 mEnTL32
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Joined: Apr 2008  OR, USA
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Posted: 3/12/2012 2:56:12 PM
I bought 2 Spike's mid length LE uppers from AIM.
The first one I bought, I put a DD rear sight on, and sighted it in with Federal M193. I don't recall the size of the groups, but it must have been OK since I ordered my second upper soon after. Then I got my second in. I changed the front sight block to the YHM one that folds down. Changed the flash hider to a Levang. Put a 1-4x Nikon scope on it. Changed the forearm to a MOE. I went and shot some M855 and the groups were bad. I usually shoot at a 6" black circle at 50 yards, and it was throwing rounds all over the page. I don't get to shoot my AR's every time I go to the range, so I've slowly been diagnosing this issue. First I removed the Levang and scope and put a rear sight on. I shot some M193 through it and it seemed OK. I thought maybe my scope mount was loose, or even the Levang was interfering somehow. Last week, I took it out and shot it with the scope. M193 made a neat little group at 50 yards. I was hitting a little 1.5" sticker with no problem. I took out the M855 and shot some. I could barely keep all my shots in the 6" circle. Really frustrating. I also had some Winchester Q3131. Those made a nice group, but POI was shifted 3" to the left. Weird. What do you think? I'm surprised to see this gun is so ammo sensitive. I don't have a ton of rounds through it yet, so maybe this is a break-in issue? (I don't have easy access to the first middy since I leave it at my parent's place, otherwise I'd compare the two. That gun I mostly shoot at cans with cheap steel ammo. Hits everything I point it at, but it's not very scientific) |
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cormorantslayer
Tactical Lamp Maker
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Posted: 3/12/2012 4:47:23 PM
Ammo, especially surplus ammo can have considerable variations and like it or not two otherwise identical barrels can shoot differently with the same ammo; he barrel decides what load it will shoot best.
If one of your guns does not like the M855 and you do not like the accuracy then don't shoot it in that gun. When I want accuracy out of a particular AR that I own I know which load gives the the best performance and I use it. |
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mEnTL32
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Posted: 3/12/2012 4:52:10 PM
That's how I've always looked at it, but I thought these 1:7 barrels were made for M855. I'm surprised to see 6" groups at 50 yards with it.
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RangeWarrior
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Posted: 3/12/2012 6:55:03 PM
Originally Posted By cormorantslayer:
Ammo, especially surplus ammo can have considerable variations and like it or not two otherwise identical barrels can shoot differently with the same ammo; he barrel decides what load it will shoot best. If one of your guns does not like the M855 and you do not like the accuracy then don't shoot it in that gun. When I want accuracy out of a particular AR that I own I know which load gives the the best performance and I use it. sorry but no ammo should give target size groups at 50 yards... something doesn't seem right but blaming the upper doesn't seem fair at this point... |
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badazzar15
Spike's Tactical
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Posted: 3/12/2012 7:19:35 PM
Not sure what's going on but we have no problem looking it over or replacing it.
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mEnTL32
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Posted: 3/12/2012 11:54:55 PM
I thought you might say that
 anything I can try before I head down that road? |
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midwestoffroad
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Posted: 3/13/2012 12:09:28 AM
I would guess its ammo. i have many warious rounds and PCM bronze seams to work quite well. most of the american eagle stuff has not as well as it should.
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DyNo541
Professional Tree Killer
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Posted: 3/14/2012 8:27:11 AM
[Last Edit: 3/14/2012 8:29:08 AM by DyNo541]
Howdy! Here's a video that might give you a few things to check out to ensure that you get the most accuracy out of your rig:
What kind of M855? Are they factory loads or reloads using pull-down bullets? 6" is a bit big for 50 yards but be advised - I have 75 grain ammo that groups at more than 1" at 50 - near 3" at 100 - and slightly over 3" at 200. Some bullets take longer to stabilize but 6" at 50 yards is too much. Even big velocity changes wouldn't throw it off that much/that close. I bet something is wrong with the actual bullet. |
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mEnTL32
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Posted: 3/14/2012 12:06:35 PM
Nice video. Here is the ammo I am using:
The M855 is Federal, came in a 30 cal box. It groups in my S&W SBR (11.5") with a 1:9 twist. I didn't measure the group. |
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