READING THE GROUPS
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savage 110, 6.5 cm. 100 yds,,,,,,, went out with one load each of 3 different powders, each the result of several previous sessions, and was looking for real ood groups out of each......one was excellent, one better than previous session, and one was 2" , stacked almost perfectly straight up.. not sure of sequence.......
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First thing to suspect is an out of square bolt face. Be sure the two halves are clean and the pin that hold them together is clean and lubed.
Check the bolt face for a sliver of brass or scrap of primer.
Bedding-- Anything that bends the action also makes the lugs bear un-evenly. Check the magazine box to be SURE it's not causing a 'high center' in the action.
Check the tang screws--Front one first. Hold the stock and action an slowly loosen the tang screw. Did you feel it move? That is the problem.
Check the rear screw while holding action and stock. Move? That's a problem too.
Check the barrel-- Can you gently squeeze the barrel and stock and feel the barrel move? That's good! How about side to side?
Be sure the scope mounts are tight and the rings tight to the mounts.
'Take up the slack' in the scope adjustment-- back off the elevation half a turn and then back in to the original setting.
Check the crown with a magnifier. Look really close for notches, pits, dings, dents and marrs at the very edge of the rifling.
The old BR trick to stop vertical stringing was to increase the velocity.
Check the bolt face for a sliver of brass or scrap of primer.
Bedding-- Anything that bends the action also makes the lugs bear un-evenly. Check the magazine box to be SURE it's not causing a 'high center' in the action.
Check the tang screws--Front one first. Hold the stock and action an slowly loosen the tang screw. Did you feel it move? That is the problem.
Check the rear screw while holding action and stock. Move? That's a problem too.
Check the barrel-- Can you gently squeeze the barrel and stock and feel the barrel move? That's good! How about side to side?
Be sure the scope mounts are tight and the rings tight to the mounts.
'Take up the slack' in the scope adjustment-- back off the elevation half a turn and then back in to the original setting.
Check the crown with a magnifier. Look really close for notches, pits, dings, dents and marrs at the very edge of the rifling.
The old BR trick to stop vertical stringing was to increase the velocity.
wow JBelk, as usual you have a lot of good info..........I will inspect my rifle per your suggestions. As far as checking the magazine box for 'high-center'....is there a way to measure or more of how the gun goes together putting the action in the stock. Probably more questions after inspecting my gun, Thanks.
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I'm not sure how your rifle is put together. About 99.218% 
of my accuracy work has been on Remington, Winchester and Ruger rifles. Some of those have a magazine box that fits in the stock mortise and is only held in by the trigger guard and 'bottom metal' that the tang screws go through. MANY times the mag box is taller than the natural space between action and bottom metal. that puts a 'bow' in both parts. I like a sixteenth clearance to make sure the action sits down in the bedding straight, solid and square.
Now that we covered the rifle and scope maybe we should take a look at the 'loose nut behind the trigger'.
If the toe of the stock is resting on the bench top, it causes vertical stringing. If the barrel is resting on the front rest, it causes vertical flinging. If you drape your hand over the scope to push the rifle down (instead of squeezing the rear bag which controls elevation), vertical displacements can happen.
Round groups are almost always a sign of a healthy rifle. Big and round makes the barrel the suspect. Clean it and re-fresh the crown (88% cure rate) before scrapping the barrel.
of my accuracy work has been on Remington, Winchester and Ruger rifles. Some of those have a magazine box that fits in the stock mortise and is only held in by the trigger guard and 'bottom metal' that the tang screws go through. MANY times the mag box is taller than the natural space between action and bottom metal. that puts a 'bow' in both parts. I like a sixteenth clearance to make sure the action sits down in the bedding straight, solid and square.Now that we covered the rifle and scope maybe we should take a look at the 'loose nut behind the trigger'.
If the toe of the stock is resting on the bench top, it causes vertical stringing. If the barrel is resting on the front rest, it causes vertical flinging. If you drape your hand over the scope to push the rifle down (instead of squeezing the rear bag which controls elevation), vertical displacements can happen.
Round groups are almost always a sign of a healthy rifle. Big and round makes the barrel the suspect. Clean it and re-fresh the crown (88% cure rate) before scrapping the barrel.
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Barrel bedding can cause vertical stringing as well. That "bump" on the fore end that puts pressure on the barrel for "accuracy can and will cause vertical, angular and horizontal stringing and in combination of the three. With the wispy spider leg barrels that are on most hunting rifles now that "bump" can really raise havoc.
As others said, scope mounts, barrel crown, a poorly fitted magazine all can cause stringing.
Start with the easiest first, the "bump". If you "need" it, it should fit the contour and alignment of the barrel. If not, I get rid of it entirely.
RJ
As others said, scope mounts, barrel crown, a poorly fitted magazine all can cause stringing.
Start with the easiest first, the "bump". If you "need" it, it should fit the contour and alignment of the barrel. If not, I get rid of it entirely.
RJ
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Well just a guess but first thing I'd look at is bedding. I have had good luck with full length barrel bedding but seems a bit better with free floated all the way or bedding just under the chamber. The actual reason? Not a clue and don't really care. A rifle either shoots well of it doesn't. If it doesn't it gets a new bedding job, doesn't matter where the problem is, bedding should get rid of it. The thing other than the rifle that would concern me is me! hard to pinpoint a shooting problem when every group you shoot is different even though group size may stay the same. part of that has to be difference's in the case and bullet and there your pretty helpless! Bigger part on a factory rifle I believe is rifle bedding if you have a factory rifle. Those rifle's are mass produced for the most part and I doubt consistency is there to make a match quality rifle. Biggest problem may be the shooter. I have three rifles that will pretty much always go 1/2", well actually average 1/2". Reason I think that is, is that some days I'm just better on my game!
Not the biggest problem with stringing is not so much the stringing but the size of the group. You get five shots into 1/2" and the group is actually taller than wide, who really care's but that would be stringing, just not bad enough group to bother us.
If I remember right, in Warren Pages book "The Accurate Rifle" He did talk about that; where to look for bedding problems that give stringing, vertical and horizontal. Book well worth reading. Trying to remember, I think vertical stringing you look into the action bedding. Tighten down the action and then loosen the front screw slowly and watch for movement of the barrel and action. Easiest place to see it would be top of the stock at the tip of the stock. Generally indicates a bind in the action. But unless the barrel is floated, could be a high spot in the barrel channel. In that case the front of the action may rise but at the tip of the stock it probably won't Do a paper test sliding a paper under the barrel and down the barrel channel and feel for a high spot, you'll notice it right away. I like best for paper two pieces of stationary paper, Will mean more float in the barrel but doesn't really matter much, float is float! better a bit much than not enough!
Not the biggest problem with stringing is not so much the stringing but the size of the group. You get five shots into 1/2" and the group is actually taller than wide, who really care's but that would be stringing, just not bad enough group to bother us.
If I remember right, in Warren Pages book "The Accurate Rifle" He did talk about that; where to look for bedding problems that give stringing, vertical and horizontal. Book well worth reading. Trying to remember, I think vertical stringing you look into the action bedding. Tighten down the action and then loosen the front screw slowly and watch for movement of the barrel and action. Easiest place to see it would be top of the stock at the tip of the stock. Generally indicates a bind in the action. But unless the barrel is floated, could be a high spot in the barrel channel. In that case the front of the action may rise but at the tip of the stock it probably won't Do a paper test sliding a paper under the barrel and down the barrel channel and feel for a high spot, you'll notice it right away. I like best for paper two pieces of stationary paper, Will mean more float in the barrel but doesn't really matter much, float is float! better a bit much than not enough!
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Vertical stringing can be duplicated anytime you like with a solid bottom action like the 40XBR. Simply lay a piece of sewing thread crossways the inletting half way between the tang screws. INSTANT vertical group twice to three times normal C to C group measurement. Bedding is IMportant. Vertical stringing means the action is not correctly bedded because vertical stringing is caused by un-even lug pressure.
Sorry to repeat but it's fact.
Sorry to repeat but it's fact.
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I have a couple of rifles that will string up and down for NO reason. One load gives a 0.35 group and the next a 2 inch vertical stringer. That's why we do what we do. I hate it as much as the next guy. lol
I've got two really accurate sporter rifles, I've watched friends and relatives with an inconsistent bench shooting technique shoot terrible groups with both of them. Just saying that with the limited information we have it's almost impossible to make an informed guess as to what the problem is. How many times have we seen pictures of people shooting off wood blocks or laying down in the back of a pickup?
Interesting......as far as the "loose nut", I have learned to hold the rear bag to keep things stable,but every once in a while I do catch the rifle has eased back and is resting farther up the stock than I like. The next 2 groups fired (different loads) were round. So the rifle position may well have been the problem. I am usually in a bit of a hurry to get started shooting, and the vertical group was the first one. As far as retreshing the crown, what is your take on the different angles of cutters available ?I'm not sure how your rifle is put together. About 99.218%
Now that we covered the rifle and scope maybe we should take a look at the 'loose nut behind the trigger'.
If the toe of the stock is resting on the bench top, it causes vertical stringing. If the barrel is resting on the front rest, it causes vertical flinging. If you drape your hand over the scope to push the rifle down (instead of squeezing the rear bag which controls elevation), vertical displacements can happen.
Round groups are almost always a sign of a healthy rifle. Big and round makes the barrel the suspect. Clean it and re-fresh the crown (88% cure rate) before scrapping the barrel.
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"Angle of the crown" makes little if any difference. You don't need a 'cutter' just a lap. Any hardware store has a bunch of round headed machine screws in different sizes. Buy a couple of each from #10 to 3/8".
Buy the smallest tub of 320 valve lapping compound the auto parts store has. An ounce last two life-times.
Cut grooves on the round headed screw at right angles to the slot.
Block the bore with a patch just inside the muzzle and pick a screw head that hits the very corners of the bore. Smear some grit on the screw head and chuck it up in an electric drill.
Go at it straight to start with and look at what five seconds of lapping does. IF the shiny ring is not on the corner, go down in size until only the corner is lapped.
Rotate the drill around it's axis so most of the screw head is wallowed back and fourth and around so a groove isn't worn in the lap.
ONLY the weight of the drill is needed. Lap ten seconds and check under at least 20X magnification. SHine a bright light on it so the lapped ring shows up.
Break the corner of the lands and just barely break the corner of the grooves.
Buy the smallest tub of 320 valve lapping compound the auto parts store has. An ounce last two life-times.
Cut grooves on the round headed screw at right angles to the slot.
Block the bore with a patch just inside the muzzle and pick a screw head that hits the very corners of the bore. Smear some grit on the screw head and chuck it up in an electric drill.
Go at it straight to start with and look at what five seconds of lapping does. IF the shiny ring is not on the corner, go down in size until only the corner is lapped.
Rotate the drill around it's axis so most of the screw head is wallowed back and fourth and around so a groove isn't worn in the lap.
ONLY the weight of the drill is needed. Lap ten seconds and check under at least 20X magnification. SHine a bright light on it so the lapped ring shows up.
Break the corner of the lands and just barely break the corner of the grooves.
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I may be wrong but it doesn't seem like a good idea to use a drill for cleaning up a crown, your holding the drill by the handle off center, I could see doing it with an electric screwdriver. I use a cordless drill and a countersink bit often and it wobbles unless the drill is held directly in line with the bit.
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