The rifling is cut on rifling machines, which pull the cutter through the bore. Then the rod is pushed back through the bore until the barrel is indexed for the next groove to be cut. After a cycle has been completed (the first pass has been made on all grooves) the machine activates the lift mechanism, which increases the cutting depth. Additional cycles are completed until the grooves are cut to size. The average cut is a ten thousandth of an inch per groove per cycle, and it can take over an hour to fully cut a barrel.
The machines used for cut rifling are specialized for barrels only. There are two basic types of riflers: Sine bar and Hydraulic "B" riflers.
Sine bar riflers, usually Pratt & Whitney or Diamond Machine riflers, are single-spindle belt-driven machines that utilize a sine bar to change the rate of twist. The rifling slide is attached to the sine bar and the spindle rotates at the determined twist rate as the slide moves back and forth on the machine. Most of these machines are of WWI vintage, and are still very accurate.
A series of "new" riflers was introduced by Pratt & Whitney during WWII. Dubbed "B" riflers, they are hydraulic powered machines that have two spindles, making them capable of rifling two barrels at the same time. A leader bar, or lead screw, replaced the sine bar to determine the rate of twist. The rifling slide is attached to the machine, with a nut that follows the lead screw. The nut is held against the lead screw with the aid of a large clock spring to limit backlash and provide a uniform spiral.
The last production rifler was the Pratt & Whitney "B" rifler, as higher production rifling techniques emerged after WWII. The "B" rifler is the zenith of cut rifling machine technology to date.
LAPPING
The final stage for the barrel in raw form is lapping. Lapping the barrel ensures a dimensionally uniform bore, end to end, and provides a uniform, clean interior surface finish.
Good barrels are hand-lapped, and lead is the lap of choice among barrelmakers.
A lap is made by pushing a lapping rod, a cleaning rod without jag, up the bore 3-4 inches from the end. The barrel is then swung vertical and molten lead is poured into the bore. The lead freezes to the end of the rod and makes a cast of the rifling. This is the lap. Next, the lap is pushed out the bore, de-burred, and smeared with a lapping compound, which is grit suspended in a greasy, lubricating medium. The lap is pushed and pulled through the barrel until the barrelmaker feels an even resistance, which can take a few hundred strokes. The result is a uniform, polished finish that follows the direction of the cut groove spiral, eliminating much of the break-in process.
In this article, I can only account for the manufacturing attributes of the cut-rifled barrel. Although new developments in bore- grooving have erupted in the last 50 years, the age-old art of cut rifling has remained the staid force in accurate barrels. I hope I have given you at least a glimpse of what is endured in the process.
Next Steps
Given all that, your first consideration has to be: Stainless vs. blued? Unless you want to get into an entirely different new project, we’d stick with
Stainless! Re-bluing is like shortening the legs of a table, you start with a little, and end up re-finishing the entire gun. It’s one reason Magna Port doesn’t port that many blued guns. Little known secret: Ruger and some other manufacturers will actually re-blue your gun for free, but not as a service after you’ve hacked up their barrel!
For the “quick and easy hacksaw version”, here are the time-tested steps: -- Gun on vise, no need to remove barrel with this method
-- Mark your cut with a Sharpie (don’t go below 18 for shotguns or 16 for rifles or you’ll be creating an NFA weapon, which is a felony. Leave an extra inch or two for overcuts.).
-- Remove the bolt and block the barrel between your cut and the action with a wad of cotton to prevent sending chips into your action as you saw
-- Hack away. Yes, the cut will be crooked and rough. This step takes guts. -- Using a perpendicular muzzle facing cutter/crown cutter (available at Brownell’s, Midway, Numrich, etc.), fit the cutter a little larger than the muzzle, with a pilot chuck in the bore (we prefer brass to steel as it is softer and has less chance of scratching your bore), and, using either the manual T- handle cutter, or their attachment for your drill chuck, drown the work in cutting oil, set your drill on the lowest possible setting, and “lathe” away! -- Be sure to use a STOP COLLAR to avoid uneven cutting and to cut to perfect face, and go SLOW or you’ll end up with a much shorter (and
perhaps illegal) barrel without intending to. You’ll know when to stop when you hit the stops and all the little grind or chatter marks are gone (actually evened out).
-- Once faced (remember the 90 was just to even out your hacksaw cut), you need to switch to the crown cutter. We prefer the 11 degree crown size (sometimes called 79 as the difference from 90) due to accuracy in the higher calibers.
-- Finish the work with a scoring/radius cut done with your muzzle radius cutter. All three cutters now come in the “barrel cutting kits” offered at all the good supply houses. IMPORTANT NOTE: this cut only requires a small finishing score, and if you use your drill chuck, just give it a quick spin and you’re DONE. Make sure the radius cutter fits your barrel size range as marked on the box.
-- If the barrel is stainless, dura coating the whole thing is a great finish, or you can just leave the raw steel
-- KEY: Go SLOW. Stop every few turns to remove chips, re-oil, and keep the tip clean. This has two advantages: one, you can see what you’re doing. Two, the chips and heat aren’t accidentally ruining your barrel as you go.
Headspace Gauges and Barrel Work
Barrel work can range from simple condition appraisal to diagnostics, to repairs ranging from simple cleaning and adjustment, to deep cleaning, to complex milling and cutting.
Get a good bore inspection light, and check the barrel for wear, powder residue, cracks, obstructions, lead fouling, and general condition. Are the lands and grooves distinct and the bore smooth and still polished? Are the surfaces like new or so fouled you can’t see them? Is the steel rusted, pitted, dull, burred or otherwise damaged?
Once you render an opinion on condition, there is no greater step forward to accuracy than a good cleaning! Bore Polishing, re-crowning, reaming, adjusting headspace are all progressively more extreme accurizing tactics, right up to installing a completely new barrel, but most often a very good cleaning can take the place of days of expensive lathe work. Gunsmiths can use a series of more aggressive cleaning techniques than the general public’s rod and solvent, employing non-embedding bore cleaning compounds,
electronic “reverse plating,” deep cleaning agents, overnight soaking, etc. Headspace is a constant topic on gunsmith forums. A “go/nogo” gauge system is an important tool for checking headspace. These gauges are just like cartridges. You close the bolt, and if it closes on the go, but not the no- go, you’re “good to go.” Sophisticated gunsmiths and armorers can even tell tolerances by how far the bolt closes before stopping on the no-go. Halfway up is a great general rule.
Refurbishing
We mentioned practicing on old, worn out, “trash” guns to get experience. You’ve learned how great it can be to differentiate yourself with even light accessories to make a unique product. There are two other major topics we have to cover for a great beginning business: repair and refurbishing old guns.
In classic gunsmithing schools, many months are spent simply taking guns apart, then re-assembling them. This exercise goes on and on, and seems like a huge waste of time. But there is a point: by just taking an older gun apart, checking for rusted or worn parts, then re-assembling it, you have the basic skills to create an outstanding refurbishing business! The same is true of repairs: often taking apart, cleaning, MINOR repair, and re-assembly, and you have a fully functioning gun again and a very happy customer.
The secret to this specialty is: guns last a surprisingly long time, and can often be brought back to firing condition with very little work! If you purchase a gun with a lot of rust, a scratched or pitted stock, and very dirty barrel and action, you might pay $10 to $50, for say an old Mauser.
Get your exploded diagram from Numrich, disassemble the old thing, and check all the parts for rust and wear. Often, a good overnight soaking will make the vast majority of parts gleam again. Replace the really badly worn, rusted, damaged or bent ones with either new components or pre-built entire assemblies (trigger group/fire control group etc.). Next, strip all furniture, re- finish with beautiful modern finishes, camo, or parkerize sprays, varnish or laminate, and re-assemble. You’ve turned a junk gun into a “classic beauty.” We have one gunsmith who only sells AK pistols. He’s gotten conversions down to an art, and is making over $30,000 a month. His shop is extremely specialized and almost an assembly line, but he puts his unique mark on each with custom features and engraving and never gets bored. There is a months long waiting list for his guns.
With the worldwide market for imports of Chinese guns, SKS’s, Romanians, Russians, etc. it is getting easier and easier to “Start” with a great or even classic platform at very little cost if you’re buying in quantities of at least 10 at a time.
Engraving
Engraving can go from hand scratching detailed artwork at a world-class artist’s level, to software-controlled machine engraving. Much of the gun engraving today from the “big boys” involves disassembling 100 pistols, sending the slides to China or Pakistan, then re-assembling the “custom engraved” end products. This is the reason many engraving houses are
secretive about giving tours of their “engraving” facilities: the DON’T HAVE any.
Most gunsmith/engravers are engravers first, gunsmiths second. We say this because the capital investment or leases have to keep the machines busy, and gunsmiths soon find there is a limit to knives and guns, but no limit to ad specialties, trophies, awards, plaques, etc.
The term “engraving” is used as a catch-all for hundreds of different techniques, from diamond drag, true routing, acid etching, Cermark laser “baking,” and many others.
Although we will lease engraving machines to you as a graduate, you need to carefully think about your business plan if engraving is going to be a primary focus. It can take years to be proficient enough to create a $100,000 signed masterpiece with elephants, quail and other details. On the other hand, if you are planning to also include engraved jewelry, pens, screen- printed T-shirts and other ad specialty items, go for it!
In addition to cutting metal, customizing guns and knives can involve electroplating, chemically soaking camo patterns into guns, laser cutting stocks, routing stocks, and even screen printing logos and symbols. Sometimes it’s cheaper and easier to buy 50 custom grips already ivory carved, and put them on a 1911 batch, than trying to do it in-house. This is particularly true with China taking over most of the world’s production of almost everything.
We have one gunsmith grad who cut deals with a few Italian and German shotgun and Olympic/ big game hunting rifle manufacturers. His deal was that he’d take orders for custom engraved, one-of-a-kind items. These were FACTORY engraved, meaning special serial numbers, and he is a multi- millionaire, with orders from giant Safari outfitting companies (many in Abu Dhabi), going out more than two years at a time. Yes, there are guys that will pay $100,000 for a custom over/under that he paid $25,000 for. Just look at Les Baer! On the knife side (www.bladecombat.com), Jay Fisher, the world’s best custom knife-maker, has made several custom knives for ETI to thank them for their blade combat training videos, and advice to his LE and Military clients. See www.Becomeabladesmith.com for more information on knife engraving. Another way to engrave, especially on knives and
engraved, and soak the piece in an acid bath that “carves” only the areas with no wax. This is called acid etching.
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Some gunsmiths have had thoughts about using a Hi-Power (or clone) as a tactical sidearm. It is an excellent choice, particularly for those with small hands. My wife prefers it over all other tested weapons, including revolvers and the 1911. It's a "natural pointing" pistol, simple to operate, and very robust and dependable. However, the factory trigger is very stiff and gritty, but easy to repair.
You may want to review the following webpage:
http://www.fnhipower.com/index.html
To do a trigger job, first review the following:
Tools required for this job are:
1) a 1/16" punch (available from Sears or other hardware stores. Shorten the punch to 1/2" - otherwise, it will be prone to bend when you're removing pins.)
2) a pack of 1500 grit wet/dry sandpaper
3) a small triangular file -- jeweler's file, or similar
4) a chunk of 2x4, with a 1/4" hole drilled about 3/4" deep. This board/hole will be used to receive all pins removed. 5) acetone -- maybe a bottle of nail-polish remover
6) Q-tips for the acetone 7) regular cleaning supplies
8) hammer
9) piece of coathanger, about 10"
10) Tequila and cigars, and a Border Collie. When in doubt, ask the Border Collie -- they KNOW things.
General: Use the sandpaper to polish all surfaces, and then clean and lube thoroughly prior to re-assembly.
Step 1: Clear the weapon, then remove the slide and handgrips.
Step 2: Examine closely the trigger assembly. Pull the trigger, and observe how the trigger lever moves in its well. Also observe how the trigger lever is mounted in the trigger block, UNDER the trigger spring.
Step 3: Place the receiver on the board with the trigger pin over the hole. Using the punch, push out the trigger pin and remove the trigger assembly. During this process, the trigger lever will fall off.
Step 4: Time to remove the magazine safety. Place the trigger assembly on the board, with the mag safety pin over the hole. Punch out this pin, and the mag safety/spring will pop out. Save them for future interests.
Step 5: Since the mag safety spring was a part of the "trigger return" force, you must now bend the rear of the trigger spring DOWN
about 1/4". To make the bend, clamp the spring (using needle nose pliers) just ahead of the existing bend, and then move it down using another pair of pliers.
Step 6: Using acetone/Q-tips, remove any lubricants from the trigger assembly, from the trigger lever, and from the interior of the frame in the area of the trigger assembly.
Step 7: Cut a piece of the 1500 grit sandpaper, wrap it around the end of the small file, and carefully polish the trigger lever, all
points where the trigger lever mounts to the trigger assembly, and the interior of the trigger lever well (on the frame).
Step 8: Clean and lube the trigger assembly, and re-install into the frame. (Gotta hold your mouth just right to make this happen.)
Step 9: Remove the barrel from the slide, and temporarily put it into position on the frame. Pull the trigger a few times, and observe the movement of the trigger lever against the side of the barrel. If you feel any friction, polish the pertinent surfaces on the side of the barrel.
Step 10: Time to look at the hammer/sear interface. It isn't really necessary to do further disassembly here, but simply cock the hammer, and then bend the piece of coat hanger so it holds the hammer at its rear-most position -- hook the free end into the magazine well. At this point, the hammer and corresponding sear hooks will be exposed so that you can polish them with the 1500 grit paper.
Step 11: Clean, re-lube, and re-assemble. Trigger should be smooth, and breaking at about 4 pounds.
CAUTION
People advocating polishing and even replacing springs have to be careful, as over polishing can create a full auto weapon, and too light
a spring can cause misfires, especially in the 1911. Here is a good summary of the risks:
The Elements of a Trigger Job on an M1911 Pistol
There are four areas of concern with a trigger job: the sear and hammer hook interface, the sear spring, the mainspring, and the trigger bow. There are risks associated with the first three.
The sear and hammer hook interface can be polished and lubed. Some people will attempt to take a lot of metal off the hooks and sear face. This can make the gun dangerous by allowing the sear to slip off of the hammer hooks or not catch during the cycle. This can cause the gun to fire
unexpectedly or fire multiple rounds on a single trigger pull. A polish is good but removing metal and changing the angle of the hook-sear interface is dangerous. Modifications to the sear face and hammer hooks should
only be attempted by a trained and certified gunsmith who has the proper tools and know-how to do the job.
The sear spring puts resistance on the transfer bar of the trigger and on the foot of the sear (and also the base of the disconnector). Proper tension is critically important. The sear spring can be bent to give less resistance to the trigger, but this also reduces the tension against the base of the sear. If the tension is reduced too much, the sear may not re-engage the hammer hooks during cycling. This can result again in multiple shots and even full auto fire. Adjustments to the sear spring should be attempted only by a trained
professional. I have done it, but when I do, I use a stock Colt sear spring as a template and I do not vary significantly from the factory curves in the
spring.
The Mainspring (the spring hidden in the mainspring housing at the lower rear of the grip) controls the force of the hammer. In doing so, it also
contributes to the pressure applied to the sear face-hammer hook interface. You can replace the mainspring with a lighter mainspring and get a
significant lightening in the trigger pull. It will also make it feel less gritty.