Category Archives: Gunsmithing

Posts that touch on gunsmithing topics such as improving function, finishes, changing parts, and anything else that alters a weapon

AK & Related Rifles, Gunsmithing

Heat Treating the Lower Rails of AK Flats Before Installation

I like to heat treat my entire lower rails before I install them. Some guys just heat treat the tip but I go for overkill.  When I would get flats and rails from AK-Builder for whatever I was doing, I’d do all the lower rails at once and store them oiled in a bag for later use.

The process is simple, I heat them up with a torch to dull to medium orange, which comes out to around 1500-1600F.  Some guys use magnets and stop the heathing when magnetism is lost, some use marker/applied heat indicators – there are many ways to do it.  I tend to use my sheet metal/jewelers oxy-acetelene torch. It is known as a Meco Midget and the thing is awesome for sheet metal work.  I’ve had mine for over 10 years and never had a problem.  I have a giant Journeyman II set but find it too big and cumbersome for stuff like this.

Tin Man Technologies (TM Tech), who I got mine from years ago and you will need to search around for it or find what some call a jeweler’s torch

Next, quench the parts in room temperature used engine oil.  It works great for me.  I have an old navy fuse can with a lid glued to a piece of wood that I use for this purpose.

After that, I anneal them by putting them in a flat pan, pouring in some brake fluid with some paper towel exposed, lighting the towel and then letting it all burn it off, which is about 500.  It’s messy and you want to do it outdoors for sure – I let it all burn off and then air cool.  Some guys put them in a toaster oven at 500F for 5-10 minutes and let them slowly cool down by turning the oven off.  That works too.

Here the rails right after the brake fluid is finished burning off – you can see some of the soot that is generated:

When you weld the rails in with a spot welder, just be careful not to ruin the heat treat by letting a tong get up against the ejector tip and heating up.  I’ve done it twice over the years.  One time I didn’t notice and had to repair a peened over ejector and the other time I saw the discoloring of the tip and did a spot hardening of the ejector tip while it was in the receiver.

At any rate, I’d then oil everything and put them in a ziploc bag for future use.  I would sand the backs of the rails prior to installation to get good spot welds.

While I use OA for a lot of my work, MAPP works just fine too.

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AK & Related Rifles, Gunsmithing

Back in the stone age we had to mill our own top AK receiver rails!

Back when AK-Builder flats didn’t have the top rails cut to size, we had to do the work.  I’m talking circa 2006 and then late that year he came out with a simple layout tool that was so awesome.  You applied Blue Dychem do your flat, clamped the layout jig to the rail, used a scribe to mark the profile and then you came through with your mill (or Dremel) and cut out the shape.  It was faster than doing it all by hand and the one plus was that you could get the exact spacing between the upper rails that you wanted.

AK & Related Rifles, Gunsmithing

Setting an AK’s Internal Front Trunnion Rivets with the AK-Builder rivet jig

It’s pretty straight forward really.  You need to insure the rivet jig is sitting on good strong steel cross plates – don’t use wood.  I’ve seen guys try so don’t laugh too hard.  For the record – that one I never tried – I used 1/2″ steel plate from the get go.  Wood is not your friend under high pressures.

Be sure  to use the right rivets – AK-Builder sells the best rivets and tailors them to what you are building.  Lay them all out and identify what rivets are for the front, the swell neck rivets for the lower back of the front trunnion, etc.  A rivet should stick out 1.5x its diameter – that’s it.  Just for example and to keep the math easy for me, a 4mm rivet should only stick out 6mm.  If you go further, you are going to have problems.  As you get experienced, you can buy rivets in bulk and use rivet trimmers but you might want to save that for down the road.

Make sure the rivet and your receiver are all nice and square and that the little cup is under the rivet’s head to support it.  Make sure everything is nicely supported too.  If you don’t you will bend the receiver.  When I make cautions, it’s usually because I did it the wrong way already at some point 🙂

Only extend the rivet arm the minimum amount necessary.  The longer it sticks out, the easier it is to bend it.  I’ve done that and you may too.  If you do, just bend it straight again by pulling it out of the jig, supporting it by steel block and press it straight.

Now go slow.  Speed will only help you mess up faster, especially if you are new to this.  Extend the little set screw enough to squish the rivet and clear the trunnion walls.

Do not go crazy with the pressure.  You want to squish the rivet, not start bending stuff.  The rivet swells inside the hole and and the end caps it – that is all you need to accomplish.  Too much pressure and tooling starts to bend.

 

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AK & Related Rifles, Gunsmithing

First Romy G Build – October 2006!

So I have been taking photos of guns and tools for years and years and year.  I just recently decided to start dipping in and sharing.  I was pretty floored to find this collection of photos of my first build.  It was a 1981 Romanian G pattern AKM, affectionately known to many AK builders as a Romy G.  I’d invested in AK-Builder tools and used them and a big 20 ton hydraulic H-frame press to do the work.  You’ll notice the older AK-Builder flat bending jig is shown.  They worked great and the only drawback I ever noticed, and it was not a big one, was that the flats need to have a positioning hole for a roll pin at the end of each flat.  This definitely was not a big deal but he did evolve the design to not need that later on.

You can also see the old style AK-Builder flats.  They were great to bend but you really needed your act together to do the top rail.  I actually botched this first one and made the rails too narrow.  Because of this, the gap between the upper rails was too wide and the bolt carrier kept popping out.  So, I did a new one and was very careful to get the rails held in place nice and rigid plus I would mill a little and test, mill a little and test to dial the fit in.

I bought a HF mini mill so I could get better looking and more consistent upper rails.  Note the 3″ milling vise.  I bought that from Little Machine Shop and it works great.  I still have both the mini mill and the vise.  My one comment on the mini mill is that it is light duty.  On my bucket list is a full size mill at least with a digital read out (DRO) if not with CNC.  To this day I do a lot of “eye balling” of work and would like to be more precise.  Also, I eventually moved away from oak wood fillers to precise steel blocks at some later date.  The fun thing about writing this up later is that I recall lessons learned and stuff but remembering dates has never been a forte of mine.  As I used the mill more, I really learned to value work holding systems.  Old timers’ advise of “take the time set it up right so the work doesn’t move” proved to be a life lesson I draw on to this day.

Here’s the 1981 parts kit.  Notice how nice and smooth the barrel is machined.  Starting around 1983, the quality started going down hill and you’d see kits where the barrels literally had turning marks going down them that almost looked like threading.  By the way, the “G” series AKs were actually well made semi-auto rifles despite one some detractors would say.  They were made for the Patriotic Guard hence the “G” for Garda.

   

The wood was always so coated with goop, I would spray them down with Bix wood stripper several times until I got down to the wood and would then do finish sanding.  Now on this rifle I used satin polyurethane and over the years moved to boiled linseed oil as the latter was very easy to fix/maintain.  I used a number of reddish brown Minwax stains over the years.  I think that was red oak.

   

I had AK-Builder rivet jigs but I didn’t take photos of them while doing this build for some reason.

Here was the end result.  I would have used a US slant brake, Tapco G2 FCG and that might be a Tapco or generic brown US grip.  I used to get most of my parts from Copes, Centerfire and DPH Arms back in the day.  The finish was Duracoat but I stopped using it after a few years and moved to a combination of parkerizing and Molyresin that held up great.  The AK’s selector lever can wear a strip through a finish real fast.

I kept this around but shot it less and less then when the kits skyrocketed to about $300, I cut the receiver off and sold the kit.  The funds went to other projects but with 20/20 hindsight, I wish I had kept it for nostalgia.   My dad and other family members all had fun shooting this rifle.

 

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Flashlights and Lasers, Gunsmithing, Shooting in General, Shotguns

Remington 870 and Winchester 1200 Riot Shotguns

Ran across these photos of two riot shotguns I built – a Winchester 1200 I bought new in the early 1980s and a Remington 870 Express I got a good deal on from Gander Mountain in the early 2000s.  One thing I learned is that the Blackhawk recoil reducing stocks really make a difference.

 

To be honest, I think Remington makes a lot cheaper guns than they used to and their quality has suffered.  Some years back I picked up a Remington 870 express in great shape but one thing that drove me nuts was that the little orange plastic follower would spring out and jam the action.  I did some quick digging and found a machined aluminum replacement that I installed and never had a problem since.

Also, from a pure “keep it simple” angle, I have since stopped installing anything on a tactical shotgun other than a light.  It took to long to turn on the red dot plus worries around battery life, was it still zeroed, etc.

For lights and lasers, I really like the Streamlights.  I use a TLR-1 300 lumen LED light on my home defense 870 to this day.  They are rugged, simple, easy to operate and durable.  Having had a ton of cheap Chinese imports fail over the years, I only use proven lights and lasers on critical firearms.  To save on the CR-123 batteries, read my post on that topic.

The red fiber optic sight really worked out better than I thought.  It made target acquisition fast.  I eventually ditched the red dot optic, installed a side saddle shell holder and used just that sight.

The flashlight on the Winchester was a Hellfighter with a xenon bulb.  It was ok but I would only buy LEDs going forward and my preferences are Streamlight or Surefire.

The Blackhawk recoil reducing stocks do a very good job but make sure you buy the right model.  They sell stocks both with and without the recoil reduction system.  Also make sure you get the right model – they make them for Winchester and Mossberg.  The following is an automated search from eBay so you need to double check the product and that the buyer has plenty of trades and good feedback.

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Gunsmithing, Shooting in General

Great deal on dummy / action proving rounds – KP Tactical 9mm, .40 S&W and .45 ACP

  

I tend to use a lot of dummy rounds due to working with Kydex or whatever and normally you pay quite a bit for them.  Recently I stumbled across a very good deal on Amazon.  There is a company called KP Tactical making very decent dummy rounds by machining them out of aluminum and inserting silicone rubber in place for the primer and they are only about $1/round in bags of 10.  So, I ordered 9mm, .40 and .45 and they arrived the other day.  I’m quite happy – the machining is well done and it’s a very fair price.

 

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Gunsmithing, Tools

Use a Wen 3410 Air Filtration System to Remove Fine Floating Dust In Your Shop

Okay folks, with all the sanding of plastic I do, my shop has tons and tons of dust in it.  In 2015 I read an article about how small fine dust particles are unhealthy – in general, the smaller the particle, the more it gets to places in your lungs where you don’t want it to and it may get stuck there.  Now I may be a slob, as my wife will readily agree, but I do get concerned about safety.  Now I investigated improving my dust collection off the tools and that was way too expensive.

At some point I will upgrade my dust collection at the tools but that will have to wait.  What you will notice when talking to a lot of the vendors, and Grizzly is one example, is that they only warranty their products for wood.  What this tells you is that they are using open bearings (not sealed bearings) and if other materials get in there (like my glass reinforced plastic), it will shred them.  Grizzly product support was real cool about answering my questions and cautioning me up front before I dropped a big amount of cash on one of their dust systems so kudos to them for being up front and honest.

Fine air filter systems are supposed to be on layer of a multi-layered defense but at this point, I was really worried about were the fine particles as I already have some basic dust management in place.  In addition, I always wear a quality Moldex 2310 N99 particulate respirator when drilling and sanding but all that junk was just floating around and getting on stuff in the shop, etc.  So the immediate need was to get rid of that fine dust.  I did some digging and there is a model of suspended fine air filter that seems to be sold under many brand names.  I did some digging on Amazon, read the reviews and went with the Wen 3410.  Just to be clear, I actually bought this – you are reading a review from a real user and not someone who got something for free in exchange for a review.

The unit arrived on November 9, 2015, and I have used it a ton – replacing both the outer and inner filters many times.  Let me tell you a bit first.

Before I did anything, I plugged the unit in and tested it.  I learned years ago not to do a ton of work installing something and then test it!  Test it up front so it is easy to send back or get tech support on the line and work on it.

I figured out where I wanted to hang the air filter and bought some heavy sign chain from Ace Hardware so I could get it just where I wanted it.  The unit isn’t very heavy but given me and some expensive tools would be right under it, I went for overkill.  It’s around 30 pounds and the chain is around 120 pounds if I recall right.  At any rate, I hung the unit and adjusted the hooks until I got it level.  I then ran an extension cord over to it and turned it on.  It was a tad loud on the highest setting but definitely something I could live with – I usually have the stereo cranked in my shop anyways so that wasn’t a big deal.

The unit comes with a remote for turning the unit on and off, setting the speed (low, medium or high) and whether to use a timer setting for 1, 2 or 4 hours.  I really like the timer as I can have it set to constant on while I am in the shop and then set it to the timer so that it can keep cleaning the air after I leave to get remnants out of the air.  Truth to tell, the remote’s battery door has been the only casualty since I bought it.  The little tab that held the battery cover in place was never very firm so I resorted to a couple of layers of black electrical tape wrapped around the remote and have never had a problem since.

What I noticed over the coarse of the next few days was that stuff in the shop was not getting a thin layer of dust on it like it was in the past.  The unit has an outer coarse filter that is 5 microns and an inner filter at 1 micron.  It’s good that it is two stage like that as you can see them both getting filled with dust or at least I can.  I probably make it about 2-3 months before I have to change the outer filter and in general I make it about two outer filter changes before I change the inner filter.  The life of the filter really depends on how much sanding I am doing and the material I am working with.  Once I saw all the crap in the filters, it made me realize that some percentage of that junk was going in my lungs – probably more than I knew.

The next photo is telling – this is the exhaust side of the Wen.  After using the unit for over a year with a ton of hours, look how clean it is.  I have never cleaned it.  That gives you an idea how effective the filters are.

I go by the looks of the filters as to when I change them and I definitely keep spares on hand.  The Wen brand filters come in two packs and I’ve noted some of the sizes in case you want to try other brands of external filter.  For example, I used a few Powertec 421x241x45, 5 micron external filters worked fine.  In general, I try to use Wen.  I have only used Wen for the internal 1 micron filter but have seen other identical looking filters but have not tried them.  Note how white a new filter is (that is a new Powertec in the machine) vs. the filthy used one sitting on the blast cabinet.

   

So, I am very happy with the Wen and am actually thinking about a second for the other end of the shop.  If you are looking for a fine air filter, I’d recommend this one for sure.

2/22/2018 Update:  The Wen is still going strong.  No problems at all and I’m still very happy with it.

1/2/2019 Update:  Still going strong.  No problems.

5/21/2019 Update:  Still using it all the time.  This has really held up great.

2/19/20 Update:  Still holding up great.  Just replaced all the filters.

 

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AK & Related Rifles, AKBuilds, Gunsmithing

How to Install a Flat’s Lower Receiver Rails So They Align With The Front Trunnion

I heat treat the lower rails before I install them.  The best way I found to align the lower rails in a flat so they were both parallel with the upper rail and aligned with the trunnion was to use a drill bits of the proper size to locate the lower rail and I would then clamp the lower rail in place prior to spot welding.  This is one of those things where you want to check and double-check prior to and after each weld to make sure nothing shifted on you.

I use a Harbor Freight #45689 115 Volt spot welder with AK-Builder upper replacement tong and also tips.  It’s lasted me through quite a few builds over the years and is still going strong.  The tong makes it way easier to reach in and make the weld and the tips make the spot weld look a lot more like the real ones.  I have had to replace the tips once so far, just FYI.  You need to keep them clean to be most effective.

For beginners, there is no way to tell you how long to clamp and trigger the current for – many factors can affect how long it takes to heat the steel up enough for the two pieces of sheet metal to weld together.  You need to practice and you’ll notice the color, sound of the welder. the amount of time it takes to get a good weld and especially the feel of the clamps as they come together during the weld.  With practice you’ll feel when you have a good weld especially but it all adds up but you need to actually do it to learn.

Get scrap metal of about the same thickness to practice with.  AKM receivers are 1mm thick.  18 gauge is 1.02mm so it is good to practice with and old scrap receiver stubs are another.  With your first practice weld, go long and let the pieces really melt together so you can see.  You want to burn a hole to understand how long it takes, the sound and the feel of the tongs.  Then practice with less amounts of time until you find the sweet spot.  These welds should be pretty strong and not pull apart easy.  I do more spot welds than most and some guys look at photos of the rifle they are building and try to approximate the count and location, which is just fine.  One thing, if you do heat treat your rails before hand like I do, be careful you do not get the tongs up against the ejector and ruin the heat treat.  I’ve done it and the tell tale sign is that the ejector will be discolored from the heat.  If you do make this mistake you will need to heat treat the tip while it is in the receiver or else it will definitely peen over and be deformed in its softened state.  By the way, the steel should be relatively clean also and not have tons of grease or other contaminants on it either that might inhibit a good weld.

Just double check alignment very carefully before you spot weld and also that your welder’s tong does not get against the ejector and ruin the heat treat – assuming you did that before installation.

I hope this helps you out!

If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com. Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.