Author Topic: scope rail (Read 581 times)

Tango4N · « **on:** October 19, 2004, 04:39:32 PM »

Ok I had been having problems with "wandering zero" as can best describe it. Check the the scope mounts and they were OK. Then I removed the scope mounts from the rail and checked the allen-screws for tightness. The most forward one, the big one that rests on the barrel was loose. Also, the too locking screws on the side were loose.

So, do I tighten this up until the rail gets some upward pressure? Just until it touched with no pressure?? Back it off completely so there is no pressure?? What seems to work?

I just don't want to keep removing the scope and re-zero every time!

I can see this as being a problem as if the scope rail was not solid, then it can shift, especally with the barrel warming up and cooling down, or even with a different OAT. (Outside Air Temp) And this will affect accuracy and after all, that's the name of the game!

So what are the suggestions?? I will also do the O-ring mod tonight.

Tango4N · « **Reply #1 on:** October 20, 2004, 06:46:52 PM »

Anyone??? :cry:

Mac11700 · « **Reply #2 on:** October 20, 2004, 07:09:34 PM »

I've never had one that was as you decribed...all of mine have always made contact and weren't loose...it's possable to have enough flex from it not making contact to throw it off...that's why some here have filled the gap with quickdry liquid steel to make it rock solid...perhaps you can try running the screw down till it makes good contact...but not enough to flex the mount up and retighten the side set screws...then see if it corrects your problem...

Mac

bubba · « **Reply #3 on:** October 21, 2004, 12:20:54 AM »

I just tightened mine down until there was a good tightness to the screw but didnt crank it until it moved the base up. In fact with that tiny screw I dont know if you could. Just tighten it so there is tension against the barrel.

Donaldo · « **Reply #4 on:** October 21, 2004, 04:49:58 AM »

Tango4N,
From the way you describe this I assume you have the bull barrel which has a longer scope rail than the other rifles. I have the 223 UVarm with the bull barrel and mine is the same as you describe. My front screw was not touching the barrel so I left it alone. Mounted the scope, got the rifle shooting pretty darn good. Then I discovered that front screw. I screwed in down to just kiss the barrel plus about 1/8 turn. It changed the point of impact the next time I went to the range. Can't remember which way but anyway when I got home I backed the screw back out and everything returned to normal. The way the rail is cantilevered out over the barrel seems to me to cause a bending of the rail if you tighten it down snug. Mine has 3 screws holding to the barrel without that forward set screw.

aulrich · « **Reply #5 on:** October 21, 2004, 05:18:44 AM »

I have been considering cutting off that front screw. I would trim it just in front of my forward scope ring. It jus seems to serv no good purpose. I have also bedded the scope base with JB weld (everything covered with release agent) to that point.

BTW when you screw it in tighter it will push POI down

quickdtoo · « **Reply #6 on:** October 21, 2004, 05:53:10 AM »

FWIW, the longer rail is called an ultra scope mount in NEF speak according to their retail parts price list. It sells for $15 compared to the regular scope mount's $13. I think the ultra mount comes with all ultra models as did my .223 ultra varmint. My .204 ruger handi rifle has a bull barrel, but only has the regular shorter scope mount without the set screw.

Mac11700 · « **Reply #7 on:** October 21, 2004, 07:01:41 AM »

Running them down to just kiss the barrel will change the POI..but should stabilize each shot there after...this would be of real benifit to those using the ultra rail with very large objective scopes on them I would think...hmmm this will make a very nice project to try next time out to the range I think,I'm going to try having it loose...and back to just snug...also..the tip about the hammer spur was a good one...it definatly makes a difference,I no longer have it on mine...thanks to Jeff223 for that one........I'll let you know what happens......

Mac