Building a 4 Bore

[Big_bore]

Hello guys! So for back story, I am a big bore rifle fanatic. Ever since I learned about stopping rifles I've been hooked and started building my collection ever since. I've shot and owned many big bores in my short life starting from 45-70 all the way up 12 Gauge from $#*! (12 gauge wildcat). The mighty 4 bore has always been at the top of my "need to have" list. Unfortunately, I am not a wealthy man that can drop tens of thousands on a rifle, so it's always been out of reach. I've contacted some makers to inquire about a custom build and was quoted $5000+ not including materials and a several year wait. I figured my best and only opportunity to own one of my dream rifles is to build it myself.

To be clear, I've never built a muzzleloader, so all of this is completely new to me. I have picked up a couple of books to study to help aid me in my quest, however. Luckily for me, I am a very quick learner, a good fabricator, and am pretty mechanically inclined  given my profession. Additionally, I have access to a machine shop and machinists at work to help install the powder drum and various other parts that need precision. I can silver solder/braze as well, so I'm sure that will help with installing underlugs and sights.   

So, with all that said here is my plan. The barrel I plan on using is a Krieger made out of chrome molly. The blank comes as a straight contour at 29" with an OD of 1.45" with a groove diameter of .950". The plan is to have a gunsmith cut the barrel down to 26" and thread for the breach.

For the breach, I am wanting to get 1.5" chrome moly round stock, thread it and bring down the OD to match my barrel on the lathe, and then cut the tang section out on a mill. My question regarding the breach is heat treatment. The stock I'm looking at comes annealed. What kind of heat treatment is required for the breach?

For the stock, I'm looking for a really dense, tight grained blank. I've had a little bit of experience inleting, and I have to say I don't look forward to that part. I strongly believe that is going to be 95% of the work required for this project. Any tips to make inleting easier for a beginner is much appreciated. 


For the locks and triggers, I am undecided on my route at the moment. I know that I am wanting a percussion cap lock, but that's about it. A set trigger would be awesome for this, but if it's extremely complicated I'm ok with just a regular trigger. 

Not really modeling my build off of anything in particular, but I do like the English style rifles.

Sorry for the long post guys. I look forward to the build and all the headaches that come with it. I've wanted a 4 bore ever since I learned about them, so it will be a dream come true.

If any of you gents could offer any tips for a novice builder, or if anything I just said makes no sense, please let me know! Thanks guys!

[Craig Wilcox]

Welcome to the Forum, Bigbore!  Pretty good place to find a lot of your answers.  You will need approx. 3 tons of patience with your first build, and it is good that you have a goal in mind
Try to budget a certain amount of time EACH DAY to your build - accept no substitutes!
I've never tried to build a barrel or a breech from 4130.  I know that quite a few barrels and breeches have been built from 4140.
But I have sure welded enough 4130!  Before I retired, I built quite a few airplanes, and several had 4130 tubular steel frames.  Never "heat treated" any of it, but as a part of welding I would normalize the joint - just keep it enveloped in flame, slowly pulling the torch back.  TIG welding we didn't worry due to the Argon gas envelope - it always flows 10-15 sec after you kill the arc.  And cutting and filing always went easy, as I never came across any hardened steel.
There are plenty of experienced builders more than willing to give you good advice.  Be sure to thank them for their time.

[T*O*F]

I have access to a machine shop and machinists at work to help install the powder drum

You do not want to use a powder drum with that set-up.  You want an English hooked patent breech and tang.  Unfortunately Track of the Wolf used to be the only supplier 1-1/2 and 1-1/4 breeches, but no longer carry them.  The foundry that supplied them has gone out of business.  They can be fabricated.  Strength is an issue.

[smylee grouch]

Hi big bore and welcome. Just a suggestion here but build more than one-start off with something like a 12 bore and then go up to the big guy. A flintlock, IMHO would be easier to do. A solid pattent breech with at least a 1 inch dia. breech thread, good solid dense wood, wide and tall butt (2&1/4 x5" high). Just a few of my thoughts for what its worth.   

[Big_bore]

I have access to a machine shop and machinists at work to help install the powder drum

You do not want to use a powder drum with that set-up.  You want an English hooked patent breech and tang.  Unfortunately Track of the Wolf used to be the only supplier 1-1/2 and 1-1/4 breeches, but no longer carry them.  The foundry that supplied them has gone out of business.  They can be fabricated.  Strength is an issue.

Not contesting this, just curious as to why? My only reason originally with not doing a hooked breech is complexity in machining. Do you know of anywhere else I might find that style breech in the size I am needing?

Like I said, if you say it won't work I certainly believe you. Just trying to learn the how and the why

[Big_bore]

Hi big bore and welcome. Just a suggestion here but build more than one-start off with something like a 12 bore and then go up to the big guy. A flintlock, IMHO would be easier to do. A solid pattent breech with at least a 1 inch dia. breech thread, good solid dense wood, wide and tall butt (2&1/4 x5" high). Just a few of my thoughts for what its worth.   

Thank you for your suggestions. A 12 bore would certainly be fun, but I already have a rifle that fills that niche, however it is smokeless powder. I am pretty much immune to recoil at this point in my life... my 12 gauge rifle has more than 200 lbs of free recoil with full power loads.

I am going to tinker with a traditions kit that I am getting for free. It should help me polish my inleting skills a little bit.

If you have any idea where I can get a breech like that, that would be fantastic! If not, I'm sure I can fabricate one if I had a smaller one to go off of.

Thanks for the help!

[Longknife]

Welcome Big Bore, My wife says I'm a BIG BORE too!!!! ,,,,, I will post a link at the bottom of this post for a guy you need to talk to, Any way You really need to find and copy an original rifle so yours don't come out looking like ,,,,,,Frankenstein!!! Too often new builders mix in components and styles in their builds  and they look fine to themselves   but turn out Hideous to people that have a little bit of experience!  This would be a good one to copy::::NOT MINE!!  ....Robert Hughes FOUR bore)













https://stolzergunsmithing.com/contactme.htm

[Big_bore]

Welcome Big Bore, My wife says I'm a BIG BORE too!!!! ,,,,, I will post a link at the bottom of this post for a guy you need to talk to, Any way You really need to find and copy an original rifle so yours don't come out looking like ,,,,,,Frankenstein!!! Too often new builders mix in components and styles in their builds  and they look fine to themselves   but turn out Hideous to people that have a little bit of experience!  This would be a good one to copy::::NOT MINE!!  ....Robert Hughes FOUR bore)













https://stolzergunsmithing.com/contactme.htm

Thanks for the tip! That is a beautiful rifle! Mr. Stolzer is actually one of the guys I contacted for a build. His work is certainly worth the price, so I'm not saying he's too expensive. I just can't afford it. I wonder if he would be interested in making a breech, or at least offer me some advice. Thanks for the help!

[WadePatton]

The guys here are going to try to steer you into making a gun that is safe and bears a strong resemblance to original guns of the flintlock/percussion era of Early America. (I was a bit resistant to their tutelage and therefore my first gun isn't as "TN" as it should be-all these years later I get it.) The reason is twofold as I see it: First because that's what we're mostly about, and that doing variations on theme really only make sense once you've got a good grasp of the themes involved; secondly to help you not beat yourself up too much years later for building a "fantasy gun" that sticks out like a busted thumb any time you have it around knowledgeable historic gun aficionados. Of course any gun with a long barrel and archaic ignition sticks out considerably at the local range-that won't change no matter what you build. 

Here "fantasy gun" means cobbling something together that has major stylistic and other variations from what was actually used BITD.  The more you  know, the more subtle these things become, and you can fret over those later, if you make another.

If you haven't yet, check out the tutorial section here.  Also check the classifieds regularly for instructional books/videos, appropriate parts, or maybe a big gun.  They all get traded eventually.

Welcome and enjoy your new pursuit, there's a LOT to digest, so don't get in a rush.  You'll be doing some woodworking and finishing too.  Carving and engraving can be hired out.

PS: You might consider doing it in a flintlock, as that gives a longer time-frame (historically/stylistically-but i'm no big-bore expert) as well as simplifies the breech. 

[Scota4570]

1 1/2" barrel?  You will want to taper that.  That would be awkward if left non tapered.  Best to do that before you shorten it.  I'd probably thread it for the plug, make a plug to turn in the lathe dog, Make a center for the bore.  Then taper it by off setting the tail stock in a beefie lathe. 

[Bill Raby]

   The next video series that I will be doing is building a 4 bore rifle. I will be starting work on that one in a few weeks. I would advise against building a 4 bore for your first one. smylee grouch is right. Start off with something a bit more normal and save the big one for when you have a bit more experience. I already have all the parts and they added up to several times the price the price for a typical long rifle. This is your dream gun. Do you really want to spend that kind of money on parts before you are sure that you can actually build a really nice gun? Save the dream gun for when you have a bit of practice. You are looking at building a gun that can hurt you.

   Here is the big question. Do you want to BUILD a 4 bore or do you want to HAVE a 4 bore? Don't build a gun unless building is what you want to do. You will NOT save money by building it yourself and probably not any time either. It is going to be a rather complicated project. Your inletting will have to be very well done. If the inletting behind the breech is not perfect it is going to break chips off the wood when fired. Or shatter the stock. There is a whole lot of recoil going into that one small area. Its not possible to put in a front lock bolt. One lock bolt is the only option. Inletting the lock will have be well done or the lock is going to wiggle around.  With a project like this you just can't be sloppy with anything. A 4 bore with a heavy load is going to have around 300 ft/lbs of recoil energy. Everything has to be done right. That means lots of practice. And time.

   Don't forget about tools! They can add up fast. Not a problem if you plan on building guns for the rest of your life. But tools to build a gun cost a lot more than the gun you build with them. Then there is the time. If you took the time it would take you to build that gun and spent that time delivering pizza instead, you would have enough money to pay a professional builder with years of experience.

   If your dream is to build a 4 bore, start with something a bit simpler and work your way up to it. If your dream is to just have a 4 bore, then start saving your money.

[WadePatton]

Well-stated Bill.  I'm in agreement.

[Scota4570]

"One lock bolt is the only option. "  I made a back action lock for mine. 

I have shot mine quite a bit.  It weighs 17#.  Past about 350 gr of 1F powder recoil gets unmanageable for me.  Using 2F will cause the ball to accelerate faster and the recoil becomes vicious.  My barrel is about 36".  I question the OP's idea about gong only 24".  Velocity might be low.  On mine with the longer barrel and the 350 gr load trajectory is very curved already. 

[Bob McBride]

   The next video series that I will be doing is building a 4 bore rifle. I will be starting work on that one in a few weeks. I would advise against building a 4 bore for your first one. smylee grouch is right. Start off with something a bit more normal and save the big one for when you have a bit more experience. I already have all the parts and they added up to several times the price the price for a typical long rifle. This is your dream gun. Do you really want to spend that kind of money on parts before you are sure that you can actually build a really nice gun? Save the dream gun for when you have a bit of practice. You are looking at building a gun that can hurt you.

   Here is the big question. Do you want to BUILD a 4 bore or do you want to HAVE a 4 bore? Don't build a gun unless building is what you want to do. You will NOT save money by building it yourself and probably not any time either. It is going to be a rather complicated project. Your inletting will have to be very well done. If the inletting behind the breech is not perfect it is going to break chips off the wood when fired. Or shatter the stock. There is a whole lot of recoil going into that one small area. Its not possible to put in a front lock bolt. One lock bolt is the only option. Inletting the lock will have be well done or the lock is going to wiggle around.  With a project like this you just can't be sloppy with anything. A 4 bore with a heavy load is going to have around 300 ft/lbs of recoil energy. Everything has to be done right. That means lots of practice. And time.

   Don't forget about tools! They can add up fast. Not a problem if you plan on building guns for the rest of your life. But tools to build a gun cost a lot more than the gun you build with them. Then there is the time. If you took the time it would take you to build that gun and spent that time delivering pizza instead, you would have enough money to pay a professional builder with years of experience.

   If your dream is to build a 4 bore, start with something a bit simpler and work your way up to it. If your dream is to just have a 4 bore, then start saving your money.

Wise words Bill. Very wise indeed.

[Bob McBride]

In most instances I’m a fan of the ridiculous. Though I’m not much interested in shooting a 4 bore. I’ll settle for watching.

[Daryl]

Big_bore - your .950 groove dia. barrel will have, if only .012" rifling depth, a bore of about .925" which makes it a large 6 bore (.919"), not a 4 bore. Even a 5 bore will have a bore dia. of .977", much larger than the groove dia.
ML's are "gauged" by the bore, not by the groove dia. and even at that, the barrel is not a 4 bore.
A solid breech is recommended., of course, not a drum, although the breech pressures will be very low, compared even to a smaller cal. rifle. It is unlikely you will surpass even 8,000psi with normal loads.

Here is a 6 bore (top rifle) English gun, compared to smaller bored rifles.



This is Dan's English rifle, a 16 bore:




And mine, a 14 bore.

[smokinbuck]

Bigbore,
You might look at the actions built by Pete Allen. I did a .72 caliber with an Oregon barrel that looks good and hopefully will shoot as well. Solid breech, good lines and appears to be very durable.

[Bob Roller]

Please notice in that cased gun there is an ABSENCE of a drum and nipple and for good
reason. That style of breech is designed to minimize the pressure on the base of the nipple
and a drum and nipple is a lawsuit waiting to happen.If it blows out it's an oddly shaped
projectile that will be capable of severe injuries or death to anyone it hits.
The IS a GOOD reason NO English rifle was made with a drum and nipple.
Bob Roller

[Joe S.]

My two cents,have a look in the mirror,do I have the skill sets required, patience and perhaps most important the ego required to ask for help,advice if I get in over my head.Only you know the answers to those questions, if yes,I say jump in the deep end,heck of a first build.As far as building a gun that can hurt you,we all do that with any build if you don't do it right,your only building a bigger one.If it's what you wanna do, go for it,do your homework and build it right,build a safe gun,good luck.

[davec2]

When I was a lad of about 13, and having been a shooter all of my very young life, I loved shooting.  So much so, and with the blissfully uninformed courage of youth, I would step up to fire anything that had a trigger on it.  A friend of my Dad's was an African big game hunter and brought a side by side .557 magnum elephant gun out to the range one day.  He asked me if I wanted to shoot it and I jumped at the chance.  With the rifle tightly held to the shoulder, and leaning well into it, I lined up the sights and pulled the trigger.......have you ever heard the expression that someone was hit so hard "he left teeth and eyeballs behind" ?  Well, I think whoever came up with that expression must have been at the range that day and watched me shoot that gun.  Within a few minutes many of my teeth were bleeding at the gums and within a half an hour I had two black eyes....all just from the recoil.

Now one of the beauties of a muzzle loader is that you can, within limits, load it up or down to suit your tastes and the situation, so a 4 bore doesn't particularly frighten me.  In fact, I have built and shot three 4 gage blunderbusses over an entire range of what I would call light to ludicrous loads.  The light loads are very pleasant to shoot.....the higher end loads not so much.  But then, these are very short barrel smooth bores firing a handful of 00 buck and not designed to drop an artillery shell sized projectile on a target at 300 yards.  Just guessing, but ballistically the lighter loads in a rifled 4 bore might require a very tall rear sight to get a quarter pound ball out to 50 yards.  So the heavier, much more uncomfortable loads may need to be the required norm.

I say go ahead and build anything your a mind to......but I had to laugh out loud at Hungry Horse's post:

"Great ...posterity gets another ugly gun, in a ridiculous caliber, that's been shot and dropped four times."         

[smylee grouch]

I love this topic, not because I ever plan on building a 4 bore or even shooting one but to hear the antidotes of others which reinforces my resolve to stick to my varmint gun, a 16 bore. Thats four times smaller than the Big Boy and thats fine with me. My round ball will come in at around 400 or so grains and the powder charge will be some where from 3 1/2 drams to 5 drams but like Dave C. just said you can if you want shoot reduced loads with out losing your teeth.   

[sz]

I have made several of them.
4 bore in action by Steve Zihn, on Flickr
P2040007 by Steve Zihn, on Flickr
P2040006 by Steve Zihn, on Flickr
P2040003 by Steve Zihn, on Flickr
IMG_0104_zpsb2d73ef9 by Steve Zihn, on Flickr
2005 8 by Steve Zihn, on Flickr

These and about 8 or 9 others.


If you PM me I'll give you my phone number and you can call as you go.  I'd be happy to give you some pointers. I am not taking any work now, and will not be for a few more years because my back-log is too long for someone of my age,  and I need to catch up, (I don't want to die before I get all the guns made I have promised) so I am NOT going to offer any work for you, but if you want to know how to make them I'd be happy to help you with advice and tips.

[smylee grouch]

Steve, that first picture says volumes and BTW, nice work on those rifles.

[LynnC]

A generous offer from an accomplished builder. Great people on this forum.

[Joe S.]

Steve, that first picture says volumes and BTW, nice work on those rifles.

Yes,a mans rifle indeed.That ones not hanging in the ladies room