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Discussion Starter #1
On my (1950 vintage) Colt OMS, the original owner had replaced the original("Coltmaster" rear sight)with an("Acro" rear sight)!

I now have a completely assembled "Coltmaster" rear sight. Can the complete "Accro" rear sight, just be removed as a unit and then, can the "Coltmaster" rear sight, just be screwed into place(As a unit?)? Or, is it more complicated than this, to do it this way? Is there a simple proceedure for doing this? As I sure don't want to mess-up my nice OMS!

[This message has been edited by Colt38 (edited 01-16-2005).]
 

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If I'm not mistaken, the Officer's Model Special was discontinued around 1952, not in the 1960's.

It's been a LONG time since I've been around an OMS sight, but as I recall, you should be able to just remove the Accro sight and install the Coltmaster sight.
 

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Discussion Starter #3
Dfariswheel:

You are correct, my OMS was made in 1950(Not 1960, in my erroneous post!)as I just made a typo error!

Since I've never removed any sights before, I wanted to be sure not only which way to turn the sight screw(To remove it?)but also, to be certain, that the sight would not fly apart whenever trying to remove it(As a unit!)? Lastly, if there are any "Precautions, that I'll need to take(To avoid damaging anything!)upon removal of the rear sight? Thanks!
 

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Sorry, it's just been too many years since I was into a Coltmaster sight.

Best advice is to just be careful and don't force anything.
 

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I do not see how a Coltmaster sight could be replaced with an ACCRO (often all uppercase in Colt literature) sight. The Coltmaster is installed in a DEEP dovetail in the top strap, with a boss around the dovetail, while the ACCRO has a forward "tail" inletted into the top strap with no boss around the sight, and the blade portion sits in a notch at the rear of the top strap. The Coltmaster does not screw into place. It is driven into the dovetail from the side. If the top strap of an OMS has been milled to accept an ACCRO sight, which seems highly unlikely (what fills in the deep dovetail?), installing a Coltmaster sight will not remove the milled out areas for the ACCRO tail and the notch for the blade portion.

Are you sure you have an OMS with an ACCRO sight and not an OMM, which uses a variation of the ACCRO?

Something is wrong here. Just looking at a Coltmaster sight and ACCRO sight would reveal that there is no way they can be interchangeable.

Please tell me more, or post pictures.

[This message has been edited by JudgeColt (edited 01-22-2005).]
 

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Discussion Starter #6
JudgeColt:

1)No, my Colt revolver is an OMS(Not an OMM)!

2)I could have guessed wrong that the rear sight is an ACCRO(But, I know that it isn't a COLTMASTER sight!)so, I'll post a picture, as soon as I can get signed up with www.photobucket.com as my new picture host?

3)Yes, I'll appreciate your looking at my rear sight(In the picture to come!)and then you can give me your thoughts about whatever rear sight is actually on my OMS now(And, if it's possible to install the Coltmaster sight, in it's place, without any problems?)? I have never changed a rear sight on any Colt before!

Following is a link to the picture of my OMS rear sight that I want to remove to be replaced with a COLTMASTER rear sight:


[This message has been edited by Colt38 (edited 01-27-2005).]

[This message has been edited by Colt38 (edited 01-27-2005).]

[This message has been edited by Colt38 (edited 01-28-2005).]
 

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Colt38,

Where did you find a replacement Coltmaster sight assembly? They are pretty tough to come by!

I've never worked on the Coltmaster but I believe the Judge is correct, the Micro rear sight assembly would have to be drifted out with a punch and the Coltmaster drifted in. I'll take a close look at my OMS with Coltmasters to see if the dovetail is even close. I've also got an OMS with sights very similar to the ones pictured. Look on the top of the sight, I'm betting it says "Micro" not ACCRO.

Scott

[This message has been edited by SEBCo (edited 01-28-2005).]
 

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Discussion Starter #8
SEBCo:

1)You could be correct, that the rear sight on my OMS, is a Micro(Instead of an ACCRO!)? I will have to dig this gun out of my inventory, and will report back here, with whatever I find out, after looking for the name on top of the rear sight?

2)COLTMASTER REAR SIGHT: I was searching for one of these, for a long time(To no Avail!)then I posted on the classified section of this forum-and, another member responded, leading me to one other person, that he said(Possibly?)could have this COLTMASTER rear sight? Man, did I get "Lucky" as he had just one in his inventory-and, he told me, that if I didn't buy this one, that I'd probably never find another one of these sights(Ever again!)!
 

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I measured the base of the dovetail on my OMS with Coltmasters and the one with the Micro sights, the base is 14mm on each and it should be just a straight forward drift out drift in procedure. On a beater I would probably take a whack at it myself, but on a mint specimen like yours, I'd find a professional gunsmith and let them do it right.
 

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The signt on the OMS does not appear to be an ACCRO to me. I agree it probably is a Micro sight designed to replace the Coltmaster. (Most Micro sights have the "Micro" script word on them. Does this one?) An ACCRO as used on Colts of that era would not fit on the OMS without machining, and then there could be no reasonable return to the original.

I do not recall if there is a set screw on the Coltmaster, but there may be one on the Micro shown. If there is a set screw, just loosen the set screw and slide out the old and slide in the new. If they are an interference fit, I would use a sight pusher to move them in and out. If you do not have a sight pusher, either buy one, or use a brass drift punch and a hammer to carefully force the exchange. It appears there may be a dent in the top strap just below the base of the sight body so perhaps it was driven in and the dent happened at that time.

The good news is that the OMS is not altered as it would have to have been to accept an ACCRO rear sight.

(By the way, I am writing this from the NSSF lounge at the SHOT Show!)
 

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Judge,

The "dent" you note on the photo below the sight assembly base was milled there to accept the original Coltmaster sight base. The indentation correspondes to the Coltmaster windage adjustment screw.

Hope you enjoy the SHOT Show!

Scott
 

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Discussion Starter #12
SEBCO:

1)Does your OMS, have a set screw to hold the base of the Coltmaster sight in place, like JudgeColt, had mentioned-or,?

2)Do you know if your Coltmaster sight, can be pushed into place(Or, if it would have to be driven in?)?
 

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Assuming that you have the complete Coltmaster assembly, this old post addresses R&R of this sight. Keep the spring and the horseshoe shaped (detent) device under control lest you lose them!

Sometimes I do this sort of job in a large, clear plastic bag.

Bob
 

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SEBco, obviously, I did not have a OMS handy in the NSSF lounge as I made my last response. I had forgotten about the adjustment screw being inleted into the top strap, which I saw as a "dent" in my hasty response. I will have to dig out an OMS to see just how the sight is held on. Colt38 ought to be alble to tell if there is a set serew just by looking at the sight assembly.
 

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Judge,

It took a pretty sharp eye on your part to note the shape of the millwork from the photo! I had the luxury of responding while my OMS's were on my lap. If I had not just sighted in the OMS 22 with Coltmasters, I would have taken them apart to get a more complete answer.

Scott
 
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