Springfield Armory 1911 Ranger Officer 45ACP - PI9128LP

General Information


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Information / Notes (mostly cut-and-pasted from various online forums)

examine the wear that you see on the slide stop pin, is it where the barrel lugs are or where the link is? Wear should be where the barrel lugs are.

rear adjustable sight cut for the Springfield Range Officer is an LPA cut (NOT a bomar cut)

front sight dovetail is a "Springfield Cut".  Possibly 60x .330"x.078"

Struggling to stay focused on the front sight is best remedied with lenses like a reader or computer type Rx. It's normally your regular distance Rx with 0.25-0.75 plus diopter added.

How to test if the hammer's half-cock notch is hitting the sear (which is BAD). Hold the hammer back and pull trigger to rear. Once trigger is to the rear hold it there. Now slowly ride hammer down. If you feel a little bump, the hammer is hitting the sear. If you have an over-travel screw in the trigger, back that screw out until the hammer doesn't hit the sear anymore. Then turn it out extra 1/2 turn.

I'm a big fan of the RO Springfield. One thing I don't like about them is the metal used in the stock sear and hammer. You have to replace hammer anyway, I'd get a USMC kit from Cylinder and slide.

You should not drop the slide on an empty chamber (or more accurately when no round will be stripped from magazine).

[Tim:H11] I dropped the slide with the slide release (on empty chamber, with no mag. inserted) and the hammer followed the slide stopping at half cocked. [Jon Eulette] Stock gun shouldn't fall to half cock. Your springs aren't applying proper pressure. You need approx 2# on center leaf of spring. To check this remove grip safety and allow hammer strut to rest out of frame. With mainspring housing in, test trigger weight. It will only be pressing center leaf. Make it 2#. Adjust left leaf until pulling 4# when reassembled.

1911 Sear Spring adjustment - Knowing how to bend the leafs is just as important as which one you bend. Always bend from the near the bottom of the leaf (just above the pivot point) as shown or you change how they work.

Great info about sear spring adjustment

Brownells article about 2.5lbs trigger pull (includes info on bending sear springs)

The anti-MIM crowd almost universally suggests replacing: sear, disconnector, and hammer.  Some also suggest replacing the mainspring, mainspring cap and mainspring retainer, as well as the guide rod plug, plus the sear spring (?).

1911 Gunsmiths (mostly for Bullseye guns)

Gunsmithing Tools & Information

National Guard Marksmanship Training Unit - Manual for Accurizing 1911s

Brownells Stones List

Washita Arkansas Stone Set

Manufacturer Info

Springfield Armory Product Page

Parts and Part-Specific Information

1911 Parts Manufacturers

    EGW (Evolution Gun Works)   - makes nearly every 1911 part, well-respected... known for barrel bushings, slide stops, pins, etc.

    Smith & Alexander (S&A)   - mag wells, mainspring housings, grip safeties, grips

    Ed Brown   - makes nearly every 1911 part, well-respected, also makes complete guns

    Cylinder & Slide (C&S)   - makes nearly every 1911 part, but best-known for their trigger pull kits and parts

    Wilson Combat   - makes nearly every 1911 part, generally well-respected

Mainspring Housings (with or without magwells), Mainsprings (a.k.a Hammer Springs), Mainspring Pins, Caps, etc.

Instructions for changing the ILS mainspring housing with a normal one

Ed Brown Mainspring Housing Flat with Drop-In Maxi-Well 1911 Checkered 25 LPI from MidwayUSA (2-piece design)

Wolff Mainsprings from MidwayUSA

EGW Pin Set from MidwayUSA

Wilson Pin Set from MidwayUSA

Mainspring Housing Rebuild Kit from Brownells

Wolff Mainspring set (19, 20, 21) from Brownells

S&A Mainspring Housing with Magwell       From Dawson Precision

S&A Mainspring Housings (no magwell)       From Dawson Precision

Dawson IPSC Magwell & Mainspring Housing

Dawson ICE Magwell & Mainspring Housing

Recoil Springs, Guide Rods

Notes from Forums

use a light enough recoil spring (when mounting a red dot on the slide). You know you are light enough when the slide locks back after the last round.  Or, put another way... Use the heaviest spring combination (recoil & main) that you can that locks the slide back most of the time when the magazine becomes empty.  An undersprung gun will see a different set of function problems (and damage over a longer period of time) just as function problems occur in an oversprung gun (but the gun doesn't get battered with an oversprung gun)

Normal/Colt-stock is 23lbs mainspring / 16lbs recoil spring.

The recoil spring works in concert with the mainspring to slow the slide down during recoil. Make sure you protect your gun by using the correct combination. Suggests 19lbs mainspring / 19lbs recoil spring. Using 17lb main springs deliver some weak primer hits.

With a slide-mounted 30mm UltraDot - 11lb might be soft enough for the slide mount, 18-19# mainspring and that ammo combo. I use a 10lb in the summer and 9lb in the winter.

Greg Derr uses an 11 pound spring with a Matchdot on the slide using the Clark mount. Some others suggest 10 pound or 12 pound or 14 pound springs

The recoil spring needs to be adjusted until the gun cycles reliably, and the slide locks back on empty.

How far the brass is thrown can indicate that the recoil spring is not right. You want 3-6 feet to the right and back. Someone said a too-heavy spring will cause brass to fall short (maybe because the slide is not going all the way back?)

a gun that previously ran well, then started stovepiping, was fixed by replacing the recoil spring (no weight change, just an old spring)

rich.tullo said: after 2500 rounds, change the recoil spring 
rich.tullo said: #12-16 Iron sights, #10-12 slide mounted scope

ISMI springs (made of chrome silicon wire) will last a lot longer 

If brass is hitting your red dot... change out the recoil spring to a higher weight. It will slow down the flying brass and lessen its impact. you should be running the heaviest spring that your gun will take and still function with.

Article about 1911 Ejection Tuning: http://www.brazoscustom.com/magart/ejection%20perfection.htm

Recoil spring poundage depends on whether you are shooting irons or a slide mounted optic, what mainspring you are using, as well as whether you have a radiused firing pin stop

Wolff Recoil Springs from Dawson

Wolff Recoil Springs from Dawson

Barrel Bushings

EGW Bushings

Wilson Combat Barrel Bushing Wrench (polymer)

Brownells Enhanced Bushing Wrench (aluminum)

Red-dot Sight Mounts (slide-mounted and frame-mounted), and Slide Rackers

Notes from Forums

rear adjustable sight cut for the Springfield Range Officer is an LPA cut (NOT a bomar cut)

Rock River slide rail that has the built in slide racker

use the Weaver Zee rings, they work fantastic with the UltraDots

Those rings are Weavers and I much prefer them to the ones that come with the Ultradot. You can get them in blue or silver and in 3 different heights. I would advise using the Medium 'cause the Low's tend to make the cases mark the sight and eject erratically.

We use the Weavers #49046 4x4 for the one inch tube on a 45 is great. The standard 30 mm in Med. height.

Joe Chambers says: Use Weaver Top Mount or Burris Signature rings

RRA 1911 Slide Mount/Rib

Clark Custom - slide mount rail and other parts

Clark Slide Mount Rail from Brownells

Marvel slide mount rails

Weigand Frame Mounted Rail

David Sams also makes frame-mounted, single-sided rail

Weaver quad-lock (4x4) rings. Suggested is 49046 (1" Medium, Matte) for use with 1" Ultradot

Weaver 30mm 6-hole rings from MidwayUSA

Weaver 30mm 4-hole rings from MidwayUSA

Burris 30mm zee rings from MidwayUSA ($53 at Amazon, $61 at Brownells or Optics Planet)

Slide Racker (when rear sight removed)

CZ LPA-cut slide racker (with red dot mounting holes)

Heinie Slide Racker from EGW(I used one from EGW for a Heinie cut. Not an exact fit but it works)

49413 - Optima / JP Mount for LPA dovetail (for Optima, J-Point or Delta Point red-dot sight)

Mounting plate to mount a Docter sight to a JPoint Mount (goes on top of JPoint LPA mount, above, to mount a Burris Fast-Fire)

Mounting shim and 1/2" screws (goes under the mounting plate to level it)

Grips, Grip Spacers, Grip Screws, Grip Screw Bushings/Escutcheons, Grip Tape

The grip screws on the 1911 are a non-standard size.  Grip screw threads are 0.150" - 50 NS-2. "superfine".

To fix poorly-countersunk hole in the grips themselves, use a 9/32 brad point bit.

Range Officer comes with grip screws that require a Torx-15 wrench/screwdriver to remove/install.

Wilson Combat Frontstrap Checkered

Pearce Rubber finger groove inserts

Extended grip screw bushings (for thicker grips)

CMM grip spacers (metal shims that go under the grips to provide extra width).

Grip Tape - most people use skateboard tape.  Second most common is 3M tread tape found in Home Depot or Lowes.  Third is made-for-guns, pre-cut items like:

    VZ has 2 varieties: VZ 1911 Front Strap Grip Tape - Gritty  or  VZ 1911 Front Strap Grip Tape - Rubbery

    Ankert Customs Grip Tape for 1911s

Target / Anatomical Grips for 1911s

    Herrett - Herrett Target Grips (custom) - Herrett Camp Perry Grips (custom) - Herrett Nationals for 1911s (not custom) - cheaper Nationals at Bullseye Gear

    Rink - 1911 Grips

    Nill - Pistol grips

    Morini - Anatomical Grips

    Vitarbo - 1911 Grips at Bullseye Gear

    Randall Fung - 1911 Grips

    Precision Target Pistol Grips (Andrew Berryhill) - Custom-made 3-D printed grips for a variety of guns

Grip Safety

Springfield's use a .220 radius grip safety, whereas most 1911's use a .250 radius grip safety.

Smith & Alexander (S&A) Grip Safety Page (includes fitting jig)

Beavertail Info from Harrison Custom


Magazine differences article

Magazine feed lips article

Check-Mate Magazines

Extractors & Ejectors


An article about extractor testing from Dave Salyer

Regarding failure-to-eject (FTE) on last round in mag only, where the casing gets jammed between the slide (at the front of the ejection port) and the mag feed lips (of the now-empty mag)....Your problem is caused by the last round falling off the extractor, the rounds in the mag keep the fired case in position to hit the ejector, the last round doesn't enjoy this and stove pipes. Strip the slide and slide a case under the extractor and center it on the breach face, look down the muzzle end and move the case down slightly (I do it with the barrel in the slide and when you move the barrel out of battery the round will be in the position for ejection) you'll find it falls off, (not held in position). Pull the extractor and stick the back end into the extractor hole in the slide, slip a 3/8" box end wrench over the protruding extractor and bend it slightly until it holds a loaded round against the breach face while shaking the slide, loose is better than too tight, it doesn't take much. If the problem re occurs later, replace the extractor with one that will hold it's tension. EGW makes a good one. Read your fired brass for extractor marks, you might want to polish and relive the head, but that's another story.