ARMS #18 shims

Nic3500

Nic3500

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Greetings gentlemen, I have a Norinco "M-14" with an ARMS #18 scope base. I went to the range today and the base is pointing WAY too high, I do not have any elevation correction left and I still need to lower my reticule.

So I was thinking, I need shims at the back of the mount to tilt it down. How does one calculate what thickness is needed? Is my only recourse to try a bunch until I find the right one?

My problem - as always being in "no rifle land (Qc)" - it's hard to get things like shims but on the other hand buying a whole lot for nothing from a web supplier is not cost effective.

Thanks for any ideas, Nic
 
The front little allen screw is resting on your handguard. You either need to cut a little slot or dremmel a divit so the mount and handguard aren't touching.
 
There are a couple possibilities. The first thing to check, as mentioned, is if the allen screw is touching your handguard. I got rid of mine completely and installed a headless set screw. You use a much smaller allen key, but once it's installed and loctited, it will work just fine.

The second thing to check is to make sure you have not cranked down the front stabilizing pad. You are suppose to tighten that until it *just* touches the receiver, then you tighten the set screw. If you overtighten it, it will cause the problem you describe.

Finally, make sure you set the tension pad at the rear of the mount before you cranked the attachment screw tight. If not, you will have cantelevered the mount.

The only other thing is your splines could be out of tolerance, but it's doubtful they would be out that much.

In all honestly, I have set up a number of ARMS18 mounts for guys on Norincos and it is NOT a DIY job for a lot of folks. One little thing wrong and it will seem like the mount is a POS rather than the good kit it really is.

On a few I've had to adjust the fit by filing the male splines on the mount itself. This can be a PITA as they are not very accessible and are pretty hard.
 
i always ditch the horse shoe retaining washer on the main mount bolt as well.
these guys have pretty much covered any adjustments or things to check.
if everything with the mount is o.k. I'd be looking at your optic.
I've had to send scopes back to manufacturer a few times for improperly set sight tubes/adjustment features. mostly just with older bushnells though
 
Tighten the side mount screw first, tap mount with a rubber mallet, retorque screw... (it will turn again), tap mount.... torque.... tap mount until the screw doesn't turn. I found this to be the best way to center the ARMS 18. Tighten dovetail then adjust front contact. Get rid of front screw and replace with set screw, no more contact issues.
 
Here is a pic of the front pad that adds or subtracts elevation but don't froget to put back the retainer clip;
ARMS18mount.jpg


Also the rear hex bolt when it is removed you will see the same looking slot cut threw a circle as you seen on the front pad to ensure that your mount is level. Please use this pic for referance;
arms18.jpg


Here are the instructions just in case yours did not come with any;
ARMS18mountfrontbackpages.jpg

ARMS18mountmiddlepages.jpg


As for windage, try what Holleyman said.
 
Personally, I don't remove that lock ring around the front pad. I just ground screwdriver into the required profile so it fits over the ring ;) But then, I've installed more than one...
 
I would not use shims. The mount is designed for full-length contact at the receiver splines. If you shim, you may lose this contact and the result would be a mount that is not solid.

If you can;t get your ARMS18 to fit properly, I would suggest selling it and getting Sadlak or Smith Ent mount. Either will fit and is less positionally sensitive than the ARMS18. The Sadlak is not much more money and is very good (the steel one). Avoid the aluminum version.
 
Thanks!

Wow thanks guys for all the ideas, I will try all this.

I did replace the regular screw in front for a headless version but I think it still touches the hand guard. Check #1.

Then on with the other suggestions.

I know it's not the scope, I tried 3 different to be 100% certain.

Thanks again!
 
Problem #1 solved, on to #2!

Okay, I finely got time to reinstall the mount properly for elevation. What I did differently this time:
- replace front screw with set screw
- cut a little bit off the hand guard to ensure the front set screw does not touch it
- make sure the front pad touches only lightly the receiver

Ok elevation is good.

Problem #2: I used up all the windage adjustment on my scope and it still points 4 Mils right at 100 yards (yes, that's ~15 inches!). I tried the mallet thing, no help there.

So what now? Someone in a previous post suggested this:

Check your receiver splines at the aft end of the groove for any burrs. It you find any, stone them down and try again.
Click to expand...

Any other ideas what I should be looking into?

Thanks again for any help, Nic
 
do you have the ARMS side bolt retaing clip in place?

if so..... strangely enough when i have run out of ideas trying to fix the windage issue..... I omit the side bolt retaining clip and on many rifles...... the windage issue disappears...... ymmv
 
M14Doctor said:
do you have the ARMS side bolt retaing clip in place?
Click to expand...


If you mean the small metal ring that holds the bolt in place on the side mount, no it's gone.

Options I thought of:
- insert a shim between the side of the rail and the ring to move the back ring a bit. Not sure what that would do to the scope though...
- shim behind the bolt, under the mount
- grind / sand down the mount
- declare this mount a !%$^@#$%@# and reinstall my old 20$ mount. I was replacing with this ARMS since it is so cheap.
- declare the Norinco receiver a !@##%!@# and get something else (!)

Any suggestions?

Nic
 
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