cold bore shift
- Thread starter stagpanther
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stagpanther
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You win 1/3 point--but what else is missing?
bamaranger
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shift
We had a Glenfield 336 in the family for a while that would string vertically the hotter it got. I was just a kid, but seems if I remember right that loosening or tightnening the barrel bands a bit helped with the problem.
We had a Glenfield 336 in the family for a while that would string vertically the hotter it got. I was just a kid, but seems if I remember right that loosening or tightnening the barrel bands a bit helped with the problem.
Lever guns are hard. The barrel band/handguard make for inconsistency. As for cold bore, one should only really look for it, all else being equal. That is same ammo, temp, bore fouling, etc.
My hunting rifles, I pretty much sight them in "cold bore" since 95% of all big game animals I have harvested were 1 shot, cold bore. Then look for the drift, if any, at 3 and 5 rounds.
For match rifles, I do my best to eliminate cold bore shift, and for the most part, with free floated barrels, knowing my powder sensitivity, etc, they don't have any cold bore shifts.
One thing folks who live in humid climates don't account for is moisture. A fouled bore will have some moisture in it, which is basically gone after 1 round. That can result in a slower, or faster first round depending on parameters.
Also, with semi-autos, many will have a 1st or last round different POI than the rest of the group. Those are easy to determine and adjust for, per rifle, if you are a good fundamentals shooter.
My hunting rifles, I pretty much sight them in "cold bore" since 95% of all big game animals I have harvested were 1 shot, cold bore. Then look for the drift, if any, at 3 and 5 rounds.
For match rifles, I do my best to eliminate cold bore shift, and for the most part, with free floated barrels, knowing my powder sensitivity, etc, they don't have any cold bore shifts.
One thing folks who live in humid climates don't account for is moisture. A fouled bore will have some moisture in it, which is basically gone after 1 round. That can result in a slower, or faster first round depending on parameters.
Also, with semi-autos, many will have a 1st or last round different POI than the rest of the group. Those are easy to determine and adjust for, per rifle, if you are a good fundamentals shooter.
Shooting would be easier if you finished putting the rifle back together. first...
I think comparing hunting riles with match rifles is like comparing race cars with pickup trucks. Other than having certain major things in common (like 4 wheels, for example) they are made quite differently, for very different uses.
Lever guns with barrel band, guns with tube magazines, semi autos, and about everything with a barrel bedded in the stock will shift POI as they get hot. ANYTHING touching the barrel that doesn't heat and expand exactly the way the barrel does will have an effect on barrel harmonics as the barrel heats and expands. Guns made for match shooting, strings of fire, and not just a shot or three at game animals are made with features that minimize or eliminate the issue.
I expect hunting rifles to be just that, and accept the fact that they may only shoot well enough to do their job.
A 2MOA rifle will put venison in the freezer (provided you do your job right) but isn't the best choice for woodchucks or other small varmints. Doesn't win "smallest group from a bench" challenges, but does the job it was built to do, just fine.
I shoot "one hole groups" every time I shoot my single shot rifles or pistols.
What does group size tell you, anyway? How far off point of aim any shot can be expected to be, with no other factors taken into consideration.
Nice to know, but not everything one needs to know, or take into consideration, I think.
stagpanther
New member
I think MarkCO has it--it makes sense to me that you really need to zero for just the first cold bore shot and then "predict" the follow up shots with warm barrel group testing in case your first shot doesn't get the job done when hunting.
Accuracy can be severely degraded when there's no bolt.
Yes! bolt is missing too--you would have scored a trifecta if you had mention ejector spring was missing, but I'll give credit since that is kind of small.
Accuracy can be severely degraded when there's no bolt.
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FrankenMauser
New member
If the bolt is missing, the ejector should be, too.
stagpanther
New member
And the screw. I saw someplace someone makes a replacement lever screw with a burled head for tool-less field stripping--kinda like the idea (but can't remember where I saw that).
FrankenMauser
New member
Ranger Point Precision, Beartooth Mercantile, and a few others.
They're generally large, gaudy, obnoxious, and aluminum. I'd rather keep a screwdriver on hand.
There used to be a guy making a large pan-head shoulder screw (about the diameter of a dime), meant to be removed with a coin. I might be able to handle that; but I haven't seen them on the market in quite some time.
They're generally large, gaudy, obnoxious, and aluminum. I'd rather keep a screwdriver on hand.
There used to be a guy making a large pan-head shoulder screw (about the diameter of a dime), meant to be removed with a coin. I might be able to handle that; but I haven't seen them on the market in quite some time.
stagpanther
New member
Aluminum would be a non-starter--would grind itself up eventually in working the lever I would think.
stagpanther
New member
More to the point than you might think--much of my experience agrees with that.