Aligning the ARMS 18

Stevo

Stevo

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Can someone please point me towards the sticky or other instructions for aligning an ARMS 18 on a M305? I'm sure there's one here but I'll be damned if I can find it.

Yes, I have searched.:(

Thanks!

Edit: see post 2.
 
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Okay, I think I've got it figured out.

If I follow the ARMS instructions in order, I end up with the mount not aligned with the bore. Is it okay to bring the mount into alignment by tightening the stipper clip guide bolt first and then the main mount bolt?

That seems like it should work, but this is the first time I've installed a mount on the receiver of an M305.
 
No

Stevo said:
Okay, I think I've got it figured out.

If I follow the ARMS instructions in order, I end up with the mount not aligned with the bore. Is it okay to bring the mount into alignment by tightening the stipper clip guide bolt first and then the main mount bolt?

That seems like it should work, but this is the first time I've installed a mount on the receiver of an M305.
Click to expand...

Place the stripper clip guide in the slot - lay the mount on the receiver and align the vertical tab and the horizontal rail into the receiver - push the mount against the receiver locking in - start the side screw while puting pressure on the mount against the receiver and align the stripper clip guide hole with the mount and start the allen screw. Tighten the side screw snug then the stripper screw snug - then tighten each bit by bit with bias to the side screw - do not overtighten.
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:ar15:
 
chopper 1 said:
Place the stripper clip guide in the slot - lay the mount on the receiver and align the vertical tab and the horizontal rail into the receiver - push the mount against the receiver locking in - start the side screw while puting pressure on the mount against the receiver and align the stripper clip guide hole with the mount and start the allen screw. Tighten the side screw snug then the stripper screw snug - then tighten each bit by bit with bias to the side screw - do not overtighten.
Click to expand...

That's not going to solve my problem. The rail will still end up pointed off the bore line.

If I only use the side screw, the mount doesn't line up with the bore. It fits nicely with the receiver, just not pointed the right direction.
 
I took the instructions to mean to get the locking bolt that goes into the side of the receiver to torque and seated correctly before dealing with the other two contact points.

I had the parts installed, but the screws loose while I dealt with the locking bolt as per my post that follows. After seating the arms 18 I followed the instructions for setting up the front receiver pad and locking down the dovetail for stripper clip guide.


NavyCuda said:
I just finished installing my ARMS18 purchased online from Wolverine Supplies.

Dealing with Wolverine via email I would have to say that they recieve top marks for shipping and efficiency but I'm going to have to say that their email correspondence could use some work. That being said, I will be ordering my rings from them.

Following the provided instructions I found that there was some information that could have been included for better results.

There was no mention of throughly cleaning the guide slots in the side of the receiver. I used a thin stainless wire "toothbrush" to clean the slots with a little bit of varsol, this really smoothed them down without removing any material from the receiver other than some of the coating on the sharp edges.

I also cleaned the mating surfaces the same way on the ARMS18.

I used brake clean to prep all of the surfaces and fasteners to ensure they were free of grease, dirt and build up.

When torquing the locking bolt down, I did not have an inch pounds torque wrench, so I used 8.5 ft. lbs on my Snap-On 3/8"s drive click type. After I torqued it once, I used a soft face dead blow hammer and hit the area surrounding the lock bolt. Re-torquing, the lock bolt took another 1/4 turn. This time I ensured the receiver was secured against a block of wood and repeating seating the ARMS18 with the dead blow, this time with more force, due to having the rifle positioned better. The lock bolt did not take any more torque, so I was satisfied it was not going anywhere. All fasteners were lock tite'ed as per instructions.

Following the rest of the instructions I found the ARMS18 was a real breeze to install. I was disappointed to realize that my Aimpoint CompM4s wouldn't fit on to the ARMS18... oh well it's getting a scope anyways and the Aimpoint can go back onto the CZ.

Range report on rifle reliablity next time I go out. As it sits now, I'm very happy and feel this mount is well worth the ~$250(shipped) new.
Click to expand...

I took my rifle out to the range, only got to put about 100 rounds through it, but everything stayed tight, all casings ejected smoothly and in a nice pile that was easy to pick up.

edit

Stevo said:
That's not going to solve my problem. The rail will still end up pointed off the bore line.

If I only use the side screw, the mount doesn't line up with the bore. It fits nicely with the receiver, just not pointed the right direction.
Click to expand...


Did you inspect both mating surfaces for burrs, debris or potential mechanical binding, did you use a dead blow or a block of wood and a hammer to ensure the arms 18 was completely seated down against your receiver?

I remember reading M14 Doctor saying something about using a straight tube down the center of the arms 18 to help with the initial line with the bore.
 
I took the instructions to mean to get the locking bolt that goes into the side of the receiver to torque and seated correctly before dealing with the other two contact points.

I had the parts installed, but the screws loose while I dealt with the locking bolt as per my post that follows. After seating the arms 18 I followed the instructions for setting up the front receiver pad and locking down the dovetail for stripper clip guide.
Click to expand...

That's the way I read them, too. If I follow them, the mount is not lined up with the bore.

The mounting surfaces are all clean with no burrs. I'm using a string from the front sight to the rear to get the centerline for the mount.

Using some chalk on the receiver I was able to see that the only parts of the mount coming into contact with the receiver are the horizontal and vertical "keys" on the the back side of the mount. The horizontal key seems to have less contact towards the rear of the receiver. I'll try the dead-blow hammer thing to see if it fits up better.

I'm guessing that the slots in the receiver are undersized, or the keys on the mount are oversized.

Either way, I understand now why there are so many #18 mounts in the EE. Definitely not a simple bolt-on job.

Edit: This is the quote I've found that refers to removing material. Given that my mount doesn't appear to be touching the receiver in that area, I'm not sure it applies.

Due to differences in commercial receiver geometry the user may find that a little
judicious removal of metal at the underside corner of the mount’s front end may be
necessary to get a # 18 mount to fit perfectly.
Click to expand...
 
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Don't mean to hyjack this thread, but is the Arms 18 mount as good quality as a Sadlak? I just bought a M14s with a Arms mount on it, and I was curious if the quality of the Arms mount was as good as a Sadlak?
 
I have a Sadlak on one of mine and while Fabsports is the Canadian dealer for Sadlak they they will ship some stuff direct. I needed a new hex screw, called this morning and its alrady in the mail.
 
With my arms 18 the large OD threaded section of the dovetail contacted the receiver, but not any portion of the arms18 itself. The dovetail insert is just an anchor, so thread the insert until it is just contacting the receiver but you have put no torque on it. Then lock the assembly with the socket cap screw provided.

On the front, same thing, run the insert down with a 1.5mm flathead, or similar pointed tool until it just contacts the receiver, then lock up the socket cap screw that runs parallel to the barrel.

Hope this helps.

*iPhone needs better spell checking and less autocorrection to the wrong damn words.
 
The only thing I can figure out is that the side of the receiver, or the spline cuts, are out of proper spec. With no contact on the mount other than at the splines, the mount will not line up with the bore unless the dovetail screw is cranked down first. This means that the rear of the spline is not in full contact with the mount.

From all the reading I've done over the last couple of days, this sort of non-spec receiver is certainly not exclusive to Chinese guns, but can include SAI, and yes, even USGI M14 receivers.

I'm trying something different right now. I'll see if it works.
 
Stevo said:
The only thing I can figure out is that the side of the receiver, or the spline cuts, are out of proper spec. With no contact on the mount other than at the splines, the mount will not line up with the bore unless the dovetail screw is cranked down first. This means that the rear of the spline is not in full contact with the mount.

From all the reading I've done over the last couple of days, this sort of non-spec receiver is certainly not exclusive to Chinese guns, but can include SAI, and yes, even USGI M14 receivers.

I'm trying something different right now. I'll see if it works.
Click to expand...

You said you used chalk on the receiver, did you use the same thing on the "splines" or rails... I don't know what they should be correctly called, in see how they were seating against each other? This could very well show you were the excess material is.

Is your mount noticeably out of line or just slightly and barely perceptible to the eye?
 
NavyCuda said:
You said you used chalk on the receiver, did you use the same thing on the "splines" or rails... I don't know what they should be correctly called, in see how they were seating against each other? This could very well show you were the excess material is.

Is your mount noticeably out of line or just slightly and barely perceptible to the eye?
Click to expand...

I was using boot polish today, on the entire rear of the mount, including the splines. They were the only points of contact with the receiver and contact was equal across all of the spline surface. That's how I came to the conclusion that the receiver side, or spline cuts, or both, were out of spec.

Noticeably out of line. If it was barely perceptible I wouldn't have been concerned as long as my scope had enough windage.
 
Stevo said:
I was using boot polish today, on the entire rear of the mount, including the splines. They were the only points of contact with the receiver and contact was equal across all of the spline surface. That's how I came to the conclusion that the receiver side, or spline cuts, or both, were out of spec.

Noticeably out of line. If it was barely perceptible I wouldn't have been concerned as long as my scope had enough windage.
Click to expand...

Damn that sucks. Going to use a different mount?

I have to say I really love the arms18... it's so low and just sits right on the rifle... looks so good.
 
NavyCuda said:
Damn that sucks. Going to use a different mount?

I have to say I really love the arms18... it's so low and just sits right on the rifle... looks so good.
Click to expand...

Yeah, it does. I've got a couple more ideas to try out.

Since I removed some material to eliminate one contact area and to shape the splines for better contact, I've managed to cut the resale value to nothing. So, I've got nothing to lose.

Besides, if the side of the receiver is out of spec, will any other mounts work correctly? I'd probably go with the Troy Battlerail if I try something else. That way the receiver side isn't a factor.
 
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