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Posted: 5/17/2004 10:16:22 AM EDT
I recieved a used AR 15 from my grandfather and took it to the range yesterday and the rounds are going in sideways. The rifling looks good. Anyone know what could cause this?
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A projectile that's too heavy (long) for a slow twist barrel will cause this. How old is the rifle? Model number? What ammunition are you using? www.ammo-oracle.com |
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It's possible that a heavy bull barrel has a slower twist for use with 45gr varmint rounds. I doubt it's a lack of cleaning issue, but Shooter's Choice is a good copper remover. click here |
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"Mic the bore" = measure with a micrometer. "measure twist" = put tight fitting cleaning patch on cleaning rod. Get it started in bore, mark the rod. Push untill the rod makes one revolution, mark the rod again. Remove rod from barrel measure distance between marks. This will give you 1 in 14, 1 in 12, 1 in 9, 1 in 7....etc. One turn in how many inches. |
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You may have a bad crown on the muzzle. Uh, when it was cleaned, was it ever from the front end of the barrel? Ask Grand dad if thats the way he cleaned it. Your using FED, clean muzzel (no flash hider or brake), rounds not hitting the ground, and it key holes (what range?) I'm down to copper fouled, worn out barrel or the crown |
The "crown" is the very end of the rifling. Any damage there, will degrade accuracy. The barrel will need a bright light at one end and examination from the other. From your questions, i venture to state you don't have a bore scope. What round are you feeding your AR? I could see a 77gr. bullet getting sideways from a 1 in 9 twist. Is there a muzzle device? If so, is there any contact marks on the inside of the M.D. . The www.ammo-oracle.com/ might have your answers. mark mcj |
I just tried this and kept on comming up with 1 and 11' twist. There is no muzzle devise. The only thing I can see on the barrel is it is stamped 223B. |
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