time between shots for best accuracy
Okay, someone out there/here must have a recomendation about how long to wait between shots from the benchrest to obtain the "best" grouping. Do I wait until the barrel is entirely cold again or warm or hot to the touch or does it really matter? Thanks.
08-30-2009 06:12 PM
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Barrel Temperature stabilization
It's a question of barrel temperature stabilization.
I shoot mostly military bolt action rifles, which tend to be more robust and less affected in the first let's say 10 shots (2-3 minutes). A shooting session for me is typically a box of 50-60 reloads. I take notes, measure muzzle velocity (with a chronograph) and grouping. With the walking to the targets, transcription of results, cleaning (every 10 shots), this will take me about 2 hours. So on average 2 minutes per shot. But in fact it's more like 2 shots per minutes, with periods of doing something else in between. Bottom line is I never noticed that results were significantly different in the last minutes, than in the first minutes in such a typical session.
Until I happen to try my fathers 308win Remington in a light sporter version (don't remember which model, that's too long ago). I could not stabilize in the first shots. First and second shot where close; I was making corrections to the scope to zero it in. But shots started to be all over the place and I wondered if I was not making an error on scope corrections (dam, did I just go clock wise or CCW?) or if something had gone loose.
Then an old hunter in the next stall told me "do you have a problem?" I explained. He said "did you listen to your self? Your shooting much too fast. You got to let your gun cool down."
Wow, is he serious? I replied: "What the point in saving a few pounds weight of metal (hunting Sporter compared to say a military Mauser) if I can't shoot twice at the same spot? His answer: "Only the first bullet counts, and those three more pounds of steel to your shoulder, you will feel at the end of the day walking in the woods".
Undeniably, that experience hunter's had a point . Still, I wonder how he adjusts his scope.
I try to stay constant. A shot every 30 second is what allows me to enjoy and relax. I eject right away and leave the barrel open while I look in the scope to check my impact point. I run a brass bristle thru the barrel every 10 shots and then go to the target. The barrel temperature will raise to about 120-140 degree F (warm-hot to the touch) in 10 minutes and stay there the rest of the session. With most of my bolt actions, I group below 1 moa (1 inch at 100m) when using a scope and a tuned load. For semi auto, larger groups (two-ish), except the Colt .223 HBAR: I just don't believe this rifle. Half inch groups at 100 m are nothing to write home about. And it slams the next round into battery so fast.
Don't forget a whole lot of other factors affect accuracy much more. If you just look at the factors that can vary once your'e sitting at the bench rest: Load, crimping, cartridge overall length, wind, rest and how you hold (restrain) your rifle, rigidity of scope fixture, you the shooter, and mostly, relaxing and what's going on in your mind when the shot goes off.
That's what make shooting so fun. I have a Mauser Oberndorf 1899 in 6,5x55 with Soldrin peep sight with which I make fun of shooters with new and scoped rifle. It's insensitive to warm-up and from cold standby, will punch 1,5 inches 5 shot groups anytime, winter or summer. Would I bring a scope in the woods? Not a chance.
And by the way, with sights, you don't need to look at the target; looking just at the sights (with the target resting fuzzy in the background) will do wonders.
Luke: "I don't believe it!" Yoda: "That is why you failed."