At a lost with this m305

MozPhoq

MozPhoq

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Hi guys,

I'll make a long story as short as possible. I got rid of an m305 shorty I had seated into a Blackfeather stock a couple months ago since I was never able to make the thing shoot reasonably well: It was just all over the place. I decided it was a lemon and got rid of it for 300$ disclosing what it was and what it wasn't.

I bought a 22" from Marstar in January, finally got it not before some delay, had the barrel recrowned by a local gunsmith to put all chances on my side right away, and installed it into the Blackfeather. Surprise! Not much better! At a 100 meters I will get half of the shots into an inch, and the other half spread like so many flyers....

Not knowing me you'd think the problem may be with the shooter, I get that. But I assure you I know how to shoot. I dismounted and switched scopes also just to exclude this option. Ammo is factory but gives satisfactory results in a bolt action. I will try two handloads tomorrow. Also I noticed the USGI flash hider I installed following the removal of the Norc factory had a slight cant with the barrel, could it be an issue? I have took it off and will give a try tomorrow. If these two changes don't help I just don't know what to try anymore...

Anyone here has ideas of things I may have overlooked?

Thank you.
 
Tengoo said:
How did the guns shoot in their original stocks?
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The first one had only shot it once @50 meters with iron sights, it wasn't bad but it's difficult to compare. As for the second one it went straight into the Blackfeather.
 
tlovell said:
Could it be the adjustable op rod guide?
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I've left it at original setting. But then it's the lack of consistency that's strange. I would not expect the oprod/stock tension to create such random impacts. But I'm no specialist on the subject.
 
My vote is the oprod guide and oprod. If there is any slop in the guide you'll see that kind of inconsistency in your groups. While you're at it it might be worth the $50-60 to swap out the oprod spring guide.
 
Half the shots were into an inch at 100 yards? How large were your groups when you included the fliers? These are battle rifle clones, if you can get five rounds into anything under 2-2.5 MOA without considerable tuning you're already doing well.
 
I'm no specialist either. I did own a Springfield in a Blackwater and if I remember correctly the adjustable op rod guide changes the tension, which in turn affects harmonics. (Someone correct me if I'm wrong) I know it's a pain to change out, but I shot mine for awhile with the original op rod guide. I didn't notice much change in accuracy. But it might be worth a try just to see.
 
Pop said:
Half the shots were into an inch at 100 yards? How large were your groups when you included the fliers? These are battle rifle clones, if you can get five rounds into anything under 2-2.5 MOA without considerable tuning you're already doing well.
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Okay an inch was meant more as an image. Let's say two in reality. But the spread including the flyers is awful, like 10 inches.
 
What was the overall group of 5 shots?
It's not an M700.
If you put 5 shots within 3" at 100 meters in that configuration then I would be pretty happy with myself.
Also sounds like your barrel is off index (canted flash hider) but that shouldn't effect groups with a scope mounted.
Get some actual measured groups at 100 meters and post a pic or two. Op rod and guide etc isn't going to be throwing groups off 12 inches at 100 meters etc
 
You probably do this anyway but ensure your gas plug is/stays tight , this can affect accuracy too. It seems like m305's of late have even more issues than usual , someone correct me if I'm wrong.
 
MozPhoq said:
Okay an inch was meant more as an image. Let's say two in reality. But the spread including the flyers is awful, like 10 inches.
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Were both rifles producing fliers like that? If so I'd suspect either your scope mount or something wrong with how it's installed in the stock. What scope mount are you using?
 
Travis Bickle said:
What was the overall group of 5 shots?
It's not an M700.
If you put 5 shots within 3" at 100 meters in that configuration then I would be pretty happy with myself.
Also sounds like your barrel is off index (canted flash hider) but that shouldn't effect groups with a scope mounted.
Get some actual measured groups at 100 meters and post a pic or two. Op rod and guide etc isn't going to be throwing groups off 12 inches at 100 meters etc
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When I say the flash hider has a cant, I mean it points upward (so little it's barely noticeable) compare to the barrel's line.
 
MozPhoq said:
When I say the flash hider has a cant, I mean it points upward (so little it's barely noticeable) compare to the barrel's line.
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That could definitely be the problem. Check the inside of the flash hider for signs of bullet strikes. Even if you don't see any, try removing it completely for your next range session and see what happens.
 
Pop said:
Were both rifles producing fliers like that? If so I'd suspect either your scope mount or something wrong with how it's installed in the stock. What scope mount are you using?
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A CASM. Scope was my initial suspect, I doubt the mount is moving in any way. I thought for a while the scope didn't keep zero. It's even back at Bushnell repair as we speak, so much I was convinced the problem was there. But using another one didn't straight things up at all.
 
Pop said:
That could definitely be the problem. Check the inside of the flash hider for signs of bullet strikes. Even if you don't see any, try removing it completely for your next range session and see what happens.
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Absolutely, this was already my plan. Thanks.
 
About turning the gas piston off, do I simply force that screw a quarter turn? It seemed to resist a bit ...
 
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