Suggestions on settings for a BDC reticle scope

[David Milisock]

My only interest in opinions is for suggestions on setting up the zero for BDC, I have my idea but since I have not used an LPVO for rifles, I have used only scopes designed for longer range work I thought I'd seek opinions. I don't care for suggestions about more expensive scopes, cheaper scopes or scopes that people think are better, the decision has been made and they will be here very soon.

My son has an astigmatism which makes using iron sights interesting for him, he has a Stag Arms SR1 (I believe, I know it's a 16" standard barrel Stag Arms) in 5.56 x 45 so, I've decided to get him a flip up military back up iron sight and a Sig Sauer Tango MSR SFP 1 x 8 x 24 for his birthday. He can remove the carry handle and reconfigure the sighting systems. He's a very good son! If I had any good wish for a man, it would be for them to have a son like I have!

I got the Sig Sauer Tango-MSR SFP 1 x 10 x 28 for my 16" Aero Precision M4E in 6MM ARC.

I configure iron sights to keep the target at the top of the sight picture, I set the aperture at 300 and adjust the front post to be on at 300. I fire to establish trajectory from the muzzle to 300 then simply adjust the hold on the fly as needed.

Without moving the front post, I then adjust the aperture to 500 and fire to establish bullet trajectory from 300 to 600. This keeps the target fully visible in the sight for 99.999% of all situations with 99% inside 300.

I picked the scopes as a general-purpose utility sight; they have illuminated reticles that replicate a red dot well at low power for work out to 300 yards. They have arguably a true 1 power setting for up close and personal. The long rage work would be their weak point, they have no ability to adjust parallax and as they are lower/medium priced devices do not have the best glass. They were bought for a specific set of ranges with single specific ammunition.

I like the KISS principle, (keep it simple stupid) and as such my thought is to zero the scopes at 100 yards, map the trajectory out as far as accurately possible and generating ballistic tables for the elevation and windage markings.

I have posted an image of the reticle with some notes on it.

 

[Charlie-NY]

I have a few BDC reticle scopes. They work well for hunting out to 400yds or so. Since my drops never exactly match the wires for 200yd, 300yd and 400yd, you have to compromise somewhere. I've found that sighting in with the 400yd crosshair dead on at 400yds leaves the least amount of error at 200yds and 300yds. The center crosshair is used for 100yd & 200yds.

I hope that makes sense.

 

[David Milisock]

I have a few BDC reticle scopes. They work well for hunting out to 400yds or so. Since my drops never exactly match the wires for 200yd, 300yd and 400yd, you have to compromise somewhere. I've found that sighting in with the 400yd crosshair dead on at 400yds leaves the least amount of error at 200yds and 300yds. The center crosshair is used for 100yd & 200yds.

I hope that makes sense.

It does make sense. Thanks!

 

[Kracken McGraw]

Since it’s sfp the center dot should stay the same at all yardages, I would sight that dot in where you think he would shoot it most. Maybe do the holdover marks at 8X to get your longer yardages.

 

[David Milisock]

Since it’s sfp the center dot should stay the same at all yardages, I would sight that dot in where you think he would shoot it most. Maybe do the holdover marks at 8X to get your longer yardages.

Thanks, these are second focal plane scopes so the BDC marks only work at full power.

 

[Kracken McGraw]

Thanks, these are second focal plane scopes so the BDC marks only work at full power.

Yes supposedly, but you could crank the power down if needed to make the bdc marks work to your load but it would take a lot of playing with it..
I have the Nikon spot-on app that shows the subtensions at different powers. If you know you bullet, speed and caliber I could plug it in that app and see if something was close.

 

[Coyotefurharvester]

This would be a 200 yard zero, reticle drops on top magnification. 55 gr self defense ammo. Drops are +,- about 1". reticle subtensions are the same in 6,8,10 bdc models.

 

[David Milisock]

Yes supposedly, but you could crank the power down if needed to make the bdc marks work to your load but it would take a lot of playing with it..
I have the Nikon spot-on app that shows the subtensions at different powers. If you know you bullet, speed and caliber I could plug it in that app and see if something was close.

I'm mentally preparing for some work!

 

[David Milisock]

This would be a 200 yard zero, reticle drops on top magnification. 55 gr self defense ammo. Drops are +,- about 1".View attachment 1550538

That's the kind of thing I'm looking to do. Finding the zero point that fits the trajectory for the load will be the work.

 

[Coyotefurharvester]

I went to Hornady, selected 223 55 gr critical defense ammo specs ballistic chart. Played with zero distance in 25 yard increments. Having your rifles muzzle velocity would be closer, but you get the idea. Sight height above bore is important also, I used 2.5" since the msr mount comes with the scope.

 

[Cecil S.]

Being a "newbie" here and not shooting competition a well dialed in BCD might be faster for a follow up shot. Just sayin.

 

[Kracken McGraw]

Being a "newbie" here and not shooting competition a well dialed in BCD might be faster for a follow up shot. Just sayin.

Those hash marks on dial up scopes have two purposes.

 

[Jeff Porter]

I have used the fat part of the crosshair on a duplex reticle out to 600 by turning power down to have the reticle match the drop. Seemed counter intuitive to turn down the power as the target got farther away but I was able to make hits and shoot a decent group doing that.

 

[Cecil S.]

Those hash marks on dial up scopes have two purposes.

Hey Bro, being a "newbie" would you please explain your reply. Thanks

 

[Kracken McGraw]

Hey Bro, being a "newbie" would you please explain your reply. Thanks

Probably not the correct words that I used, but the hash marks below the center crosshairs are used to range drops with moa or mils if you don’t have time to dial your dope. The hash marks on the horizontal are used the same for wind.

 

[Dimner]

My only interest in opinions is for suggestions on setting up the zero for BDC, I have my idea but since I have not used an LPVO for rifles, I have used only scopes designed for longer range work I thought I'd seek opinions. I don't care for suggestions about more expensive scopes, cheaper scopes or scopes that people think are better, the decision has been made and they will be here very soon.

My son has an astigmatism which makes using iron sights interesting for him, he has a Stag Arms SR1 (I believe, I know it's a 16" standard barrel Stag Arms) in 5.56 x 45 so, I've decided to get him a flip up military back up iron sight and a Sig Sauer Tango MSR SFP 1 x 8 x 24 for his birthday. He can remove the carry handle and reconfigure the sighting systems. He's a very good son! If I had any good wish for a man, it would be for them to have a son like I have!

I got the Sig Sauer Tango-MSR SFP 1 x 10 x 28 for my 16" Aero Precision M4E in 6MM ARC.

I configure iron sights to keep the target at the top of the sight picture, I set the aperture at 300 and adjust the front post to be on at 300. I fire to establish trajectory from the muzzle to 300 then simply adjust the hold on the fly as needed.

Without moving the front post, I then adjust the aperture to 500 and fire to establish bullet trajectory from 300 to 600. This keeps the target fully visible in the sight for 99.999% of all situations with 99% inside 300.

I picked the scopes as a general-purpose utility sight; they have illuminated reticles that replicate a red dot well at low power for work out to 300 yards. They have arguably a true 1 power setting for up close and personal. The long rage work would be their weak point, they have no ability to adjust parallax and as they are lower/medium priced devices do not have the best glass. They were bought for a specific set of ranges with single specific ammunition.

I like the KISS principle, (keep it simple stupid) and as such my thought is to zero the scopes at 100 yards, map the trajectory out as far as accurately possible and generating ballistic tables for the elevation and windage markings.

I have posted an image of the reticle with some notes on it.View attachment 1550503

First, how old is your son? I only ask this in reference to his ability to remember trajectories and settings. If young, you may want to keep is simple like you mentioned. I would probably just set the zero where you want and then give them one or two hash mark yardages. If he's full gun nut like the rest of us, go hog wild with dope charts!

One thing to mention, you can map out those hash marks/subtensions at any magnification. However, as you know, since it's SFP those subtensions (except the center dot) will change at each magnification. I mention this because, you will want your son to practice with the scope in the applications he wants to use it. Then he may have a preference for what magnification he is most comfortable with.

For example, on my SFP hunting rifles with BDC scopes, I never chart my subtensions at max magnification, because that I not what I am comfortable with when hunting deer. 12x or 14x is just too much magnification.

Since the rifle is 5.56, I would personally use the scope on 1x 90% of the time. 4x 9.9% of the time. and 8x 0.1% of the time. So I would make my dope card using the 4x magnification. Which also will work better with the 5.56 round. The only time I would use 8x is if I was plinking steel at long range. And at that point you don't really need to know the distances for your 1st shot.

I guess I'm saying, find out what the preferred magnification is, and use that for the dope chart. I have the Vortex Strike Eagle 1-8x and my chart is for 4x.

 

[Dimner]

I still have Strelok plus on my phone. So I mocked up some results for you...

I'm using a 55gr Hornady BTSP at 3050fps for this. Zero distance is at 150 yards. To me, the 150 yard zero makes sense. You will have 0.5" high at 100 yards, which in the grand scheme of AR15s is pretty close to zero anyway.

The scope they had in the database was the 1-6x version, but with the same BDC6 reticle. So I altered the max magnification and left the subtension settings to be calculated at 6x.

 

[Coyotefurharvester]

I go with max magnification(most sfp bdc scopes) for any shot past zero. Since your zero on the center reticle feature(dot,crosshair) doesn't change with magnification change you can hunt(shoot) with the power setting matching the situation. If shooting situation ranges further than zero(often 200 yards) I want the extra magnification, easier and quicker just to turn to max.

 

[CJ6]

Guys he's using 6 ARC.

 

[Dimner]

Guys he's using 6 ARC.

OP has a 6 ARC, but this is for his son who has a 5.56, at least that's how I read the request... as setting up the scope for his son's present