Optics Binding -- Lapping Rings, etc.

Potshot · August 08, 2009, 23:01

Gents,

Went to the range today to try out new scope. Was shooting off bags at 25x, and had some issues with the thing patterning like a shotgun (way worse than with irons). I'm certain my technique was good, could see muzzle flash and round exit.

Had one group in particular that was .2MOA vertically and 1.2 MOA horizontally. Looked like someone just lined up all the bullet holes left to right. Adjustments kinda behaved funny too.

Came home and noted an area on the scope mount (DSA extended) that were rubbing on the left hand side, and after lapping the rings noted that they weren't as straight as they likely need to be.

So I changed out the scope mount for a standard one (non extended), lapped the rings in (which was a PITA).

Does this sound familiar to anyone?

BTW also used two bolt/carrier sets with differing vertical play at rear of bolt. No difference.

FNfreak · August 11, 2009, 06:37

What Brand scope and rings?..If it's a Tasco, BSA, Simmons...it may just be the cheap scope not being able to handle the recoil. BSA and Simmons are bottom of the quality barrel and do not hold up worth a crap on anything other than .22's. Some Tasco's are okay...again, they fail over the long haul with loose recticles and turret knobs that fail to hold zero...

Potshot · August 12, 2009, 00:05

Falcon/Seekins.

Should be good stuff.

Was using questionable ammo.........

chromestarhustler · August 12, 2009, 01:31

how light is the trigger a good height but a long group sometimes means too heavy of a trigger, you might be pulling slightly on the gun. what do they say a thousands of shift equals one inch at 100 yards.

let me know what you find out if that helps let me know cause if it does i am gonna go lighter on mine, my 22-250 fal can put three side by side by side touching or almost touching at 100 with a fse fcg and some polishing and a trigger pull reduction kit. but they wont cluster or group up.

kotengu · August 14, 2009, 15:49

There have been some reports of the scope mount itself inducing stresses into a rifle/receiver and slinging rounds. Some have reported better groups by loosening a single screw (just aft of the ejection port, IIRC).

I have personally noted my groups are much worse with a scope than with irons on my FAL (known good scope). I usually shoot irons anyway so I haven't tested the theory enough to track it down - I just took the scope and mount off and started shooting better groups.

ggiilliiee · August 14, 2009, 16:14

full length barrel ???..or shorty ..chrome, do they say that ???..hmmmm wonder what could happen if ya cut a barrel down and got .oo6 tir where ya cut ....hmmmmm.....light bulb ....anyone ...hehehehe

Potshot · August 14, 2009, 20:47

Haven't measured runout on either end... hehe

But this rifle has shot MUCH better before.

I did try removing some of the screws in the scope mount, no joy.

Right now I suspect shitbomb surplus stuff and/or the dum-dum hunting bullets I had available.

Need to find some FGMM....

August 08, 2009, 23:01	#1
Potshot Registered FALaholic #: 6398 Join Date: May 2002 Location: xxx Posts: 1,104	Optics Binding -- Lapping Rings, etc. Gents, Went to the range today to try out new scope. Was shooting off bags at 25x, and had some issues with the thing patterning like a shotgun (way worse than with irons). I'm certain my technique was good, could see muzzle flash and round exit. Had one group in particular that was .2MOA vertically and 1.2 MOA horizontally. Looked like someone just lined up all the bullet holes left to right. Adjustments kinda behaved funny too. Came home and noted an area on the scope mount (DSA extended) that were rubbing on the left hand side, and after lapping the rings noted that they weren't as straight as they likely need to be. So I changed out the scope mount for a standard one (non extended), lapped the rings in (which was a PITA). Does this sound familiar to anyone? BTW also used two bolt/carrier sets with differing vertical play at rear of bolt. No difference. __________________ "The most foolish mistake we could possibly make would be to permit the conquered Eastern peoples to have arms. History teaches that all conquerors who have allowed their subject races to carry arms have prepared their own downfall by doing so." --- Adolf Hitler "If it was up to me, no one but law enforcement officers would own hand guns..." Chicago Mayor Richard Daley "Armas para que?" ("Guns, for what?") -- Fidel Castro

August 12, 2009, 00:05	#3
Potshot Registered FALaholic #: 6398 Join Date: May 2002 Location: xxx Posts: 1,104	Falcon/Seekins. Should be good stuff. Was using questionable ammo......... __________________ "The most foolish mistake we could possibly make would be to permit the conquered Eastern peoples to have arms. History teaches that all conquerors who have allowed their subject races to carry arms have prepared their own downfall by doing so." --- Adolf Hitler "If it was up to me, no one but law enforcement officers would own hand guns..." Chicago Mayor Richard Daley "Armas para que?" ("Guns, for what?") -- Fidel Castro

August 12, 2009, 01:31	#4
chromestarhustler Registered FALaholic #: 19815 Join Date: Apr 2006 Location: kansas Posts: 3,427	how light is the trigger a good height but a long group sometimes means too heavy of a trigger, you might be pulling slightly on the gun. what do they say a thousands of shift equals one inch at 100 yards. let me know what you find out if that helps let me know cause if it does i am gonna go lighter on mine, my 22-250 fal can put three side by side by side touching or almost touching at 100 with a fse fcg and some polishing and a trigger pull reduction kit. but they wont cluster or group up. __________________ My God in heaven, watch over me and please let me be victorous over mine ememies, but if i must fall in battle let me be brave i am a member of the ammo hoarders of america, ask me about selling your ammo for my fun and your profit

August 14, 2009, 15:49	#5
kotengu Registered FALaholic #: 1594 Join Date: Nov 2000 Location: Baxter, TN, USA Posts: 3,066	There have been some reports of the scope mount itself inducing stresses into a rifle/receiver and slinging rounds. Some have reported better groups by loosening a single screw (just aft of the ejection port, IIRC). I have personally noted my groups are much worse with a scope than with irons on my FAL (known good scope). I usually shoot irons anyway so I haven't tested the theory enough to track it down - I just took the scope and mount off and started shooting better groups. __________________ "The way is in training." - Miyamoto Musashi

August 14, 2009, 20:47	#7
Potshot Registered FALaholic #: 6398 Join Date: May 2002 Location: xxx Posts: 1,104	Haven't measured runout on either end... hehe But this rifle has shot MUCH better before. I did try removing some of the screws in the scope mount, no joy. Right now I suspect shitbomb surplus stuff and/or the dum-dum hunting bullets I had available. Need to find some FGMM.... __________________ "The most foolish mistake we could possibly make would be to permit the conquered Eastern peoples to have arms. History teaches that all conquerors who have allowed their subject races to carry arms have prepared their own downfall by doing so." --- Adolf Hitler "If it was up to me, no one but law enforcement officers would own hand guns..." Chicago Mayor Richard Daley "Armas para que?" ("Guns, for what?") -- Fidel Castro

August 11, 2009, 06:37	#2
FNfreak Registered FALaholic #: 1081 Join Date: Sep 2000 Location: Georgia on my mind.... Posts: 812	What Brand scope and rings?..If it's a Tasco, BSA, Simmons...it may just be the cheap scope not being able to handle the recoil. BSA and Simmons are bottom of the quality barrel and do not hold up worth a crap on anything other than .22's. Some Tasco's are okay...again, they fail over the long haul with loose recticles and turret knobs that fail to hold zero...

August 14, 2009, 16:14	#6
ggiilliiee banned again FALaholic #: 17179 Join Date: Mar 2005 Location: orygun Posts: 4,838	full length barrel ???..or shorty ..chrome, do they say that ???..hmmmm wonder what could happen if ya cut a barrel down and got .oo6 tir where ya cut ....hmmmmm.....light bulb ....anyone ...hehehehe

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