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Posted: 10/29/2010 10:47:38 AM EDT
| I have a Del-Ton upper and lower mated with a Dez arms carbine barrel. It functions fine, but it is beating the crap out of the front of the ejection port and the nut that the free float rails are attached to. What would cause this? Is it a case of short stroking some, but not enough to make it fail?? I think the chamber of the Dez barrel might be a little tight as well. |
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Sounds like weak Ejector spring, meaning that the extractor is hanging onto the round too long. Ive seen bolts from the factory with buggered up ejection springs. I would completely dissasemble your bolt and inspect everything and lube it all up real good after a good cleaning. Ive found BRAKE cleaner does a good job.
If its short stroking, it wont even get the round out of the receiver, it would hold it in there and try to pick up the 2nd round and you get a big ole traffic jam in there.  Or it might try and get the round out but when it short strokes, the bolt comes forward before the round can leave the ejection area and usually you get a stove pipe. If your rounds are clearing the ejection port area, im still going to go with either tight ejection port opening or ejector spring weak.
Also when you inspect the bolt, manually move the extractor to make sure its not binding and its allowed to move, this could also keep the round on the bolt too long. |
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Not short stroking, more likely the opposite. From your description making a presumption that you have a 16" carbine gas configuration barrel...
High bolt velocity can also do that... are you getting some wear at the rear of the ejection port and/or on the deflector also? With very high cycle speeds the cases will sometimes bounce forward off the rear of the ejection port or the deflector and then hit the front of the ejection port or other parts as you describe. This can happen with overgassed barrels with light buffers. The previous suggestion of inadequate ejector force can also work in combination with high cycle speed to do this. Check the ejector and extractor as mentioned, and try a heavy buffer (probably 9mm weight) and see if that doesn't tame the ejection pattern. |
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Quoted:
Not short stroking, more likely the opposite. From your description making a presumption that you have a 16" carbine gas configuration barrel... High bolt velocity can also do that... are you getting some wear at the rear of the ejection port and/or on the deflector also? With very high cycle speeds the cases will sometimes bounce forward off the rear of the ejection port or the deflector and then hit the front of the ejection port or other parts as you describe. This can happen with overgassed barrels with light buffers. The previous suggestion of inadequate ejector force can also work in combination with high cycle speed to do this. Check the ejector and extractor as mentioned, and try a heavy buffer (probably 9mm weight) and see if that doesn't tame the ejection pattern. What I was thinking. |
| Thanks guys. I just pulled the bolt and checked the tension the ejector and extractor and they feel (by hand) just like the factory Colt that I have. My fist thought (well second) was that it might be over gassed. I'm going to try the Colt BCG and see if that clears it up. If not I will try a heavy buffer and new spring or maybe just a new buffer spring???? Of all the parts in the rifle (I have built many) that is the only part that I just dug out of an old parts box. Do you think it could be a weak buffer spring causing this as well??? |
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Quoted:
Thanks guys. I just pulled the bolt and checked the tension the ejector and extractor and they feel (by hand) just like the factory Colt that I have. My fist thought (well second) was that it might be over gassed. I'm going to try the Colt BCG and see if that clears it up. If not I will try a heavy buffer and new spring or maybe just a new buffer spring???? Of all the parts in the rifle (I have built many) that is the only part that I just dug out of an old parts box. Do you think it could be a weak buffer spring causing this as well??? What kind/weight of buffer are you using? High spring tension doesn't do much to slow the cyclic rate. |
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Yeah,
That 12:00 ejection happens sometimes.....I've seen internet slow motion films that show it happening. One round every once in a while bounces off the back of the port and goes directly forward. When it happens, sometimes, it's like the brass does not eject all that far away and lands 1-3 feet from the rifle. I wouldn't worry too much unless it malfunctions. |
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In a normal cases, you have the spent case pressure bound to the bolt face, the extractor holding the rim, and the ejector applying pressure on the spent case to pivot it out as soon as the rearward movement of the Buffer and B/C come to a halt on the back dead blow effect. This stall allows enough time for the spent case to be pivoted rearward.
Now if the spent case is not pressure bound to the bolt and the eject tension is not strong at the stall, then as the bolt moves forward, the spent case will be driven off the bolt as it moves forward. Next comes the extractor having too much grasp, and again the spent case not leaving the bolt face until after the stall since it can not be pivoted off by the ejector tension fast enough before the bolt moves forward. Lastly, comes the rearward buffer stall itself, and if not great enough due to a weak stroke, then again, the again, the bolt starts moving back forward before the spent case is ejected. But, to throw a monkey wrench into the works, the concept of rearward spent case ejection was created by the dead blow effect of the buffer alone, which was designed to slow the rifle rate of the rifle down. In the Beginning of the full auto AR-15 (before there was the M-16 series), the rifle did not contain any dead blow weights in the buffer, and since there was no rearward stall, all the ejections of the rifle where on a forward path (about 2:30). Now having said this, and the fact that ejection path of the rifle is really irrelevant, so long as the spent cases are being ejected cleanly out of the port, making a standard rifle eject the spent cases in a specific direction is really contrary. Simple, unless the rifle is really having problems with the case itself not clearing the action on ejection, then any ejection of a semi rig within the 2:30 to 5:00 ejection path is going to be fine. |
| Sounds like the gun is "overgassed", sometimes caused by an oversize barrel gas port hole. I bought a used carbine that performed like that. In a way, ejecting hot casings forward, instead of sideways, is a good feature when you've got other shooters in close proximity on the range. Kinda beats up the gun though. |
| Well here's an update and it's worse now. Put in a heavy Spikes buffer and it still ejects forward and now every now and then it jams. The jam will be the spent case stove piping over the next round that is half chambered and the stove piped round keeps the bolt from returning to battery. Drop the mag, yank out the spent case, drop the bolt, insert the mag and fire again. On slow rate firing I don't think I had any jams, but pick up the rate and all you had to do was wait for it to happen. Next test Factory Colt BCG to see if that helps/cures the issue. If so I will be in the market for a new ejector/extractor set up. How hard is a new ejector to install. That's the only part I have never replaced in a rifle. I'm guessing just put it in a padded vice and tap out the pin. Replace and repeat??? |
| My understanding is that the ejector pin should be compressed before the retaining pin can be pushed out or in. There's some tools out there for the process. Just google ar15 ejector tool. I haven't used any of them so I can't speak of one being better than the other. |
| My LWRC ejects forward, the bolt is a bit shallow and when I replaced the spring there was too much spring tension and it prevented the bolt from going home on a case. So I put the original slightly shorter spring in and it works fine except the cases going forward. |
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Quoted:
My LWRC ejects forward, the bolt is a bit shallow and when I replaced the spring there was too much spring tension and it prevented the bolt from going home on a case. So I put the original slightly shorter spring in and it works fine except the cases going forward. So... It didn't change a thing? For either of you. OP, put things back to the original condition as the "Fixes" have caused more of a problem. 458 |
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