I bought an ARMS 18 because it was the lowest but will not fit on my unchopped Norc. The receiver is thicker on the left front and there is no way in h*ll I can get the scope mount to sit straight. I wound up buying a m14.ca mount and will be sighting it in this AM.
Best mount...Easy, the LRB M25 receiver.But at an incredible steep price.
The common alerations I made over the years when installing arms18 mounts are:
Ditching the C clip
Stoning the mount on the forward portion on the raised "key" that fits the long slot on receiver.
And sometimes stoning the vertical key that mates with receiver.
I have probably had a 99% success rate installing Arms mounts but there is always a rifle that throws a curve.
It takes such a small amount of metal in the wrong spot to cause the mount to not sit true... It's finding it and remedying it that is kinda a pain in the azz sometimes
Still my favorite mount though![]()
ipscgraz.. From 45ACPKING : He recommended removing the c clip on the inside of the side mounting bolt in a previous post. This was throwing the alignment off .
Did that. Did everything I could think of. I didn't want to let go of that expensive mount but wasn't going to f-up the receiver or p*ss around with shims that would eventually work free.
CASM genII extended. It replaced the ARMS18 mount which would cause empty casing jams. I trimmed the springs, put in a GI bolt, cut out the center with a cutting disc and grinder, all the things to make the ARMS 18 not cause jams. The CASM solve the problem. It puts the empties in a area I can grab them beside me and not forward of the firing line. I used the CASM mount this weekend and got my come ups out to 500 yards with no issues. Fired about 100 round with no scope mount jams like the ARMS 18 mount. Jams in Service Rifle cost points.
There is no way i'm changing extractors, cutting springs etc etc..
I used the CASM mount again at a Service Rifle match a week or so ago. 225 shots over 2 days and not one scope related hiccup. Glad I got rid of the ARMS 18.My brand new ARMS 18 mount caused 5 out of 20 rounds to jam..... and jam good. There is no way i'm changing extractors, cutting springs etc etc... Considering the CASM mount now.