Looking for Advice on New Rifle Design

[dreyfus]

I'm looking for advice on a new design that I have lodged a provisional patent on.

The action is quite unique. I have searched the patent literature extensively and haven't found anything similar. I won't provide great detail here- suffice to say it is something like a tilting bolt design without the bolt carrier.

Because the bolt does not require locking lugs it should be possible to produce a very cheap to manufacture bolt but I would like to make it even cheaper. I want to produce a gun that would be cost competitive with an SKS- hopefully in the $300 range (new), using AR-15 mags and specced for both military 5.56 and remington 223.

The aim is to produce a backup gun for the prepper movement who are currently unable to provide an AR15 for their whole family/friends and tend to purchase WWII bolt actions or SKS and low grade AK-47 variants. I think a very low cost semi-auto compatible with AR-15 mags and ammo would be very sought after.

The idea is not to make a gun able to survive 50,000 rounds, but maybe 10,000- even if it takes a waiver to be signed by the purchaser. Most of these guns will just collect dust waiting for Armageddon and that's easier to accept at $300 a copy than $800-$1000 a copy.

My ideas to simplify the bolt and rifle cost are as follows:

In many bolt designs, a considerable amount of material is machined from the base of the bolt to allow it to pass over the mag lips. I think it would be easier to use a stamped steel "sled" shape piece that attaches to the bottom of the bolt. Probably two pins would be enough. The sled would also hold a channel for a full length ejector rod. The face of the bolt accepts the forces of firing as per normal. The sled just rides on the rails, the ejector fits between the mag lips, picks up the cartridge and feeds it into the bolt face recess as per normal.

By using a simple spring steel hook extractor at the top of the bolt and combined with the ejector rod sliding between the sled and the bottom of the bolt, the action would provide a simple vertical eject.

The only machining I see as totally necessary would be the recess on the bolt face for the cartridge- but there would be no need for a sophisticated extractor and spring.

The firing pin would be hammer fired because this can exploit the economies of scale of numerous trigger groups on the market and keep the bolt simple.

I would like to know if this bolt would be better cast or milled in terms of cost. If cast, then the firing pin hole would need some kind of cast in recess to allow "gymnastic" fingers to insert a retaining spring on the firing pin and fit the assembled firing pin inside the bolt itself.

I'm also unsure if any cast bolt will need a minimal amount of machining anyway e.g. the firing pin hole may need to be drilled just to verify clearance. The pin holes for the sled attach to the bolt would need to be drilled as well as the hole for attaching the extractor spring. Pins may not be durable in these holes and hence they may need to be tapped for screws. Then there is machining the bolt face recess.

If all this amount of machining is required anyway, would there really be any cost savings from just setting it up in a CNC mill and letting the whole thing be machined?

I'm aware that large production runs significantly reduce per unit costs and also that Ruger have great expertise in casting - after a significant investment in the technology.

Comments welcomed.

 

[badkarmamib]

I think it would be a fine idea to make one for yourself, but, for $200 more than your goal, one can buy a mil-spec AR, and have parts commonality for however Armageddon lasts. Just my $0.02.

 

[barnbwt]

Cast parts are hard to make strong enough & require expensive molds. How about doing a prototype first, and see if the cost savings would be significant?

TCB

 

[dreyfus]

Thanks for that. Is the price you quoted for a built up Ar-15 (i.e. DIY)? I was hoping there would be more people unwilling to build up an AR themselves and more likely to buy something new off the shelf.

 

[dreyfus]

The problem with a prototype to estimate cost is that the price of one off components and labour (while u learn the design) doesn't generalise well to full manufacturing.

I'm wondering if anyone knows in ball park terms what % of rifle cost tends to come from bolt machining alone?

I would imagine with an AR-15 with rotating lugs, barrel recesses and cam etc that it would be pretty high.

 

[badkarmamib]

Palmetto State Armory frequently has sales that can get one a mil-spec AR for $500, and the only assembly is pushing 2 pins.

 

[ECVMatt]

I think one of the appeals of the AK and the SKS is that they can withstand thousands of rounds. Having a person sight a waiver that states their gun will break could be a deal killer as well. I understand your concept and I think you have some good ideas, but I would look to build durability into your design. I would look at something along the line of the M3 (Grease) gun. I think you want something that is cost effective, simple, and strong. I am not a prepper, but the ones I know are freakish about durability, parts, and being able to keep their systems running over the long term.

 

[taliv]

is it something that parts could be 3D printed?

 

[briansmithwins]

The action is quite unique. I have searched the patent literature extensively and haven't found anything similar. I won't provide great detail here- suffice to say it is something like a tilting bolt design without the bolt carrier.

One of the reasons that tilting bolt designs went out of favor is that they require a bigger and heavier section of the receiver to take the loads from firing. That increases weight and bulk.

In many bolt designs, a considerable amount of material is machined from the base of the bolt to allow it to pass over the mag lips. I think it would be easier to use a stamped steel "sled" shape piece that attaches to the bottom of the bolt. Probably two pins would be enough. The sled would also hold a channel for a full length ejector rod. The face of the bolt accepts the forces of firing as per normal. The sled just rides on the rails, the ejector fits between the mag lips, picks up the cartridge and feeds it into the bolt face recess as per normal.

By using a simple spring steel hook extractor at the top of the bolt and combined with the ejector rod sliding between the sled and the bottom of the bolt, the action would provide a simple vertical eject.

I suspect the time and effort required to get a two part bolt working right will be more expensive than just machining the whole thing from steel stock. Once it's set up machine costs are minimal on larger production runs. Plus you have to control the bolt length to keep headspace within spec. Plus steel itself is cheap.

Vertical ejection makes using an optic harder.

Just to be curious, is your design a self loading arm or manual?

BSW

 

[dreyfus]

One of the reasons that tilting bolt designs went out of favor is that they require a bigger and heavier section of the receiver to take the loads from firing. That increases weight and bulk.



I suspect the time and effort required to get a two part bolt working right will be more expensive than just machining the whole thing from steel stock. Once it's set up machine costs are minimal on larger production runs. Plus you have to control the bolt length to keep headspace within spec. Plus steel itself is cheap.

Vertical ejection makes using an optic harder.

Just to be curious, is your design a self loading arm or manual?

BSW

All good points. In a way, the tilting bolt design adds weight in the receiver that otherwise would be in the bolt. However the machining of the bolt can be simplified especially if compared to a rotating bolt and barrel recesses.

I agree that a large production run of bolts in a CNC setup might be more cost effective than cheap cast bolts assembled by cheap hands.

The vertical ejection I had in mind would incorporate a deflector hood or scoop as part of the top cover. That would ding cases to the right. Not elegant but it would prevent cases hitting an optic or my neanderthal forehead. It might be tough to provide sufficient clearance for the optic without being to high above the barrel.

The design is self loading and I will provide more detail in a separate post.

Thanks for your comments. V helpful.

 

[dreyfus]

is it something that parts could be 3D printed?

I wish I knew. I don't know if 3D metallurgy is strong enough for rifle barrels....

 

[dreyfus]

I think one of the appeals of the AK and the SKS is that they can withstand thousands of rounds. Having a person sight a waiver that states their gun will break could be a deal killer as well. I understand your concept and I think you have some good ideas, but I would look to build durability into your design. I would look at something along the line of the M3 (Grease) gun. I think you want something that is cost effective, simple, and strong. I am not a prepper, but the ones I know are freakish about durability, parts, and being able to keep their systems running over the long term.

Yes in general arms manufacturers want to be known for quality rather than cheap n nasty. And I have a fear that lawyers would swarm to a liability-fest. What's wrong with putting 20,000 rounds thru a 10,000 round action? What's wrong with putting a 10 ton truck on that 1 ton jack stand? I know....

The grease gun as a blowback weapon is limited to pistol calibres and I would want a 5.56 round for compatibility. Also I always found it odd that a grease gun on full auto was like most people in fast semi auto!

yes the quality thing is complex.

 

[dreyfus]

Palmetto State Armory frequently has sales that can get one a mil-spec AR for $500, and the only assembly is pushing 2 pins.

That's hard to beat. I have a bit of a marketing strategy to counter it...maybe. I'll explain in a separate post.

 

[ford8nr]

Don't know if there is a need
If your looking for a cheap semi I'm looking at a HiPoint at around 300.
If I'm looking for a cheap bugout 5.56 I'm looking at a base / composit lower, spec AR, factory assembled with tons of available replacement parts, even from salvaged guns at under $500 on sale.

 

[dreyfus]

Thanks for everyone's comments. Very helpful and informative.

I probably need to explain the second part which is the marketing strategy. As they say, if you have a better mousetrap then the world will beat a path to your door.

Except "better" is in the eyes of the beholder. Better could be more dead mice per hour or the fact that all mouse gore is hidden and a flashing light just tells you to take the box to the trash.

Here's my "better" based on some questionable assumptions:

First, the prepper movement (no disrespect to anyone) suspect that in any large scale calamity then their guns will be siezed by govt- black rifles first.

My design is semi-auto, 5.56, uses AR-15 mags but is designed to be as unlike an AR-15 or any assault rifle as possible in appearance. Lots of cheap wood or wood-like synthetic, flat sided like a lever action. Closer to grand dad's deer gun than tacti-cool.

Second, although gas operated there would be a retrofit kit available that blocked the gas port, fitted a new pump foregrip and incorporated a pump mechanism. Not hard to do and really a remington 7615 is not much different from an AR-15.

Why do this? Because the prepper can hold up his civilian retrofitted pump action former semi-auto and say "officer, it's just a pump action". Any black rifle modified similarly would still look like a black rifle.

Would it even matter? Would authorities be that dumb? Or would they just sieze anything with a barrel? I don't know. Who does? But preppers may see some sense in caching a cheap as dirt semi auto that uses AR-15 mags, looks like a deer rifle and can be converted to pump if there is a general ban on semis.

Maybe credible, maybe not.

So really this issues are whether the design can be built cheaply enough.
Whether the cheapness can avoid liability issues.
Whether preppers would cache a $500 DIY AR-15 in preference.
Whether they think the deer rifle appearance is really an advantage
Whether they think the pump action conversion is really an advantage.

And whether all of this is any advantage at all compared to just caching a half dozen mosin nagants.....

Thanks again

 

[briansmithwins]

All good points. In a way, the tilting bolt design adds weight in the receiver that otherwise would be in the bolt. However the machining of the bolt can be simplified especially if compared to a rotating bolt and barrel recesses.

A rotating bolt can be easily machined from round stock and then heat treated. A receiver that has to take stress from a turning bolt is likely going to be much harder to make and be heavier.

By using a rotating bolt and barrel extension (like the AK47, M16, or G3) you can make the receiver out of sheet steel, aluminum, or plastic. The stressed parts are easily manufactured and cheap, which is why pretty much everybody makes self loading rifles that way.

BSW

 

[Kendal Black]

I'm a fan of firearms innovation. A lot of it amounts to flashes in the pan, so to speak, but some of it gets traction and becomes the new normal. Everything accepted now as a matter of course was once an innovation.

I have a question. What is the cost differential if you make your simplified action to last 50,000 bangs instead of 10,000? If if is a question of a few dollars per rifle and half a pound in weight, it might actually be a more viable product if you toughen it up a bit. It seems to me that it would make the rifle more reliable over all, even if it is never shot a whole lot--as you note, many guns are not. The simplified tilting bolt with its "sled" underneath seems to be what offers most of the cost savings in your design. Making it a bit more robust does not sound like it would add much expense. Of course I have not thought that matter through: That's just how it seems off the top of my head.

I think top eject will be fine, for the older Winchester 94's work that way; it just limits your options in affixing sights.

 

[barnbwt]

The problem with a prototype to estimate cost is that the price of one off components and labour (while u learn the design) doesn't generalise well to full manufacturing.

I'm wondering if anyone knows in ball park terms what % of rifle cost tends to come from bolt machining alone?

I would imagine with an AR-15 with rotating lugs, barrel recesses and cam etc that it would be pretty high.

Far, far too many variables with what paltry info we have here to even pretend to make an estimate about anything. Sorry. Prototypes are worth ten thousand ideas, and their entire purpose is to answer the questions you have.

-Will it work?
-Will the machining operations I used to build this thing cost too much?
-Are the right materials I need available at the right price?

All that is up in the air so long as the idea is still an idea, and will never get answered.

TCB

 

[barnbwt]

One of the reasons that tilting bolt designs went out of favor is that they require a bigger and heavier section of the receiver to take the loads from firing. That increases weight and bulk.

To be fair, it is possible to do a front-tilting bolt like the VZ52 rifle and end up with a small barrel extension or receiver lug near the breech. Same goes for the VZ58 locking piece scheme, whose lug surface is about 3/4" from the breech. More complex, but possible.

I wish I knew. I don't know if 3D metallurgy is strong enough for rifle barrels....

Selective laser sintering of metals (3D printed steels) is how you get a $40,000 Hi Point. Literally the most expensive fabrication method there is, especially for volume (for a one-off, drop-forging is only slightly worse, but per unit cost is halved the instant you make a second part with the dies)

So really this issues are whether the design can be built cheaply enough.[how can we tell you with no information?]
Whether the cheapness can avoid liability issues.[how can we tell you with no information?]
Whether preppers would cache a $500 DIY AR-15 in preference.[If your marketing hinges on evasion of the law, I don't see why they wouldn't evade it with a more popular/proven/quality/effective tool]
Whether they think the deer rifle appearance is really an advantage[Why not simply market the design on its own merits, rather than what it doesn't have in common with an AR? I for one prefer the slab-sided look to deflector bumps & forward assist warts]
Whether they think the pump action conversion is really an advantage.[It's not, seeing how pump-action ARs only exist in places like England and Connecticut, but the ability to readily switch between them can have advantages]

TCB

 

[dreyfus]

A rotating bolt can be easily machined from round stock and then heat treated. A receiver that has to take stress from a turning bolt is likely going to be much harder to make and be heavier.

By using a rotating bolt and barrel extension (like the AK47, M16, or G3) you can make the receiver out of sheet steel, aluminum, or plastic. The stressed parts are easily manufactured and cheap, which is why pretty much everybody makes self loading rifles that way.

BSW

Good points. However I'm not looking to compete with an AR-15 on weight or even performance. Something heavy and in the ballpark of performance s fine given that this is (hopefully) an armageddon weapon, although undoubtedly someone could possibly still try yo hunt deer with it in 30 years time. Even without armageddon.

 

[dreyfus]

Far, far too many variables with what paltry info we have here to even pretend to make an estimate about anything. Sorry. Prototypes are worth ten thousand ideas, and their entire purpose is to answer the questions you have.

-Will it work?
-Will the machining operations I used to build this thing cost too much?
-Are the right materials I need available at the right price?

All that is up in the air so long as the idea is still an idea, and will never get answered.

TCB

True to a large extent. However some things seem to be known or at least are known to be more difficult than others- even without prototyping- and would suggest they should not be tackled lightly.

For example a blowback design using rifle cartridges is accepted to be silly because of the required bolt mass. No prototype required.

Equally I have never heard of a rifle bolt assembled from stampings presumably because the metallurgy is not up to it.

However my question is really around a bolt assembled from castings- which tend to be metallurgically robust. The issue is whether this could be made cheap enough to provide a weapon for a very niche market caching low quality weapons for the apocalypse.

Like many questions it seems to be asking how long is a length of string but peoples' insights are interesting anyway.

 

[Mosin Bubba]

At this point, the AR is so mature that it's just really hard to compete with. Like others have said, I can jump on the internet right now and get a 16" carbine for 500 bucks. I can drive right down the road and get a $600 DPMS in half an hour. Both of those guns will shoot probably no worse than 3 inches at 100 yards, run with 99.9% reliability with any commercial ammo I feed them, mount any optic with Picatinny rails, and I wouldn't even worry about a round count unless my barrel is shot smooth.

I'm all for new ideas, and I'd be interested to see what you have planned. But man, with a field as technologically mature as small arms and a with product that's been polished for 50 years, it's really tough to see how a new design would beat out the $500 AR.

If you want a cheap beater to keep running through an apocalypse, rifles don't come much tougher than Russian surplus.

 

[WestKentucky]

I like the idea, and it seems sound. I would be concerned however. Looking at other "non ar" rifles trying to squeeze in alongside the AR shows us where the market is. Your competition is in the sks rifles you already mentioned, keltec, ruger mini, etc. step out of the .223 game and you join hi point, just right, more keltec, and so on. I am sorry to say it, but I'm afraid your good idea is going to be lost in the weeds of current products before it even gets a fair shake. Don't get discouraged though, your ideas are good and your sure to hit a home run at some point. This one I think would have been a hit 30 years ago in the world of thousand dollar AR rifles and 700 dollar used pickups.

 

[dreyfus]

Interesting comments. In general, reliability costs money and it is often hard to predict how much reliability those extra dollars provide without exhaustive testing and even that would need to span environments/conditions to be really useful.

In general, a single unit machined bolt should be stronger than one pinned together however removing the necessary material in the single unit should be more expensive (so I thought) than assembling cast components- especially if the assembly labour is cheap.

To me it boils down to constant cheapish cost of production via rough casting and assembly (which doesn't scale very well) vs large up front tooling costs that deliver declining per unit production costs with volume. The former has the advantage of lower startup risks.

Clearly this is not something I would personally do, but perhaps a manufacturer somewhere would appreciate the lower capital risk incolved.

The latter approach of sophisticated, mass machining has the advantage of better quality products but my idea is to produce a kind of disposable gun bought based on cost and limited lifespan.

As to the question of "why not beef up the design and just make a normal gun?" my answer is that I suspect that reaching the robustness of a fully machined bolt via an assembly would create a very large action would make it far too heavy to be practical.
Also why build a gun for the same market as everyone else? I don't my innovation would be any better than other actions, just cheaper to make- maybe. So why not exploit this advantage rather than take on 40 years of AR-15 development head to head?

Rather than produce yet another design to compete with assault rifles in their own market, why not just produce a very cheap assault rifle that doesn't pretend to be a black rifle?

The easy engineering approach is just to underscope the performance both for cost and competirveness. If 50,000 rounds is normal, just meet a requirement of 10,000.

As far as liability is concerned, plenty of products have limits on proper use. Many cars have subsize spare tires meant to just get you to a garage. If someone drives 1000 miles on one, blows it out and is killed, is the manufacturer sued for not providing a "proper" tire?

 

[dreyfus]

I'm a fan of firearms innovation. A lot of it amounts to flashes in the pan, so to speak, but some of it gets traction and becomes the new normal. Everything accepted now as a matter of course was once an innovation.

I have a question. What is the cost differential if you make your simplified action to last 50,000 bangs instead of 10,000? If if is a question of a few dollars per rifle and half a pound in weight, it might actually be a more viable product if you toughen it up a bit. It seems to me that it would make the rifle more reliable over all, even if it is never shot a whole lot--as you note, many guns are not. The simplified tilting bolt with its "sled" underneath seems to be what offers most of the cost savings in your design. Making it a bit more robust does not sound like it would add much expense. Of course I have not thought that matter through: That's just how it seems off the top of my head.

I think top eject will be fine, for the older Winchester 94's work that way; it just limits your options in affixing sights.

Interesting comments. In general, reliability costs money and it is often hard to predict how much reliability those extra dollars provide without exhaustive testing and even that would need to span environments/conditions to be really useful.

In general, a single unit machined bolt should be stronger than one pinned together however removing the necessary material in the single unit should be more expensive (so I thought) than assembling cast components- especially if the assembly labour is cheap.

To me it boils down to constant cheapish cost of production via rough casting and assembly (which doesn't scale very well) vs large up front tooling costs that deliver declining per unit production costs with volume. The former has the advantage of lower startup risks.

Clearly this is not something I would personally do, but perhaps a manufacturer somewhere would appreciate the lower capital risk incolved.

The latter approach of sophisticated, mass machining has the advantage of better quality products but my idea is to produce a kind of disposable gun bought based on cost and limited lifespan.

As to the question of "why not beef up the design and just make a normal gun?" my answer is that I suspect that reaching the robustness of a fully machined bolt via an assembly would create a very large action would make it far too heavy to be practical.
Also why build a gun for the same market as everyone else? I don't my innovation would be any better than other actions, just cheaper to make- maybe. So why not exploit this advantage rather than take on 40 years of AR-15 development head to head?

Rather than produce yet another design to compete with assault rifles in their own market, why not just produce a very cheap assault rifle that doesn't pretend to be a black rifle?

The easy engineering approach is just to underscope the performance both for cost and competirveness. If 50,000 rounds is normal, just meet a requirement of 10,000.

As far as liability is concerned, plenty of products have limits on proper use. Many cars have subsize spare tires meant to just get you to a garage. If someone drives 1000 miles on one, blows it out and is killed, is the manufacturer sued for not providing a "proper" tire?

Sorry for the double post