Smoothing the Browning Hi-Power

The handgun originally called the Browning 9mm Parabellum and more widely known now as the Browning Hi-Power was the innovative gun inventor’s final pistol development. Presently sold by Browning Arms Company as a sporting and defensive weapon, it is the standard military sidearm of several NATO countries, and is still being manufactured by Fabrique Nationale, Belgium. There’s no need to describe the takedown of the pistol for the purpose of this article.

The NRA Guide to Firearms Assembly or Gun Digest’s book of disassembly/reassembly dedicated to pistols do that very well—with the exception of the firing-pin block, which has been added to the newest version of the Hi-Power, the MK III. I’ll cover that feature because it is pertinent to the project being undertaken here.

If you have a need or desire for a more in-depth look at the original Browning, send a check for $3 made out to The Commissioner of Patents and Trademarks, (Washington, DC 20231), and ask for a copy of U. S. Patent #1618510 granted February 22, 1927. You can do the same for any firearm wearing a patent number. I’m not ashamed to admit that I’ve done this many times when no other references were available to detail howa gun operates or how its parts relate to one another. Why the Heavy Trigger?

In this case, the blame for the heavy trigger can’t be laid entirely on an overly cautious legal department. The Hi-Power was designed to be a battle weapon demanding zero ignition failures. As a result, the Browning has a reputation for a heavy, sometimes gritty trigger pull, and it takes a pretty sturdy thumb to cock the hammer due to the husky mainspring.

The MK III I received was no exception. (I’m talking single-action here.) The pull was scratchy, in excess of 10 pounds, and cocking the hammer nearly popped a tendon in my aging thumb—and then there were the im prints of serrations on my palm after racking the slide with the hammer down.

The question in my mind was: "Does it really have to be this way?" I reasoned that any query made to Browning regarding trigger-pull reduction would probably raise the issue of warranty violation, and I would be admonished for having the audacity to rework the pistol rather than to loose several hundred rounds downrange to "smooth it up and wear it in." (We’ve all heard words to that effect when advised not to return a gun to the factory or an authorized service center.) In this particular case, time did not allow me the luxury, or fun, of blasting four or five boxes of FMJ at helpless paper targets.

My customer had secured a concealed-weapon permit almost simultaneously with his purchase of the pistol, and due to circumstances known only to him, he was most anxious to holster his new Browning. (In retrospect, "anxious" is a gross understatement.) I’ve believed for awhile that the best custom parts made for the Hi-Power are available from Bill Laughridge, the "head honcho" at Cylinder & Slide, Inc. Fremont, NE 68025; www. cylinder-slide.com).

His catalog is crammed with neat stuff for the Browning and the M1911. It costs a mere and refundable five bucks, and you’d do yourself a favor by having one on hand. (Incidentally, Bill was elected Pistolsmith of the Year for 2005 by the American Pistolsmiths Guild.) The similarity and simplicity end when it comes to trigger work.

The match-grade sear lever (arrow) was among those parts not used for reasons explained in the text. As soon as my order from Bill arrived, I opened the drawer labeled "tooling" and pulled out Ron Power’s Power Custom Series I stoning fixture. An article on this unit appeared here awhile back. The fixture has been my right and left hand for hammer/sear/ trigger work, and has been used with over a dozen different guns.

You’ll find it and a list of its firearm-specific adaptors in Brownells catalog Ron provides extensive instructions with every fixture, so I’ll skip the details of how to use it this time around. Planning the Job With the Customer I was sure he didn’t want to be packing a trigger pull in excess of 10 pounds, so most of the components I ordered from Bill Laughridge related to reducing it.

One exception was an extended slide release—a drop-in substitute for the factory part and a highly recommended remedy for a stubby right thumb. Prior to installing any of the performance-enhancing parts, I arranged a short conference with the gun owner to go over various options open for the work that lay ahead. His choices will become apparent as I take you through the overhaul. Let me say this first.

I was fortunate that this particular Hi-Power hadn’t fallen under non-experienced hands for a "trigger job" involving reworking of the factory sear. More about that sear a little later, but over-cutting it can lead to a serious bending of the sear pin. This happens when too much material is removed from the sear, resulting in a lack of support for the pin which is under tremendous pressure from a 32-pound hammer spring. I assured myself that the pin wasn’t bent by rolling it back and forth on a true surface.

After a total takedown of the pistol, and smoothing up the few rough spots I discovered (excluding any on the OEM hammer and sear), I relegated the latter two components to a home in my parts inventory. The factory sear is a casting, and would not hold its edge after stoning. The new sear is CNC milled to precise tolerances, heat treated to 52RC, and certain to indefinitely maintain the stoning given its engagement surfaces.

The Laughridge sear, 54.5RC hammer, and target spring set had been voted "in." The wide combat trigger and light trigger-pull sear lever were voted "out" by my customer, in spite of their potential contribution to a lightened trigger pull. He had his reasons. In his mind they were irreversible, and any protest I made fell on deaf ears.

After assuring him the pull would not be as light as it might be if he dropped his objections to the two components, I caved to the old adage: "The customer is always right." When it comes to guns and gunsmithing, following that adage is not always the best solution, but I understood his concerns and abided by them. In the case of the combat trigger, I even tended to agree with him.

Its installation would have involved defeating the magazine disconnect and would have made it possible to fire the pistol with the magazine out. This would void the factory warranty and only take the trigger pull down by about 1/2 pound. His objection regarding the lightpull sear lever was based on pure cosmetics. He wouldn’t budge, but I’ll take you through how the job should be done, because this lever is key to reducing the pull beyond hammer/sear stoning and spring replacement alone.

Before tackling the lever, however, all work with the hammer/sear/springs must be completed and thoroughly function checked with the pistol assembled. Installing the Sear Lever This job requires some work with a milling machine. It doesn’t have to be computer controlled, though that feature would be nice. Gut the slide and secure it on its side in the machine’s vise, square to the drilling head.

The lower slide rails must be maintained parallel to the axis of the cutter, otherwise known as the 2.45mm drill supplied with the lever. Use it to locate the existing sear-lever pin hole in the slide. Rotate the drill 180 degrees by hand to ensure the alignment. Make absolutely certain you measure the hole placement exactly, and double check everything before the actual drilling begins. Replacement Browning slides cost dearly. Okay, you’re assured. Lock the mill table and reset the dials to zero.

The lined area on the honing stone atop the fixture indicates the length of shim stock to be epoxied to the bottom of the stone to protect the fixture’s roller. Unlock the table, move the drill bit .250 inch to the rear of the slide, and relock the table. Replace the present bit with a #1 center drill, and start your new hole through the slide serrations. Switch back to the 2.45mm bit, and drill all the way through at 660 rpm, using a constant flow of cutting oil.

Remove the slide from the machine and deburr the holes in both sides. There are enough variations in slides to require precise fitting to a given pistol, so the match-grade sear lever is oversize in length and thickness to facilitate this. The nose end (front) of the lever is enlarged, Beware of the firing pin; its spring transforms it into a dangerous weapon. Eye protection is mandatory. allowing it to be fitted so the sear is able to clear full-cock engagement with the hammer.

Behind the nose, the angle is left thick enough to allow exact fitting to the lever’s trough in the slide. There’s no easy way to do this. You have to fine file a little, stone a little, try the fit, insert a magazine, cock the hammer, slip the slide on the frame, pull the trigger, and see if the hammer falls. If it doesn’t, the sear and hammer are still engaged. File a little more, stone a little more, until the engagement is broken.

After that you have to be sure the nose of the sear lever rides below the flat surface of the slide. If it’s above, the lever can strike the trigger bar as the slide goes forward and disengage the sear from the hammer. To correct for a high sear lever, a small amount of bending is permissible and necessary. Clamp the front end of the lever between padded vise jaws and tap the rear, or paddle end, lightly with a small hammer.

This bending has to be done in small increments, accompanied by frequent checking with the lever installed in the slide to see that the sear still clears the full-cock notch. (Having a well-made, properly fitting sear-lever slave pivot pin would be highly useful, what with all the taking down and putting back together.) Don’t meddle with the OEM sear-lever spring. Cutting coils off it will cause the lever to "float" downward while the slide is moving forward and could allow the sear to disengage.

A pleasant plus with the Laughridge match-trigger lever is that it can be installed in older Brownings not equipped with a firing-pin block by filing off the paddle-shaped end. Installing the Hammer and Sear By following the disassembly instructions in the aforementioned reference sources, you’ve taken apart the sear, hammer, and safety portions of the frame. What you were not informed of is the terrible consequence awaiting the uninformed disassembler within the slide of any Browning with a firing-pin block.

It is the firing-pin spring. The thing is so strong it can raise a blood blister if you’re foolish enough to try and stop the firing pin as it is launched from the slide with your thumb. Anytime you are removing the firing-pin assembly, there’s only one way. First, if you haven’t been wearing

This hi-tech Hi- Figure 1. Power disassembly/assembly tool is made from a #12 common nail. It slips over the hammer stem and under the beavertail to maintain compression on the mainspring. The tool lets you get rid of a clamp and gives you more room to work. eye protection all along, you should be. Second, the slide is placed upside down on your bench. Third, the nose end of the sear lever is depressed to clear the firing pin and the pin itself is pressed inward through its stop plate with a punch.

Fourth, use the punch to lever the stop plate upward enough to capture the firing pin, which is still under pressure from its almighty spring. Fifth, place a large wooden block behind the slide. Sixth, keeping your fingers clear of the firing pin, continue to move the stop plate upward with the punch and be prepared to duck. If the wood block is hard enough, the firing pin will not be driven too far into it.

You have to be almost as careful when installing the new spring, but compared to the factory monster, it’s a pussycat. Now remove the strut/mainspring assembly from the factory hammer by driving out the strut pin. Be sure to attack the pin from its smaller diameter (dimpled end) to avoid tearing off the head on its larger-diameter end, and use a nylon bench block as a base for the removal.

You have also, by following the instructions accompanying the Power Custom Series I stoning fixture, polished the hammer full-cock notch and recut the sear. (Note: Never cut the nose of the sear to be narrower than the cocking notch.) When you install the strut on the new hammer, do it so the Below left and Internally, the two have become (continued on page 17) very different animals. large-diameter head of the strut pin seats in the countersink on one side of the hammer’s pin hole.

Reassemble the back end of the pistol in reverse order, place the slide assembly on the frame, insert a magazine, and check the work done so far. Rapidly pull the Browning’s slide all the way to the rear and let it slam forward. Did the hammer follow down? Maybe you overdid things in the stoning fixture and the sear isn’t completely engaging the full-cock notch. Is the sear spring installed correctly? Hammer follow can also be caused by a lack or loss of sear-spring tension.

Increase it by removing the spring, placing it on edge on a sheet of paper, and tracing the spring outline along one side. Then use your fingers to bend the upper section of the spring toward the front of the pistol. Don’t use pliers or wrenches on a sear spring, please. Double check the thumb safety. You want to be absolutely sure it will block the sear when it’s engaged. Cock the hammer, pull the trigger, and release the safety. The hammer shouldn’t follow.

If it does, the safety isn’t moving far enough up into its slide cutout to block the sear. This happens occasionally due to differing tolerances. Correcting for it calls for the removal of a small amount of material from the safety stud. Figure 1 shows the proper area to be reduced, and you’ll usually only need to take off a couple of thousandths. To double check your work, reassemble the fire-control system. The safety moves into its slide cutout? Good. But is it blocking the sear like it’s supposed to?

Cock the pistol, engage the safety, look down into the frame so you can see the hammer/sear interface, and pull the trigger. The sear should not move. When sear and safety are properly fit in a Browning Hi-Power, the sear must never move up to expose any of itself above the hammer full-cock notch. That’s not quite all there is to checking the thumb safety. Will it move up enough in its cutout to lock the slide open? If not, the sear nose

has been shortened excessively in the stoning process. Throw out that sear, replace it with anew one, and let the added expense be a lesson to you. After all this work is done and confirmed functionally, install the new sear lever as previously described, replace the brute firing-pin spring with the spring received from Bill Laughridge, completely reassemble the pistol, and run yet another function check.

The Final, Full Measures Test fire the pistol using a two-hand hold with only three rounds in the magazine for the first 50 rounds of testing. Sound like a pain? Could be, but if the overhauled Browning is going to go full-auto, it’s better if it does so with three rounds instead of a full magazine to feed the eruption. The bottom line on this rework: What came in with a 10-plus-pound trigger pull went out with a safe and smooth 6 pounds that felt more like 4-1/2 pounds.

But I insisted the owner bring the gun back after 100 rounds so I could reweigh the trigger and make adjustments, if necessary. He wanted to know why. I answered: "Because it’s a Browning Hi-Power." ■