Switching to iron sights

All of my pistols and revolvers except my 1911 have iron sights and I am thinking about switching the 1911 to iron sights as well. The 1911 is a SA milspec t that was originally redone by Dave Salyer and it has a full length sight rib with a match dot tube red dot sight.  I was looking at the Aristocrat full length rib with the built in adjustable sights and wondering if that would be a solution to changing to adjustable sights without having to do any milling on the frame.  Also if I went this route would I need to increase the weight of the recoil spring?

Thanks

I recently looked into this... the Aristocrat rib has a different hole pattern than the typical Clark/Bomar rib. I ended up finding a Bomar rib to replace my aimpoint/Kodiak rail. Weight was nearly the same, no spring change required.

Dave

I think your best option would be to machine the slide for BoMar sight and dovetail front sight, and then shorten the existing rib so that it can fit between the sights, this way you can switch between optics and irons.
I can do this for you if you are interested.

by any chance does the Rock River combo rib match the hole pattern?

Rock River actually should match the Bomar pattern, but it adds a lot of weight to the slide, it's made from steel, not aluminum, and some people say it exceeds the max permitted weight for the CMP service pistol.

op is talking about replacing his dot with a rib anyway, so prolly not having service pistol on his radar...yet

The Bomar Rib will match the hole pattern of the Clark scope mount and Rock River's scope mount (and probably their combo rib as well) with one potential conflict.  Bomar changed the screw pattern once or twice so those scope rail manufacturers use the last version.  From what I remember it will be the front screw hole that will be off.  It would be pretty easy to drill and tap that one hole in the slide so I wouldn't think it's a deal breaker but just something to watch for.  Both of my wad guns now have Bomar ribs on them and they were converted over from RRA scope mounts.  In my case, I got the correct hole pattern right away but that was probably luck I suppose.

Good luck.
John

Thanks everybody.

I looked at the Rock Island rib with sight and it looks like a nice piece of equipment. Is there a reason people like the Bomar better?

Thanks

Bomar is only a pattern now.
Long since out of production as I recall.

troystaten wrote:I looked at the Rock Island rib with sight and it looks like a nice piece of equipment. Is there a reason people like the Bomar better?

Thanks

For me personally it’s because I like the old school cool look of it. They are narrower and a bit shorter top to bottom but neither of those affect the function of one over the other.  My plan is to shoot irons until I can’t anymore and if I switch to dots I won’t be going back and forth so the combo feature is irrelevant to me.  Bomar is gone so your only option is to find an old one but they are out there. The Rock River is current and really easy to get so if you are moving forward soon, one those would be your best bet. 

John

Revisiting this idea, a gunsmith I know has a NOS Bomar Rib with a sight, more expensive than the Rock River.  Are there any functionality advantages with the Bomar?

Thanks

The Bomar were the best back in their day. But today? There may be as good or better which will depend on the manufacturing quality. The market has shifted away from iron sights on pistols. I’m sure the current crop are likely to be as good as the old Bomar if not better. I haven’t heard of many complaints.

troystaten wrote:Revisiting this idea, a gunsmith I know has a NOS Bomar Rib with a sight, more expensive than the Rock River.  Are there any functionality advantages with the Bomar?

Thanks

There isn’t really a functional advantage of an original Bomar rib.  If anything the Rock River is more versatile and it too uses Bomar style sights so that component will be similar between each of these brands.  If the old school look and feel are of any importance to you, pick the Bomar.  If aren’t into the nostalgia or think you may want to try dot sights in the future, the Rock River rib would be the better choice.  

John

When I had a Rock River combo rib mounted I found it liked to shear mounting screws. Jerry Keefer thought the next size up Torx screws for rib screws was a better idea, so I think he was correct.

We are competing in Precision Pistol, so everything we do is unconventional and wrong compared to standard practices. We're off the map for a lot of things and end up exploring.

Well I bought the Rock River Sight and rib but unfortunately the hole patter is about 12 thousands of an inch longer front to back than the marvel rib that my 1911 has on it so it does not seem to be usable for my pistol.  Argh.  The pattern looks the same but the measurements are just enough off so it does not fit.

I swapped out the dot rib on one of my wad guns to a new Bomar iron sight rib. Pistol weighed 42 oz. Minus a mag. I would think the RRA steel rib would be too heavy and exceed 45oz.

Hey Jimmy did the Bomar rib screw holes line up?

Yes.  Bomar's early ribs had the front screw closer to the end of the slide than later models where the front screw is around 1" from the end of the slide. All the new dot ribs follow the later pattern.


The "new" bomar rib I had was from the 80s. I just keep it all these years.

troystaten wrote:Well I bought the Rock River Sight and rib but unfortunately the hole patter is about 12 thousands of an inch longer front to back than the marvel rib that my 1911 has on it so it does not seem to be usable for my pistol.  Argh.  The pattern looks the same but the measurements are just enough off so it does not fit.

   I can’t speak specifically about a Marvel scope rib but the Rock River rib will follow the later pattern of Bomar rib for sure.  I’ve had three different guns with Rock River scope mounts that I dropped Bomar ribs directly on to and the holes all lined up.  The Clark scope mount followed this pattern too I think.  On the older pattern of Bomar rib the rear three holes are the same and it’s the front hole that is off.  A new hole can be drilled and tapped but that requires some work of course so not really drop in.  
  I wonder if your specific scope mount was made differently. This could have been intentional or not but either way the holes are slightly off.  If that mount was drilled and tapped to a bare slide when your gun was built it didn’t much matter at the time but I see your problem now however.  If you wanted to do the work, the holes in the slide can be filled and new holes drilled and tapped for a fresh start.  It would be something I would want a gunsmith to do but once done, you would be all set.  I’m not sure any sight rib will drop on if your original mount is off the standard specs.  

John

I'm confused!  Why would someone fill, drill and tap new holes in the slide rather than adjusting the holes in the rib?  It sounds like a slight bit of oval would solve this much easier than working on the slide.

What am I missing?

My understanding is that if elongated the holes you would be depending upon the clamping force of the screws to keep the rail from shifting, I thought that as well but maybe one of the people who knows more than myself (most people) could add to that thought.

If you elongate ALL then the clamping force is all that’s holding the rail from shifting.  

However, all that said, in these applications a #6 screw of any thread can’t take much shear, particularly in the threads.  Couple that with the concept that a #6 screw in single shear would try to pry out the threads leaving a volcanoes stripped hole.  And a #6 screw doesn’t have a lot of clamping force (neither does a #8 screw for that matter)…so…what is the dynamic here?  A #6 screw with about .050 thread engagement has a shear capability of 210 pounds and a pullout strength of 100 pounds.  



As an engineer… I’d rather rely on a hardened steel pin which Is hard to fit, but would be better.

Thanks Wobbley, I remeasured the screw hole spacing and using a dial caliper The RR rail holes are 5.167 from the front of the front hole to the back of the back hole and on the Marvel it is 5.140. I could see elongating 3 of the 4 holes.  I don't relish the idea of filing holes in a steel rail so I need to think about this some more. Or just shoot with the dot sight and leave it at that.

Wobbley wrote:...
As an engineer… I’d rather rely on a hardened steel pin which Is hard to fit, but would be better.

There is not a lot of meat in the front part of a slide, but in the back I think you could put a piece of key stock somewhere inbetween the rear sight and breach face. That would be able to take on all comers for shear.