Ask a gun designer a question

Is there anything you want to know about the science of gun design? Tobias Obermeit is a design engineer at Kel-Tec and is their chief designer on the Kel-Tec PMR-30 project. He has kindly agreed to answer a set of questions which I will select from the comments below.

Feel free to post questions about gun design in general, the PMR-30 pistol and the PMR-30 SMG.

UPDATE: The questions have been answered here.

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • Carl

    Why is there no .22lr version? What are the problems (if any) with a large capacity .22lr magazine?

    How does it operate? I read somewhere that it is a mix of blowback and some sort of locking system.

  • Ben

    I’m not trying to start a flame war but I’m curious:

    As a gun designer, do you think the future of assault rifles is in the bullpup design? And what did Kel-Tec learn about bullpups in the development of the RFB?


  • Tim

    Are there any plans for a carbine version like the old Grendel R-31?

  • Colin

    2 questions, if I could?
    Could you use opposing magnets on an assault rifle/smg operating system (one on bolt carrier other in the receiver) to reduce “felt” recoil?

    From a multi-calibre point of view, If you had a bullpup in 762 how easy would it be to change to 556 – different lower, same upper and bolt carrier?

    I’m trying to design one as a hobbie, but being in the UK I have no access to any firearms, so things like material sizes, etc, are a complete guess!

  • Dom

    I’ve noticed that certain combinations of barrel length, action, and caliber are hard to come by. Say, for instance, a 2.5″ semi-auto .45 ACP. Why is this, exactly? What envelopes are you pushing to design a gun like that?

  • Wade

    How much commonality is there between the new design and the old Grendel .22 WMR pistol?

  • Mouse

    How did he get into the field. That is something that I’m genuinely interested in knowing, because it’s what I intend to do. I’m going to work on a degree in mechanical engineering.

  • SpudGun

    How realistically far away are we from replacing gun powder with water (i.e. hydrogen fuel cell technology)?

    Are H&K angry with Kel-Tec for stealing their handgun design aesthetic for the PMR-30?

    and following on from that –

    Are Kel-Tec angry with Ruger for stealing their P3AT design aesthetic for the LCP?

    Will Kel-Tec be re-jigging the SU-16 to a more traditional AR set up for the upcoming Army trials?

    Kel-Tec firearms have always had a reputation for being ‘cheap and cheerful’, what steps are the company taking to reinvigorate the brand, improve materials, QC, etc.?

  • Ray

    Would there ever be an opening in the UK market for Kel-Tec long barrell pistols? Be intertesting to see what you guys could come up with.

    • Ray, pistols are banned in the uk as are centerfire semi-auto rifles so there is no market for kel-tec

  • Todd

    I realize that it sort of defeats the purpose of the PMR-30 but are there any plans to produce a low-cap (10 round) magazine for those of us who live in capacity restrictive states like NY?

  • Pete

    Will there be a carbine version in the future (like the SMG but s/a)?

    Also, I would buy one tomorrow if it was .22lr. I’m not so interested in .22 magnum. Will there be a .22lr version?

  • Jesse

    Not a question more of a please make this, I found the biggest concern with concealed carry for me was the width of the gun, not the height or length. To that end the PF-9 is a great carry gun because it’s thin but if it were a bit longer and taller (say similar to that PMR-30 in those dimensions) I could get a gun with a better sight radius and a few more rounds in the mag which would be the ideal carry gun in my opinion.

  • Is there a plan to make the PMR-30 SMG fully automatic?

    In general, where is the starting point in designing a gun? What component is designed last?

  • Ryan

    When is the gun going to be available? I used to own a Grendel P30, and had great expectations for it. Unfortunately it didn’t function very well. What design elements were used from the P30, and what has been done to improve it’s shortcomings (mainly the magazine)?

  • Guy

    How do you make a good gun? Do you start from scratch or base it on a previous moddel?

  • Variance

    Please give a brief overview of the typical firearm design process, with some details pertaining to the beginning of the process and initial development of a design.

    (Not a question, I know, but as an engineering student, this is what I’m most interested to hear about.)

  • Freiheit

    What are some of the biggest advances in how a gun is designed? CAD/CAM? Available materials? R&D? Other stuff?

    As a shooter, what should I know about how guns are designed that will help me use them to their best effect?

    When shopping for a new gun, what are the signs of a good design? A bad one?

  • WeaponBuilder

    When prototyping your weapons, what materials does Kel-Tec use for their reinforced polymer casting moulds?

  • What are the names of your softwares that you use to design your pistols?

  • ericire12

    Why has Kel-Tec not pursued a lawsuit against Ruger for copying the design of the P3AT

  • KC

    I know the PMR-30 SMG stock is primarily for testing but are there any plans to ever release it for those of us that want to put the PMR-30 on form 1?

    what is the general process of developing a firearm like?

  • TAP

    Do you believe that the .22wmr is an adequate man-stopper to be used as a primary self-defense round? Is the PMR-30 intended for self defense duty?

  • Roman Empire

    What do see the main use for the PMR SMG? The round is not known for its great stopping power or armor penetration. So who will it be marketed to?


  • H.L.

    Does form follow function? Where do you place ergonomics when conceptualizing a design, before or after caliber or other design aspects?

  • Zach

    Question 1: plastics/polymers are a relatively new material, with materials like nylon 6 seeing widespread use only in the last 60 years or so. How much do we know about their long term durability? Should a buyer expect a Kel-Tec, Glock, or other nylon-6 framed pistol to be completely reliable and as good as new in 30, 50, or 100 years? I ask this because we know that steel doesn’t deteriorate over time if protected from corrosion, and we know that some plastics used in other applications do become weak and brittle in just a few decades, even in inside the house use.

    Question 2: It seems that 4140 steel is the current material of choice for nearly all non-stainless barrels (with a few being 4150) and for a lot of receivers, including some parts of the PMR30. Is 4140 used because it’s all around the best material in terms of strength and durability, because it’s the best material within cost limitations, or for some other reason?

    Question 3: The vast majority of polymer framed pistols use nylon-6 or some variant, but until recently Ruger used a polyurethane “Isoplast” polymer for its pistols (P95, P97 using it, SR9 apparently using nylon). Why has nylon-6 been the overwhelming choice over other polymers?

  • Kyle

    Tobias, thanks for fielding questions.

    Do you have any word on .22 Mag loadings from any manufacturers that are optimized for pistol-length barrels?

  • Greetings from Texas,
    There has been speculation in government, primarily anti gun circles, about making it impossible for a firearm to be fired by anyone but the owner. I believe one system was a ring the shooter had to wear. Some science fiction writers have approached this as well.

    I am not a fan of this idea but it is interesting. Do you feel a firearm with such safeguards could ever built practically.

  • Does Kel-Tec have any plans for a larger caliber handgun?

    What about a rifle chambering 6.8mm?

    How does one get into the firearm manufacturing industry?

  • Darrell

    Why so short a barrel? Will there be a longer barrel/target version?

  • RSP

    (First of all, sorry about my english, it’s not my mother tongue :P)

    I’ve always been interested in firearms design, and i just wonder if you could explain me a little about the process behind the creation of a gun: How many people is involved? How many time does it take to be fully developed? Which are the security measures taken to avoid it to fail during operation?

    I was amazed with the impressive PMR 30 SMG prototype, but I´ve heard there are still some troubles with malfunctions. It has something to do with the rimfire ammo it’s using?

  • Dave

    How difficult is it to get into the industry? My son has a pretty fair understanding about how things go together, and an interest in firearms. What sort of schools/training get a person to be a firearm designer?

  • Vitor

    How do you guys feel about the great reception given to the RFB and the reputation chaning from “budget company” to “the innovating company that solved the bullpup flaws” ?

  • Hogan

    I am curious about the early versions of the p-3at. Why did the original slides have the 2-part muzzle ends? Was that ever deemed unsafe, as the modern versions are now solid?

  • Bryan S

    Is it harder to find acceptance with a revised design over a new to market design?

    How does (BATFE and state) regulation fit into pricing?

    Thanks for the opportunity!

  • richard

    I’m wondering who, in your informed opinion, are the great gun designers of all time?

    Some of the names come to mind as potential candidates:

    John Moses Browning, Gaston Glock, Mikhael Kalishnikov, Eugene Stoner, Gerald Bull

  • Wolfwood

    How does a gun get from idea to production? After all the calculations and computer design, do you build a bunch of slightly different ones to see how they work, or do you take one design and just continually refine it?

  • Raoul O’Shaugnessy

    How does this gun differ, other then cosmetically, from the Grendel P30?

  • Christian

    What advice would you give to someone like me who would like to become a gun designer when they grow up? And what type of degree do you need to become a gun designer?

  • Kace

    What sort of material advances are just on the horizon for smallarms development, and what will these advances do that contemporary materials cant?

    Will we ever see a 7.62x39mm SU-16 that takes AK mags?

  • Ulysses N. Owen

    Nice Pistol&SMG, but why does the RFB poop brass?

  • Jonah

    What would be the minimum number of parts required to make a safely working auto pistol?

  • Miles vining

    I would like to know what are some of the issues and problems associated with the manufacture and sale of high capacity magazines of all types. Both currently and historically. I collect hi cap mags whenever I can and would like to research them more in depth, thank you very much.

  • What are the obstacles and considerations that go into ramping up production rates? It is clear that the market demand for the Kel-Tec RFB is on the order of at least several thousands of units, yet it’s trickling out to distributors so slowly you’d think they don’t even begin to mine the ore to build a new unit until the previous one is out the door! Likewise, the Sub2000 has a niche all to itself with (from what I know) demand in the tens of thousands of units, but even though it’s a mature design it’s being produced a prototype rates.

    Once you have a producible design in high demand what keeps you from ramping up production to meet that demand? And don’t you realized economies of scale from doing so?

  • Clodboy

    I’m curious on the idea-generating process in a company as innovative as Kel-Tec.

    Do they use advanced brainstorming techniques and market research? Or is it more of an “Eureka!” thing (“I just saw my kid play this sci-fi FPS on his XBox where your character has a bullpup sniper rifle and thought “how cool would that be in Real Life?” and just drew the first sketch of the RFB on a paper napkin”)? Or simply personal experiences with other manufacturers’ products that make you think “we can do better than that”?

    Actually, do all the people involved in the design have an extensive firearms background? Or is it sometimes those with little prior firearms experience that bring in ideas from “outside the box”?

  • Andre’

    What schooling should I get in order to become a designer for a major gun manufacturer?

  • HeavenlySword

    Did you guys solve the power problems? Is the RFB in full production yet?

  • Ernunnos

    Yes, how does it operate? I love the .22 WMR, but I’ve always been frustrated with gun designers who assume that because .22 LR semi-autos are blowback, .22 WMR should be too. Or at least, blowback with some kind of additional retardation that never seems to work too well. We have plenty of known mechanical solutions to locking a chamber, why all the resistance to applying them to .22 WMR? By all reports the PMR-30 finally has a mechanism that works reliably, but it’s sad we had to wait this long.

  • Nathaniel

    Mr. Obermeit, I have questions about the RFB, which appears to be one of the more successful forward ejection bullpup designs of late. Did you choose tilt-locking specifically because of the extractor arrangement, or because perhaps you were working from a bullpupped FAL? What design problems did you encounter with forward ejection? What did you learn about the dreaded “triple feed” that forward ejectors like the F2000 seem to be prone to? Did you experience problems with friction, and with rounds popping out of the extractors? Finally, a minor question, what made Kel-Ted refuse Magpul’s offer to do the furniture on the RFB?

    I have been involved in an initiative to design a new bullpup service rifle for caliber greater than 5.56mm, and I would very much like to glean some knowledge from Kel-Tec’s experiences with the RFB.

    Best wishes, and thanks,

  • Steven

    Like tools, guns are designed and built to perform certain functions or fulfill specific roles. What purpose, function or role does the design of PMR-30 pistol and SMG fulfill?

    When designing the PMR-30 pistol and SMG to fulfill said tasks, what part of the design did you focus on first? (Caliber, Action, Barrel, Magazine,…etc)

    What did you consider when you expanded your design from its first step? Was this process different from your usual method?

    What problems or hurdles did you face with your initial designs? How did you overcome them?

    How do you forsee the PMR-30 pistol and SMG effecting the future of firearms and the current market?

    Does your design directly compete with any currently on the market, and what does your design bring to table out do your competition?

    What is/was your favorite part in the designing new firearms?

  • shankbone

    What was the most difficult challenge to overcome in designing this handgun?

    As a designer, which comes first, form or function?

  • zeonxavier

    The option for a longer barrel on the PMR-30 would appeal to me. Here’s my question:

    Has anyone at Kel-Tec contacted ammunition manufacturers about making .22 WMR more suitable for use in handguns?

  • Underwhelmed

    Kel-Tec should offer a handgun in 7.62×25. I think a modern US made handgun in this chambering would have a market.

  • 1. Have you ever run into a situation where you’ve had to shelve a design because the materials and techniques needed are just too expensive or just not technologically feasible at this time? Any examples?

    2. What do you think will be the next great leap forward in gun design? I’m not talking about layout changes (bullpup) or caliber/bullet shape.

    3. What kind of background do most gun designers have?

  • Dashiell Andrews

    I think that if they used their double-stack rimfire magazine design on a 22LR rifle it would be very successful. Will Kel-Tec be doing this in the future? I know I would buy one. Thanks

  • Anton

    Will this model be available in the Netherlands at some point?

  • Marc

    I’d like to know how you come up with new projects. Is it something that just comes to your mind or does your company do market research to find what people want and then try to fulfill these wishes?

  • Kyle Huff

    Q: Is the Beretta rotating barrel system a good idea, or not? e.g. Cougar and Px4.

  • Jonathan

    How do you become a a gun designer? What kind of back ground do you need? What inspires you when you design a gun?

  • Why is it difficult to produce a semi-auto HMR .17?

  • Why has every comment I’ve seen on this gun asked about a .22LR version, good Lord, there are other calibers out there you know? .22Mag is pretty awesome and I for one would trade in my Mark III for one of these anyday.

    My question for the gun designer is this, every time I look at a new gun lately, they have a completely different grip pattern than any other gun. With grips on pistols having been around a long time, why hasn’t the industry figured out the “best” way to ‘wrap hand’? I mean, I can understand having different widths and inserts to accomodate big hands vs little hands, etc, but the texture and cut pattern of the grip should have been figured out by now don’t you think?

    I’m a big fan of Kel-Tec btw, and if you ever need someone to come down to Florida and help test guns, just shoot me a note!

  • Greetings and thank you for giving us an opportnity to ask questions!

    1) In your design, how often do you have to consider individual state gun laws restricting what you can do? Is normally driven by economics (completely understandable) or some other factors?

    Living in NJ, a non friendly state to gun owners, we are the only ones restricted to 15 round magazines. Other states restrict to 10 or have no restrictions. This made it economically non profitable for some companies to produce 15 rounders, they simply do 10 or max capacity allowed by design. Do you have similar considerations?

    2) Will we ever see a KEL-TEC revolver? Why or why not? Ruger (LCR), Taurus (Judge), and Chiappa seem to have made them commercially viable again.

    Thank you,

  • Pete

    How do firearm designers deal with thermal expansion of metal? Size of parts and tolerance between parts take into account thermal expansion? Is this thermal expansion significant or neglectable?

  • Way excited about this

  • I’m wondering if there is truly a market for a .22 SMG. It seems like a lot of fun for super-plinking (especially with that sweet stock that holds three more mags), but I can’t for the life of me come up with a military or police application.
    Is this a high-tech Class III experiment, or is there truly a use for a low-powered cartridge SMG?

  • Anon

    Do you design specific pistols for people with smaller hands? If so, how does that work– do you have someone with small hands handle mock-ups or do you just size down existing grips?

  • Nick T.

    I would like to know how something like the PMR 30 comes to be.

    Did they see a gap in the market, and decide to fill it? did they receive questions or suggestions about it? or was it just created from a designers idea that was deemed good enough to try?

    I have always wondered what the though process is that goes behind the designs of modern firearms

  • Jordan

    What was your most difficult challenge in designing this pistol? What were some of the benchmarks that were handed to you? Was there anything you didn’t achieve that you set out to do for this model? Thanks.

  • Redchrome

    How do you measure the ‘timing’ of a breech-locking mechanism? I.e. how do you make sure that the bullet has left the barrel and the pressure dropped acceptably before the cartridge case starts to be pulled free of the chamber.

    I can think of several ways; but I want to know if there are some I haven’t thought of.

    Also, how do you come up with a first guess as to how heavy the bolt/slide should be, both for locked-breech designs and blowback designs? Can you give some example calculations?

  • Bill Lester

    Beyond the chambering and large capacity magazine, what if any technical similarities are shared between the new PMR-30 and the old Grendel P-30?

    BTW, I can’t wait to get my hands on a PMR-30!

  • Andy

    What do you think is the place of polymers in firearms? Handguards, sights, and butt plates are one thing, but do you think in the future we’ll start seeing all-polymer trigger components (even the hammer) or even bolt carriers? In other words, where would you draw the line as regards to its usefulness?

  • Lloyd

    I’m a student. How do I get your job? Did you do mechanical engineering in undergrad or grad school or get into the industry some other way?

  • Jesse Rivera

    What sort of market or “niche” research goes into the planning stages of gun design? I’m sure for every gun actually made there are dozens of designs and ideas floating around so what makes a design take the leap to reality?

  • Michael

    How much influence do the departments of accounting, finance, and marketing have on weapon designs. Enthusiasts often lament the discontinuation of a firearm that developed a small fan base, but proved to be unsuccessful profit-wise for the firm. We also often witness me-too type copies of successful designs being brought to market by competitors.

  • Matthew S.

    What “outside the industry” design influences do you guys take into consideration for your own projects?

    What do you consider the top shelf pieces of firearm design & why?

    What considerable advances do you think will be prevalent in the industry 10 years, 20 years, from now?

  • R.A.W.

    First, I would like to thank Tobias for agreeing to field some of these questions, and thank Kel-Tec in general for being so open about the art of firearms design. This is not the first time they have gone out of their way to answer questions from the public about the specifics of their designs. The earlier interview about the RFB at snowflakes in hell:

    Is definitely worth the time for anyone interested in this sort of thing. This sort of attempt to have a public forum to help demystify and educate is really outstanding.

    I would like to know what the designers at Kel-Tec think of the relative merits of the various methods of bolt lockup. Since Kel-Tec has now designed and produced rifles using the Stoner-Johnson rotating bolt (SU-16) as well as a tilting bolt (RFB), I think their designers would be well qualified to talk about the pros and cons of each. I’m very curious to hear why they think the Stoner-Johnson style bolt is the most popular in new designs while the tilting bolt has fallen by the wayside, particularly since Kel-Tec appears to be going in the opposite direction, and using the tilting bolt on their newest rifle design!

  • What are the 3 most important factors that make a gun, any gun, accurate?

  • Red

    How do you get into the business of gun design?

  • steve b

    “Ray, pistols are banned in the uk as are centerfire semi-auto rifles so there is no market for kel-tec” Steve

    not the case steve, here in the UK we’re very good at exploiting technicalities, anything with a barrel over 12″ and with an overall length of over 24″ is classed as a rifle, so we (they) just make the handguns longer

    (proof: )

    Here in Northern Ireland, it’s not an issue, as due to our colourful past, we’re still allowed handguns for self defence and target shooting/practical pistol

    • steve, I had no idea about those long barreled pistol! Very interesting.

  • Gator

    I am a Firearms Instructor with a Federal Law Enforcement Agency. From widely available studies, the effectiveness of the 12ga far exceeds that of any other round available to law enforcement. Unfortunately, tube magazine fed 12ga weapons are limited to five rounds for any weapon of suitable length for CQB. The Saiga has brought the idea to market of a box magazine fed 12ga, but it has yet to be adopted by many Law Enforcement Agencies and the manual of arms is significantly different from the AR platform, which most Law Enforcement Officers are familiar with.

    Can Kel-Tec fill this gap in the LE and Home Defense market?

    If not with an AR based 12ga platform, them possibly an RFB variant in 12ga?

    Thank you very much.

  • Ed

    Considering the popularity of the Taurus Judge and various 45LC/410 derringers, would a modern Le Mat revolver be feasible? The combination of a shotgun and revolver would be great for hikers and campers. A break action revolver with 22mag/410 combo would be fine for snakes and small game. Thank You.

  • El Duderino

    I’ve posted many times on the KTOG forum on what Kel-Tec SHOULD be designing…

    I really like the .22 / .410 revolver idea! Although I think Taurus would make this before Kel-Tec would. The new polymer Judge does have a Kel-Tec feel to it though.

    PMR-30 is the perfect pistol to release right now. So many of us are afraid of another AWB-like law (with no sunset provision), and if we get our PMR-30s and mags now, we’ll have an irreplaceable item. There is nothing wrong with marketing uncertainty — insurance, all-wheel drive, and home defense shotguns come to mind. And, well, it looks to be a lot of fun to shoot!

    I’m no engineer (that was my old man), I’m a salesman — how does one become a field salesperson for a big firearms manufacturer???

  • Dave

    What is it about the 1911 that prevents someone from making one that runs like a Glock at Glock prices?

  • Jim S.

    Why has the Pat-3 never jumped up into the 9x19mm caliber?

    The PF9 was close, but it was still too bulky, especially for pocket carry. I feel that there could easily be a 9×19 version that would increase the magazine well, frame, chamber etc by 2mm (9×17 (.380) to 9×19) and strengthen said frame to accommodate the more powerful ammo. There’d be springs and stuff involved too, but from a common person point of view, it seems fully reasonable.
    Just think, a 9×19 cartridge would be easier to find, have a wider array of choices in defensive ammunition, and would have a significant increase in muzzle velocity (or at least I’m told). Did I mention the ammo would be cheaper too?
    At the moment, pocket 9×19 lovers seem to have the Rohrbaugh R9 as their only choice. at the $1000 mark that I’ve seen them go for, a person could but 4 Pat-3s. Why not have Kel-tec slightly beef up the Pat-3 and severely undercut the R9, give me a reliable pocket pistol in a caliber that I can find for a reasonable price, and make me happy in general (and send me a free one for giving them the idea 😛 )

  • Jim S.

    Also, please replace all “Pat-3” with “p3at”…my dyslexia gets the better of me…

  • Bill Lester


    I pocket carry a Kel Tec P-11 all the time. It’s no larger nor heavier than a steel J-frame.

  • Tungsten

    What’s the best advice you can give to a high school Senior who wants to go into gun design?

  • Marisa

    When will you be making one in 5.7x28mm?

    5.7×28 is capable of delivering a 40 grain bullet at about 2050~ FPS from a 5 inch barrel when given a proper powder charge. These velocities are obtainable through reloading, though FNH does not load their SS197 to this pressure, due to fears from gun grabbers, because at that velocity the bullet would defeat a level II Kevlar vest.

    The PMR-30 and .22WMR deliver a 40 grain at about 1230 FPS, according to a Kel-Tec rep’s post on the KTOG Forum.

    Its clear that 5.7 would be a far better choice for defense, and that .22LR would be a far better choice for range use due to price and availability.

    Why .22 Magnum?

  • Bob

    I have a few questions:
    1. when designing a gun do you need to be creative or do you mostly only use technical knowledge?
    2. what can an average gun designer expect to make for a living?
    3. how much college is needed for a career in gun design?
    4. is there very much room for advancement or many opportunities for jobs?

  • Garrett

    As a student in high school interested in gun design , I have a few questions for you:
    1. Which College/School did you attend?
    2. What was your major in college?
    3. Did you start out as a gun designer at Kel-Tec or did you advance from another job lower in the company?

    Thank you so much for taking questions, your advice will be really helpful.

  • mrw

    Did these get answered in another thread I missed?

    • mrw, he is very busy the moment but he will be getting back to me soon (I hope!) with the answers.

  • Tyler

    I am looking for help identifying a pistol my grandfather has. It has an Over and under barrel marked – Bar Pistol -. Pivoted flat four chambered cylinder makked-with Deutschland and Belgian Patents. Cylinder release catch at the top of the standing breech. Folding trigger walnut panel. Markings on the gun are: the number 278 ,England 11998, russland, nord amerika. 25 caliber bullets used. Any information would be greatly appreciated. 

  • Redchrome

    I’ve seen pictures of such a gun, but can’t find a link right now. It was made in the early part of the 20th century, I think in Austria. I have it in my head it was an early Steyr-made pistol, but I may be totally wrong on that.

    Try asking over at

  • Axel

    What kind of educations are common among your engineers? How many engineers were working on the PMR during the development period?

    / Engineering student interested in firearms design