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Posted: 6/27/2010 4:28:28 PM EDT
| I can only put the selector on safe when I have cocked the rifle. This does not seem normal. When not cocked, it won't turn off of "fire". Any ideas what may be causing this? I took the spring out and put it back in, no joy. I do have an aftermarket grip, not sure if that matters. |
| Not to sound harsh, but before troubleshooting a rifle one really should know how the rifle operates and what is normal functioning. Taking out springs, replacing grips... and not knowing what is normal functioning and what is not is a sure way to muck up a perfectly good rifle. There is no shortage of places on the internet to download manuals of all types and especially the AR-15/M16 class of rifles. Before doing any more modifications to your rifle it would be a good idea to get the manual and spend some time reading so IF you have a problem you will know it really is a problem and you will not end up trying to fix something that is not broken. |
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"I can only put the selector on safe when I have cocked the rifle. This does not seem normal. When not cocked, it won't turn off of "fire". Any ideas what may be causing this? I took the spring out and put it back in, no joy. I do have an aftermarket grip, not sure if that matters."
How does one fire an uncocked AR rifle? If you are unable to fire a rifle, wouldn't it be safe? Have you ever studied the "fire control group" and how the trigger, hammer and safety selector interact? When the hammer is uncocked the distance from the hammer pivot pin to the bottom radius of the hammer is such that it tips and holds the rear of the trigger rigid up into the slot in the safety selector shaft. This does not allow the safety selector to be rotated out of fire position. When the hammer is cocked the front edge of the trigger snaps up into a notch in the hammer, this allows the rear of the trigger to drop down and allows the selector to rotate so that the full diameter of the selector shaft locks the trigger into a rigid position and locking the hammer in safe position. Pretty basic mechanics. 
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Quoted:
Not to sound harsh, but before troubleshooting a rifle one really should know how the rifle operates and what is normal functioning. Taking out springs, replacing grips... and not knowing what is normal functioning and what is not is a sure way to muck up a perfectly good rifle. There is no shortage of places on the internet to download manuals of all types and especially the AR-15/M16 class of rifles. Before doing any more modifications to your rifle it would be a good idea to get the manual and spend some time reading so IF you have a problem you will know it really is a problem and you will not end up trying to fix something that is not broken. Isn't this like saying, "Don't go near the water until you know how to swim!" I thought it was a fair question. |
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Bottom lob of the hammer is oblong .
When the hammer is uncocked, the bottom lob of the hammer cams the front of the trigger downward, preventing the selector from being set to safe (read back of the trigger now too high). Simply, unless the hammer is cocked back (read as in the weapon charged) the selector can not be set to safe. |
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lob?
Main Entry: 1lob Pronunciation: \ˈläb Function: noun Etymology: probably of Low German origin; akin to Low German lubbe coarse person Date: 1508 dialect British : a dull heavy person : lout Main Entry: 3lob Function: noun Date: 1851 : a soft high-arching shot, throw, or kick Main Entry: 2lob Function: verb Inflected Form(s): lobbed; lob·bing Etymology: lob a loosely hanging object Date: 1599 transitive verb 1 : to let hang heavily : droop 2 : to throw, hit, or propel easily or in a high arc 3 : to direct (as a question or comment) so as to elicit a response intransitive verb 1 a : to move slowly and heavily b : to move in an arc 2 : to hit a tennis ball easily in a high arc An oblong? Cam? Main Entry: 1cam Pronunciation: \ˈkam Function: noun Etymology: perhaps from French came, from German Kamm, literally, comb, from Old High German kamb Date: 1777 : a rotating or sliding piece (as an eccentric wheel or a cylinder with an irregular shape) in a mechanical linkage used especially in transforming rotary motion into linear motion or vice versa The hammer does not cam at all. The bottom of the hammer is round, the radius is consistant to the pin hole. The radius on bottom of the hammer holds the trigger rigid consistantly during the cocking (charging) process, it's a straight line action not a cam action. Any cam action would cause excessive pressure on the trigger. when the hammer is rotated completely (charged) the leading edge of the trigger snaps up in to a notch in the hammer, dropping the rear of the trigger allowing the safety selector to be rotated to safe position allow the selector shaft to hold the trigger in a ridgid locked position. With all due respect. I'm just trying to understand. |
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Take a piece of wood and drive a finish nail through it.
Now put the hammer on the nail (though the pin hole), and stick a nail/pin at end of the sear corner (as if the trigger sear just cleared it, now turn the hammer on the nail like it is uncocking. Your going to get a few degrees of hammer turn, but no where near a true uncock rotation since the bottom round of the hammer is going to pushing the loose nail/pin outwards. Sames happens with the trigger, being once the trigger clears the sear edge, the hammer bottom round shape presses the front of the hammer downwards/back upwards. The bottom round on the hammer is somewhat constant, but if you add in the sear inward step as the start point, it does create the over all radius cam lob. |
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