sighting a rifle


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zamboxl
December 19, 2006, 02:37 AM
Hey guys i got a mn 91/30 with a weaver scope and a darrel scout mount that i need to sight. I have never done this before so could some one let me know how to go about this

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KevlarSix
December 19, 2006, 02:53 AM
Hi,

You can find good laser boresighters in eBay.

Check the link:
http://search.ebay.com/search/search.dll?from=R40&satitle=laser+bore+sighter

KevlarSix

darkknight
December 19, 2006, 03:10 AM
wat happens if you cant afford a boresighter im in a simular position and am looking for alternate methods to sight it in.

Blackfork
December 19, 2006, 03:38 AM
Did you mount the scope or is it already mounted? I'm going to assume its mounted correctly, everything is tight and it's the correct mount and scope combination for the rifle.

If it's already mounted, the first thing I would do is sandbag the rifle- that is, secure it unloaded on something solid but pointing down range, and check by boresighting. Remove the bolt and look through the scope and then the bore and see how close they line up. You could do this looking down a hallway or out a window, just make sure you start with an unloaded rifle. If you can't see the target through the bore, then take the windage and elevation caps off and click the knobs until you can. Look at the knobs to see which way to click. One MOA equals one inch at 100 yards.

Boresighting just gets you in the rough. Even at the range it's the first thing I would check on a rifle/scope combination. If you CAN see the target through the bore and in the scope then I would take 20 rounds of ammo and move to actually firing the rifle.

I'd start at 25-50 yards shooting at the BACK of a target or the middle of a large piece of white paper. Put a black paster or mark in the middle, set up the rifle on a bench and with GOOD bench technique*, dry fire about five times and then shoot three rounds. If the rifle was boresighted it ought to be shooting on the paper.

Check the size and placement of the group. If its not on the paper recheck the boresighting. Let's assume it IS on the paper, above the mark and just slightly to one side. Click it to the center line but leave it high.

Now, move a target to the distance you want to zero. 100 yards? 200 yards? 50 yards? You'll have to know and decide. Let's say you decide 100. Shoot a group and see where it is at your chosen range. Use the elevation and windage knobs to move it to the center. I'd move off three shot groups, not single shots.

All bullets start falling to earth as SOON as they leave the muzzle. Gun designers therefore tilt the barrels slightly up to take advantage of the arc of the bullet. If you zero the rifle at 100 yards that means it may be slightly high at 50 yards, right on at 100 and lower at 200 as the bullet arcs. If you zeroed for 400 yards, the bullet would be MUCH higher at 50, 100, 200 and 300 yards and drop in at 400, then be low at 500. Make sense? Most military rifle IRON sights are designed to be high at 100 and drop in at 200 or 300 yards. Your scope can be zeroed wherever you want it, just expect the bullet to be higher or lower at closer or farther ranges.

Now....Mosins are light, cheap rifles. They kick. They are loud. The ammo can be pretty good or really awful. They may shoot touching holes or make a 5 inch group at 100 yards. Just depends. If i had to guess I would think they would be rough on a scope. Make sure the bayonet is folded, if there is one.

I'd be sure I used some reasonable ammo I was going to be able to buy a lot of and use earplugs and muffs. And hold it tight to your shoulder. Shooting a light, powerful rifle is like boxing. You are going to get hit, just protect yourself and get used to it.

* Proper bench technique: Rifle resting on a bench with a support under the WOOD stock but not touching the barrel. I'd stay away from the end of the wood as well. Put a rest or sandbags about where the front sling swivel is or behind.

Feet flat on the ground. Shoulders and hips pointed about 45 degrees away from the gun-target line. Grip the rifle by the pistol grip and pull it tight to the shoulder. Starting at the chin and to the rear of the buttstock SMEAR a cheekweld onto the rifle so that the full weight of your head is sitting on all the cheekfat you can muster. What do you think mom fed you all those Happy Meals for? Find the correct distance from the scope to eye so that no shadowing around the edge is apparent. If your cheekbone is sitting on the back of your thumb thats good. Your head is going to ride the recoil. Be tight, because your fingertips or knuckle can easily break your lip under recoil. (The scope can cut your eyebrow if its too close.) It's better to weld all that together and not leave any separation. It will smack you.

Now, take your useless, flopping around OTHER arm and put a fist under the back edge of the buttstock near your armpit. That fist is going to control elevation. Both elbows ought to be on the tabletop. Wearing long sleeves? You ought to be. And a coat for padding.

Now, rebuild the position adding more height, if you need it to the front rest, a sandbag under the buttstock if available, settle in and dry fire the rifle for a while. You usually don't need to work the whole bolt, just lift the handle and close it to reset the trigger. Dry firing a centerfire rifle doesn't hurt it. Do it until you can feel exactly where the trigger is going to break. Test the safety to see if it works while you are at it. Double check your feet and shoulder position. After a while the rifle ought to feel like it is pointing exactly at the center of YOUR target without you having to muscle it to one side or the other. Double check your cheekweld. Take a deep breath. Exhale until you are comfortably at the bottom of your breathing cycle. Watch the crosshairs settle on the target. Pull the slack out of the trigger. Break the trigger.

Focus on the crosshairs and repeat. Watch the crosshairs jump and try and minimize it. Take some time. Feel the trigger break. Breathe. Relax. Hold the rifle tight. Stand up, walk around, sit down and rebuild your position. Your brain may think it knows what to do after reading this but your body doesn't know it yet. Takes repetition.

Blackfork
December 19, 2006, 03:49 AM
Never load a rifle indoors or away from a range even to "check" something. Don't dry fire at anything you aren't willing to shoot a hole in. Treat every firearm like it's loaded. Be safe, be safe, be safe. Also be patient and courteous to everyone at the range. It's a good idea to ask some folks for help, but lots of BS floating around out there!

And if someone offers to let you shoot their rifle, take them up on it. And offer yours in return.

When you go downrange unload and leave your bolt open. Don't walk downrange in front of a loaded rifle!

zamboxl
December 19, 2006, 05:55 AM
thanks for the info guys, so a set of sand bags should be enough to keep the rifle stable? i never shot the rifle at 100 yards but i have manage to keep 5 shots in the black at 75 yards, and i'll be the first to admit the rifle is far more acurate than i am.

Grumulkin
December 19, 2006, 06:02 AM
With a gun you can look down the bore on:

1. Look down the bore and center the target in the middle of the bore with the gun on sandbags or other secure rest.

2. Look through the scope. If the crosshairs are above the target, move the adjustment UP and if down move them DOWN. Similarly, if to the right, move to the right, etc. Adjust until the target is centered in the bore and the scope.

3. Then get fairly close to the target (a large piece of cardboard works well) and take a shot. By fairly close, I mean 15 to 25 yards depending on whether it's a handgun or a rifle. Adjust as needed to get the bullets hitting where you want them to whilst moving back until you get to the range you wish to sight in at. NOTE: Now the situation is different; if the bullets hit high, adjust the scope down, etc.

With a gun you can't look down the bore on:

1. Get a big target (the broad side of a barn is best...just make sure it's your barn).

2. Get close as noted above and fire away. The mistake I've noted most often in sighting in, is being too far away from the target. The target is missed completely and the shooter has no idea if the bullet went right, left or above.

3. Adjust scope as needed.

With a bore sighter:

With this life is easy but I've never used one so someone else can comment.

Legionnaire
December 19, 2006, 07:03 AM
Here's one of the best, and in my opinion most entertaining, sources on the web. Enjoy!

http://www.charm.net/~kmarsh/scope.html

.38 Special
December 19, 2006, 01:56 PM
Good advice on boresighting, IMO. I've never seen the need for laser boresighters and collimators for bolt guns, as you can achieve the same results for free by looking through the bore.

I'm also a fan of the "one shot zero". With the rifle very firmly bedded into sandbags -- or much better, a proper rest -- fire a single, careful shot directly at the bull. Now, realign the rifle so that the scope is again looking directly at the bull. Find the hole in the paper and -- being sure not to move the rifle -- adjust the scope so that it is now pointing at the bullet hole. The gun is now sighted, although it's a really, really good idea to fire a few more shot to verify. And if the gun is innacurate, you may want to initially fire a three shot group and then adjust the scope to the center of that group.

HTH!

SniperStraz
December 19, 2006, 02:08 PM
Fire 3 carefully aimed shots (without any air in your lungs for consistancy) and then find the geometric center of those three shots. Do this three times. The end result will be 9 shots and three grouping averages. Average the three averages into one average and then use a ruler to measure how far off you are from your mark. Then go back to your scope and adjust the sight for distance and how far off your mark you are accordingly. That should do it. Its alot of work but its the best way I know of to get be able to use your rifle to swat a fly. I know that may have been a little confusing so PM me if you still dont understand it and i'll be happy to help. Have fun and be safe.
-Sniper

Thefabulousfink
December 19, 2006, 04:20 PM
Boresighting is great and will save you a lot of time. If you don't want to buy a boresighter, most gunshops/gunsmiths can do it fore you. The last time I tried to scope a rifle (ar15 with a 4x scope) without boresighting it took me close to 30 rounds.

If you still don't want to boresight, here are some tips that I learned (the hard way ;) ).

1. If possible set the rifle in a rest or vise that will keep it from moving. Look down the sights or bore and mark where they line up at about 20 yards. Carefully mount the scope and adjust the crosshairs to the mark (do not let the rifle move). This should get you on paper at 20 yards.

2. Get the largest target possible (I'm talking 3'x3' or bigger) and shoot from a rest. Shoot 3 rounds to begin with (and hope they hit paper), they should group close together. If the rounds don't group then you have another problem that you need to fix first (probably a loose scope mount). After the initial group, begin adjusting the scope towards the center of the target. If you are comfortable with your shooting ability you really only need one shot per adjustment.

3. Work from close to far: get all your shots to hit dead center at 20yrds then move to 50yrds, then to 100yrds. Because of the ballistic trajectory of the bullet, dead center at 20yrds will not be dead center at 50, but it will be close enough to be on the paper. Dead center at 50 will get you on the paper at 100yrds, and from 100yrds you should be able to zero the scope at any range you want.

Zeroing a scope without boresighing is quite possible, it just takes a lot of time and ammo. Boresighting lets you skip to step 3 and will require much less adjustment to initially get on center. I did the above process with my AR and my FAL, but I would never consider it with something like a .300win mag.

Edit: The one shot zero that .38 special described is great and the fastest way to get on target if you have a good solid rest. My rest isn't very good and I couldn't be sure of the rifle not moving, so I used a target with 1" lines running in a grid. I would fire, see how many inches off the bullet hole is, move the crosshairs 3 clicks then fire again. The distance that the point of impact will move per click changes based on the range to the target. Your scope should say how much it moves per click, usually 1 MOA (approx. 1" at 100yrds) but some scopes differ.

zamboxl
December 20, 2006, 08:57 AM
thanks for the help guys.

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