The Kitchen Table Gunsmith
Main menu  



Fine-Tuning a Rock Island Armory M1911A1
by Roy Seifert

Click here to purchase a CD with this and all Kitchen Table Gunsmith Articles.


Disclaimer:  This article is for entertainment only and is not to be used in lieu of a qualified gunsmith.  Please defer all firearms work to a qualified gunsmith.  Any loads mentioned in this article are my loads for my guns and have been carefully worked up using established guidelines and special tools.  The author assumes no responsibility or liability for use of these loads, or use or misuse of this article.  Please note that I am not a professional gunsmith, just a shooting enthusiast and hobbyist, as well as a tinkerer.  This article explains work that I performed to my guns without the assistance of a qualified gunsmith.  Some procedures described in this article require special tools and cannot/should not be performed without them.

Warning:  Disassembling and tinkering with your firearm may void the warranty.  I claim no responsibility for use or misuse of this article.  Again, this article is for entertainment purposes only!

Tools and firearms are the trademark/service mark or registered trademark of their respective manufacturers.

If you have been keeping up with my articles you know I wanted to get into shooting SASS® Wild Bunch matches based on the movie The Wild Bunch.  These matches require large-caliber, big-bore guns; a lever-action rifle – my Marlin 1894 cowboy in .45 LC will work, a Winchester 97 or model 12 pump-action shotgun – I just finished modifying a Winchester 97 (refer to my article Modifying a Winchester 97 for Competition), and a 1911 .45 automatic pistol.  I have two modern 1911 .45’s in my gun collection, but I wanted to shoot traditional which meant I needed a standard, G.I. pattern 1911 .45.


I found a phenomenal deal on Gunbroker for a new-in-box Rock Island Armory M1911A1 .45 for $330!  One other person bid on it and raised the price from $330 to $345; but it was still an excellent deal.  With shipping and transfer costs the total came to $392, but Armscor was having a $50 rebate program at the time so total cost to me was $342.  If you can purchase a 1911 .45 for under $600 nowadays you are doing well, but under $400 is a steal!

This is the second Armscor Rock Island Armory 1911A1 I’ve owned.  The first one I purchased I gave to my son as a Christmas gift.  It had a number of problems; most of which I was able to repair.

  • The feed ramp was milled off-center in the frame.  I couldn’t fix this but it didn’t seem to affect the feeding reliability of the gun
  • The trigger pull was 10 pounds.  I replaced the sear and disconnector to get a decent trigger pull.
  • The chamber in the barrel was undersized and would not chamber ammunition.  I had to ream out the chamber to proper specifications to get ammo to chamber reliably.  Refer to my article Reaming a .45 ACP Chamber.

By the way, my son reports that he has never had any failures with that gun, and all of his friends want to shoot it because of the excellent trigger.  You just can’t beat a 1911 with an excellent trigger!

Armscor makes a fine, functional handgun built to G. I. specifications.  But because they are mass produced nothing is hand fitted and many of the parts still have rough tooling marks from the manufacturing process.  The manual that came with the gun stated that the gun would need approximately 500 rounds to break it in.  That’s a lot of ammo!  The process of breaking-in a firearm is really nothing more than shooting it enough so the parts will be polished and wear-in together.  I can eliminate much of the break-in requirement by polishing the necessary parts and areas myself.  This will improve both the function and reliability of the gun, not to mention saves on ammo.

Initial Assessment
After I picked up the gun from my dealer I did a cursory examination and function check.  Everything worked as it should and the trigger pull was actually decent at 4 1/2 pounds.  The thumb safety required a hydraulic press to operate (ok, I’m exaggerating, but my thumb is still sore from trying to engage the thumb safety) but I can polish and re-contour the edge that rides along the plunger to make this easier to function.  This gun came with the narrow WWI front sight so I will have to install taller, wider sights which are legal for a traditional gun.

I took the slide off of the frame and found most of the mating surfaces had milling and tooling marks left over from the manufacturing process.  These will have to be polished out to facilitate reliability and smooth functioning.  Everything on this pistol was Parkerized, which meant they all had a rough finish which will also need to be polished.  I wonder if WWI and WWII era 1911’s came off the wartime assembly line rough like this.  Perhaps they had to in order to meet wartime production needs.  These guns were designed to function in the dirt, dust, and mud of war and were loose out of necessity.  Accuracy was “minute-of-enemy soldier”, not bull’s-eye.

So am I trying to make a silk purse out of a sow’s ear?  Not really; I just want to make a mass-produced handgun function reliability.  It’s not a target or tactical pistol, but it is a competition pistol so it has to function reliably.  I don’t have to get all shots to touch at 25-yards; I only have to keep a group to “minute of steel” accuracy.  I have built three 1911 pistols from scratch so I will apply many of the polishing and fitting techniques I learned from the late Dave Sample to this gun.

Slide Work
I decided to start with the slide since this will require the least amount of work.  I completely stripped the slide; removing all internal parts.  Just so I only have to say this once, when I exposed bare metal after polishing, I applied cold blue to protect the metal.

Polish the Slide


I placed the slide upside down in my padded vise leaving about 1/4” of it above the top of the jaws.  I used a bastard file and draw-filed the bottom of the slide rails to remove the milling marks.  Draw filing moves the file back and forth 90-degrees to the surface being smoothed as shown in the above photo.  This removes metal but doesn’t leave deep filing marks.  I was careful to keep the file flat so the rails were nice and flat.  I didn’t want to remove all of the tooling marks since the slide was already loose on the frame, just polish down the high areas.  I finished polishing with 400-grit wet/dry sand paper to complete the process.


The small rail where the disconnector and hammer ride had a lot of tool marks so it too needed to be polished.  I first used a #0 Swiss pillar file I purchased from Brownells #191-398-990 to smooth this area of the slide, being sure to keep the file flat against the rail.  I didn’t use a lot of pressure on the file; I let the file do the work for me.  I completed the process with 400-grit paper to get this surface smooth.


In order to make it easier to feed a round from the magazine I smoothed the breech face so that it shined and all of the tool marks were removed.  I used a 400-grit stone using very light strokes, then finished with a 600-grit stone.  Again, I wanted the tools to do the work for me.

Working the Barrel

Based on my previous experience with a RIA gun I first checked the chamber to make sure it was up to spec.  I dropped a couple of different reloads into the barrel and they chambered just fine.  I also dropped a .45 ACP go headspace gauge into the chamber to make sure it fit.  This chamber seems to have been reamed correctly at the factory.



I polished underneath the barrel where it sits in the barrel bed of the frame, and the top of the barrel and barrel hood.  I shoe shined this area using 400-grit paper to get it nice and smooth.  I didn’t remove the tooling marks, just made these two areas smooth by knocking off the high spots.


I used a 400-grit stone and smoothed the back and sides of the lower lugs where they hit against the frame when the barrel unlocks and drops down out of battery.  This just needed to be smooth, not pretty.


I used a Cratex tip to polish the front of the lower barrel lugs.  These lugs ride against the slide release pivot pin so they needed to be smooth.  I was careful not to allow the bit to slip or touch any areas other than the front of the lower lugs.


At the top of the feed ramp in the barrel throat is another sharp edge I needed to bevel so cartridges will feed reliably.  I took the safe edge of a file (the edge with no teeth) and scraped this edge back and forth to make a very slight bevel, just enough to break the sharp edge.  Then I polished the entire throat with a Cratex bit.

Working Slide Parts
All of the internal parts of the slide have to fit and function together properly for reliability.  I worked each part individually which consisted mostly of polishing.

Checking and Adjusting Extractor Tension


Tuning an internal extractor is basically bending the extractor (adjusting tension) until the extractor will hold a loaded round.  I completely installed all the parts in my slide and inserted a loaded .45 ACP cartridge under the extractor hook and against the breech face.  On my pistol the cartridge stayed in place as shown in the above photo indicating the extractor tension was correct.  If the cartridge did not stay in place I would have had to adjust the extractor tension. 


The proper tool for adjusting extractor tension is the Weigand Extractor Adjusting Tool available from MidwayUSA #931460 or Brownells #957-000-037.  This tool bends the extractor to add the proper amount of tension to hold a loaded round in place.  My extractor did not need any adjustment.

Fitting the Firing Pin Stop


The firing pin stop fit very tightly in the slide.  This is a good thing to prevent the firing pin stop from dropping out of the pistol during recoil.  However it required a punch to remove and replace it in the slide.  I laid the flat back of the firing pin stop on a piece of 400-grit paper and polished the rear until the Parkerizing came off.  I tried the firing pin stop in the slide and continued to polish until I could insert and remove the stop with my fingers, but it was still tight in the slide.  I was careful not to remove too much metal; it still needed to be tight.

Polishing the Firing Pin


The firing pin was binding inside the firing pin tunnel which could cause misfires.  I chucked the firing pin into a drill and polished the front of the pin where it fits through the firing pin hole, and the collar around the rear of the pin where it rides in the tunnel.  Now the firing pin moves freely in the firing pin tunnel without binding.

Replacing the Sights
As mentioned before this gun came with the narrow WWI front sight.  I wanted taller and wider sights for a better sight picture.  Rather than purchase new sights I fabricated my own out of 1/8” flat steel bar stock.  Although I have made dovetail front sights before (refer to my article Fabricating a Custom Front Sight) I wanted to maintain the original staked-on front sight.

I found some examples of taller front sights on the Internet that I decided to copy.  The front sight I chose to copy was 0.180” tall as measured from the top of the slide.  Jerry Kuhnhausen states that the rear sight should be 0.035” – 0.045” higher than the front sight.[1]  I chose the middle at 0.040”.  Now for some basic math:

0.180” - Front sight height above top of slide

0.180” + 0.040” = 0.220” - Height of rear sight above slide

0.09375” – Depth of rear sight dovetail

0.220” + 0.09375” = 0.31375” – Total height of rear sight including the base

0.125” sight base – 0.050” depth of notch = 0.075” – Metal left in sight base

0.31375” Total height of rear sight – 0.075” = 0.23875” – Height of rear sight blade

The rear sight blade needed to be 0.23875” which I rounded up to 0.239”. 


I milled a 1/8” slot 0.050” deep in my 1/8” flat steel bar stock, then cut out all of the parts.  I used a small file to remove any burrs and sharp edges.  I squared the square notch in the rear sight blade with a flat jeweler’s file; the result was that the notch measured 1/8” (0.125”) which is normal for target sights.


I tinned the slot in the base and the bottom of the sight blade with silver solder, then held both pieces in place with vise-grips and heated them until the solder melted.  I also ran a bead of silver solder along the seam on both sides of the blade so it would run into the joint.  I allowed the sight to air cool; cooling by using compressed air or water can cause the silver-solder joint to become brittle and weak.  I took a flat jeweler’s file and removed any excess solder from the base and blade.

I set the blade in my machinist’s vise with the base up and used a 0.032” feeler gauge to level the base.  The feeler gauge ensured the base was not touching the top of the vise jaws.  I used a 65-degree sight base cutter I purchased from Brownells #080-621-495 and milled the dovetail angle on both sides of the sight base.  Because the cutter was made of high speed steel I kept the speed of my mill to below 700 RPM per Brownells instructions.  I removed just enough metal so the sight would just barely start in the dovetail.  I used a 65-degree dovetail file I purchased from Brownells #080-648-165 to finish removing metal so I could insert the sight halfway into the dovetail with my fingers.  I finished tapping the sight in place with a brass punch.  The goal here is to make the sight easy to drift in the dovetail slot to make windage adjustments, but tight enough so it won’t move under recoil.


The specifications for the rear sight call for a 0.094” radius on the front and rear.  0.094” radius is 0.188” diameter which is 3/16” or 0.1875”.  With the rear sight in place I put masking tape on the sides of the slide to prevent marring the finish and leveled it in my machinist’s vise.  I used a 3/16” ball end bit to add the radius to the front and rear of the sight and positioned it 0.005” above the top of the slide.  I milled each radius until I removed 0.032” from each face of the sight blade.  This allowed me to thin the blade from 0.125” down to 0.060” as called for in the specifications.  I removed the rear sight, bead-blasted it with glass bead media, cold-blued it, then reinstalled it into the dovetail.  It looks like it was factory produced.

Now for the front sight.  I removed the original front sight by first using a pair of vice-grips and wiggling it back and forth until it broke off of the stem.  I was careful not to mar the finish on the slide.  I used a small punch to drive the leftover stem out of the slide by punching it through from outside to inside.

The thickness of the new front sight measured 0.124”.  The narrow tenon needed to be 0.056” so I used my hobby CNC mill to remove 0.034” from each side of the tenon.  The new front sight fit perfectly in the slot in the slide. 

I bead-blasted the sight using glass bead media, then cold-blued the sight.  You can see the result in the above photo.


I applied some green Loctite #609 to the tenon and inserted the sight into the slot.  I protected the sides of the slide with blue painter’s tape and put the slide upside-down in a machinist’s vise with the top of the sight touching the base of the vise.  I used a prick punch and steel 1/8” punch to carefully peen and expand the end of the tenon until it filled the bevel inside the slide.  The bevel was deep enough so I didn’t have to remove any excess peened metal so the barrel bushing could rotate freely.


Here is the gun with the new sights installed.  If I did the math correctly I should still be able to hit steel and be fairly accurate.  If not, I can always drift the rear sight, or fabricate a new front sight.

Working the Frame
The frame needed some polishing so parts would fit and function together smoothly.  Also since most of the parts were rough Parkerized, they also needed to be polished to work together smoothly.

Polishing the Barrel Bed


I wanted to polish the barrel bed where the barrel sets against the frame when it is out of battery.  When I started to polish the bed I found two raised burrs at the end of the barrel bed.  These appeared to have been raised by something striking the end of the barrel bed; probably the recoil spring guide rod.  I took my #0 narrow pillar file and carefully knocked off these burrs.


I wrapped some 400-grit paper around the top of the barrel, turned the barrel upside-down and polished the barrel bed in the frame.  Again, I left a lot of the tooling marks behind; I just polished down the high spots.

Re-Contouring the Hammer Spur


I am one of those shooters that suffer from hammer bite.  After shooting only five rounds with my son’s pistol the web of my hand was torn open.  The hammer spur on the G.I. 1911 has a thick, sharp edge at the bottom rear.  I put a fine sanding drum on my Dremel tool and thinned and rounded this edge.  I then polished with a Cratex bit and cold blued.  Hopefully this will eliminate the hammer bite.

Re-Contouring the Thumb Safety

As mentioned before the thumb safety required an excessive amount of force to engage and disengage.  I used my Dremel tool and a fine sanding drum to reduce the radius of the front shelf of the thumb safety where it rides against the plunger.  I removed a little metal at a time and tried for fit and function.  When it functioned the way I wanted it to I used a Cratex bit to polish that surface.  Now I can engage and disengage the thumb safety easily. 

Adjusting and Re-Contouring the Grip Safety
The grip safety was disengaging from the trigger almost at the end of its travel.  That meant I would have to grip the gun tightly to disengage the grip safety.  In the heat of competition I may not always grip the gun the same way every time so I wanted the grip safety to disengage earlier.


I filed the bottom ledge under the front lobe of the safety until it disengaged earlier in its travel.  I took a few strokes with a #0 narrow pillar file and tested the function frequently.  It still needed to function properly as a safety, but now it disengages much earlier in its travel.  I also beveled and polished the sharp edges on the bottom-rear of the grip safety.  I didn’t want these edges to dig into my hand during recoil.

Polishing the Trigger Stirrup


I used my Dremel tool and a Cratex bit to polish the sides and rear of the trigger bow.  This removed the rough Parkerizing and made these surfaces smooth.  I cold blued all exposed surfaces after polishing.

(viewed from the front)

The sear spring has three leaves that needed to be polished.  I polished the front of the left and center leaves, and the rear of the right leaf.  These surfaces ride against the sear, disconnector, and grip safety so they needed to be smooth.

I polished the front and back of the bottom of the disconnector by rubbing these areas on 400-grit paper set on a flat surface.  I used a Cratex bit to polish the tip of the disconnector.  The sear and sear spring ride against these surfaces so they needed to be smooth.

I also polished the rear and bottom of the sear.  The trigger bow, sear, disconnector, and sear spring all rub together so they needed to be polished and smooth to facilitate a smooth trigger pull.

Hammer Follow
After polishing the parts of the fire control group I performed a test for hammer follow.  I locked the slide back, and with no magazine in place, pressed down on the slide release and allowed the slide to slam into battery.  The hammer dropped to the half-cock position every time, which is called hammer follow.  This is caused by one or both of two conditions; either the sear spring was too weak, and/or the hammer and sear mating surfaces were cut incorrectly.

To test if the hammer and sear mating surfaces were cut incorrectly I again locked the slide in the open position and held the trigger depressed when I released the slide.  This time the hammer stayed in the full cock position meaning the hammer and sear mating surfaces were correct. 

I disassembled the gun and bent the center leaf of the sear spring forward to add more tension.  This increased the trigger pull to 4 3/4-pounds – still acceptable for competition – but eliminated the hammer follow problem.

Function and Fire Tests
I loaded one round in a magazine, loaded the magazine into the pistol, charged the round and fired the pistol.  The empty case was ejected and the slide locked back as it should.

Next I loaded two rounds in a magazine, charged the first round, then fired the pistol.  I was looking to see if the gun would double-fire or go full auto.  This gun did not.  I fired the second round and the slide locked back as it should.

Finally I fired a full magazine to see if the gun functioned properly, and it did.  I think it’s now ready for competition.

Wild Bunch Match October 25, 2014
I attended my first Wild Bunch match sponsored by the Walnut Grove Rangers in Ellenboro, NC.  We fired 105 pistol rounds spread over six stages.  My RIA 1911A1 functioned flawlessly!  I did not have any failure-to-feed or failure-to-eject malfunctions.  I had one reload that did not have enough powder in it so it short-cycled the gun causing a jam which I had to clear on the clock, but this was the ammo’s fault, not the fault of the gun.  More importantly, the front sight did not shoot loose or come off.  I was a bit worried since this was the first time I installed a front sight by staking it in place.  I still suffered from hammer bite; the web of my right hand had a bloody blister by the end of the day, so I guess this is something I will have to live with.

As for accuracy the new sights allowed me to place the shots right where I needed them to go.  When I did my part I was ringing steel all day.  Believe it or not, I had two stages where I fired the pistol clean, but missed a rifle or shotgun target.  Well, as they say, there is no target big enough, or close enough that you can’t miss.  By the way, I fired traditional which meant I fired the gun one-handed.  I came in third place in the traditional category out of four shooters, and placed 6th overall out of 12 shooters.  Not bad for my first Wild Bunch match.

I could have purchased a G.I. slide, slide parts, and frame parts to convert one of my modern 1911’s into a G.I pattern pistol, but purchasing these parts would have cost almost as much as this entire pistol!  Plus my two modern pistols were all hand fitted so another slide might not fit properly.  I built a 1911 .22 pistol (refer to my article Building a Dedicated 1911 .22LR Pistol) so I could have purchased the parts to convert it to a G.I. .45, but again the total cost of the parts would have been almost as much as this RIA pistol.  If the price of the gun had been much above $400 it would have been cheaper to purchase the parts, but now I have a complete pistol without having to swap out parts.

Many of the specifications I used to fabricate parts came from Mr. Rio Benson of Benson Consulting, LLP.  He developed a complete set of technical drawings for the M1911-A1 pistol.  You can download the complete set of drawings by clicking on the link below.

M1911 A1 Drawings

[1]Jerry Kuhnhausen, The .45 Automatic A Shop Manual – Volume 1 in the Kuhnhausen M1911 Pistol Series (Heritage-VSP Publication, McCall, ID, 1990) 138.



   © Copyright 2014 Roy Seifert.