I chrono'd at 2930 fps. I don't really know what to use for BC though.

For example, if I enter in my load data, zero'd at 100, this shows a 300 yard hold.

That's the app I've been using

[00bullitt]

Using .240 for a BC is rather accurate. I know .269 is not true as I have shot it and validated the BC to .240.

I don't put much faith in chronographs with two sensors as they all prove to have error to some degree and not uncommon for as much as 10% variance. It just seems to change based on the light.

To truly eliminate variables, you need an artificial light source inside a box. And you still only have a baseline at that point.

I have yet to ever shoot rifle ammo over a chronograph and have it match when I true at distance.

It is however, possible that the reticle is not etched exactly as specified. I seriously doubt that Burris checks every scope they send out on a collimator to ensure such.

You need to confirm reticle spacing with a grid target at a true 100 yards. The 400 yard line should be 6.4" below center dot at 100 yards

If that correlates at 100, then you have much less velocity than you chronographed. 2710fps is not unrealistic.Its just not ideal for a low BC bullet like the 55gr. FMJ.

[Onagoth]

Thanks,

Some work to do on my part.

[larry weeks]

Back to the original question, I'd go for great glass and learn the holdovers for whatever reticle you have. The glass - and the coatings - in something like a Swaro, will let you see the targets much better. I don't shoot scope in 3-Gun because I can't get them low enough to keep my head on the stock when prone but I have one on a 6.8 and it is amazing to look through.

[Jesse Tischauser]

I think FOV is king personally since we do so much shooting at various different angles of fire. Plus a big FOV on 1X means the scope looks like a red dot. I use my reticle for about 3-5 shots per match. Obviously those 3-5 shots are high value long range targets so they are important. I run the Swarovski Z6i w/BRT reticle. It is easily the cleanest most applicable reticle for the game we play. I zero my first hash which is 1 mil at 300 since I run different ammo for different matches/targets and my drops are never 100% on with the mil reticle marks. With my 300 yard zero my center cross hair is slightly off at 100 & 200 but not so much that I can't still put it center mass on a steel target and hit it. Then 400, 500, 600 line up fairly close with the reticle since we shoot large targets at those distance close is usually good enough.

Edited May 25, 2012 by Jesse Tischauser

[M ammo]

If only someone wrote all this down in put it in a book with pictures and Diagrams.