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Posted: 11/9/2015 9:58:11 PM EDT
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I have a 12" SBR that shot on video the other day with and without a suppressor. I noted later how it changed the ejection pattern, so I figured I'd throw it out here for opinions. Barrel is a Larue 12" STEALth (note capitalization - I got the $200 deal a few months ago) with carbine length gas. I'm running a WMD NiB M16 BCG with an H3 buffer. Can is a SiCo Saker 7.62 on a Trifecta mount. Rifle has run flawlessly since assembly - about 300 rounds downrange, maybe 1/3 with the can on. With the can off, brass flies at about 3 o'clock. With the can on, brass flies at about 1 o'clock. I'm not inclined to change anything because it isn't broke. What do you think of the ejection pattern? |
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Is the bolt face retracting back past the back of the ejection port with a full rearward charging handle pull. Hence this will tell us if the spent case is tagging the back of the ejection port window on the way out (that could cause problems with a stove pipe jam).
When the brass is being ejector'd out cleanly (not hitting the back of the ejection port window by the bolt face retracting back past the back of the window), is the brass hitting the upper receiver defector or not. Hence if the brass is being ejected rearward out of the ejection window during buffer stall (The dead blow effect of the buffer is what causes the rearward path of the ejection in the first place), then as the brass hits the upper receiver defector, this alone can cause the direction change in the cases from the rearward path, to the frontward defected path instead. Are the extractor and the ejector working correctly, hence if the ejector is having a problem on the pull of the spent case out of the chamber, then the case is no longer on the bolt face at the back of stroke, and the ejector is not going to eject the spent case off the bolt face correctly. Same goes for if the ejector is binding in the bolt face channel, or the ejector spring is weak to being with. So on that note, get back to me with the above answered, and maybe even a video of the rifle ejection brass. As for if all the above it good, then with a forward ejection and the cases not hitting the defector on the way out, then there is a problem with the buffer not stalling the B/C at the back of stroke correctly, and why the spent cases are being ejected forward instead. To add, the can will add back pressure to the barrel bore, which will increase the gas pressure to the B/C to cycle the bolt rearward. I bring this up, since if the bolt is now unlocking too fast, then this cause a over function problem with the residual pressure in the bore pressure welding the spent case to the chamber walls too much at bolt unlocks/ case pulled and caused the action to shot cycle with not enough pressure of the buffer hitting the back of the receiver extension to allow the buffer to dead blow effect stall the B/C at the back of stoke for the spent case to be pivoted off the bolt via the ejector in a rearward patch. To to wrap it up, Short of the spent cases hitting the upper receiver defector to change the ejection patch angle forward of the spent cases after they have left the ejection port window, the brass should never have a forward ejection angle out of the ejection port itself to being with. Bluntly put, the only AR's that I have that will forward eject the brass out of the ejection port, are match rifle that the extractor spring has been clipped to put the brass in a pile on my shooting mat during matches (so I'm not spraying/raining them on to the next shooter over to the right) and Mac jack rig/s that has the buffer weights in the buffer packed so they don't move/will not dead blow effect, to greatly increase the cycle rates instead. |
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