Gunsmithing How to build a gun (design)

[wolfenstien]

I know this has probably been asked a Million times, but lets do it one more time. I want to build a firearm. In particular a rifle. But I don't know how. The gunsmithing books I have seen so far cover maintenance and barrel and stock work. But I haven't been able to answer the following questions.

How do you build an action so that you can set your headspace correctly?

How do you decide how to attach your trigger assembly to your bolt assembly and most importantly make that combo safe?

I want to build a scratch built 50 bmg, I don't mind starting smaller, but I just don't have the answers to all the why is this part of the trigger like that type questions.

Any books on there dedicated to firearms design not so much how to fix, but how to design a safe and functional firearm? So you start with a hunk of metal and we cut here and here with an explanation of why. Mostly looking for bolt and action design I guess.
Thanks all

 

[LWILLIAMS]

Re: How to build a gun (design)

Good luck finding the answers to your questions.

 

[seanh]

Re: How to build a gun (design)

I'd start by finding blueprints of the general firearm design you're interested in. If you don't already know proper machining techniques, you may want to take some classes in that...maybe shadow a machinist.

headspacing- hint go / no-go gauges

you've kind of got a loaded question here. It's doubtful that a gunsmith will give you all the answers due to the liability issues, Heat treat for example...do you know this?


Check your local laws on what you're wanting to do

 

[CS223]

Re: How to build a gun (design)

There are a number of print sets available for .50BMG builds. The Maadi Griffin is one, can't recall the other one off hand. These would at least give you some guidance on the materials and hardening criteria if you didn't what to follow the plans exactly. Do a search on Scribd probably fin e plan sets there.

 

[LRI]

Re: How to build a gun (design)

Assuming you have machinist experience:

Latch onto someone with lots and lots of experience.

Choose materials carefully and learn about heat treatment.

Good luck.

C.

 

[karagias]

Re: How to build a gun (design)

Hire a mechanical engineer. Rifles are machines and mechanical engineers design machines.

 

[gunnergirl81]

Re: How to build a gun (design)

Sharpen your Google-foo, grasshopper, and you will find what you seek.

http://action_enterprise.tripod.com/FiftyPro.htm
http://www.amazon.com/50-Caliber-Rifle-Construction-Manual-Follow/dp/1581603460/ref=pd_sim_b_2

And these guys can fill you in on the detail from their experience:
http://www.practicalmachinist.com/vb/gunsmithing/building-maadi-50-bmg-126350/

Why was the girl able to find all this? Hang your head in shame boy.

 

[wolfenstien]

Re: How to build a gun (design)

Wow never thought I would get so many responses so quick. Thank you all for your input. Machining background limited, but I can hold my own. I have a lathe and full size Bridgeport of my own. Material properties arn't the problem. I am a Senior in Mechanical engineering so I have the classroom background as well as some experience there.

Its more the fit form and function that I am looking for. I mean most people say, avoid the trigger and design it for something off the shelf. (BORING). I just want to know. Then I want to do it myself. Never hurts to be in the know.

Sorry guys, but the college classes just don't give you the knowledge you need to get it done. It akes some hands on experience that I just don't have. I have the Maddi Griffin designs as well as the Gun metal designs and the holmes I have also been in touch with Mark over at SERBU.

I think you are right though. I need to get in tight with a gunsmith who already has years of experience and just absorb. That way I can ask questions as I go. I have several barreled actions, but I have never taken one apart, because I didn't want to buy a head space gauge. Not to mention I want someone who know what they are doing willing to walk me through it the first time. I guess I will just keep looking around local. I feel like this is a dying art.

Thanks for the input. Let me know if there is someone on here willing to be bombarded with questions as I finish my design. BTW I am in no rush I have been starting and stopping the BMG project for over a year now. I like my face just the way it is. I don't want to blow it off cause I didn't understand something.

 

[jwSubMOA]

Re: How to build a gun (design)

Howdy. I designed and built my 50bmg,some photos are posted on this site. I have been a machinist for nearly twenty years and gunsmithing for much of that. I also have an engineering background.I'll give you a couple pointers. Design it for an off the shelf trigger,I used a Jewell for a Remington 700. There is NO point to building your own just for the sake of doing it. Use a Timney for a Mauser to make it even easier.Check the Lilja Barrels website for some articles and discussion about bolt thrust and design. Research what some quality 50 actions are made of. To make the job easier and in my opinion get better results, use fluidized bed heat treatment as you can finish your critical parts with minimal overstock and finish it quickly after heat treat. As far as I'm concerned you MUST design your bolt in such a way that the firing pin is captured and cannot touch the primer until the bolt is closed. Study how a Mauser bolt does this. If you do not and you have an Out Of Battery Detonation you will have a no good,awful, very bad day. Design a good muzzle brake,and don't just copy the neat looking brakes you see on many 50s. Do a search for artillery muzzle device technical papers and pay attention. Good luck!

 

[Stonewall2]

Re: How to build a gun (design)

Action Build Log


Check Benchrest.com also.

Glenn

 

[kortik]

Re: How to build a gun (design)

Breathe,

There is no way on the face of the earth you'll find an experienced gunsmith (rifle builder) who'll have time to educate you how to build a .50 cal. from the scratch.

If you want to play with "gun design", start with some standard configuration of reliable firearm, modify things here and there, and do not touch action and other stuff which happens to be under considerable stress. You got lots of good advice, but remeber, firearm, .50 cal in particular, is in fact a controlled explosive device. If you make a mistake, it may kill you. Stay safe, my friend.

 

[STR]

Re: How to build a gun (design)

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TheodoreKaragias</div><div class="ubbcode-body">Hire a mechanical engineer. Rifles are machines and mechanical engineers design machines. </div></div>

You wouldn't happen to know a really good one, would you Ted?? Love your rings!!

 

[monteboy84]

Re: How to build a gun (design)

There's a lot more to it than a design that functions, it has to not blow up in your face, which requires some rather involved calculations and process work to say the least

Not saying it can't be done, but ask how to do it is the first step of a very long process. Firearm manufacturers have far more resources than you or I, and they still tend to spend several years in the design process of any new firearm. They though, have the ability to recoup this investment by selling a great number of guns following the original design.

-matt

 

[chpprguy]

Re: How to build a gun (design)

lurk around here a bit..

http://www.homegunsmith.com

 

[hero's machine]

Re: How to build a gun (design)

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: chpprguy</div><div class="ubbcode-body">lurk around here a bit..

http://www.homegunsmith.com </div></div>

Yup...been done a good many times there. Some really Sharp talented guys.

 

[Clark]

Re: How to build a gun (design)

My father responded to requests for quote from Detroit Arsenal and designed the M55 with a copy of the book "Hayes Elements of Ordinance". That was his first gun design. A lot of the patents he got on that gun he used on the M107 and M110 designs.

My brother saw a picture of an 1831 Haston percussion cap pistol and made one as a shop project in the 10th grade. He only had a pic of the right side, so that is the only side that looks correct. He designed his own lock with coil springs lying around in the garage. The barrel is seamless tubing.

I just saw that pistol. It has been in someone else's basement for 40 years.

 

[Thaddeus Bookend]

Re: How to build a gun (design)

You also may look up some of Bill Holme's works on the subject. If I remember correctly, he has a book on this exact topic. Now, I am not a machinist in any way, shape, or form, but he seems to explain things in a logical manner. Granted, he is also not using the most advanced tooling, but his principles seem sound. And as always, double check your answers with another source. Just my $0.02, from looking into this myself a while back.