Posted: 9/13/2010 11:41:07 AM EDT
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This is reposted from GD. Apparently no one actually shoots there.
Shooting the AR at the range. 100 yards. I shot a 10 round string and every shot was about 1.25" high. After I loaded up the magazine again, I dropped the elevation on the scope down 5 clicks. Should be nuts on now. First 2 shots were a quarter inch apart, 1.25" low of bull. Put it back up 5 clicks and was on. Next target I really take my time, try to remember everything, breathing, trigger pull, etc. First 3 shots were in the x-ring. A guy drove up and I pulled the 4th. (I like shooting alone and worry when people are around watching. Its stupid, but I choke like that). 5th shot in the bull. The guy came up and we started talking. I'd say we talked for 30-45 minutes. The last 5 shots of my mag were all high and not tight at all. After that, I let him shoot a mag at some steel (he was from Chicago and his glock was the first firearm he'd ever owned. he was excited to shoot the AR and enjoyed it.) When he was done, I loaded 10 rounds of Black Hills and I was making a ragged hole with a few small flyers. My best group yet. On a different day at the range, I shot 10 rounds at 100 then 10 rounds at 200. The size of the groups was roughly the same. The 100 yard was slighty tighter than the 200 group. This would mean that I was shooting much better at 200 than 100. So, essentially the same thing was happening. Later strings are much more accurate than the first strings. Given all of that, it seems that when my barrel is warm, the rifle shoots much more accurately. Even the Fiocchi shoots much tighter when the barrel is warm. My question is: Is it normal that a barrel needs 10 rounds to warm up and be accurate? That seems a bit excessive both for number of rounds needed and how much of a difference it makes. I mean 1.25 moa is pretty far off. Just seems like it shouldn't be that bad. Specifics that may or may not be relevant: RRA Coyote- 20" free floating barrel Shooting on sandbags Bushnell elite 3200 scope sighted in at 100. Fiocchi .223 ammo for sight in and general target shooting. Thanks in advance for any experience or expertise. |
| This has not been my experience based on the rifles I have shot. The shots usually open up as the barrels have gotten hotter. Every rifle/barrel is a little different though. You need to shoot your rifle and learn what ammo it likes and how it acts when hot or cold. Keep a log book. If your not shooting head shots past 300 yards, it shouldnt really matter. If you will be doing most of your shooting hot, then warm it up. If not, sight it in with your cold bore zero. All depends on your application..........A sniper owuld always use a cold bore, where as a competition shooter shooting multiple shots may want a warrmer barrel........ |
| Perhaps instead of heat being the primary factor, perhaps it was that a dirty barrel shoots better than a clean one. No doubt that barrel temp will play some part, but that variable should be very repeatable, whereas a clean barrel may not be repeatable. Don't most match shooters do a fouling shot first? When I hunt, I make sure the bore has a few rounds thru it and I adjust the scope for that slightly dirty barrel. .....just a thought. |
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Barrel heat will affect accuracy.
Case#1: Shooting my 20" HBAR AR15 a few weeks ago, the groups shifted up and to the left just after I went over about 100 rounds. Was shooting some AQT's, so there was enough rapid fire to really heat up the barrel. Groups stayed tight, but were up over 5" and to the left about 3" at 100 yards. Case#2: Shooting the same AR15 at an Appleseed a couple of years ago, it was out in the sun, and the much warmer barrel had a much different POI in the afternoon than it had in the morning. Case#3: Shooting a Marlin 60, as the day wore on, and the sun heated the barrel, groups were up 2" at 25 yards with the warmer barrel. |
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was your barrel clean when u started?. if so, it will shoot diffrent till that oils/solvet is burned out, and the barrel is "seasoned"... this is why you DONT clean a good shooting barrel till it stops shooting good...
or you will need to "re season" it again... |
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Some rifles "open up" as they heat up. Sometimes the barrel is touching unevenly in the barrel channel of the stock or there is something odd/wrong about the way the barrel attaches to the receiver or maybe the barrel was "straightened" and stresses of heating up "bend it" again.
Some rifles are not affected by the heating up. I had a rifle once that would throw the first shot out of a cold barrel about 1" out of the group. The rest of the group would tear a single ragged hole in the paper but that first shot would always go somewhere else. Since that was a hunting rifle I had to trade that one in on a compound bow. To disagree with common beliefs/statements I have always run an oily patch down my barrel as the last step of barrel cleaning but I've never had an issue with it affecting my first round or two, but then I'm not shooting .174" groups at 100 yds. I'm just killing paper, water jugs, pop cans, deer, groundhogs, etc. |