Tag: accuracy

Telescopic Trivia

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Wow, you look like a Clark Kent version of your last picture!

OK, scopes. I’ll quote CoPilot:

”First focal plane (FFP) scopes scale the reticle with magnification for accurate holdovers at any zoom, while second focal plane (SFP) scopes keep the reticle size constant, prioritizing clarity and simplicity.”

Let me translate: With an FFP scope, when you increase or decrease magnification, the reticle changes size as well. with an SFP, the reticle stays the same size. The practical effect is that the hashmarks on the FFP measure the same amount in relation to the target. If you see a target that is 2 MOA in width, it will remain two MOA regardless of magnification. With an SFP, the only time a hashmark is an accurate measure, is at its true magnification point (this will be marked on your magnification ring).

Practically, it makes an SFP a bit easier to adjust your shots on the fly (it also enables you to determine the range of the target more quickly).

An example: you are shooting at a target at 600 yards. You shot hits at what looks like a foot to the left. At 600 yards, that would be 2 MOA. You line up your scope on the impact point and, lo and behold, the target lines up perfectly on your right 2 MOA hashmark. Yup, 12 inches. So hold 2 MOA right of the target, and you’ll hear an impact on steel. And if you’re shooting at 800 yards, your 2 MOA hashmark will measure 16 inches. Amazing.

The SFP scope can do this as well, but only at its true magnification point. One of my scopes has a magnification range of 6 to 24 times. At 18, it is true. And it’s a pretty good setting that allows a wider field of view, but shows the target clearly.

FFPs are a bit more expensive.

Yes! While it’s nice to have a laser rangefinder, you don’t always have it available. But some simple math based on angle and distance will give you a fairly accurate range. The formula for using MOA is:

Known target size in Inches X 95.5/Target size in MOA= Distance to target in yards

Let’s plug in some numbers. You see a target and know that it is 2 feet tall, or 24 inches. 24 times 95.5 is 2,292. You line up your scope and see that it measures 6 MOA in height. 2,292/6 =382 yards.

If you happen to be using a scope that uses Milrads (milliradians) instead of MOA, the formula is slightly different:

Known target size in Inches X 27.77 divided by target size in mils = Distance to target in yards

Ballistics

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a: the science of the motion of projectiles in flight

b: the flight characteristics of a projectile

Or, how to shoot stuff and try to have it land in the same zip code.

Well, then. What info do we need to feed into a ballistics program for it to give us a solution?

  1. Rifle details
  2. Scope info
  3. Cartridge details
  4. Density Altitude
  5. Distance to target
  6. Wind
  1. Rifle details – caliber, barrel length, twist rate
  2. Scope details – type, height above barrel, sight type
  3. Cartridge type – caliber, bullet size, bullet weight, bullet shape, muzzle velocity
  4. Density Altitude – from your device or local online info
  5. Wind – speed and direction

Most of these things you can get from your manual or online info, but how about muzzle velocity? Well, some commercial ammo gives MV, but only from their test rifle and barrel length. If you are going to be accurate, you MUST have a chronograph that measures your shots from your rifle at your DA. Otherwise, you are just guessing and GIGO comes into play – Garbage In, Garbage Out.

DOPE – Data On Previous Engagement.
Once we have entered all of this info, the ballistics program will give its proposed solution:

Screenshot

Welcome to reading the wind, Emily.

Brief diversion

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Yep, shooting God’s own caliber today.

It finally got above freezing today (33 degrees), so I shot the ladder test for my new .45 ACP 200 grain copper-plated semi-wadcutters. And got a clear winner.

10 yard 3/4” group from a sandbag. I’ll take it. But I do need to move that new rear sight a tad right.

Of course, Emily. And yes, we’ll get right back to ballistics.

Zeroing the scope

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Yup. Show us the windage turret and what you see.

1 CLICK = 1/4 MOA.

Well, this sounds familiar! Yes, adjustable turret scopes tell you how and how much to move your bullet impact on the target. The Windage knob will adjust the bullet right or left. The Elevation knob on top will move it up and down.

Start by firing a group of three or four rounds at the 100 yard target.

Check the group.

I’d say we want to bring the center of that group down three inches and left three inches. So, if 1 click is a quarter of an inch, 4 clicks is an inch and 12 clicks is 3 inches. Dial the elevation down 12 and the windage left 12. Shoot three or four more rounds. Voila!

Not bad. I’d move windage right 3 or 4 clicks and see if the center of the group is dead on. Don’t be afraid to expend some ammo to get it right where you want it.
Once zeroed, you need to be able to return to this setting routinely. Scopes have various ways to do this.
This zero point is the basis for everything you will do henceforth.

Chapter 1

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No one may touch a firearm until they know the Four Rules by heart, and can recite them back to you.

Next, what is a AR? It is Not an “Assault Rifle”! The AR comes from Armalite, the first maker of Eugene Stoner’s iconic design. It is a semiautomatic rifle, NOT a select fire (machine gun). It requires one trigger pull for each round fired. Select fire (such as on the military M 16 or M 4) will continue to fire so long as the trigger is held back and ammunition remains.

There are so many designs of the original that they are now known as “AR pattern” rifles. They function similarly and are quite modular and can be tricked out in many ways. There are somewhere between 20 and 30 million AR 15s in the USA; hence, it is sometimes known as America’s Modern Sporting Rifle.

It fires a quite small bullet, but very fast. There are many variations of rounds, but the original military round was 5.56 millimeters in diameter, weighing 55 grains and had a muzzle velocity around 3,000 feet per second. The civilian version is the .223 Remington – there are some differences we will get to later.

It is a magazine-fed rifle with a standard capacity of 30 rounds.

Today, we are going to cover loading by looking at the Charging Handle, the Bolt Release and the Magazine Release Button. Below, locate the Charging Handle at the rear of the receiver, the Bolt Release on the left side near the magazine well, and the Magazine Release Button on the right side magazine well.

Found them? Now (observing the Four Rules!), pick up your AR, right hand on the pistol grip, finger outside the trigger guard and left hand on the barrel handguards. Pull the stock butt against your hip. Does the rifle have a magazine in it? Remove it by taking your trigger finger and pressing the Magazine Release Button. Catch the magazine with your left hand and set aside. Left hand back into position.

Now, with the first two fingers of your right hand, pull all the way back on the Charging Handle. If there was a round in the chamber, it will have ejected off to the right.
Keeping the Charging Handle all the way to the rear, depress the bottom of the Bolt Release and slowly let the Charging Handle forward until the bolt is caught, then push the handle all the way forward. Rotate the rifle 90 degrees to the left and look in the chamber. It should be empty. You can now turn the safety lever to Safe from Fire.

Take a loaded magazine and energetically push it into the mag well; you should hear and feel a click. If not, rap the bottom of the mag with your left hand. Check that mag is secure by trying to pull down on it.

To load a round into the chamber, smack the Bolt Release with the heel of your left hand. The bolt should go energetically forward, stripping a round off the top of the magazine and ramming it into the chamber. You are now ready to start the shooting process.

Having fun with my G21

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Putting new sights on DILIT’s G44 got me focused on Glocks for a bit. There just may be a little order coming in from Midway. In the meantime, I thought I’d strip the 21 down and do a little cleaning and trigger work. So pop out the three pins and here is what you get:

These are the parts we will be polishing to remove friction in the trigger assembly.

Post-polishing:

Reassembly:

Where metal meets metal.

Reassembly into frame:

And, finally, testing trigger pull weight:

4 to 4.25 pounds. If it was just for targets, I’d put a 3.5 pound trigger bar in. Having it go into the carry rotation, I’ll keep it firm.
Yup, winter is for projects. I’ll be looking for that Midway package.

Yes, I have been ignoring short arms.

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No, not short arms inspection.

Caliber .45 Automatic Colt Pistol! I hauled out an ammo box of ten 100-rounds plastic boxes and it felt a little light. After full inventory, I discovered a shortage of 200 grain Semi-Wad-Cutters.

Had to switch out the bullet seater to flat nose.

Then, make sure they pass the “plonk” test.

Maybe test it tomorrow?

Back to Winter Shooting

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So how did the 156 Bergers shoot? Not bad:

That’s 4 rounds of the 39 g. load. The 40 g. load opened up a bit, but looking at SD and ES, there was at least one bad reload.

To make the point, I shot my last two rounds of it at a 300 yard silhouette:

Just over an inch. I’ll take that all day long. And when I shot the Dueling tree paddles, the impact was impressive. Nothing like upping the M in the F=MA.

But the best surprise of the day was shooting some Hornady 120 ELD M I had put together a while back:

4 rounds, baby!

🖐🏻 8 👫

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Yup, been on a 10-day one. And worse, no shooting! Well, I fixed that today:

The Long Range just had its annual clearing and I may have been the first one to shoot. 76 degrees, humid, density altitude of 2473’, and a left to right light breeze.

I used the opportunity to wring out the Hornady 120 grain ELDM load. After doing the paperwork and weather, I loaded up and got going.

I’m very pleased with the round. It shot flatter than my Applied Ballistics program predicted by about 2 MOA at distance. Hits at 525, 829, 867, 875, 975 and 1,106. The wind did not seem to affect it any more than my standard 140 g loads.

And, after I was done, I did a drone tour of the newly cleared range. I just might post it soon!

Back to load ladder test

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I think I can say I’ve maxed out the Accurate 4350 powder – I’m not going to get more than 2800 fps with the 120 g. bullet and the 22” barrel. I also think that great load from the other day is the node:

Upper left – first two rounds were touching at a quarter inch, and hitting in the same spot as before, about a half inch right and half inch high. Then, what I think is a clear flyer. Everything else is around an inch. And I think I’m at the point where the slower burning powder has no more time to combust.
But it’s been a nice test. I’ll load up a bunch of the first and take it out to distance. See if the wind affects it significantly more than the 140s.

And I still think DJT is the laser pointer president.