Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
Member Login
Posted: 9/1/2001 9:29:57 AM EDT
I would greatly appreciate your pointers on improving my groups. I can't say that I'm not happy with this kind of group but I keep hearing that 1 MOA is what I need to be at. [b]Please offer up your tips!![/b] These are the details of the shoot: Armalite AR10A4 Swift 6-18x50 (set on 6x) Federal Gold Medal Match 168gr. .308 100 yards, fired while seated at a table rested on a rolled up sleeping bag. Slight wind (I think weather channel said 5-7 mph) blowing to the right. 20 rounds fired from 2 10 round magazines Sorry for the large pic... [img]http://wsphotofews.excite.com/034/Th/sI/bj/IY89913.jpg[/img]
Link Posted: 9/1/2001 9:46:30 AM EDT
Link Posted: 9/1/2001 9:54:20 AM EDT
I won't say for sure that I know how to properly measure groups but, I thought that this was basically a 2 inch group. Isn't that 2 MOA at 100 yds? BTW, thanks for posting some feedback!
Link Posted: 9/1/2001 9:54:51 AM EDT
[Last Edit: 9/1/2001 9:56:43 AM EDT by e8ght]
Nothing really wrong with that group, but you can try a few things to improve it. First, do the box test with your scope - shoot a group, circle the group and its individual holes, move it 10 MOA left, shoot a group, 10 MOA down, shoot a group, 10 MOA right, shoot a group, and 10 MOA up and shoot another group. If all is well then the first and last groups will overlap exactly. This tests your scope for repeatability of adjustment and might also reveal any consistent patterns in the group. Shoot a couple of fouling shots before shooting for accuracy. Avoid winds near 90 degrees if you can, especially if it's gusting. Try varying the rest point if you can - resting on a different point along the barrel or on the bottom of the mag might reduce the groups somewhat. Cranking up the power might allow you to select a particular corner of the target's intersecting lines to aim at. Parallax adjustment maybe - probably not much of a problem there. Free floating handguards might help. Try taking more time between shots to allow the barrel to remain at a consistent temperature and hence dimension. And of course try a few boxes of other ammo just in case your gun hates the good stuff. :) All in all I can't see a problem but one or more of the above may still work. Edited cuz I can't tell my right hand from my up hand...
Link Posted: 9/1/2001 9:56:12 AM EDT
Well, first I'd like to know the shot sequence.. The right dispersion could be attributed to wind, but as to the vertical stringing, I'd guess it was your "rest" (Sleeping bag) settling.. Try it again, with a brick, or cinder block wrapped in a towel, or a firm sandbag.Also, where you rest the barrel will affect vertical dispersion. Good luck! Meplat
Link Posted: 9/1/2001 9:58:41 AM EDT
Originally Posted By e8ght: Nothing really wrong with that group, but you can try a few things to improve it. First, do the box test with your scope - shoot a group, circle the group and its individual holes, move it 10 MOA left, shoot a group, 10 MOA down, shoot a group, 10 MOA right, shoot a group, and 10 MOA up and shoot another group. If all is well then the first and last groups will overlap exactly. This tests your scope for repeatability of adjustment and might also reveal any consistent patterns in the group. Shoot a couple of fouling shots before shooting for accuracy. Avoid winds near 90 degrees if you can, especially if it's gusting. Try varying the rest point if you can - resting on a different point along the barrel or on the bottom of the mag might reduce the groups somewhat. Cranking up the power might allow you to select a particular corner of the target's intersecting lines to aim at. Parallax adjustment maybe - probably not much of a problem there. Free floating handguards might help. Try taking more time between shots to allow the barrel to remain at a consistent temperature and hence dimension. And of course try a few boxes of other ammo just in case your gun hates the good stuff. :) All in all I can't see a problem but one or more of the above may still work. Edited cuz I can't tell my right hand from my up hand...
View Quote
I've never heard of that technique before but I like it! Thank you for the advice, I will definately try it next weekend.
Link Posted: 9/1/2001 10:01:05 AM EDT
[Last Edit: 9/1/2001 10:01:44 AM EDT by FMJunkie]
Originally Posted By Meplat: Well, first I'd like to know the shot sequence.. The right dispersion could be attributed to wind, but as to the vertical stringing, I'd guess it was your "rest" (Sleeping bag) settling.. Try it again, with a brick, or cinder block wrapped in a towel, or a firm sandbag.Also, where you rest the barrel will affect vertical dispersion. Good luck! Meplat
View Quote
I tried to make sure that the forward sling swivel was just touching the rest to ensure that I got the same spot every time (kind of like nose on the charging handle...). Would it make a difference if I changed the rest point but kept it consistent? ie:touching the mag well? Thanks everyone for helping me out with this! Edited to point out that the barrel was not resting, the handguards at the very forward edge...
Link Posted: 9/1/2001 10:31:11 AM EDT
Link Posted: 9/1/2001 2:19:00 PM EDT
Just thought I'd get this in front of the o'clock crowd...
Link Posted: 9/1/2001 2:54:49 PM EDT
Link Posted: 9/1/2001 3:03:48 PM EDT
Link Posted: 9/1/2001 4:05:43 PM EDT
A free float tube may help in solving your problem. I got groups very similar to that with my AR-15 until I got the free float tube which brought me down to a good consistent round 3/4" group. Just guessing from looking at the group I would say that as the barrel gradually heats up and expands it makes the shots go to the right and down. Just my .02. Matt
Link Posted: 9/1/2001 6:14:35 PM EDT
Meplat already touched on what I was thinking when I read your first post here. Avoid using anything resilient or springy for a shooting rest. Use something as "dead" as possible, such as a leather bag filled with sand or lead shot. If that isn't high enough by itself, get a sturdy adjustable rest or a solid block of wood to set it on. Even your fingers laid across a log or tree stump would be much better than a rolled-up sleeping bag. The reason for this is that the rifle begins to recoil before the bullet leaves the barrel. Now, suppose for the sake of illustration that the front end of your rifle weighs 4 pounds. If rested on something totally "dead," it would take a full 4 pounds of upward force to lift it even the tiniest fraction of an inch off that rest. BUT, if you got it sitting on that bouncy sleeping bag, it's in a sort of equilibrium situation between gravity and the springyness of the rest and just 1 ounce of upward force will cause that whole 4 pound barrel assembly to immediately begin rising upward. Again, while the time interval is very small, this DOES begin to occur before the bullet clears the muzzle. The average deer hunter would never know the difference, but as you get down to 1 MOA it starts to become important. Aside from possible shot-to-shot variations in the resiliency of the sleeping bag, any unnecessary movement of the rifle while the bullet is still in the bore (even if uniform in itself from shot to shot) is a variable you do not want to deal with because it amplifies other variations in bore time, etc. Hope this helps you improve your shooting up to a respectable level.
Link Posted: 9/1/2001 11:45:00 PM EDT
Hey man, looks like a pretty good group to me. I would definately be happy with that. Snake
Link Posted: 9/1/2001 11:56:56 PM EDT
Two words: [b]Hand Loads[/b] sgtar15
Top Top