Questions regarding Maximum Point Blank Range with Iron Sights

[DMW1116]

As some may know I’ve been shooting mostly with iron sights lately in an A4 clone with a 20” barrel. I’ve also been working with a Marlin 336 and Model 60 both fitted with aftermarket aperture sights.

I generally set them up in their final form for a maximum point blank range (MPBR) appropriate for their uses and chambering. Usually it’s a 6” circle with whatever handloads I finally settle on, or a 2” circle for the Marlin 60 as it’s my rimfire silhouette rifle.

My question is would it be better to set the entire circle above the sights since they obscure anything below them? For example if I want to use a 6” circle for the 336 should I set it to hit a maximum of 6” above the line of sight so I can see the target above the sights all the way to the maximum distance?

Also, based on on-line calculators, setting the whole circle above the sights extends the MPBR a little bit.

For reference, these are all target rifles. I haven’t hunted in years and when I did only the Marlin 60 would have been appropriate for the quarry. I know the 336 isn’t a target rifle but it’s been in my family for 2 generations and I couldn’t stand not to shoot it.

 

[jmr40]

That is all well and good if you're shooting at the range or at deer standing out in open fields. I don't like using MPBR for anything. I zero my rifles at a specific range and either memorize drops or print out a cheat sheet taped to the stock.

For brush hunting I don't want my bullet more than 1" above or below my line of sight for as far as possible. When hunting in brush you don't shoot through the brush, but through holes in the brush. If you start zeroing a rifle so that it is 3" above line of sight and 3" below line of sight to hit a 6" circle you're going to start hitting brush, and deflecting bullets instead of threading them through the openings.

I've not looked at what it would take for a 30-30 to do that, but would suspect that a zero at around 50-75 yards would keep the bullet within 1" of line of sight out to about 100 yards or a bit farther. You'd just have to run the numbers through a ballistics calculator. It wouldn't take much hold over to make hits at 200 and that is about as far as you need to be shooting game with a 30-30 anyway.

 

[Varminterror]

I’m not convinced a lollipop or pumpkin on a post sight picture does anything at all to extend MPBR. I’m also not a fan of this sight picture as a whole, because any change in lighting conditions or change in target design suddenly puts you off center. I use a “setting sun hold,” aka “center hold” or “half & half hold,” so my target center is sitting at the tip of my front sight. The only exception has been indoor small bore competition for which I used a rear aperture and front globe with circle reticle insert, so I could align concentric circles of my rear peep, front hood, front reticle, and aiming black - this has been the most precise iron sight aiming picture I have ever used - but outside the context of THAT target, on any other non-uniform target, it effectively burned to a crisp...

So for me, having btdt with pumpkin on a post hold, hard pass. Center hold.

 

[DMW1116]

It’s not much and is based on calculations and not actual shooting, but for the same load in my 336 there is an increase from 210 to 235 yards. If that is confirmed that’s a decent distance for such a round. I’m using Shooters Calculator and a velocity of 2250 fps on a Hornady FTX with BC of 0.330. Sight height is 0.75”

 

[DMW1116]

That is correct for a 30-30 with my load. 1” above or below has a max calculated range of about 136 yards. That’s a small window and a surprising range for what is considered a brush cartridge/gun.

 

[ms6852]

For me, on my 94 winchester 30-30 I like to use 150 yards as MPBR, and I never want to cover my target. Using the front post I determine whether it will hit high or low but am still able to see the target. It is like using the sights on the picture below.

 

[Varminterror]

It’s not much and is based on calculations and not actual shooting, but for the same load in my 336 there is an increase from 210 to 235 yards. If that is confirmed that’s a decent distance for such a round. I’m using Shooters Calculator and a velocity of 2250 fps on a Hornady FTX with BC of 0.330. Sight height is 0.75”

All you’re really talking about is zeroing at your max range rather than using a true MPBR. By using a 6” standard, never impacting below your blade, you’re zeroing the sight at your max range which only arcs 6” above LOS, then comes back to LOS.

212yrd MPBR with +/-3” versus 235yrd zero with +6”, -0” trajectory to get there. Proportionately, 23 yards on top of 212 sounds substantial, but when you consider the real implication, especially for a target shooter with aperture sights, eh... it’s largely meaningless.

But functionally, when you use a 6” aiming black, your pumpkin on a post plan is going to yield a different point of impact in the morning than it will in the afternoon. When you set the aiming black on your front blade, it WILL appear larger or smaller depending upon lighting conditions. We see a reduced influence of this same effect even using a center hold, but much, much reduced compared to a 6 o’clock hold below the black - brighter light makes the aiming black seem smaller, and when we push our blade to center, it’s actually higher than normal, so our shots go high - “light’s up, sights up” - we have to drop our muzzle by raising our blade to put us back on target. When using a pumpkin on a post sight picture, the apparent shrink is larger, so the push is farther, we send rounds higher, or have to raise our front sight higher to get back to center...

So what have you gained? More variability in your POI due to light condition sensitivity, to gain a calculated 23 extra yards? Boo for that.

 

[DMW1116]

Now that is some interesting information. I have not noticed that type of thing when shooting, but I largely shoot at the same range at the same time of day. I will have to vary my times and make some notes about weather conditions as the seasons change to see how noticeable this is.

 

[Varminterror]

Now that is some interesting information. I have not noticed that type of thing when shooting, but I largely shoot at the same range at the same time of day. I will have to vary my times and make some notes about weather conditions as the seasons change to see how noticeable this is.

Spend a day at the range. From first light to midday, and back to waning sunlight, you’ll see the target shrink and re-expand. If the humidity is great, you may even see it dancing the hula, and if the stands are close to the ground, you might see half of your target disappear. Light, how it bends, and how our eye receives it is truly miraculous.

 

[DMW1116]

I have to rezero my silhouette rifle for Sunday’s rimfire competition. I’ve been zeroing it to hit center of a 3” circle at 60 yards from a 6 o’clock hold. Maybe I’ll change it and see how it goes.