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Posted: 5/24/2006 8:08:47 PM EDT
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I just bought AR-15 from a private seller. model1sales 6.8 SPC upper... RRA Lower. The Bolt operated smoothly, opening, closing it seems to seat correctly. But when I cycle a round onto the chamber it locks up.  I am unable to pull the charging handle back to remove the round. The only way to remove the LIVE round is to seperate the lower from the upper and pull like hell to release the bolt. I am afraid to fire the rifle... What could be the problem?  Please help. |
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You will need to get an ammo check gauge (L.E. Wilson Case Length Gauge 6.8 SPC to check the ammo), a head space gauge to check the barrel chamber, and even a Stoney bullet seat gauge. It could be that the chamber is not reamed correctly (too short), the ammo is not produced correctly (shoulder bulge from crimping or case too long), or that the ogive of the bullet in embedding into the rifling at loading (bullet OAL too long for ogive/chamber throat). |
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Since you didn't build the rifle, let me share one or two things to check as well. I've never tried to use a 223 bolt with a 6.8 barrel, but the 6.8 uses a different bolt than the 223. Make sure the bolt is a 6.8 by comparing it with a known 223 bolt - you should be able to see a difference. You might want to check your ammo. The 6.8 is still in sort of a state of flux and there are several different specs running around out there. You didn't mention brand of ammo you're using, but if it is Remington or Hornady it should not measure more than the spec OAL. If it is someone else's ammo, check it with a micrometer. the bullet could be seated too far out. Assuming all is okay with the bolt and ammo, then you're definitely going to need the guages. |
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The upper was bought new as a complete 6.8 SPC upper. Only the lower was actually assembled. Here's a comment from a group I belong to. "Neither tight or loose headspace causes rifles to blow up. Loose headspace does cause excessive case stretch which weakens the brass in subsequent reloadings. Machine guns run MUCH longer headspace, but .gov does not reload the cases... Tight headspace is just an annoyance in that "standard" size ammo will not chamber." Randall Rausch www.ar15barrels.com [email protected] See my feedback forum: www.ar15barrels.com/comments I assume you're using the Silver State ammo that was included with the deal? I have been told by many people on different boards that they have had problems with the tolerances of Silver State, and that you should try cycling Remington rounds and see how it works. I should also mention that I contacted Model1 about the problem and they said he could send it back to the factory and they would ix it or just replace it all together. It sounds like they have very good customer service. |
It's funny to see my comments cross posted... Nothing to see here, move along now... And do try some Remington ammo to see if the problem is isolated to the SSA ammo. Early SSA ammo in Model 1 barrels is a "known issue" |
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You werent by any chance using Silver State Armory 115gr Extreme round were you? Be advised, some ammo in 6.8 isnt designed for AR use. It might shoot, it might not chamber properly, it might not eject properly, it may even blow up your upper reciever. Knock on wood. |
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I have had a few MDL1 uppers, check the following: 1) Correct bolt 2) Use Remington factory ammo 3) If you are reloading, check your dies. 4) If you try all the above and still no luck, send it back to MDL 1, they have a great customer service department, call ahead and send the upper back with a detailed letter and wait for the brown truck! *Do not use any hot loads in the upper! |
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