Yes everything was tight, this is the second optic I have had on it, and I have tried with iron sites as well, still no dice. I would expect 1-2" groupings with the ammo I was running especially since I get at least that with my XCR in 7.62x39 with cheap surplus.
Terrible AR-15 Accuracy need help
- Thread starter shoota
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Yes everything was tight, this is the second optic I have had on it, and I have tried with iron sites as well, still no dice. I would expect 1-2" groupings with the ammo I was running especially since I get at least that with my XCR in 7.62x39 with cheap surplus.
Brass seems normal. It also ejects fine and I have never had a jam.
Good grief. Just shoot the thing without anything supporting the barrel/handguard before making the decision to send it back as others recommended. It's a stupid easy test that will only cost you a few rounds. I'm telling you, I've had the same issue when I was sighting in my buddy's M400.
If you look at the setup, the optics are mounted on the upper receiver and not on the barrel (as is the norm) and the barrel is not free floating but supported by the sled under the handguard which is connected to the delta ring and cap on the barrel. IE unless you can exert the exact amount of pressure on the rifle each time as you fire a round, you'll be chasing groups all day long.
If you look at the setup, the optics are mounted on the upper receiver and not on the barrel (as is the norm) and the barrel is not free floating but supported by the sled under the handguard which is connected to the delta ring and cap on the barrel. IE unless you can exert the exact amount of pressure on the rifle each time as you fire a round, you'll be chasing groups all day long.
even with that type of forend system, an 8-10" group at 50 yards is obscene. if the problem can't be solved with easy and simple solutions then return it for warranty repair. an M400 is a quality piece, but even the best have let duds out of the factory. digging deeper is on your dime and might void your warranty.
P0WERWAGON
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have you had anyone else shoot it? if they cant hit that would rule out user error.
8-10" groups at 50yrds? You're right, there might be something way off here.
OP, any signs the bullets are keyhole-ing?
P0WERWAGON
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floating the barrel should only help with vertical stringing, and only if he loads the crap out of the the handguard. even with that, it wont effect the horizontal unless he is an APE with it.
Probably not your issue: i once had a barrel nut actually come loose (or more likely, was never properly tightened). Accuracy was trash...like 8-10" groups at 100.
It wasn't really noticeable until actually grabbing the barrel nut and being able to turn it by hand. The barrel wasn't "noticeably" loose.
It wasn't really noticeable until actually grabbing the barrel nut and being able to turn it by hand. The barrel wasn't "noticeably" loose.
Most rifles don't have a free float hand guard. Most rifles can still hit a target. Grabbing the barrel isn't going the throw his groups off that much. His problem is not how he's holding the rifle, let it go.
Agree with 741 as I have experienced issues with new piccatiny rails and scope mounts seating in. Remove scope mount and check rail on rifle and mount for machining burrs and rough spots or machining flash. Carefully file/sand and remount and torque to spec. After every 10 rounds or so for the first fifty keep checking the mount torque until seated and holding. A sharpee marker can be use to touch up and bare aluminum showing after cleaning an de seating in---Dieseldog!
So here is the update:
I wasn't crazy
Sent it back under warranty to MDC.
Was told there was a bad crown, MDC recrowed and test fired and they were still not happy with it. They spoke directly to SIG and they don’t see issues like this with the M400’s (occasionally with the 516’s being piston driven).
Next they were going to replace the barrel assembly, however to save time and eliminate other factors that might effect the accuracy they replaced the complete upper (barrel & receiver).
They test fired it and said it was holding zero now.
+1 for the warranty work by MDC
+1 for fast shipping back to me once the problem was solved.
I will do my own shooting test shortly to see how she groups and post a range report.
Cheers,
I wasn't crazy
Sent it back under warranty to MDC.
Was told there was a bad crown, MDC recrowed and test fired and they were still not happy with it. They spoke directly to SIG and they don’t see issues like this with the M400’s (occasionally with the 516’s being piston driven).
Next they were going to replace the barrel assembly, however to save time and eliminate other factors that might effect the accuracy they replaced the complete upper (barrel & receiver).
They test fired it and said it was holding zero now.
+1 for the warranty work by MDC
+1 for fast shipping back to me once the problem was solved.
I will do my own shooting test shortly to see how she groups and post a range report.Cheers,
