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Posted: 1/3/2010 6:14:55 PM EDT
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I know on handguns, loading and unloading the same ammo (in the chamber) will cause the slug to work loose. On my AR, the bullet gets chewed a bit more than on my bolt guns. I've been trying to minimize the loading and unloading, but toting the rifle around for 3 days while hunting, would result in 3 unloadings.
Has anyone seen much affect on accuracy? What do LEO's and mil types do? And this is not fmj, these are 68gr HP. |
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Quoted:
I know on handguns, loading and unloading the same ammo (in the chamber) will cause the slug to work loose. On my AR, the bullet gets chewed a bit more than on my bolt guns. I've been trying to minimize the loading and unloading, but toting the rifle around for 3 days while hunting, would result in 3 unloadings. Has anyone seen much affect on accuracy? What do LEO's and mil types do? And this is not fmj, these are 68gr HP. cycle the ammo in the mag. Put the one you loaded before a couple rounds under and load a fresh one in, it will create set back which will affect accuracy slightly, you will more than likely never notice it though unless your shooting some sort of accuracy competition. |
| Another to think about is the extractor taking small chunks of brass off the neck every time you eject the round. This was noticed during a weapon inspection at the PD where I used to work on a round in a guys gun. It seems this guy would unload his duty gun every night when he got home for 6 months because of his kids. He then put the same round back in the chamber everyday for work. During the inspection his round failed to eject. The cause was determined to be that the extractor could no longer grap the rim of the round in a certain spot because it had been cycled so many times it chewed the rim up |
| At a wound ballistics workshop I worked a couple of months ago we got a recommendation from a Rep from ATK that handgun rounds should not be loaded/unloaded more than 3 times without taking them out of rotation in a defensive situation. Practice was one thing, but they shouldn't be relied on to save your life because of the possibility of bullet/cartridge seperation. He gave us a technique where you empty your magazine, line the rounds up and place the round you unloaded from the chamber first in line and start loading. That way your loaded round has to make it all the way back through the line before it is chambered again. Takes awhile to get loaded 3 times that way. |
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doc roberts posted about "misfires" from one police dept (in a fire fight) that chambered the same rounds a few times (clearing chambers ends of shift) and the floating firing pins repeatedly hit the primer to cause it not to fire when needed.
I guess they only use chambered rounds on the range since this discovery. |
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Bullet set back can create excessive pressure and is in fact a big deal. We carry our rifles in "cruiser ready" condition which is bolt forward on an empty chamber with loaded magazine inserted. If a round is chambered and not fired it gets turned in and replaced. It is not a daily occurrence here and we keep lots of ammo.
In my personal rifle I will rotate rounds that have been chambered and not fired to a training magazine after inspecting them. Ammunition is designed to be chambered and fired once, the trip from the magazine, up the feed ramps and into the chamber is fine once. Add extraction and ejection and that round is not going to be the precise piece of engineering it started as ever again. For hunting I would still rotate the rounds out as you want all the accuracy your rifle is capable of. Use the non fired but chambered rounds for practice. |
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Thanks for the replies, typically I just keep a full mag either in the gun or in the case with an empty chamber, but it's not really practical for hunting, too noisy to chamber a round when you finally see something you want to shoot.
I guess I'll start a culled ammo box for chambered rounds that I save for the range. |
| Prior USMC and our rule was 5 patrols. We stayed condition 3 (Mag inserted, no round in chamber) when in the FOB, and of course Condition 1 when on patrol. When we had reached 5 patrolsthe individual was responsible to download the first round of the magazine and place it in a range box and replace said round with a shiny new one. I never really saw any difference in what we had placed in the range box as far as accuracy or reliability, but as always it is better to be cautious. |
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I hunted this year with my 6.8 and each day I would single feed the round with an open bolt. Not nearly as rough on the round. I must have chambered that one round 12 days before finally getting a shot. No problems, it went off and split the heart in half on a big ole doe.
That is what I have been doing and it has worked for me so far. I also am not relying on the rifle to protect my life each day too. |
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I think there may be some misinformation at work here.
First, cartridges of different types headspace differently. Most rimless (semi-auto pistol) cartridges headspace on the case mouth. That means the edge of the case mouth contacts a "shelf" at the far end of the chamber. Most rimmed cartridges headspace on the cartridge rim - i.e., the cartridge "stops" when the rim engages the mouth of the chamber. Bottle-neck cartridges (like the 5.56/.223) generally headspace on the shoulder of the cartridge. That is, the shoulder of the cartridge contacts the tapered portion of the bore aft of the rifled portion of the barrel and seats there. In NONE of those cases does the repeated chambering of a bullet "loosen the slug". Now, repeatedly cycling rounds through a magazine, banging the cartridge around, otherwise applying force to it, and even recoil, CAN cause bullet setback or even loosening in extreme cases ... but that's what crimp is for. I think the main risks to repeatedly chambering and unchambering rounds in an AR-15 are two-fold: 1. Damage to the rim from the extractor, and 2. Primer dents from the floating firing pin. So - rotate your rounds in AR's when you are required to carry with a round chambered to avoid repeated primer strikes and rim damage. But the likelihood of bullets coming loose from the case due to loading and unloading is remote. I'm speaking from the perspective of a handloader who has loaded thousands and thousands of rounds. . . |
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