Rifle Scopes new pic rail out of spec?

chadrp

Private
Full Member
Minuteman
Feb 12, 2017
400
132
Central Iowa
So I am thinking the new picatinny rail is out of spec?

G2 Razor in Seekins rings

When I mounted it up I made sure to push both rings forward against the recoil lugs. I have moved this scope several times to different rifles with no issues. Tonight I go to put it on my new ctr rail and with the front ring lug in the grove, the rear ring lug hits on the rear of the lug with the front of next Ridge or whatever you call it. Meaning I will have to slide the ring forward slightly to fit in the grove.

I have tried it on 8 different rifles/rails I have and it fits on all of them fine. I want to be able to move it and I figure if I move it in slightly it won't fit anything else.

Thoughts?
Thanks
 
Interesting. Because there is usually plenty of room +/- to play with what you are describing seems something may be way out of spec, if I am reading correctly. Once you have the rings in position to fit into any two grooves you should be able to move the scope into any other pair of grooves. Get out the micrometer and protractor and take some measurements.
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/8\/84\/Picantinny-recoilgroove-diagram.gif"}[/IMG2]
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/6\/6a\/M1913A_Rail_CrossSection.svg\/800px-M1913A_Rail_CrossSection.svg.png"}[/IMG2]
 
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Interesting. Because there is usually plenty of room +/- to play with what you are describing seems something may be way out of spec, if I am reading correctly. Once you have the rings in position to fit into any two grooves you should be able to move the scope into any other pair of grooves. Get out the micrometer and protractor and take some measurements.
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/8\/84\/Picantinny-recoilgroove-diagram.gif"}[/IMG2]
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/6\/6a\/M1913A_Rail_CrossSection.svg\/800px-M1913A_Rail_CrossSection.svg.png"}[/IMG2]

I was measuring some last night and Google this image but I was al little confused with the groove measurement.

Is it .206 + .008 = .214 ?

I'll go and remeasure for sure but if it's .214 then I think that's my problem. I think my groves are .206 which would move them closer together giving me the problem I have.
I'll double check
 
Ok did some measuring. My rings span 10 grooves.

On the new rail the grooves measure .2075 and risers are .1845 which puts the centers at .392 slightly under the .394 center to center in the specs.
When I measure the groove span my rings sit in it measures 4.13, minus one groove for measuring from front of first groove to rear of 10th groove and I get 4.13-2.075= 3.9225/10=.39225 or slightly undersized.

All of the other rails I measured over the 10 groove span front to rear of grooves measure 4.1445 to 4.148 which is about what I'm off fromm fitting on the new one.

I loosen one ring and slid forward so both rings were tight forward on new rail and move to a different rail and of course it won't fit. If I loosen the ring back up and keep one ring tight forward in the groove and the other ring tight to the rear of that groove on the new rail I can move it to different rail.