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Posted: 4/29/2009 6:39:20 AM EDT
| Just starting to learn about AR's. Noticed that my Bushy firing pin is unshrouded & was wondering how much difference it makes as compared to some that are shrouded. |
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The one drawback to un-shrouded bolt carriers, is that in some weapons the firing pin retaining pin gets beat up during firing. If your rifles FP RP is not showing any signs of damage, then you should be ok.
If it does show signs of damage, inspect it often and replace when you see the need. |
| On certain rifles, the firing pin can hit the hammer as the bolt cycles. This pushes the FP up and bends the 'cotter pin' that retains the firing pin. IIRC, in some cases the cotter pin breaks, which can release the FP and bolt cam pin, causing a disastrous disassembly under fire. If your cotter pin is not being damaged during firing, your rifle is not one of these. In any case, a shrouded carrier is better for this reason. |
I like to avoid them when I can - the risk is that the tip of the hammer catches the firing pin each cycle, which can result in the firing pin retainer getting bent. This is a bigger concern when combined with an AR15 hammer (as opposed to a cut-down M16 hammer). You will probably be just fine, but keep an eye on the firing pin retainer, and if it is getting bent be sure to replace it before it gets too beaten up... when they break, they can lock the gun up solid (ask me how I know  ).
ETA: Others beat me to this explanation. Frankly, this modification is just another stupid example of Colt trying the save the world from "illegal full-auto conversions"... just like with the silly block they used to insert in AR15 lowers, the dumb "large pin" thing, and the AR15 hammer. I avoid such half-assed parts whenever possible. |
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ETA: Others beat me to this explanation. Frankly, this modification is just another stupid example of Colt trying the save the world from "illegal full-auto conversions"... just like with the silly block they used to insert in AR15 lowers, the dumb "large pin" thing, and the AR15 hammer. I avoid such half-assed parts whenever possible. If I understand it, the idea is, if the hammer is NOT being held down by the trigger/disconnector, like someone trying to intentionally create bump/slam fires, the hammer should get caught in the firing pin before the bolt goes all the way home and thus stop the functioning of the weapon, at least bending the cotter pin if NOT worse damage as well. |
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I have the "half circle" type in mine. Are they good/bad/doesn't matter? If your rifle functions with it, realistically, it doesn't matter. There's no reason for it not to. The half-circle carrier weighs a whopping 0.8 ounces less than an M16 carrier. |
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To the OP: Recent Bushy's I've examined had the AR 'enhanced' style carrier, with a shortened lower circle, but a fully shrouded FP. Which of the pictures actually looks like your Bushy's?
A now-departed HBar had the half circle carrier and the unshrouded pin; I could feel the FP collar dragging over the hammer when handcycling, but it never caused trouble when firing. No real reason to have an unshrouded carrier, and there is some potential for mischief. Moon |
Two pics at different angles of unshrouded firing pin carriers, unshrouded carrier on left of the pics. There are many manufacturers that makes them, the OP said he got a Bushmaster, I've had them from the early '70s Colt SP1 and other various Colt models until around 2005, the newer ones are half-circle. The only part that I wear out on my AR that I usually replace are the firing pin retaining pins, it's a good idea to keep some spares. |
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I have 2 of each and didn't really pay attention that there was a difference until last night. I just don't have my AR apart at the same time to ever have a chance to notice the difference. I log onto Arfcom to see why there is a difference and whallaa, the answer. Thanks Arfcom.  |
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