AR Sponsor
Posted: 9/7/2015 8:29:17 PM EDT
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CBC is good quality ammo and the Sportical is the bottom rung of DPMS rifles.
Get your rifle fixed. If DPMS hassles you and says it's CBC, it's BS. It's DPMS. Otis dry lube in a DI AR is generally not ideal. If you use too much, it can gum up the rifle and cause friction with the bolt, slowing/retarding cycling. Slow cycling is what causes cases to eject at the 5:00 and back location. Otis dry lube also does not emulsify carbon, so the carbon just builds up and creates friction. If this rifle has barely been fired and the bolt is moving slow, it's usually from friction due to insufficient lubricant, or from under-gassing. Under-gassing can come from gas loss somewhere in the system, or from an impedement in the system like an obstruction or misaligned gas port-gas block. The other option would be too heavy of recoil spring and buffer, but for a .308 that would take a lot spring and buffer weight. We would need more information to determine why parts broke, but immediately I can only think of either metal fatigue or the rifle was improperly assembled at some point either at the factory or by someone outside the factory who was dicking around with the rifle before it was shot... |
| That's very informative. I didn't know about the dry lube acting like that but it was borrowed, I forgot to bring mine; I had intended to lube it before shooting it. I am quite sure it was assembled improperly damaging the pin. I'm going to find an aftermarket replacement and try different lube and ammo. I know the rifle is "cheap" but that's what you get when you drag $600 through walmart. I did however think that the major components of a DPMS 308 rifle were reliable. I might replace furniture and the horrible trigger but all I want from this one is reliability. |
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I would blame the lube (or essentially the lack of lube) for the cycling issues, but I can't speak to the busted pin.
I use motor oil, but whatever you use, ARs like to be run glistening wet. My .308 Oracle will cycle 110gr loads down to about 1700fps before it will stop locking open on empty mags. It has over 2000 rounds without any issues. Btw, just so I understand, you did not clean or lube it before shooting it the first time, correct? Good luck! |
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I've said this repeatedly:
If you're paying $600-$700 for a .308 AR, it's going to be a tinkerer, gunsmith, troubleshooting project special. That's what I personally would fully expect, knowing that there are going to be issues with the gun that need addressing before I would even want to shoot it. I've irreparably bent at least 3 firing pin retaining pins in my .260 Rem, because it's just pure hell on primers, and the resulting rearward speed of the firing pin, which impacts the FPRP. I can also see this being a problem with a CLGS .308 AR, where extraction conditions and timing of the gas system are violent and premature. First thing that has to be replaced on the LR-308 Sportical is the gas block, as they have always been aluminum when I've handled them. Aluminum gas blocks on CLGS are garbage, should not even be allowed to be thought of. They will fail after a few hundred rounds, sooner the more concentrated your shooting is. Next is the buttstock. That Fardus stock will break at the slightest hint of impact on the toe, especially in cold weather. It should have never been born. Then you need to seriously mitigate the CLGS and buffer weight. I personally would replace the RE tube with an A5, and use a heavier buffer or JP SCS if I felt like pounding money down a rat hole. The tiny carbine-length buffer on these guns simply does not have the space to cascade the weights well in the return stroke when going into battery. This is why KAC and ArmaLite use longer RE tubes for the carbines, with heavier buffers. I would also get the GII extractor upgrade from DPMS, since it is one of the few things that is back-compatible, and is made from better steel, with better controls on metallurgy. The legacy extractors are known failure points. The chambers tend to be tight on these guns in many cases, so a chamber cleaning might be a good idea if you have any factory ammo you intend to shoot that won't come out with gravity after a full seat. You need to keep spares on hand for the tiny small parts with these guns. I have a little Dewalt storage box in my Storm case for my .260 Rem AR with spares, tools, everything for the scope mount, just in case. |
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Quoted:
I would blame the lube (or essentially the lack of lube) for the cycling issues, but I can't speak to the busted pin. I use motor oil, but whatever you use, ARs like to be run glistening wet. My .308 Oracle will cycle 110gr loads down to about 1700fps before it will stop locking open on empty mags. It has over 2000 rounds without any issues. Btw, just so I understand, you did not clean or lube it before shooting it the first time, correct? Good luck! I meant to lube but forgot to bring oil. No cleaning but I see now that was an oversight. |
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...snip I knew when I first handled it that the stock would have to go. Do you have a preferred source for upgrade parts or should I just use DPMS replacement small parts from somebody like brownells? Your .260 bending the retaining pins seems really odd because when the cartridge ignites the hammer is still behind the firing pin. A5=VLTOR? I'm slowly gathering parts for another project and would have bought one the other day but the store stopped stocking them. Where would you get it? |
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Brownell's carries the A5. That is the only length extension tube you can use with an AR15 carbine-length buffer. I would use an H3 or JP SCS with the right spring option for your gas system length, port diameter, chamber, and preferred load window.
Pick any reputable Mil-spec diameter buttstock of your liking, whether it be VLTOR, LMT SOPMOD, B5 Systems SOPMOD, Magpul, LWRC, etc. Your biggest problem right now is a .308 with a CLGS, and an extractor that has a reputation for failing. |
| Please email [email protected] with your shipping info and I will get a new retaining pin shipped out. |
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Please email [email protected] with your shipping info and I will get a new retaining pin shipped out. I've already got a parts order on the way but thank you. 
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Quoted: Please email [email protected] with your shipping info and I will get a new retaining pin shipped out. Any reason for the Sportacticals to stick w/ carbine gas? Both the 5.56x45mm & the .308" have 16" bbls, wouldn't they run smoother w/ carbine gas? Could you maintain those $500 & $750 pricepoints if you switched? Those pricepoints are great btw. Those are two of my best baits to get folks to the gun counter, and I sell both of them regularly. |
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