I need to know how to measure and than correct for barrel drop. I have built a custom target 10/22 with an Tactical Innovations Stainless Elite22 Receiver, a Green Mountain 28" Stainless Bull Barrel and Archangel Stock. The Receive has a built in scope rail. I have a Hawke Endurance AO 6-24x50 scope. When sighting in the scope I have to adjust the elevation almost all the way to the bottom just to get the gun sighted in. I also have an adjustable V-Block. I need to be able to measure for barrel drop and than be able to adjust for it.
Barrel Drop
- Thread starter Sport2318
- Start date
Yes. And. I think the term you are looking for ls barrel droop. Good luck with your project; that's a neat combination.Sport2318 said:
Mlke
Here Goes:
My new 10/22 that I built when sighted in at 50 yds. requires the scope to be adjusted almost to the bottom most setting on the elevation adjustment of my scope in order to get zeroed in on the target. The gun shoots well about a 1/4" groups. The problem is I am not happy that I have to adjust the scope that way to get the gun sighted in. I have even added shims to the rear scope ring mount to try and compensate for that low elevation adjustment in the scope. I would like someone to tell me how to measure Barrel Drop. "The difference between the angle of the barrel and the angle of the plane of the scope". Since the scope is mounted on a one piece receiver/rail I am assuming the scope is the plane I need to match. The barrel must be pointing down to require the scope to be adjusted so much that the Elevation Turret requires almost full downward adjustment. I also want to know how I can correct for that barrel drop? I may not be able to and will just need to shim the scope. Forcing the scope to follow the drop of the barrel. This is barrel is a 28" Heavy stainless Green Mountain Bull barrel in a Stainless Elite 22 Receiver and Bolt. I hope this help to explain my issue. http://forum.accurateshooter.com/Smileys/default/huh.gif
My new 10/22 that I built when sighted in at 50 yds. requires the scope to be adjusted almost to the bottom most setting on the elevation adjustment of my scope in order to get zeroed in on the target. The gun shoots well about a 1/4" groups. The problem is I am not happy that I have to adjust the scope that way to get the gun sighted in. I have even added shims to the rear scope ring mount to try and compensate for that low elevation adjustment in the scope. I would like someone to tell me how to measure Barrel Drop. "The difference between the angle of the barrel and the angle of the plane of the scope". Since the scope is mounted on a one piece receiver/rail I am assuming the scope is the plane I need to match. The barrel must be pointing down to require the scope to be adjusted so much that the Elevation Turret requires almost full downward adjustment. I also want to know how I can correct for that barrel drop? I may not be able to and will just need to shim the scope. Forcing the scope to follow the drop of the barrel. This is barrel is a 28" Heavy stainless Green Mountain Bull barrel in a Stainless Elite 22 Receiver and Bolt. I hope this help to explain my issue. http://forum.accurateshooter.com/Smileys/default/huh.gif
I am sorry http://forum.accurateshooter.com/Smileys/default/lipsrsealed.gif I was miss using the term used by Tactical Innovations in their Adjustable V-Block to correct for "Barrel Droop."
ADJUSTABLE V-BLOCK FOR 10/22® & CHARGER™ - BLUE OR STAINLESS STEEL
This Adjustable V-Block is used to secure the barrel to the receiver for 10/22 and similar firearms using two cap screws which are sold separately. It has a set screw which can be adjusted in contact with the barrel to prevent barrel droop which is common when the cap screws are tightened to draw the barrel into the receiver. Using this Adjustable V-Block will allow you to set your barrel line to your optics line at any position your desire. The Adjustable V-Blocks are available in your choice of blue steel or stainless steel and ship complete with the adjusting allen wrench.
For custom builds, this Adjustable V-Block is a necessity.
ADJUSTABLE V-BLOCK FOR 10/22® & CHARGER™ - BLUE OR STAINLESS STEEL
This Adjustable V-Block is used to secure the barrel to the receiver for 10/22 and similar firearms using two cap screws which are sold separately. It has a set screw which can be adjusted in contact with the barrel to prevent barrel droop which is common when the cap screws are tightened to draw the barrel into the receiver. Using this Adjustable V-Block will allow you to set your barrel line to your optics line at any position your desire. The Adjustable V-Blocks are available in your choice of blue steel or stainless steel and ship complete with the adjusting allen wrench.
For custom builds, this Adjustable V-Block is a necessity.
I think I understand what you are trying to say. This is going to sound confusing. Is the elevation knob at the top or bottom of its travel. When the knob is at the bottom of its travel the crosshair is at the top of its travel. In your case I'm assuming the crosshair is at the bottom and the knob is at the top. Is this correct?
Wayne
Wayne
Sport2318 said:
As you have since figured out, it IS called barrel droop; it is a condition that is somewhat common in Ruger 10/22s and even more common in break barrel cocking spring type air guns. In both situations you can compensate for the problem using a scope rail with built in elevation compensation or using the Burris Signature Z rings with the offset plastic inserts or a combination of the two. With the 10/22 there is a second solution available, a replacement for the stock V-block used to affix the barrel to the receiver. For a discussion of one of one of the best, the Gunsmither block, see:
http://www.rimfirecentral.com/forums/showthread.php?t=438345&highlight=barrel+droop
For the block itself, see:
http://www.gunsmithertools.com/gunsmither-1022-elevation/
Hope this helps in your quest.
Dusty Stevens
Shiner
Bed the barrel where it has up pressure on it to correct for the "barrel drop"
Fixing the gun is called blue printing and requires the barrel and receiver threads both be re-machined exactly 90 degree to the action. I suspect this is the real problem. Dont know.
If it turns out you used a 200 pound, 6 foot barrel (exaggeration) and the receiver lacks the rigidity, they you may have screwed up. The best solution in that case is bedding forward of the action to support the massive weight of the ill advised barrel. That or lighten the barrel.
Many new factory guns have this problem due to sloppy machining. It is EASILY corrected with a moa offset scope rail. Or those burris rings that have plastic inserts that will angle the scope up or down to the same effect as the moa offset scope base/rail/. The scope base is standard fix, the rings are fine if you like Burris and like the plastic. The plastic inserts do a great job protecting the scope finish and eliminate the need to lap the rings for stress free alignment. This is not a mickey mouse fix, this is pretty much sop, unless you have a machine shop or trade the gun.
If it turns out you used a 200 pound, 6 foot barrel (exaggeration) and the receiver lacks the rigidity, they you may have screwed up. The best solution in that case is bedding forward of the action to support the massive weight of the ill advised barrel. That or lighten the barrel.
Many new factory guns have this problem due to sloppy machining. It is EASILY corrected with a moa offset scope rail. Or those burris rings that have plastic inserts that will angle the scope up or down to the same effect as the moa offset scope base/rail/. The scope base is standard fix, the rings are fine if you like Burris and like the plastic. The plastic inserts do a great job protecting the scope finish and eliminate the need to lap the rings for stress free alignment. This is not a mickey mouse fix, this is pretty much sop, unless you have a machine shop or trade the gun.
Barrel droop is the natural result where the shoulder of a 10/22™ barrel is not being held sufficiently tight and/or square to the receiver’s face combined with the barrel having a shank (tenon) outside diameter that’s smaller than the inside diameter of the receiver bore it got plugged into. The barrel shoulder pivots on its low side and it pulls away from the receiver face on its top side, all the while at the same time the barrel tenon is cocked within the receiver bore with the breach end of the tenon up against the ceiling and the shoulder end of the tenon held to the floor. All together it’ll give the barrel a nose down attitude relative to both the receiver’s centerline and to the plane of the scope rail, bullets impact way low, and the scope may well not have a broad enough elevation adjustment range to compensate.
Two lines originating at the same point and separating at one MOA grow further apart at the rate of .0002909†for every inch further away from the point of origin. So, lay a straight edge on top of the scope rail that extends out over the barrel, or lay the barreled action scope rail down on a straight flat surface. Pick a point like at the end of the extended rail and measure from the straight edge to the barrel. Pick another point a measured amount of distance from the first and nearer to the muzzle end then again measure from the straight edge to the barrel. Cipher the change in distance to the barrel, divide by the distance separating the two measurements, and divide by the .0002909†representing 1 MOA change in separation in one inch.
What if’n for example:
.400†from straight edge to barrel at the end of rail
.618†from straight edge to barrel at 25†from the end of rail
.218†increase in separation from straight edge to barrel over the 25†between the two measurements
.218/25/.0002909 = 30 MOA of barrel droop
That jack screw installed in the adjustable v-block would be used to shove the full length of the barrel tenon up to the ceiling of a loose fitting receiver bore. Once there, some folk will insist on continuing to crank on the jack screw and they’re only further stressing and will soon be distorting the receiver. The “Gunsmither†elevating barrel retainer, a rectangular block and not at all a “v-blockâ€, is the only jack screw equipped barrel retainer that’s worth a hoot, if properly installed. Even with the Gunsmither, whenever a jack screw is utilized, it’s making barrel contact and introducing some degree of stress somewhere that there shouldn’t have been either one. IMO and IME, regular v-blocks installed correctly do not cause a barrel to droop.
Amongst unnatural causes that will are (1) way over-tightened and/or unevenly tightened v-block retaining screws, where 10 to 12 INCH-lbs. is a plenty, and they should be brought up evenly, incrementally, and switching from one screw to the other. And, (2) by having the barrel incorrectly clocked, wrecking the geometry between the v-block’s angled contact surfaces relative to those of the barrel and receiver. Lots of folk will overly stress making the extractor perfectly centered within the extractor cut, all the while ignoring the angular relationship between the v-block and the receiver and barrel. A good extractor will function just fine long as there’s no contact with either of the sidewalls of the extractor cut, it does not have to be perfectly centered within the cut. Make the v-block square to and the contact surfaces parallel with those of the receiver, then clock the barrel such that the barrel is square to and parallel with the v-block, and once done so, the extractor cut automatically ends up aligned well enough with the extractor.
Two lines originating at the same point and separating at one MOA grow further apart at the rate of .0002909†for every inch further away from the point of origin. So, lay a straight edge on top of the scope rail that extends out over the barrel, or lay the barreled action scope rail down on a straight flat surface. Pick a point like at the end of the extended rail and measure from the straight edge to the barrel. Pick another point a measured amount of distance from the first and nearer to the muzzle end then again measure from the straight edge to the barrel. Cipher the change in distance to the barrel, divide by the distance separating the two measurements, and divide by the .0002909†representing 1 MOA change in separation in one inch.
What if’n for example:
.400†from straight edge to barrel at the end of rail
.618†from straight edge to barrel at 25†from the end of rail
.218†increase in separation from straight edge to barrel over the 25†between the two measurements
.218/25/.0002909 = 30 MOA of barrel droop
That jack screw installed in the adjustable v-block would be used to shove the full length of the barrel tenon up to the ceiling of a loose fitting receiver bore. Once there, some folk will insist on continuing to crank on the jack screw and they’re only further stressing and will soon be distorting the receiver. The “Gunsmither†elevating barrel retainer, a rectangular block and not at all a “v-blockâ€, is the only jack screw equipped barrel retainer that’s worth a hoot, if properly installed. Even with the Gunsmither, whenever a jack screw is utilized, it’s making barrel contact and introducing some degree of stress somewhere that there shouldn’t have been either one. IMO and IME, regular v-blocks installed correctly do not cause a barrel to droop.
Amongst unnatural causes that will are (1) way over-tightened and/or unevenly tightened v-block retaining screws, where 10 to 12 INCH-lbs. is a plenty, and they should be brought up evenly, incrementally, and switching from one screw to the other. And, (2) by having the barrel incorrectly clocked, wrecking the geometry between the v-block’s angled contact surfaces relative to those of the barrel and receiver. Lots of folk will overly stress making the extractor perfectly centered within the extractor cut, all the while ignoring the angular relationship between the v-block and the receiver and barrel. A good extractor will function just fine long as there’s no contact with either of the sidewalls of the extractor cut, it does not have to be perfectly centered within the cut. Make the v-block square to and the contact surfaces parallel with those of the receiver, then clock the barrel such that the barrel is square to and parallel with the v-block, and once done so, the extractor cut automatically ends up aligned well enough with the extractor.
Sport, Your description is confusing. Please re-confirm that you find you must dial your elevation knob all the way DOWN to achieve a 50 yd zero. Down on most scopes is turning clockwise. Seymour
Sport, Lets try the empirical route to success all around. Turn your elevation knob as far as it will go the opposite direction from where you have it now. aim at target. Fire. Now, did your bullet go High or Low ? report back. Seymour
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