Posted: 2/9/2013 8:27:34 PM EDT
| Having a problem with 18" 7.62 OBR. This is a new rifle, but not my first OBR. I received this rifle on Thursday.i have a Thunder Beast arms supressor on it. I have shot it a few times today with 168 FGMM. The primers were all cratered and the rifle did not eject. The gas block was flipped to the right (from a shoulderd position) The rims were torn from the case head in every round fired and the next round was picked up and tried to chamber. Upon clearing the rifle the case left in the chamber easily fell out of the chamber upon being turned barrel up and bolt locked back. I also shot the rifle with the gas block flipped left and the same result. In supressed the rifle fired and ejected without issue. Any advice? |
Okay you shot the OBR WITH a suppressor on it, Right ? You shot the gun with PST on suppressed (R) and it tore up cases? Then you shot it with the PST on unsuppressed ( L) and it did the same thing ( tore up cases) ? Next to last sentence, "In suppressed the rifle fired and ejected without issue." ? Anyone else confused? OP , please clarify. |
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I would call Larue. It appears you are over gassed when running the suppressor. You still have to much chamber pressure when it tries to extract the round so the case sticks to the walls and the extractor rips through the case. A heavier buffer might fix the issue, but its probably best to have Larue check it and make sure the gas ports are in spec. (or at least discuss the issue with them before making changes)
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Quoted:
Okay you shot the OBR WITH a suppressor on it, Right ? You shot the gun with PST on suppressed (R) and it tore up cases? Then you shot it with the PST on unsuppressed ( L) and it did the same thing ( tore up cases) ? Next to last sentence, "In suppressed the rifle fired and ejected without issue." ? Anyone else confused? OP , please clarify. I missed the last "in supressed" when I proof read the post. It should have read "un supressed" the iPhone auto corrects "un" to "in". It functions fine running W/O supressor. As for the other question about calling Larue. I plan to on Monday, However I have had a hard time getting in touch with someone there last week, so I figured I would seek advice here. |
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I'm glad to hear they were your first call. Try first thing in the morning if you can that is always the best time to call and actually talk to someone quickly.
I will give you a little background about my OBR's and what helped mine. I have an older 20" OBR that runs great with a sf762ss can. Never had any problems with it. I have a newer 16" that I picked up in July that did not like the surefire as much. It would short-stroke almost every shot while the PST was on suppressed side. I took it in for the Larue folks to look at. They had it fixed within a day. Their solution was to use the green spring and leave the PST switch on unsuppressed. Being a heavier spring, it did not beat up the components when using a suppressor, and it worked fine without a suppressor as well. Problem solved. I can tell you this: The PST was designed to be run with a different suppressor than you have. Most companies that run switches will tune each individual rifle to the suppresor that the operator wants to use as well as a particular type of ammunition. Suppressors are all not the same in that they generate different amounts of back pressure. To my knowledge Larue will not tune their PST switch. As for your particular problem it sounds much different than mine. Hopefully you live close by and can bring the can to them and wait while they test it on your rifle. j |
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Called John at Larue yesterday and we discussed the brass tearing situation. I happened to be near Round Rock today and I just took the rifle by for them to have a look at. Short and simple, they fixed everything up. The Thunder Beast suppressor runs with more back preassure then the Shurefire they are set up for. They put a heavier spring in and no issues. There may have also been some grit in the chamber or on the cases that had their rims ripped off accentuating the problem.
Typical Larue fashion... A++ customer service, not only do they make some of the best products available they are nice people as well. |