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Posted: 10/10/2011 12:49:16 PM EDT
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Hello All,
I was testing a batch of hand loads today (first batch for this gun) which should have been consistent... +/- .002" OAL variation is my allowance. Individually weighed powder for each round. The rifle has a 20" gov. profile barrel with a DCM free float tube. I shoot this gun with Iron sights and bulk ammo and I can't recall the last time I put a scope on it and measured groups with good ammo. I got vertical dispersion of about an inch and horizontal dispersion about 2 inches (10 shots) with a good scope (Zeiss on a GGG mount). I can accept the general accuracy but it seems odd that it spread horizontally. I am inclined to think it is the gun because my groups with a hunting rifle (also pistol gripped, which ought to mean similar trigger habits) I zeroed were strongly vertical as it heated up (~3/4" horizontal variation). Am I kidding myself by blaming the gun? If it is the gun, what could cause this trend? |
Doesn't sound to me like a bad group at all!
However the type of dispersion you you are describing would have me scratching my head as well. The most common cause of the symptom you are describing (other than shooter error) is something is loose. I'm sure your aware it could be a number of things, but I would check the mounting screws really well. Next time you go out pay particular attention to parallax/consistent cheek weld. Would'nt hurt to invest in a box of match loads and see how the dispersion looks against your loads. If it is still driving you nuts after that, try another known good scope. A high dollar good scope CAN still fail. |
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Assuming your equipment is secure and good to go, my first inclination is that the horizontal stringing is most likely due to trying to "muscle" or "nudge" your sight onto target (i.e. problems with your NPOA). If not that, then I'm thinking trigger control problems.
However, you're aware of NPOA and don't think it's the problem. It's time to break it down every step of the way and really look at what you're doing. Assuming wind isn't a problem, horizontal stringing is rarely caused by a mechanical problem (possible, just not likely). At what distance are you shooting? |
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What kind of projectiles?
Now you are using a standard barrel, and I havent noticed a difference using a precision barrel with Nosler 77gr projectiles when I individually weigh the powder charge or just fill them from the powder measure without measuring each one. My point is unless you are shooting at several hundred yards with a precision barrel and good projectiles, individually measuring each load is not worth it and is a waste of time. |
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