Bren semi auto build - USA

I recently purchased an MGS WWII Bren 1 Parts Kit as a project My dad and I could work on. I have most of the mechanical questions worked out, but before I begin any of the welding on the demilled receiver I would like advice on what kind of ATF form(s) may need to be filled out. Do I need to submit a request to manufacture a receiver and the $200 tax? Some forums I looked at implied that it wasn't required unless you plan on selling the final product. Can someone who has made a welded receiver advise me on how you handled it?

Once I have this question answered I will document the project as it progresses.

Gart,
I have two MGS Bren kits.... through a Weaponeer group buy, I got the semi auto conversion parts kit for one of them.

Left to do is the blocking of the receiver and the welding like you mention.

You do NOT need to file ATF paperwork to make your own rifle. A semi auto design is allowable....

The $200 tax you are referring to, is based on a transfer of a NFA weapon I believe. As you probably know, post 1986 manufacture of a machine gun is prohibited by the general public. New manufacture machine guns are only as post 86 dealer samples transferable to other dealers / manufacturers and law enforcement.

I would stick to a proven Semi Auto design, and insure that it is engraved somewhere that it is Semi Auto only and has a legible serial number. This is to keep you outta trouble if you are stopped and asked about it.

I know that some folks keep the ATF letter of the proven Semi Auto design with their rifles, just in case they are questioned.

The big pearl of wisdom to share, is to convert as much of the rifle as possible to the semi auto (bolts and FCG's)... and weld in a blocking bar, before welding up the original receiver. As you may know, the torch or cut pcs are just interesting items until you start fabing... then they could become "intent" to manufacture.

As to selling the semi auto rifle..... it is permissable to sell your own manufactured rifle. However, it is a grey area due to the fact that you don't have a manufacturing license... I would intend to keep the rifle after you finish it, if I were you. Besides, that rifle would have questionable value, onless you are a recognized individual or corporation building such devices.

If you are doing a novel Semi- Auto build, then you may want to submit that design for proving, to the ATF. This would be a prudent measure.

These are just my opinions, and I am sure others will chime in. It is always best to follow up with your research, since I may be in error, and don't have a law license, and am not an expert in regulations governing all ATF and local/ state regs.

I look forward to your build! Ask if you have further questions!!

Thanks!
The ATF website has a form: ATF F 5320.1 (Form 1) — Application to make and Register a Firearm. That caused the confusion, apparently it is legal to make a firearm and not register it. I will be calling the ATF for a quick confirm, and then get it in writing.

I will be using the semi parts kit from MGS and plan on duplicating their effort with the FA parts that came with the bren kit to make a complete second set of SA parts. (that may or may not turn out too well).

I will be manufacturing my own welding jig as I cannot find one for less than $125. The measurements for how everything fits can be done using the internal components and magazine as guides. Remembering to allow for shrinkage. The Jig will be a stack of sheet metal tack welded together then machined to add copper plates behind the weld areas. Unless it costs more than $125 to do it that way.

Gart,
Sounds like we have common effort/ purpose. I am planning on fabing up a second set of SA parts for my second build also... I believe the SA parts kit was sourced through Weaponeer, and is indeed the MGS.
I agree on the jig also. I have kept my eyes peeled, but it always comes down to $$. I was hoping to come across a nice BREN print to create the jig, so I don't have to reason out critical dimenions.....
To take into your account for shrinkage, remember to put in splices (virgin metal or donor torch cut). When I get a chance, I will link you to a website where the guy took the torched parts and milled them, and inset an exactly spaced pc. This controlled his contraction upon cooling. Some fella's go with 8620 steel, others 1045.

I have access to MIG, stick and gas. TIG is the preferred method for rewelding....

I know of several gunsmiths who have been cautioned by the ATF to report rifles that come in without serial numbers. As a matter of fact, one such rifle appeared during an ATF inspection at the gunsmiths. The ATF did follow up with the owner on where he got the rifle. Hence my cautioning of insuring that you have a legible SN on your manufacture.

You are probably referring to: Bren
Also found limited blueprints on Bren blueprints...

this is one im going to follow post lots of pic's eh

Hey Garthok I've just had a look at your BREN suggestion (post 5). It's amazing........ I wouldn't have believed it to be as possible and as good if I hadn't seen it myself. It's not just the good machine shop and welding facilities but the multi-skills of the fellow too. Great pictorial essay. Do you know him or did you just pick it up?

Quote:

---

Originally Posted by Peter Laidler

Hey Garthok I've just had a look at your BREN suggestion (post 5). It's amazing........ I wouldn't have believed it to be as possible and as good if I hadn't seen it myself. It's not just the good machine shop and welding facilities but the multi-skills of the fellow too. Great pictorial essay. Do you know him or did you just pick it up?

---

I just found that site while googling bren kits, it was that site that has inspired me to try this project. He does make it look easier than it probably is.

you are teasing us canucks with this one though :p we have to get a new receiver machined and that in it self would cost quite a bit not to mention if your design is not approved your receiver gets choped not a big deal with something like a sten but a real big deal with a bren

I hate to say it, but I think I bought the last semi auto parts kit from MGS. They removed it from their online store just after I bought it. After several hours of grinding slag, everything "fits". I am torn between paying somebody to do the welding or learning to weld on my own. Both can be expensive. I have ordered the gas selector and a magazine, and MGS is sending me the missing barrel bolt. Anyway here it is roughly assembled:

Attachment 33887

We have a saying here that '.......you could spoil the ship for a hap'worth of tar'. Why not just ask the welder in post#5 to weld it. It's clear that he has the know-how plus the jigs, fixtures and fittings that he's used successfully before. I'm sure that he's your man..........

Quote:

---

Originally Posted by Peter Laidler

We have a saying here that '.......you could spoil the ship for a hap'worth of tar'. Why not just ask the welder in post#5 to weld it. It's clear that he has the know-how plus the jigs, fixtures and fittings that he's used successfully before. I'm sure that he's your man..........

---

that would be easy with out the rules, regulations, licences and the cost
for what you will pay to have it welded you could almost buy 3 more kits
I have welded a few and its not that hard but then they (other builders) say that the bren is the hardest kit to build
When I say its not that hard understand that I have years of welding experience. this is not something to learn to weld on.
Just remember to do all your semi auto modifications before you do any welding together of the receiver pieces...
thats cut the carrier rails, weld up the corresponding track in the receiver, weld the selector stop on the lower, weld the denial pins into the center section, cut the bolt and cut the piston post thats not all, there is more. decide what version you are going to copy and modify your lower acordingly. have fun and good luck

Garth,
Looking good. If you don't mind, someone should post some of the SA parts that you get with the kit from MGS.
I am thinking about doing one as .308 due to the "cheap" ammo. HOwever, I seem to be starting to get rifles in .303... so I may do the next as original caliber.
Great rifles and shooting examples are a nice tribute to the sacrifice made by the troops who used them.

If you are going to build a jig, let me know. I am looking for help doing that also, and may be able to help with the material cost... If you don't mind doing the machine work....

Quote:

---

Originally Posted by Midmichigun

Garth,
Looking good. If you don't mind, someone should post some of the SA parts that you get with the kit from MGS.
I am thinking about doing one as .308 due to the "cheap" ammo. HOwever, I seem to be starting to get rifles in .303... so I may do the next as original caliber.
Great rifles and shooting examples are a nice tribute to the sacrifice made by the troops who used them.

If you are going to build a jig, let me know. I am looking for help doing that also, and may be able to help with the material cost... If you don't mind doing the machine work....

---

.308 would need some major work the common thing to do is convert it to 7.62x54r thats what id do .303 brass is not cheap anymore and just about anything you find on the range floor is scrap(they are ok for converting to .410)

Projectguns does not work on kits with the cuts done to my receiver, it will require additional machining after welding.

After talking with a formerly licensed firearms manufacturer about the legality of manufacturing a firearm for personal use, I have decided to go the safe route and submit form atf-f-5320-1 Application to Make and Register a Firearm. Primarily due to the "non-sporting semi-auto from imported parts" argument. He is no longer licensed after his company was raided by the ATF, he was cleared of any charges, but some others were not so fortunate. He warned me the ATF loves grey areas, and to get written approval. The following is from the ATF website:

Q: Does the GCA prohibit anyone from making a handgun, shotgun or rifle?

With certain exceptions a firearm may be made by a non-licensee provided it is not for sale and the maker is not prohibited from possessing firearms. However, a person is prohibited from assembling a non-sporting semi-automatic rifle or non-sporting shotgun from imported parts. In addition, the making of an NFA firearm requires a tax payment and approval by ATF. An application to make a machine gun will not be approved unless documentation is submitted showing that the firearm is being made for a Federal or State agency.

[18 U.S.C. 922(o) and (r), 26 U.S.C. 5822, 27 CFR 478.39, 479.62 and 479.105]

I will post pictures of the semi auto parts later this week. I figure I have 6 months to learn to weld while waiting for approval. Again, I may not have to jump through the hoops, but would rather spend $200 than risk $10k and 10 years.

Garthok,
This should be interesting on what you get back.
I understand the argument as to 922r, and I believe to counter this is to us a certain amount of US parts. I belive the rewelded receiver will count as 1 part... along with the piston... etc.. etc...

Bottom view of bolt showing extended firing pin
Attachment 34248
New striker/hammer
Attachment 34256
showing fit with modified bolt carrier
Attachment 34255
Bottom of bolt carrier modified to never catch in open bolt position
Attachment 34254
Side view of modification
Attachment 34253
Magazine follower, bottom plate and trigger. Compliance parts.
Attachment 34252
New gas piston another US made part
Attachment 34251
rails shortened to allow install in semi receiver
Attachment 34250
channel cut in old hammer to allow passage of extended firing pin
Attachment 34249
channel cut in front of bolt to allow install in semi receiver
Attachment 34257

This is the part that seems a bit confusing, these are my assumptions of how this works. if anybody comes across actual instructions for installation please post here.
Not all of the parts shown here are required all the time.
Attachment 34260
The hammer has recesses for two springs and their guides
Attachment 34259
The top three parts shown separate are a reliability addition to reduce binding when the hammer moves forward and gives it more energy to solve light primer hits. Again I'm assuming as I have not seen these in other builds.
Attachment 34258
Showing a rough guesstimate of how the parts are supposed to fit together
Attachment 34261

The guide/spring/tube at the top require drilling a hole in the stock to install.
Most of this is compiled from a post I found once and cannot find again.

Ignore the previous post, all of the parts are required for this version, the big spring replaces the existing bolt carrier spring in the stock, the small spring, plunger, tube are used as the hammer spring to drive it forward.

You do not have to file a Form 1 (and pay for the $200 tax stamp) with BATFE to make your BREN. The Form 1 is for "making" an NFA weapon such as a SBR, SBS or silencer. Notice the term "making". The Form 1 allows you to "make" one (1) NFA weapon that is listed on the form. Making is for your personal use. Manufacturing is a completely different beast and it requires licenses from BATFE. These licenses allow you to "Manufacture" as many wepons as you want and they can be sold like any other firearm.

Regarding your BREN build the only things you have to make sure of is that your finished weapon is semi-auto only and it complies with 922r in order to make a "non-sporting semi-auto from imported parts". There are twenty (20) imported parts as determined by the powers that be listed in 922r. You can make a semi-auto rifle from an imported parts kit as long as there are NO MORE than ten (10) of the imported parts used in making the rifle. That means you must replace enough imported parts with US made parts in your build to bring the total of foreign parts down to 10 or less. Some firearms do not have all of the 20 parts listed in 922r. An FAL, for instance, only needs seven (7) US made parts because there are only 17 of the 922r parts in the firearm to begin with. The BREN has no trunion because it is an integral part of the receiver and it is not a separate part.

A listing of the 922r parts for a number of firearms can be found here:
Section 922(r) Parts Count

Unfortunately, the BREN is not one of the firearms listed.

I hope this helps.

Chris
aka CGinCT

I have been getting pretty good with my welder, I am making a jig to line up the receiver sections for welding. The jig will be a block of aluminum milled to fit inside the bren receiver with copper plate directly under where I will be welding. I guess I caught the bug, I also purchased a 1919A4 parts kit to make a semi auto beltfed.:D

Other notes, as I do not have a mill, I have taken the ill advised route of using my drill press and a cross slide vise as a light duty mill. It is barely stable enough to make the cuts from the aluminum.

Garth,
Good to see you doing it!
And yes... the 1919 is probably an easier build than your bren.
The "mill/ drill" press idea is for people who are desperate. Watch or the chuck could come out of the drive shaft. On most, they are only tapered fits. Fairly dangereous at high speed and the chuck comes off.

Looking forward to your Bren progress. I also need a jig, but haven't taken the steps to make my own yet...

I finally broke down and purchased a Harbor freight mini mill after breaking a few of the milling bits, as soon as the mill comes in, and I get it set up I should be able to finish the jig in one sitting(you need to go really slow with a drill press). I have also joined the weaponeer forum(same name) and will eventually duplicate my posts over there.

money well spent!!!! A mill and a lathe are so handy, you will wonder how you did with out.

Weaponeer is a good site... and I post there under the same screen name as here.

I also broke down a number of years ago and purchased the Mill/ Drill from Harbor Freight. It works fine for most milling operations. You just need to go slow, and keep that ROUND column tight. I suspect that you didn't get my model however, if you call in a mini mill. Just remember if you got the model I suspect, go real slow.

I also have added DRO's as $$ has allowed. These are battery operated gizmos, that have improved my accuracy, if not my machining skillls! LOL!

I look forward to your updates on both forums!

My SA kits slumbers yet in its box. As previously mentioned, I would like to go out and do the build as a .308, but did miss a group buy through one of the forums on a run of .303 to .308 barrel conversions (and barrel length and Flash Hider could be altered I believe).

Pics of bren jig, I probably should have measured more, the parts fit tight but the rails are a bit narrow. I have to modify it to complete the front weld. These are from before adding the denial pins, I had to add an additional short channel to clear those.
Attachment 39397
Attachment 39398
Attachment 39399

At this point I have all of the denial welds and pins completed, I have welded the back three sections and dressed up only the back weld. I am waiting for some better mill bits to clean the inside to make sure everything fits where its supposed to.

Hey Gartock......... You're another of those like the Centurion tank owner in Australia and the Half Track restorer on this site. You ought to put this Bren rebuild all into a readable format and when it's done, mistakes an' all, get it printed into a soft cover book to sell on to those who also want to do something similar. I did it with the No 32 scope book and look where it got me. They say if you want to become a poor author, start off as a rich one, self publish and become a poor one naturally!. No, seriously, that's what you ought to do, believe me. My friend did it with a restore-it-yourself book on MG Midgets

Not much progress on the bren, but I did complete the semi 1919a4, now building a tripod. I want to find a safe place to test it, so haven't fired it yet. I also purchased a semi-Madsen LMG, and had a blast at the range:) While I was there I met another member on this forum, I need to get back to building the Bren.
Attachment 41855
Attachment 41856

Quote:

---

Originally Posted by Peter Laidler

readable format

---

I tend to ramble a bit, I started keeping a binder with all of my notes, pics and ideas. I will post the contents in a roughly chronological order when complete. It definitely wont be bestseller material, but may make sense to somebody:D

I was practicing a weld with copper back plate. The copper was melted onto the weld and difficult to remove. Is this to be expected or am I doIng something wrong; to hot maybe. Once removed it cleaned up nicely but would be hard to get off while backing in a receiver.

If you start to burn through the copper it will stick, you can try going with thicker copper or let it cool a bit between passes. I am alternating opposite sides and going slow to try and minimize warping and shrinkage. I had burn through issues when I was trying to use brass as a back plate on another project. With my aluminum jig I can wipe off the burn marks, it hasn't melted at all.

I have to say that I truly admire your perseverance Garthok. Can we see a couple of up to date-ish photos of your progress. Thanks. When you hear a Bren roar into life for the first time again, you'll appreciate just how worthwhile it was. A bit like restoring a 750cc Norton Commando motorcycle engine and hear it roar again. No tinny Japanese screamer there, believe me!

I remember one day after rebuilding mine (the Commando that is.....) I was stopped at a busy junction, waiting to pull out, when a bloke in the car next to me slowly wound his window down and said to me '..... just for old times sake, will you blip that throttle once again, just so that I can drive home a happy man' He got his wish........

Well, I have the lower semi mod complete, the upper rails welded, the blocking pin for the bolt on the right side, the left side cut is right where I am placing the pin and will be added after tack welding. I stopped here after I realized the middle two parts are slightly off, im going to have to cut it apart and redo :banghead: at least there was progress...
Attachment 42767

garthok,

I was looking through this forum searching for ZB39 Mags for the Bren and saw your post. Rebuilding the MGS demills into a working semi-auto is a challenging task. The IO demills are much easier.

I noticed you have not yet welded the cut through the barrel socket. Here are a couple of tips that will possibly save you a lot of grief.
When you have the cut jigged up and ready to weld put the barrel in place with the barrel nut and take the bolt without the extractor in place and slide it in the reciever. Put an empty case or go gage in the barrel and slide the bolt up aganist the case (or gage). With pressure on the bolt the case should be held snuggly in place. If it is not check the two lugs on the inside of the reciever they should allow the bolt to go fully aganist the case head. If they do not reset your jigging until they do. They appear to be there to prevent the bolt from battering the end of the barrel. If they interfere with the bolt travel you will never be able to headspace the gun correctly. Once you have this set correctly check to be sure the mag can be inserted and the mag catch works properly. If the spacing for the barrel socket weld is not right the mag may go in but the catch won't work. These issues arise only in the MGS demill because of the location of the demill cut through the barrel socket.
I've built two semi-auto brens (USA). The MK II was a MGS Demill.

Keep up the good work,

Joe

The internal parts in the body you mention Joe are in fact the breech block stops are are there to stop the breech block from touching the face of the barrel. HOWEVER, if you cannot get CHS because it is always too great, then it was permitted to carefully stone back the front beating face of the breeck block so that you could get CHS AND that it would clear the barrel face.

That's a great idea to align it all up with a breech block and a CHS gauge. After all, that is the ultimate true-to-life alignment set-up!

This only applied to the 7.62mm L4 guns but the theory and practice SHOULD also apply to the old .3093" guns

Keep up the good work Garthock

Thanks! that looks like the hardest part to complete. I got lucky on my kit, they missed the actual socket and cut just behind it.

bump to read

As a matter of interest, a question........ If the gun body has to be cut into 3 or 4 pieces, why can't the gun be cut straight using a torch (or body) held in a rolling jig as used in cutting steel plate. Or better still, using a plasma / laser cutter. Or are the bubba type torch cuts meant to be like that, just to make life difficult?

What does the bump to read note mean tr63?

Quote:

---

Originally Posted by Peter Laidler

Or are the bubba type torch cuts meant to be like that, just to make life difficult?

---

The guns were meant to be destroyed Peter, they were never meant to be resurrected.

Quote:

---

Originally Posted by Peter Laidler

What does the bump to read note mean

---

It means he dredged up a thread from four years ago and brought it back to life...instead of reading and leaving it.

They used to cut them with a band saw which made welding so much easier. Then several years ago, ATF changed the receiver destruction requirement to three torch cuts removing 1/4" of metal each in the process making life much more difficult. After 1968 until May 1986, many cut Brens were rewelded into fully functional registered LMG's. I'd guess the majority were done in the 1980's when the kits became available in quantity. The double dovetail 1940 date gun that we changed the gas cylinder on several years ago was one of those. The phosphate and baked Suncorite 259 refinish made it look much better than it ever had although if you looked real close you could see where the welds weren't perfect. It hasn't changed the function though. It runs like a new gun at my friend's place in Virginia. I'll never forget that job. The long distance Armourer's course, unscrewing the original gas cylinder while my partner Craig held the huge torch on it and keeping it cherry red hot gave me a pucker factor of 12! If those fine threads had galled in my friends $25,000 gun, I hate to think of fixing that. Welding in a sleeve and rethreading etc, etc, etc.

Old treads like this one never get old . They are like a fine wine and get better with age .

I think the bottle is empty TR...?