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Putting a Williams FP receiver sight on my 464 SPX

andrew678122

andrew678122

.270 WIN
Hey all, it's been a while since I posted here so I figured it was time for an update.

I'm in the process of putting a Williams F.P. receiver sight on my 464 SPX. I had been looking at them for a while and then I saw one on eBay, new/old stock, I got it for $17.50, a real bargain. At first I was going to take it to a gun smith but looking at it, the installation looked so simple, so I decided to do it myself. I used the base as the template for center-punching the holes on the side of the receiver. My son has a small bench drill press and he helped me keep it lined up as I ran the drill into it. The holes are a #31, and I went real carefully, measuring the hole depth with a vernier caliper so I didn't go through into the bolt channel (I really don't think it would matter if you did). Williams supplys the mounting screws, 2 x 6-48 machine screws about 5/16" long.

I mounted it so the horizontal slide is directly over the rear scope mount, so I can't have a scope mounted at the same time. I could have moved the sight rearward about 3/4" and it would clear the scope mount, but then it would interfere with disassembly, I wouldn't be able to get the 'Locking Bolt' out without first removing the receiver sight. I decided I wasn't going to use a scope (not for a while anyway) and I'd like to be able to disassemble it completely so...

I was also assuming I had to change the front sight, but that is not the case. The front sight is high enough and the receiver sight sits low enough so no change is needed.

I'm not quite done, I'm waiting on a 6-48 tap to arrive, but before the week's out it should be done.

I've posted some pics of it so far:
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And here's the final installation, I ended up drilling 3 holes in the receiver I can use either the front 2 holes or the back 2. If I use the back 2 then a short scope base (very short) can still be installed on the receiver. With the look-through scope rings, both the scope and the Williams receiver sight will be usable. The receiver sight is aligned with the original iron sights so there's no need to remove it, it may even help the sight picture...
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A caution: be very-very careful when tapping the holes, make sure the tap is well oiled to help its cutting and back it off every 1/4 turn to clear chips and get oil to the cutting edge. If it is too tight (difficult to turn) back it off more frequently, making sure it's well lubricated. DO NOT RISK BREAKING A TAP !!!!!!! A steel receiver can dull a tap pretty quickly, you may need more than one...

Also: I went to the range to try it out and had a couple of problems. The sight could move, I didn't tap the holes deep enough. I ended up very carefully running the tap all the way through. I used a small round needle file to remove the burrs in the Bolt channel and then some 1000 grit paper to polish it. I drilled three holes in my receiver. As it turns out, at 50yds, if I use the front two holes I can't zero it since the sight contacts the top of the receiver and can't go low enough. If I use the rear two holes the sight misses the top of the receiver. The only problem is, using the two rear holes means I have to remove the sight to get the Locking Bolt out. I can still remove the Bolt, just not the Locking Bolt (if you're confused, look at the Mossberg exploded view and parts list of the 464).

Overall I'm very pleased with it, but need some more range time, I'll try and go this week...
 
Glad to see you're getting it figured out Andrew.

Thanks for posting your progress and results. I'm looking forward to your update...
 
I went to the range again, intending to just shoot, get used to the receiver sight. I didn't touch any adjustments, just shot. These targets/groups are all shot at 25yds and I started at the twelve o'clock position and went clockwise, shooting the center target last. Each group was 3 rounds (my reloads btw). I'd love to be able to do them all like #6.

Ignore the off-target holes, they were shot from the back, previously...

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Nice.



I've had the same sight on two different guns and still have it on my deer rifle. It looks good on your 464.
 
MikeD said:
Nice.
I've had the same sight on two different guns and still have it on my deer rifle. It looks good on your 464.
Click to expand...
Thanks Mike, I like the looks of it too, and it almost doubles the sight radius relative to the original iron sights. My first reaction is the aperture is too large, it's .125 (1/8th) of an inch, but it looks like it would be good for hunting. I do a lot of target shooting so I'm going to get a smaller one. Williams has one down to .050. .050 seems too small, but I'll get that and drill the aperture out until I get it right.
 
Update:

I was at Brownell's website a few days ago and I saw they had the 'Target' knobs for the Williams FP receiver sights, those will mean I can adjust it without needing any tools. The elevation knob was out of stock, but they had the elevation Lock knob and the windage knob, so I ordered both. They have two different lengths of windage knobs and failed to mention what length I needed, so I ordered both.

In my FP 12/37 I needed the long windage knob. It fit perfectly. If you replace yours, hold the sight so the elevation and windage locking screws are up and slacken both a few turns. Then without changing the sight's orientation (lock screws up), unscrew the windage screw (left-hand threads), and very gently pull it out. A ball bearing that does the click stops will be free (and lost if you're not carefull), that is why the sight has to be oriented with the lock screws up. Slide the new knob into the hole, it should easily go past the ball, then start threading it into the threaded aperture holder. When it's most of the way in, a push on the knob will get it in a little further and the ball will jump into the groove with the click-stops. Then do the lock screw up snug (NOT TIGHT).

Since I bought both short and long windage knobs, I planned to use whichever was left over as the elevation knob. But then I discovered the thread is different, left-hand thread on the windage knob and right-hand thread on the elevation knob, so I'l have to back-order the correct elevation knob. I rechecked Brownell's website and they now say it's in stock, so hopefully wednesday or thursday I'll have it.

The elevation lock knob would have been a simple remove and replace, except the threaded shank was too long, it hit the side of the receiver. I had to grind about 1/8th inch off the threads before it would miss the receiver. Works like a champ now.

Just for your information, one click on the FP adjustment moves the poi 1/4 moa. I calculated it using the 19" sight radius on my 464, the FP adjustment screws are 40 threads per inch and there are 20 clicks per revolution on the adjustment screws.

So far it looks pretty good, I'll post a pic when it's done...

Edit: I got the elevation knob, the short one is the correct one for the FP 12-37. Adjusting it is a snap now, though there are still 2 screws that lock the adjustments. The same screws also keep the adjustment shaft in place, but the shaft will not fall out since the ball-click mechanism creates a strong detent retaining. I'm just going to leave the lock screws slightly lose.

Overall the Williams Foolproof 12-37 is a very nice sight, especially with the target knobs...

RE-EDIT: The long elevation knob is the right one, not the short one, either will work in most cases but if you use the FP receiver sight at its extreme up position you may run out of screw...
 
Here are a couple of pics taken while at the range (Ft. Bliss Rod and Gun Club, if you live in the area they are well worth a membership).

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I spent and hour and a half, or so, shooting and getting the sight adjusted, I shot at 25 yards, adjusted the sight, shot again, and then shot at 50 yards.

These were at 50 yards (I am pretending the flyer in the first one never happened):
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This morning I went to the range and shot my 464 SPX + Williams FP receiver sight at 100yds. I really like the receiver sight, I find it easier to be accurate with it as opposed to the stock sights. The only change I'm going to do at this point is get a Lyman target front sight, that way I'll be able to see the target at 100yds rather than have it hidden by the blade front sight.

This is the best group I shot, but quite a few groups were close to this:
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Update:
This is my 464 SPX after fitting a Lyman 17AHB target front sight to it:
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The 17AHB is .404 high, base of dovetail to center of aperture. If the FP receiver sight was mounted further forward, then the top of the receiver would prevent the rear sight from being lowered enough and you would have to use the taller Lyman 17AMI (.494 base to center of aperture), but either combination should work fine. The 17AMI is the same height as the original 464 SPX front sight.

The FP receiver sight can't be mounted any higher, unless you try a different model, possibly adapting one intended for an H&R Handi rifle, by drilling an extra hole in the base. If you did that you wouldn't have to drill the side of the 464's receiver like I did. You could use the existing rear hole in the Williams FP-H&R and drill a new forward hole, correctly spaced to pick up the second screw hole on the 464's rear scope mount. You would then have to cut off the forward extension of the FP-H&R base but it would give you a nice, relatively easy Williams FP receiver sight conversion. If you did it this way, don't order a front sight until you get the rear sight attached and you can measure the sight height. You will need at least the 17AMI (.494 height) and possible the 17AUG (.584 height).

I used the Lyman front sight because it's available as a single unit, rather than the comparable Williams front sight, where you have to buy the sight and then have to get the right size spacer to use between it and the barrel.
 
andrew678122 said:
Update:
This is my 464 SPX after fitting a Lyman 17AHB target front sight to it:
DSC01184B.jpg

The 17AHB is .404 high, base of dovetail to center of aperture. If the FP receiver sight was mounted further forward, then the top of the receiver would prevent the rear sight from being lowered enough and you would have to use the taller Lyman 17AMI (.494 base to center of aperture), but either combination should work fine. The 17AMI is the same height as the original 464 SPX front sight.
...
Click to expand...
Update: I was at the range today 9 Oct 2013 and I have to report that the Lyman 17AHB is too short, at a hundred yards I was unable to sight it in, I was shooting about 8" too high with the FP as low as it'll go. I don't know how I got it wrong, I did all the calculations... I guess this is just algebra getting even.

So, if you do this mod, use the Lyman 17AMI (.494" sight height) instead.
 
I've been reading this post for sometime. It has been a huge help, thanks. I have posted my results with the skinner lo-pro receiver sight which has been similar to yours elsewhere in the 464 "information". It seems to me that we are going to have a real issue getting the front sight high enough to get some sort of acceptable zero at 100yds. Once we get the front sight tall enough, it's exposure to being damaged is a real concern. I have a kns dual rectile receiver type front sight that is .625 high waiting to be installed on mine. It is the tallest single piece sight I have been able to find. BUT, by my calculations I will still be about 3 inches high at 100yds. So not really a solution just a bandage. This is a heck of rifle, not much fits it yet. By the way your pictures have been a huge help. Thanks again.
 
doug said:
I've been reading this post for sometime. It has been a huge help, thanks. I have posted my results with the skinner lo-pro receiver sight which has been similar to yours elsewhere in the 464 "information". It seems to me that we are going to have a real issue getting the front sight high enough to get some sort of acceptable zero at 100yds. Once we get the front sight tall enough, it's exposure to being damaged is a real concern. I have a kns dual rectile receiver type front sight that is .625 high waiting to be installed on mine. It is the tallest single piece sight I have been able to find. BUT, by my calculations I will still be about 3 inches high at 100yds. So not really a solution just a bandage. This is a heck of rifle, not much fits it yet. By the way your pictures have been a huge help. Thanks again.
Click to expand...

Hey Doug,
The way I mounted the FP receiver sight on my 464 I can sight it in with the stock 464 front blade. The FP receiver sight can really be adjusted low. The stock blade sight on my 464 SPX measures ~.515" from bottom of dovetail to center of the fiber optic bead. I did my calkylashuns and had decided that the 17AHB at .404" from base of dovetail to center of aperture would work (A lower front sight gives a greater adjustable range on the receiver sight, for long distance shooting). But I screwed up somewhere in my figuring and need the 17AMI instead.

If anyone tries using the FP-H&R receiver sight, try it with the stock blade first and see if you can sight it in. If you can't and the gun is shooting too high, you'll need a taller front sight, probably the 17AUG which is .584" base of dovetail to center of aperture. The FP-H&R receiver sight won't allow the rear aperture to go quite as low as the FP 12/37 mounted on the rear two holes, that I used.

Re the pics, glad they of some help...
 
nitesite said:
You can get 4895 powder??? I hate you! Just kidding. :D
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LOL, last I checked they had both H4895 and IMR4895, I've recently been reloading for a .45-70 and been using IMR SR4759 which they also have in stock. All in all we're lucky having that shop in El Paso...
 
Hmmmm, in the picture with the Williams set in the rear position, it didn't appear to be lower than the skinner. So, now I am nervous. If you can use the standard front sight, that is a real good option since it is a "glow in the dark" and also round. I don't have a drill press, but I maybe getting one, cause I'm gonna make this work!!! But I'll try the kns first just for kicks.
 
doug said:
Hmmmm, in the picture with the Williams set in the rear position, it didn't appear to be lower than the skinner. So, now I am nervous. If you can use the standard front sight, that is a real good option since it is a "glow in the dark" and also round. I don't have a drill press, but I maybe getting one, cause I'm gonna make this work!!! But I'll try the kns first just for kicks.
Click to expand...
Here's a picture where I tried to show how low the FP sight sits on the receiver, at its lowest, the center of the aperture is ~.25" above the receiver. If you look at the picture closely you can see that the cross piece of the FP is ~.125" below the top of the receiver:
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