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Posted: 11/16/2011 10:31:39 AM EDT
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I have an AR (factory RRA with a 1/8 wylde chamber) that opens up way too much at about 200 yards. The barrel is not shot out. It is clean. I have completely disassembled it and looked for anything not right. I cant find anything at all. I suspected the crown, but it looks good to me and I had another person check it as well. The only thing left to try is squaring the receiver. I have never done this, but was told to use something like this from brownells http://www.brownells.com/.aspx/pid=20220/Product/AR-15-M16-UPPER-RECEIVER-LAPPING-TOOL
How exactly do you use it? Never done it. |
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What load are you shooting? Have you tried handloads so that you can tune them to the rifle? If you are shooting good groups and then they suddenly open up at 200 yards, then it sounds like a bullet stability problem which means it might like heavier or lighter bullets out past 200 yards.
My dad had a 1:12 remington bolt that would shoot 55 gr. through one hole all day long but at 200 yds, they would start to yaw and keyhole. |
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What load are you shooting? Have you tried handloads so that you can tune them to the rifle? If you are shooting good groups and then they suddenly open up at 200 yards, then it sounds like a bullet stability problem which means it might like heavier or lighter bullets out past 200 yards. My dad had a 1:12 remington bolt that would shoot 55 gr. through one hole all day long but at 200 yds, they would start to yaw and keyhole. Trust me when I tell you I have been around the block...twice with this upper. I have tried multiple ammo types. |
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Anyone wanna just let me know how that tool exactly works? ETA - I guess I made it sound like it only starts to open up as 200 yds. It opens up pretty consistently, but I just notice it a lot more at 200 yds and I havent taken it past that. If you are shooting groups at 100 yards fine and it consistently opens up @ 200 yards. Its not the rifle. |
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Anyone wanna just let me know how that tool exactly works? ETA - I guess I made it sound like it only starts to open up as 200 yds. It opens up pretty consistently, but I just notice it a lot more at 200 yds and I havent taken it past that. If you are shooting groups at 100 yards fine and it consistently opens up @ 200 yards. Its not the rifle. Again, it opens up pretty consistently. What I mean by this is that a 3 inch group at 100 yards turns into about a 5 inch group at 200 yards. Again, I was asking if anyone can elaborate on the use of the tool I put a link to on my first post. |
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Anyone wanna just let me know how that tool exactly works? ETA - I guess I made it sound like it only starts to open up as 200 yds. It opens up pretty consistently, but I just notice it a lot more at 200 yds and I havent taken it past that. If you are shooting groups at 100 yards fine and it consistently opens up @ 200 yards. Its not the rifle. Again, it opens up pretty consistently. What I mean by this is that a 3 inch group at 100 yards turns into about a 5 inch group at 200 yards. Again, I was asking if anyone can elaborate on the use of the tool I put a link to on my first post. Ummmm.... You just described a smaller group at 200 than at 100. |
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Anyone wanna just let me know how that tool exactly works? ETA - I guess I made it sound like it only starts to open up as 200 yds. It opens up pretty consistently, but I just notice it a lot more at 200 yds and I havent taken it past that. If you are shooting groups at 100 yards fine and it consistently opens up @ 200 yards. Its not the rifle. Again, it opens up pretty consistently. What I mean by this is that a 3 inch group at 100 yards turns into about a 5 inch group at 200 yards. Again, I was asking if anyone can elaborate on the use of the tool I put a link to on my first post. 
That is what should happen. a 3" group @ 100 yards is 3MOA, a 5" group @ 200 yards is 2.5MOA |
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Quoted: I have an AR (factory RRA with a 1/8 wylde chamber) that opens up way too much at about 200 yards. The barrel is not shot out. It is clean. I have completely disassembled it and looked for anything not right. I cant find anything at all. I suspected the crown, but it looks good to me and I had another person check it as well. The only thing left to try is squaring the receiver. I have never done this, but was told to use something like this from brownells http://www.brownells.com/.aspx/pid=20220/Product/AR-15-M16-UPPER-RECEIVER-LAPPING-TOOL How exactly do you use it? Never done it. i never have either, but if you notice the instructions are on the site. http://www.brownells.com/userdocs/learn/Inst-594%20AR%20Receiver%20Lap%20Tool.pdf before you get into this, have you benched your gun? what sights are you using? what ammo? |
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OverScoped - Didnt notice the detailed directions on the site. Thanks.
The grouping I listed was not exact, just an estimate, although it is close. I have achieved sub-moa with identical "match" barrels (as rra advertises) in same configuration. I have tried ammo from AE 5.56, Winchester .223, IMI 5.56 and more. I even tried some custom loaded 70 or 75 gr hp's that have done well in other weapons. Everything else on this weapon is gtg. ETA - I use a Millett DMS in an ADM Recon mount. Not the best setup I know, but I also know what it has been and is capable of. |
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OverScoped - Didnt notice the detailed directions on the site. Thanks. The grouping I listed was not exact, just an estimate, although it is close. I have achieved sub-moa with identical "match" barrels (as rra advertises) in same configuration. I have tried ammo from AE 5.56, Winchester .223, IMI 5.56 and more. I even tried some custom loaded 70 or 75 gr hp's that have done well in other weapons. Everything else on this weapon is gtg. ETA - I use a Millett DMS in an ADM Recon mount. Not the best setup I know, but I also know what it has been and is capable of. Did you not read my last post, or the one above it? |
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OverScoped - Didnt notice the detailed directions on the site. Thanks. The grouping I listed was not exact, just an estimate, although it is close. I have achieved sub-moa with identical "match" barrels (as rra advertises) in same configuration. I have tried ammo from AE 5.56, Winchester .223, IMI 5.56 and more. I even tried some custom loaded 70 or 75 gr hp's that have done well in other weapons. Everything else on this weapon is gtg. ETA - I use a Millett DMS in an ADM Recon mount. Not the best setup I know, but I also know what it has been and is capable of. Did you not read my last post, or the one above it? Did you not read my post directly above? Do you know what this barrel is capable of? I have had the same barrel from Rock River in similar configurations and I know what I have shot and what it is capable of. 3 inch groups at 100 yds are not the best this barrel can do. If you want to say it is the shooter, fine say it. I know what I can shoot and what this barrel should shoot. |
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That tool will do little to nothing to tighten groups. I use it on all my builds but it is to get the barrel square with the bore so that you end up with your sights in the middle, not cranked over to one side or the other. I have shot rifles before and after truing and while it does get those sights back in the middle where they belong, I have not seen any change in accuracy, pro or con.
I think you problem lies elsewhere and not with the squareness of the front of the receiver. I suppose it could affect accuracy but it would have to be way off, so far off to the point of making your rifle almost impossible to zero with irons or optics. What that tool does is square the front of the receiver so that the barrel locks in straight and points directly ahead, not canted off to one side or the other. If there is an angle on the upper, and every upper I have ever used this tool on has shown them all, even billet uppers, to be slightly out of square, then if it is bad enough you have to crank your sights way over to zero. That is pretty much what the tool eliminates and allows one to keep their iron sights and optics centered in their adjustment range. What kind of groups are you getting? You or someone mentioned three inch at 100 and 5 inch at 200. That barrel should be doing a LOT better than 3 inches at 100 yards. First thing I would do is remove the FS and see if that helps. Doubtful but a place to start. You do not need a thread protector on there when you shoot it without the FS, just shoot it. If that affects your groups, then it could be a simple case of bullet striking the FS, albeit small, on the FS or over torquing of the FS putting stress on the muzzle. If that helps I would get another FS and tighten it no more than 20 ft-lbs. If that proves nothing, the next thing I would do is re-crown even if it does look OK. I had a RR M4 barrel that had an obvious nick on the crown and re-crowning turned it into a real shooter. I used a 1/4 inch round head brass bolt chucked in a drill motor with some 600 grit valve grinding compound. Work it around so you get a nice beveled crown and do not grind a groove in the bolt head. It is very simple to do and pretty fool proof. Not as good as a lathe turned crown but damned if it doesn't work and using this method I have turned some really bad groupers into decent shooting rifles. After that??? I'd have to think more about it after the results from the two above tests. |
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That tool will do little to nothing to tighten groups. I use it on all my builds but it is to get the barrel square with the bore so that you end up with your sights in the middle, not cranked over to one side or the other. I have shot rifles before and after truing and while it does get those sights back in the middle where they belong, I have not seen any change in accuracy, pro or con. I think you problem lies elsewhere and not with the squareness of the front of the receiver. I suppose it could affect accuracy but it would have to be way off, so far off to the point of making your rifle almost impossible to zero with irons or optics. What that tool does is square the front of the receiver so that the barrel locks in straight and points directly ahead, not canted off to one side or the other. If there is an angle on the upper, and every upper I have ever used this tool on has shown them all, even billet uppers, to be slightly out of square, then if it is bad enough you have to crank your sights way over to zero. That is pretty much what the tool eliminates and allows one to keep their iron sights and optics centered in their adjustment range. Well im out of places to look then. Maybe the barrel is not one of their better ones. |
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OverScoped - Didnt notice the detailed directions on the site. Thanks. The grouping I listed was not exact, just an estimate, although it is close. I have achieved sub-moa with identical "match" barrels (as rra advertises) in same configuration. I have tried ammo from AE 5.56, Winchester .223, IMI 5.56 and more. I even tried some custom loaded 70 or 75 gr hp's that have done well in other weapons. Everything else on this weapon is gtg. ETA - I use a Millett DMS in an ADM Recon mount. Not the best setup I know, but I also know what it has been and is capable of. Did you not read my last post, or the one above it? Did you not read my post directly above? Do you know what this barrel is capable of? I have had the same barrel from Rock River in similar configurations and I know what I have shot and what it is capable of. 3 inch groups at 100 yds are not the best this barrel can do. If you want to say it is the shooter, fine say it. I know what I can shoot and what this barrel should shoot. But you started a thread about the groups opening up past 200 yads, now you are saying you are not satisfied by its acurracy at any range. |
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I edited my above post. Please read what I added and see if it makes any sense. So you just used the round head bolt as a drill bit, put some lapping compound on it and ground out the imperfection(s)? The crown looked good to me, but maybe I missed something. |
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OverScoped - Didnt notice the detailed directions on the site. Thanks. The grouping I listed was not exact, just an estimate, although it is close. I have achieved sub-moa with identical "match" barrels (as rra advertises) in same configuration. I have tried ammo from AE 5.56, Winchester .223, IMI 5.56 and more. I even tried some custom loaded 70 or 75 gr hp's that have done well in other weapons. Everything else on this weapon is gtg. ETA - I use a Millett DMS in an ADM Recon mount. Not the best setup I know, but I also know what it has been and is capable of. Did you not read my last post, or the one above it? Did you not read my post directly above? Do you know what this barrel is capable of? I have had the same barrel from Rock River in similar configurations and I know what I have shot and what it is capable of. 3 inch groups at 100 yds are not the best this barrel can do. If you want to say it is the shooter, fine say it. I know what I can shoot and what this barrel should shoot. But you started a thread about the groups opening up past 200 yads, now you are saying you are not satisfied by its acurracy at any range. I never posted that the groups opened up past 200 yds. In fact, I said I never took it out past 200 yds. I also clarified that I did not mean that it started to open up at that range. Like I said, it is capable of better than 3 inch groups at 100 yds. Something is not right. Not sure what it is, but I know it is not an ammo problem. |
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I edited my above post. Please read what I added and see if it makes any sense. So you just used the round head bolt as a drill bit, put some lapping compound on it and ground out the imperfection(s)? The crown looked good to me, but maybe I missed something. Correct, but you MUST use a solid brass bolt, not one made of steel or brass plated. 1/4 inch bolt size is perfect for a 22 caliber to 30 caliber barrel and easy to find at any hardware store, an inch to an inch and half long is plenty. If you use steel you may damage the barrel whereas the soft brass bolt will polish the crown and remove any burrs or imperfections. And be sure to go in both directions, forward and reverse. It must be a round head bolt, not a flat head, pan head, oval head or hex head. It does not matter if it has a standard slot or phillips head, but it must be a round head. 
Just chuck the threaded part of the bolt into your drill and put a liberal coat of valve grinding compound on it and work it around the muzzle. Stop after a minute or so and remove the lapping compound and see what you have done. Continue until you have a nice even ring all around the edge where the rifling meets the muzzle and you are done. Sometimes the defect is obvious, like it was in my M4 barrel, but sometimes there is nothing to be seen. I have a 48 Mauser 8mm that would not shoot worth a darn. The barrel was worn but I felt it should shoot at least a group and not a pattern. The crown looked OK but WTF, what did I have to lose? I lapped the crown with a 5/16 bolt and the groups were cut in half. Still not a tack driver by any stretch of the imagination but at least it would put 5 shots on a single paper target at 100 yards. Before I was lucky to get three shots on one target paper. Too bad there is not such an easy fix for a dark bore. 
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| How long have you been shooting the AR platform? It is not the same as a bolt rifle as to how you drive it. Way more parts moving around. And a 1-4 power scope is not the best to try to shoot groups with. And just because you shoota 1" group at 100 yds., it does not mean that it will get progressiveley bigger. The farther you shoot, the more detailed on your form needs to be. Bad form shows more and more as the distance goes longer. |
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How long have you been shooting the AR platform? It is not the same as a bolt rifle as to how you drive it. Way more parts moving around. And a 1-4 power scope is not the best to try to shoot groups with. And just because you shoota 1" group at 100 yds., it does not mean that it will get progressiveley bigger. The farther you shoot, the more detailed on your form needs to be. Bad form shows more and more as the distance goes longer. Ummm... yes, your groups will get progressively larger as range increases, and errors introduced by shooting technique will be constant, but proportional to the distance of the shot. |
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Just becauuse I shot a 1" group at 100 yards, does not mean that it will be 2"s at 200yds., or 3"s at 300yds. It might be 10" at 200 or more. It just does not work that way. I does work that way, up until the you get far enough out that the declining energy of the round begin to have an effect,or if external vectors like wind come into play. As others have pointed out, in this thread, if your group's from 100 to 200 more than doubled, that would indicate a problem, like your bullet not being properly stabilized. If all variables are equal, including shooter input, a 1" group at 100, will open up to around 2" at 200. Thats what the "oA" in MoA is talking about. |
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What I mean by this is that a 3 inch group at 100 yards turns into about a 5 inch group at 200 yards. . Lets not beat around the bush since you have aswnered your own question here. If you are printing 3MOA at 100 yards, then your 200 yard group should be 6MOA, not the 5MOA your getting. The reason that you are printing tighter MOA at 200 yards then at 100 yards is that your rounds are not sleeping until past the 100 yard mark. So lets take it back to speed/sleep of a loaded rounds. For 100 yard rounds, work off the bottom of the suggested start powder point until you find the right load to get the bullet to exist the muzzle in one of it two oblong end points of barrel harmonics. Not only will this give a tighter group, but the bullet will sleep before 100 yards as well. Now doing the same for the next reloads to be used at a longer distance (the bullet only need to sleep before it gets to the longer range target), start increasing the speed of the reload, again, finding one of the two oblong movement correct exit points of the muzzle harmonics, while still having the bullet sleep before it gets to the target. Simply, a load that you use at 100 yards may not be the best load for 600 yards. The reason for this come down to bullet sleep,and the faster you push a bullet,the longer down range it going to take for the bullet to sleep. Bullet sleep is the point that the bullet is flying perfectly spiral, with no yawning from tip to tail. Bullet embed to rifling has a great deal of influence on this, but there will still be some yawn to the bullet as it exits the muzzle that will take some distance until the bullet sprials out perfectly, hence sleeps. If you want to see oblong barrel movement, take a 4 foot, 1/2" wooden dowel, and whip it up and down. You will note that the end of the dowel is not straight up and down with the wipe,but has a oblong path instead. At the end of the oblong path, the very end of the dowel is at it most stable/stationary point as you are whipping it up and down, and it's of these two end point that you would want a bullet to exist the barrel as well. Note, barrels have the same oblong path a path when being fired, but very seldom are the end points straight up and down. So to take it all back to the beginning, and your current loads are neither existing the muzzle on one of the two end barrel/muzzle points of the barrels oblong harmonics, and they are not sleeping before 100 yards either. Being that that this is a reloading problem, and you have yet to find the correct loads to make that barrel sing!!!! |
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What I mean by this is that a 3 inch group at 100 yards turns into about a 5 inch group at 200 yards. . Lets not beat around the bush since you have aswnered your own question here. If you are printing 3MOA at 100 yards, then your 200 yard group should be 6MOA, not the 5MOA your getting. The reason that you are printing tighter MOA at 200 yards then at 100 yards is that your rounds are not sleeping until past the 100 yard mark. So lets take it back to speed/sleep of a loaded rounds. For 100 yard rounds, work off the bottom of the suggested start powder point until you find the right load to get the bullet to exist the muzzle in one of it two oblong end points of barrel harmonics. Not only will this give a tighter group, but the bullet will sleep before 100 yards as well. Now doing the same for the next reloads to be used at a longer distance (the bullet only need to sleep before it gets to the longer range target), start increasing the speed of the reload, again, finding one of the two oblong movement correct exit points of the muzzle harmonics, while still having the bullet sleep before it gets to the target. Simply, a load that you use at 100 yards may not be the best load for 600 yards. The reason for this come down to bullet sleep,and the faster you push a bullet,the longer down range it going to take for the bullet to sleep. Bullet sleep is the point that the bullet is flying perfectly spiral, with no yawning from tip to tail. Bullet embed to rifling has a great deal of influence on this, but there will still be some yawn to the bullet as it exits the muzzle that will take some distance until the bullet sprials out perfectly, hence sleeps. If you want to see oblong barrel movement, take a 4 foot, 1/2" wooden dowel, and whip it up and down. You will note that the end of the dowel is not straight up and down with the wipe,but has a oblong path instead. At the end of the oblong path, the very end of the dowel is at it most stable/stationary point as you are whipping it up and down, and it's of these two end point that you would want a bullet to exist the barrel as well. Note, barrels have the same oblong path a path when being fired, but very seldom are the end points straight up and down. So to take it all back to the beginning, and your current loads are neither existing the muzzle on one of the two end barrel/muzzle points of the barrels oblong harmonics, and they are not sleeping before 100 yards either. Being that that this is a reloading problem, and you have yet to find the correct loads to make that barrel sing!!!! I guess I am just frustrated because the same exact barrels from RRA have always shot better for me under the same circumstances and same loads. I do not reload, but I can have a friend work something up for me. He is the one that gave me the 75gr hp's. You dont think it could be a problem with the mating surfaces of the barrel extension and the upper? |
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OverScoped - Didnt notice the detailed directions on the site. Thanks. The grouping I listed was not exact, just an estimate, although it is close. I have achieved sub-moa with identical "match" barrels (as rra advertises) in same configuration. I have tried ammo from AE 5.56, Winchester .223, IMI 5.56 and more. I even tried some custom loaded 70 or 75 gr hp's that have done well in other weapons. Everything else on this weapon is gtg. ETA - I use a Millett DMS in an ADM Recon mount. Not the best setup I know, but I also know what it has been and is capable of. You need to role your own it sounds like. You may have to play with the Over All Length of the round (which may be effected by the depth of your chamber) and you may have to play with the powder measure and you may have to play with different projectiles by weight and/or manufacturer. You can load up a batch and start on the low end of the powder measure and work your way up to max loads. You may find what your rifle likes for longer distances. |
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