Double Grouping on Reloads? - Page 2

Damon555 · April 6, 2016, 03:00 PM

Check your parallax....I've experienced this before and it if wasn't a scope, or base/ring issue it usually ended up being an operator error involving my parallax adjustments.

Metal god · April 6, 2016, 03:12 PM

Demon :

Were you able to confirm your parallax caused you to have double groups ? It seems hard to believe that's even possible . I understand the concept but to be SO consistently inconsistent to shoot two different groups in the same string do to your cheek weld/hold seems not likely . I can see not having very tight groups because of parallax issues but to hold the rifle perfectly two different ways causing two separate groups in a string would be pretty impressive if it weren't such a bad thing .

That to me means you're on your way to being a world class shooter . Just a couple tweaks and you'll be setting records in no time .

tangolima · April 6, 2016, 05:38 PM

It always has been bedding problems in my case. Something started touching something else when the gun became hot. Barrel, barrel channel, upper handguard are usual suspects.

-TL

Damon555 · April 6, 2016, 06:56 PM

It was easy to fix once I figured out the problem....My eyes aren't that great any more so when the target is in focus the parallax is out of whack...so if I'm not wearing glasses that help me focus, the target will almost always be out of focus when the parallax is adjusted properly.....it doesn't take much movement either direction to throw the crosshairs off due to parallax.....

tangolima · April 6, 2016, 08:59 PM

Quote:

Originally Posted by Damon555

It was easy to fix once I figured out the problem....My eyes aren't that great any more so when the target is in focus the parallax is out of whack...so if I'm not wearing glasses that help me focus, the target will almost always be out of focus when the parallax is adjusted properly.....it doesn't take much movement either direction to throw the crosshairs off due to parallax.....

That shouldn't happen. There may be something wrong with how you adjust your scope.

You adjust the focus so that the crosshair is in focus. Then you adjust the parallax while focusing on the crosshair till the target image is the clearest, i.e. the image is right at the crosshair. Double check by moving your eye off the scope's axis, the crosshair should stay at the same spot on the target.

-TL

double bogey · April 6, 2016, 09:58 PM

I had this issue with a marlin 25m .22 mag. 2 shots touching, next 2 touching 3/4" from the first 2. This rifle only has one action screw. So, added an action screw, pillar bedded the action, and lo and behold, 1/4" to 1/2" groups. Since that experience, I always check scope and mounts first, then look to the action. now, this was just a rimfire, but the principles are the same. On an AR, after the scope, I would look into the barrel nut, then wouldn't know where to look.

stagpanther · April 7, 2016, 02:48 AM

Quote:

....but the principles are the same. On an AR, after the scope, I would look into the barrel nut, then wouldn't know where to look.

Good point.

Txhillbilly · April 7, 2016, 12:02 PM

I've had double grouping problems on several AR's, each one ended up being a magazine feed lip or feed ramp issue.
An easy way to know is if the 1st-3rd-5th shot hit in one spot, and the 2nd and 4th shot hit in another. I start by sanding any sharp or rough edges off the feed ramps on the barrel extension, and if it continues, change the magazine or adjust the feed lips on them.

Metal god · April 7, 2016, 12:39 PM

Txhillbilly : oh you have to elaborate on that . I''ve heard of mags in old M-14 having POI shift do to different mags . This has to do with how they fit and the real tight ones would cause the barrel harmonics to change compared to the real loose ones .

How would feed ramps effect any type of accuracy other then maybe gouging the jacket resulting in and inconsistent bullet ? Please be very detailed as to how this works

Thanks Metal

April 6, 2016, 03:12 PM	#27
Metal god Senior Member Join Date: April 10, 2012 Location: San Diego CA Posts: 6,876	Demon : Were you able to confirm your parallax caused you to have double groups ? It seems hard to believe that's even possible . I understand the concept but to be SO consistently inconsistent to shoot two different groups in the same string do to your cheek weld/hold seems not likely . I can see not having very tight groups because of parallax issues but to hold the rifle perfectly two different ways causing two separate groups in a string would be pretty impressive if it weren't such a bad thing . That to me means you're on your way to being a world class shooter . Just a couple tweaks and you'll be setting records in no time . __________________ If Jesus had a gun , he'd probably still be alive ! I almost always write my posts regardless of content in a jovial manor and intent . If that's not how you took it , please try again .

April 6, 2016, 09:58 PM	#31
double bogey Member Join Date: April 16, 2011 Location: Texas Posts: 81	I had this issue with a marlin 25m .22 mag. 2 shots touching, next 2 touching 3/4" from the first 2. This rifle only has one action screw. So, added an action screw, pillar bedded the action, and lo and behold, 1/4" to 1/2" groups. Since that experience, I always check scope and mounts first, then look to the action. now, this was just a rimfire, but the principles are the same. On an AR, after the scope, I would look into the barrel nut, then wouldn't know where to look. __________________ Nos operor non pensio volutabrum (We don't rent pigs)

April 7, 2016, 12:39 PM	#34
Metal god Senior Member Join Date: April 10, 2012 Location: San Diego CA Posts: 6,876	Txhillbilly : oh you have to elaborate on that . I''ve heard of mags in old M-14 having POI shift do to different mags . This has to do with how they fit and the real tight ones would cause the barrel harmonics to change compared to the real loose ones . How would feed ramps effect any type of accuracy other then maybe gouging the jacket resulting in and inconsistent bullet ? Please be very detailed as to how this works Thanks Metal __________________ If Jesus had a gun , he'd probably still be alive ! I almost always write my posts regardless of content in a jovial manor and intent . If that's not how you took it , please try again . Last edited by Metal god; April 7, 2016 at 05:36 PM.

April 6, 2016, 03:00 PM	#26
Damon555 Senior Member Join Date: January 11, 2012 Posts: 384	Check your parallax....I've experienced this before and it if wasn't a scope, or base/ring issue it usually ended up being an operator error involving my parallax adjustments.

April 6, 2016, 05:38 PM	#28
tangolima Senior Member Join Date: September 28, 2013 Posts: 3,824	It always has been bedding problems in my case. Something started touching something else when the gun became hot. Barrel, barrel channel, upper handguard are usual suspects. -TL

April 6, 2016, 06:56 PM	#29
Damon555 Senior Member Join Date: January 11, 2012 Posts: 384	It was easy to fix once I figured out the problem....My eyes aren't that great any more so when the target is in focus the parallax is out of whack...so if I'm not wearing glasses that help me focus, the target will almost always be out of focus when the parallax is adjusted properly.....it doesn't take much movement either direction to throw the crosshairs off due to parallax.....

April 7, 2016, 12:02 PM	#33
Txhillbilly Senior Member Join Date: July 5, 2008 Posts: 512	I've had double grouping problems on several AR's, each one ended up being a magazine feed lip or feed ramp issue. An easy way to know is if the 1st-3rd-5th shot hit in one spot, and the 2nd and 4th shot hit in another. I start by sanding any sharp or rough edges off the feed ramps on the barrel extension, and if it continues, change the magazine or adjust the feed lips on them.