|
|
|
Discussion Forums
Forum Index
> Rifles general discussion
> Problem Zeroing a Rifle
Problem Zeroing a Rifle
@ 09:54 am (GMT) |
Ryan NafeOk so here’s a puzzle that I can’t currently solve:Today I attempted to verify the point of impact at 50 yards with my grandpa’s Remington 760 pump .308, using the iron sights, and I had some very puzzling results. At 50 yards it was shooting 6 to 7 inches high, regardless of rear sight elevation or ammo type. I used Federal 180 grain soft points and Federal 130 grain hollow points, the rear sight was moved from the highest to lowest elevation, and I couldn’t get the point of impact to shift by more than an inch or so. Anyone have an idea on why that’s happening? |
Replies
@ 11:33 am (GMT) |
Paul LevermanRe: Problem Zeroing a RifleDon't take my word for it, but I think if you move the rear sight down, the POI will go up, but I was doing it with a ruler on the desk. |
|
@ 12:20 pm (GMT) |
Ryan NafeRe: Problem Zeroing a RifleThanks Paul but that’s actually the opposite. The simplest way I can describe it is this:The muzzle always has to follow the rear sight. Move it down, your point of impact moves down. Move it right, your point of impact moves right. And on and on. —- I really can’t think of why the rifle is doing what it’s doing. I can hold 2” groups with it pretty easily at that range so it can’t be related to group size or general accuracy. It’s really stumped me, so I thought I’d ask you guys and just see if anyone has some ideas. It’s an old rifle and has specklings of surface rust in a few spots, the bore probably isn’t in the best of shape either, but other than that it’s in perfectly usable shape. |
|
@ 12:37 pm (GMT) |
Ryan NafeRe: Problem Zeroing a RifleI killed a deer with the exact same rifle about 4 years ago using the open sights and Winchester 150 grain Power Points at 40 yards, no issues at all. And the rifle took countless other deer and one Canadian black bear back in it’s prime, it has a proven track record. |
@ 06:50 pm (GMT) |
Hamish GibbsRe: Problem Zeroing a RifleHi Ryan have you tried holding your tongue different? Sounds interesting, have you measured the change in elevation of the rear site from max to min, the distance between the front/rear site and worked out how much it "should" change the poi at given distance? Just something to eliminate. |
|
@ 05:52 am (GMT) |
Paul LevermanRe: Problem Zeroing a RifleRight you are, Ryan. Just had to look at it properly.Sounds like Hamish is on the right track. At your distance the change may not be noticeable. |
|
@ 07:21 am (GMT) |
Hamish GibbsRe: Problem Zeroing a RifleShooting two inch groups and the poi only changing an inch or so at 50 yards with a rifle with specks of rust and questionable bore, Im guilty of such things and in my experience its a good way to burn up ammo and only ever get a very general guess of whats going on. Not the gun guru mate but one thing I did think to check was rust/obstruction under the rear site leaf, would cause high poi and lack of elevation adjustment?Sounds like a bit of family history there maybe you could see what methods could be applied from the accurising book to give it a once over and a birthday, be a great feeling using grandpas gun if you could get it shooting where you want it. |
@ 09:45 am (GMT) |
Scott StruifRe: Problem Zeroing a RifleI used to have one in 6mm rem, but thanks to a burglar, I don't anymore. If Hamish's astute suggestion isn't the problem, and the gun is grouping half-way decent, you could file the rear leaf down. If it has the U cut in it, you can get a pack if 10 diamond needle files, 2mm diameter on amazon for $10. |
@ 09:24 am (GMT) |
Randy WikrisRe: Problem Zeroing a RifleHi guys. Just thought I’d throw this out there. Sorry if it’s obvious. Have you tried re-blackening the front sight post? This ‘could’ crisp up the front sight picture and effectively get you holding the post down a few thou. Not sure what you would use. A dab of flat black paint maybe.I guess I’m sort of jealous of those that can still focus the front sight post along with anything more than 6-feet beyond it. LOL Is it a ball and buckhorn or a flat-top post and flat rear slot like you’d see on a glock? I guess what I’m getting at is there could be a discrepancy in managing the sight picture. We were taught in the service that the clear tip of the front sight post should break the plane of the bullseye at the 6 O’clock mark. So POI was supposed to be a little high. Problem in this case however is 6” high at 50 would be a mess at 100 or further When I was a kid I was taught that the ball should lay all the way down in the circle of the buck horn and the POI was the top plane of the ball. A few of these discrepancies together could move POI by a few inches Good luck with it Thanks |
Please wait
ABOUT USWe are a small, family run business, based out of Taranaki, New Zealand, who specialize in cartridge research and testing, and rifle accurizing.
|
KNOWLEDGEBASE |
KNOWLEDGEBASE |