Ever wondered what the air around a moving supersonic bullet really looks like? Check out this video from the Bryan Litz Ballistics Facebook page. This is a Schlieren video* of a 6mm 109gr Berger LRHT bullet at about 2800 fps as fired from Francis Colon’s PRS rifle at the Applied Ballistics Lab.
Bryan Litz notes: “You can clearly see the compression (shock) wave at the front of the bullet. A compression wave is formed when the air has to move faster than the speed of sound to get out of the way, which is certainly the case for this bullet which is moving about 2.5 times the speed of sound (Mach 2.5).
That shock wave is the ‘snap’ you hear when bullets fly past you if/when you’re downrange. Also, compressing the air into a shockwave takes energy, and that energy comes directly out of the forward velocity of your bullet and gets converted into heat and noise as the shock wave forms and dissipates.
The turbulent wake at the base of the bullet shows where/how base drag applies. The third and smallest component of drag for a supersonic bullet is skin friction drag, which is a viscous boundary layer effect, and is the least visible in this image. So as you head to the range or the hunting stand, think about the absolute violence your bullets are committing in the atmosphere, before they even reach the target!”
This can be very important — even life-saving. For example, with a hang fire, i.e. a round that does not fire immediately, it is vital to keep the gun pointed DOWN-RANGE. And with a squib load, which may have left a round inside the barrel, it is vital to UNLOAD and NOT take another shot! If you did, the gun could blow up in your hand when the second, full-charge bullet hits the trapped bullet.
The Five Topics Covered Are:
Misfeed (aka Tip-Up)
Double Feed
Stovepipe (Failure to Extract)
Misfire / Hangfire
Squib Load
1. Misfeed or Tip-Up: With any misfeed you should stop firing. With the muzzle pointed safely down-range, remove the magazine, then pull the slide back and remove the round that did not feed. Check the slide for dirt, debris, and check the round that did not feed. After re-inserting the magazine, make sure the mag is seated properly.
2. Double-Feed: This is a fairly common issue with some gun types with worn springs or cheap magazines. Again you want to remove the magazine. CTD states: “Remove the magazine and cycle the action until your double-fed rounds fall out — always keeping the muzzle pointed in a safe direction[.]”
3. Stove-Pipe: This occurs when the case of a fired round does not eject fully. There can be many causes — damaged extractor, low-pressure powder charge, dirty chamber, or greasy cartridge brass. In addition the issue is common with old, worn-out recoil springs. To avoid Stove-Pipes, replace the recoil spring every 4000 rounds, and make sure your chamber is clean and the extractor is not chipped or damaged.
4. Misfires and Hang-Fires: There are multiple causes for misfires (“click no bang”) and hang-fires (slow ignition). There can be a defective primer, the firing pin could be damaged, the powder many have been bad, or the case not filled properly. With a misfire, keep the gun pointed down-range at least one minute. If the case does not fire, eject it but leave it on the ground. With a hang-fire (delayed ignition after firing pin strike), keep the gun pointed down-range, then drop the magazine and eject the (new) unfired cartridge in the chamber and inspect the gun when completely empty.
5. Squib Load: A squib load is when the gun fires, but the actual case ignition is very light with little noise, smoke, or recoil. This can be because the case had a primer but no powder. Or it can be because the powder did not ignite. Squib loads can be very dangerous in rapid-fire situations. If you EVER get a squib load STOP immediately! Do NOT fire another round! This is because the squib may have left a bullet inside the barrel.
One of our Forum members complained that he wasn’t able to set his primers flush to the rim. He tried a variety of primer tools, yet no matter what he used, the primers still didn’t seat deep enough. He measured his primers, and they were the right thickness, but it seemed like his primer pockets just weren’t deep enough. He was mystified as to the cause of the problem.
Well, our friend Boyd Allen diagnosed the problem. It was the decapping rod. If the rod is adjusted too low (screwed in too far), the base of the full-diameter rod shaft (just above the pin) will contact the inside of the case. That shaft is steel whereas your case is brass, a softer, weaker metal. So, when you run the case up into the die, the shaft can actually stretch the base of the primer pocket outward. Most presses have enough leverage to do this. If you bell the base of the primer pocket outwards, you’ve essentially ruined your case, and there is no way a primer can seat correctly.
The fix is simple. Just make sure to adjust the decapping rod so that the base of the rod shaft does NOT bottom out on the inside of the case. The pin only needs to extend through the flash hole far enough to knock the primer out. The photo shows a Lyman Universal decapping die. But the same thing can happen with any die that has a decapping rod, such as bushing neck-sizing dies, and full-length sizing dies.
Whenever you use a die with a decapping pin for the first time, OR when you move the die to a different press, make sure to check the decapping rod length. And it’s a good idea, with full-length sizing dies, to always re-check the height setting when changing presses.
There are a variety of decapping dies currently on the market, with models available from LEE, Lyman, Hornady, RCBS, Redding, and Area 419 (at Brownells).
LEE Universal Decapping Die Costs Just $11.99
Speaking of decapping tools, Midsouth Shooters Supply sells the LEE Universal Decapping Die for just $11.99 (item 006-90292), a very good deal. There are many situations when you may want to remove primers from fired brass as a separate operation (prior to case sizing). For example, if your rifle brass is dirty, you may want to de-cap before sizing. Or, if you load on a progressive press, things will run much more smoothly if you decap your brass first, in a separate operation.
Decapping Dies for Cases with Smaller Flashholes
TAKE NOTE: Some Euro Small Flash Holes are spec’d at 1.5mm or 0.059″, and max out at about .062″, so these need a smaller die pin.
The low-cost LEE Universal Decapping Die will work with cartridges from 17 Fireball all the way up to big Magnums. However, NOTE that the decapping pin supplied with this Lee die is TOO LARGE for LAPUA 220 Russian, 6mmBR, 6.5×47, 6.5 Creedmoor, .308 Win (Palma) and Norma 6 PPC flash holes. Because the pin diameter is too large for these brass types, you must either turn down the pin, or decap with a different tool for cases with .059-.062″ flash-holes.
Brownells sells the impressive Area 419 Zero Universal Decapping Die. This features a spring-loaded decapping pin, with replaceable heads. The $50.00 die works with cases up to and including .338 Lapua length/diameter with no need for different inserts.
Redding makes a Universal Decapping Die with an optional smaller-diameter decapping rod for the smaller .059-.062″ flash holes found on the BR and PPC cases. The use of this die is explained in the video below:
