Pellet adaptors in firearms: Part 1

by Tom Gaylord
Writing as B.B. Pelletier

A history of airguns

This report covers:

  • Revolver kits
  • Benefits
  • Performance
  • Long guns
  • Adaptors
  • Dedicated long guns
  • Zimmerstutzens
  • Airguns are better

Here’s a bad idea that refuses to go away — shooting pellets in firearms. This takes several forms. I will do a quick look at the most popular ones in this report.

Revolver kits

One kit fits revolvers. It has an insert barrel that fits into the barrel. It’s fastened into a larger-caliber gun like a .357 Magnum by some sort of friction fit.

The one I owned was made for a Smith & Wesson 586/686 revolver with a 6-inch barrel. Yes, they are that specific. The pellets fit into cartridge-shaped modules that accept a primer at their other end. They are then loaded into the cylinder and are fired either single action (cocking the hammer first) or double action (just pulling the trigger). The kit I had came with primitive tools to extract and reload the primers after firing.

Benefits

The benefits of such a system were touted as a cheaper way to practice with your service gun, safer and quieter operation, and the ability of shooting your firearms in your home. Let’s look at how my system performed.

Performance

My kit was in .22 caliber and of course the insert barrel was a liner for a .22 rimfire barrel. So the bore was way too large for the pellets. Read yesterday’s report to understand why. The primers launched the pellets at anywhere from 200 f.p.s to 475 f.p.s., depending on many variables like the friction fit of the pellet in the cartridge, how easily the pellets entered the barrel and the power of the primer, and even the type of primer that was used (regular or magnum).

After the pellet left the cartridge it jumped the gap between the cylinder and the breech and then you hoped it hit the rifled barrel insert dead-on, because if it didn’t it sheared off part of the head or part of the skirt or both. Accuracy was on the order of 4-6 inches for 5 shots at 10 feet. Yep — I said 10 feet! I tried shooting from farther back but then I sometimes missed the whole bullet trap!

Long guns

The same concept is offered now and again for long guns. Sometimes this is a conversion kit that is installed in a firearm as a cartridge adaptor like the handguns. The firearm barrel is used in this case, because only correct caliber firearms are selected for this. I will explain in a moment. Other times the long gun is actually dedicated to the system and cannot be made to shoot firearms ammo again. I will look at both types. Adaptors are first.

Adaptors

This approach uses adaptor “cartridges” to shoot pellets in centerfire firearms. Someone gets the idea that the bore of a .223 Remington (or a .22/250. or a .222 Remington or a .220 Swift, etc.) barrel is .22 caliber, so wouldn’t a .22 pellet launched by a rifle primer be a good thing? No, it wouldn’t! Centerfire .22 bores are even larger than rimfire bores, with a diameter that’s running 0.224-inches. These guns don’t even suffer shooting rimfire cartridges in them very well, to say nothing of the much smaller .22 caliber airgun pellet.

But kitchen-table tinkerers get excited by such things and nothing can stop them from experimenting. I found one company is still making these conversion cartridges today. Their website is hosed-up and won’t allow me to order the .222 Remington adaptor I wanted, but I was able to order a conversion cartridge in .223 Remington caliber, so I will try it in my AR-15 that veteran readers know is very accurate. Sportsman’s Guide carries a limited number of conversion cartridges, and I ordered one.

I hope it works, but past experience tells me not to expect much. I also want to check things like the discharge sound level that they claim is like a breakbarrel spring rifle (yeah — right!). The unit uses a number 209 shotgun primer that is way more powerful than a conventional large rifle primer, so it should really give the pellet a boost! We shall see.

Dedicated long guns

There have also been a number of long guns that were dedicated to the use of either primers or percussion caps to power pellets. The most recent one that I know about was the Prime Gun that came out not too long ago (early this century?). It started as a single shot firearm that was converted to shoot pellets. The problem was, once a gun is manufactured as a firearm in the U.S., it cannot lose that designation. So the gun they were converting was still a firearm. That caused a problem with the distribution (needs to go through federal firearm license holders), so thay drafted a letter to the BATF to get a waiver for their gun. But that wouldn’t have helped, because, by using the power of a primer, their gun was already a firearm! The definition of fireams includes words about “using the gasses generated by a chemical explosion”. That’s what primers do.

Zimmerstutzens

That brings me to my final observation. Primer-powered guns date back to almost the first use of the percussion cap. I know that there were guns powered just by percussion caps as far back as 1842, and the percussion cap itself only became generally popular around the year 1820, give or take a few years. It was invented more than a decade before then, but took time to evolve into something that was easily used by most people.

The early primer-powered guns were not actually Zimmerstutzens, which I will discuss in a moment, but they shared the primer-powered aspect of design with them, and there is no other good name that I can think of for this class of guns. They were parlor guns or perhaps small science experiments that a shooter could use for plinking. Bear in mind that the 1840s and ‘50s were the days before the invention of the .22 rimfire cartridge (1856), and also a full half-century before accurate airguns existed (1905), so these guns were accepted more for the fact that they worked at all rather than the fact that they were accurate.

The Zimmerstutzen is a highly refined version of a primer-powered gun that came into existence at the end of the 19th century. Zimmerstutzens are accurate small-caliber guns that were safe enough and quiet enough for use indoors, and they evolved into target rifles that were used in competition at 15 meters. Some writers say they were for Schuetzen shooters to come indoors during the winter, but if that is true they soon became a class of gun of their own. They still exist today and there are still matches for them in Germany.

That’s as far as I’m going to go with them, but if you want to know more about Zimmerstutzens, read this article that is very thorough. I will tell you that a Zimmerstutzen was on my bucket list from the time I was 13 until I finally got one, sometime in my late 40s. By then, however, I knew what a 10-meter air rifle could do and the Zimmerstutzen seemed antiquated and clumsy by comparison.

Airguns are better

Yes, primer-powered guns do work, but they cannot compete with airguns. They are louder, nowhere near as accurate and far more expensive to shoot because of the cost of the primer or percussion cap. Add to that the fact that they are technically firearms and you have no reason to shoot them beyond sheer curiosity. I no longer own a Zimmerstutzen so I can’t test that for you, but I will test the adaptor that lets you shoot pellets in a firearm. Then we will all see together.

68 thoughts on “Pellet adaptors in firearms: Part 1

  1. B.B.,

    Nice article. Over here we have the reverse. Some people turn airguns into firearms, which is very illegal. Although single shot and only .22LR still illegal. This partially explains also why our barrels and most local pellets are larger than usual. Firearm ownership here has some very tight hoops to be passed before a citizen can legally own one. So some enterprising individuals convert for some hunters/poachers use. This practice is frowned upon generally by the community as that the accuracy is subsequently lost when used as an airgun and the airgun becomes an illegal firearm.

    Siraniko


  2. BB,

    Very likely the idea of the adapter cartridge is not going to go away, but keep popping up on occasion as the price of ammunition continues to rise. With the growing popularity of big bore air rifles, we will likely see adapter cartridges in larger calibers soon.


  3. BB,

    This is way off subject but, Hard Air Magazine will soon be reviewing the Diana Bullseye ZR scope mount and I was wondering if you are planning on having an up close and personal look at one in the near future?

    I know when they first brought these out there were some issues with them and I am wondering if that has been addressed. A mount such as this would be great on uber magnum sproingers if it is dependable.

    Oops. OK. I see you have at least looked at it, but I do not recall a review. Is this due to senility?


  4. B.B.,

    Interesting article. I am sure that many readers will be interested in your .223 test.

    Perhaps even more interesting was the link. I clicked on it and wondered where I was at within the P.A. site. Backing out, I see this link is at the bottom of the main page under “articles and catalogs”. Is this something else that you do at/for P.A.? Some articles looked a lot like this blog,… while others,…. like the link,…. where far longer and much more detailed than any article here.

    Chris


  5. BB,

    I had another thought. What is there to prevent a moron from adding a little gun powder between the primer and pellet of that adapter cartridge or that primer rifle? I can see some idiot making a youtube video worthy of an episode of “Outrageous Acts Of Science”.

    Another thought. Do you think that shotgun primer will produce enough gas to at least partially cycle your AR? Maybe you should add a few grains of powder in there to help it do such? Perhaps you can video it? 😉


  6. Pingback: Pellet adaptors in firearms: Part 1 | Airguns: Air Rifles and Pistols

  7. My brother loaned me his Marlin 39A .22 rimfire rifle, with my thought that I could shoot CB rounds (in a suburban environment) and gain a lot of power compared to an airgun. On shooting over a chronograph, the results were terrible, and accuracy similarly poor compared to my .22 springer air rifle (which was unexceptional). I tried several types of “quiet” rimfire without much improvement in accuracy. The result was also louder than an air rifle. And this rifle was quite accurate with ordinary LR ammo. My conclusion was that the ammo was inconsistent.


    • JerryC,

      I was curious about how consistent .22 rimfire ammunition was so I spent a morning testing several popular brands/types with my chronograph.

      The results were shocking – extreme spreads were anywhere from 50 to 120 fps over a ten-shot string! I was expecting much better than that.

      Hank


      • Hank, the serious rimfire shooters spend enormous amounts of money to get their target grade ammo. Rimfire rounds are compromised by inherent elements of design that require great effort to control. My brother spent a few years chasing the best rifles and ammo, and it is possible to get good results, but not so easy. I’ll boldly claim that most airgun shooters who put any significant effort (and money) into their hobby are more accurate within 50 yds than rimfire shooters. See; https://www.americanrifleman.org/articles/2010/9/10/the-impossible-22-rimfire/


        • JerryC,

          I have a friend who is serious rimfire shooter – yeah they spend a fortune on the match ammo!

          I totally agree with your claim about airguns and accuracy within 50 yards.

          Seen it many times – a decent PCP and a knowledgeable shooter can easily shoot the pants off of a typical rimfire. The guys I see at the range have learned not to wager against my HW100 – too bad because I used to make a lot of “pellet-money” that way 🙂

          Hank


          • I’m sure many of us have schooled the guys in the nearby lanes at the range who look askance at the BB gun (tuned Marauder) shooter, until they see the pattern in our target. Had one guy tell me I was missing my (small paper) target altogether, and advised him to look closer – all the shots were in the black bullseye!


            • I had one of those experiences by accident once. I was with a buddy of mine at his 100 yard range. We were having a big ol’ time blasting away with my Garand and a couple of other centerfires. He wanted to try my Marauder, having never experienced an adult airgun, so we got it out for a few shots. I have no 100yd dope for my .177 m-rod, turned down to 11.5 foot-pound, so we took some shots at our big MR-31 service rifle target papers to try to get a hold-over for some gong targets. Couldn’t see the holes from the line, so moved on to other methods.

              Later, we retrieved our target papers and found this absurdly tiny five-shot .17 cal group a few feet below the MR-31 bull. Had to be like 3/4″, with all the holes touching. Well smaller than I’m accustomed to at half that distance.

              Now, I was up front with the other fellas at the range as we all gaped at the group, and told them the truth that the old m-rod probably couldn’t do that again in a million years. Still, we opened some eyes that day – including mine!

              -Jan


  8. Good morning and Happy Friday!!! 🙂

    The strangest adapter I have seen was an 16″ long .22 rimfire rifle barrel that fit into a single-shot 12 gauge shotgun barrel. It was a “custom job” intended for hunting snowshoe rabbits in thick cedar swamps in the winter where most shots are at very close range (I prefer a bow for this kind of hunting). I have no idea on how accurate it was but it was quite quiet when fired.

    About “primer and bullet”, we used to use BB-caps or CB-caps (a round or conical .22 caliber bullet crimped into a copper “starter pistol” case) a lot when squirrel hunting because they were so quiet. Compared to the pellet rifles we were using at the time, the CBs were quiet, powerful and the accuracy was pretty good.

    You never know what people will try to do. A guy I knew had the notion to make his .22 rimfire into a “bear gun”. His first “idea” was to cram the powder from two long-rifle shell into one shell and re-seat the bullet. His second plan was to use a “ram-set” cartridge (Ramsets use a special, powerful .22 blank rimfire cartridge to “fire” a steel “nail” to fasten wood beams to concrete) and a pellet. I managed to talk him out of trying either of these “brilliant” ideas.

    Hank



      • Seen those videos as well others where they were claiming higher velocity and more power than commercially available .22 caliber shells.

        Figure that if you could safely get more power out of the .22 rimfire then someone would be selling them.

        I have worked with rockets and explosives and have a bit of an idea of the pressures involved… think I will stick to the commercial ammunition 🙂



          • Agreed!

            Guess that a “super magnum” .22 rimfire would fall into the same questionable performance category as driving a .177 pellet at supersonic speeds eh?

            When we graduated from 350 fps pellet rifles to .22 rimfires we revered the rimfire as a “high power” weapon… 5 decades later I STILL consider it a high power weapon and respect it accordingly 🙂


    • Hank,

      That is always my first thought when going Bear hunting,….. grab my .22 and homemade “Bear” ammo. That way,… after I “tick” the Bear off,…. I can watch him eat me. ;( That is a good story.

      I asked the question awhile back as to why .22 ammo can not be re-loaded. From the answers I got,….. you did that guy a big favor. I hope he listened.


  9. I’ve always wanted to try this but…It seems so simple to order a 24″ Lothar Walther barrel in airgun .22 cal. with O.D. of .591 then slip it into a 20 guage unchoked/slug Bbl. use set screws to hold it far enough into the chamber that only cut down shells will fit.Yes it is still a firearm (not a problem in my area) and yes the 209 primers add extra cost of ~$35/1000 but you wouldn’t have to pump it up or worry about temps like with CO2 or learn the artillery hold(very difficult for me).I’m just not sure if the primers would be consistent enough.

    It seems like the cost would land somewhere between RF and PCP with the benefit of propulsion and ammo being much more available (again in my area).

    Sadly I’ve never been able to put together the money and time to try it,maybe someday.


  10. B.B.,

    I’m surprised there is no mention above of either the Crosman MAR177 AR-15 Upper PCP Conversion Kit or the air rifle training adapter for the Swiss K31 Schmidt Rubin rifle. Then again, perhaps your plan is to discuss and describe those in the next installment.

    Michael



      • B.B.,

        I thought they related as both of those are retro-fit items that enable a firearm to shoot airgun pellets (using compressed gas). I misunderstood the premise of your report. I was looking at it from too broad of a perspective. You meant specifically shooting airgun pellets instead of firearm bullets (using a combustible propellent).

        I was impaired by having had only my first cup of morning coffee. At least that is the story I’ve decided to go with!

        Michael


      • B.B.,

        Now that I think of it, I have actually done the opposite of what you describe above. I have taken an old, broken down air pistol not worth repairing and used it to launch bottle rockets. (And there was no danger in doing so — only the stick portion of the bottle rocket was inside the barrel.)

        Michael


  11. Im a bit late in the comment section so I hope it’s ok to be off subject. Last Saturday my grandson was able to shoot in an Umerex sponsored air rifle shoot at the Helias High School gym in Jefferson City Mo. Before the shoot he was interviewed by American Airguner film crew. So BB, if the interview makes the cut, you will recognize the curly blond headed kid that followed you arround the Ar. Airgun show. It was a good time. Just had to brag.


  12. Firing primers without proper ventilation as can be imagined with such devices is a horrifically bad idea. Lead styphnate is what gives primers thier bang, this leads to lead in vapor form that users will breathe. Unlike solid lead pellets that offer little chance of absorption.

    This is why ranges are outside or very well ventilated. Unlike a typical home.



  13. Anyone see that “Wish it and win it” promo P.A. has going on? 5,000$ in “goodies”. (Pssst!,…… I hear it’s a big scam,…. so none of you guys enter it! Really,…. you can “trust me”,……) 😉 😉 😉

    Hey,….. good luck to one and all and have a good Holiday’s.


  14. A quick note,…..

    Searching the P.A. web-site,….. the “Can I Answer Your Air Gun Questions” pop up,… popped up. Mmmmm,…. what to do???? Well,…. try I did. “Anything in the 2,000 fps range?”,….. “Not at this time”,……. “Mmmmmm,….. I may have to re-think my approach to some pesky Bears”,…. (followed by a very good answer). I did not “string” David on any longer and politely let him know that I was kidding and wished him a Happy Holidays and that I was just giving the service a “test run” .

    I was very impressed with this service. I however do not appreciate it popping up when I am trying to research a product. Still,…. “hat’s off” to P.A. once again!!


  15. As I’m deep in the midst of reloading primers, I can say that you do not want to mess with them if you can help it. Not only can they explode, but I understand that they can easily go bad from moisture. Airguns should be appreciated for their own beauty.

    I’ve also had quite the comeuppance for reloading. After getting my tolerances down to .001, I had dreams of perfection. But now I see that there infinite depths beyond this. They start with bullet runout or misalignment along the axis. There is a way to measure it and even straighten it. But apparently, no one know how this affects the neck tension and whether it does more harm than good. The other way to fix runout is to prevent it from happening with good reloading practice. But ultimately, this comes down to varying thickness in case walls at the neck. The only solution to this is something called case neck turning which I’ve only seen referenced in a Stephen Hunter where it is being done by a kind of evil reloading genius. There is also something you can do to the case neck involving a custom “mandrel” whatever that is. The short answer according to a senior reloading technician is that you will never be perfect. You get the differences down to an insignificant amount and then sort the rounds to shoot the most similar ammo together. Okay, I’m licked, I’ll just assemble my rounds and leave it at that.

    Matt61


    • Matt61,

      🙂 ,……. You are a good reminder of (me) at my most possible extreme. I love it,… and yet at the same time,…. serves as a reminder as to just how far,…. is too far. 😉

      Like (you) said,……. Your “biggest fan”,……. Chris 🙂


      • Okay, I’m pulling back from the brink. Incidentally, in response to your question of some time ago, I don’t know what a barn spike is. But judging from its name, I don’t expect it would do too well in throwing because of the instability of long, narrow projectiles.

        I’ve actually made some progress with the knife throwing. I was doing great when all of a sudden things collapsed, and I was missing everything. After much experience, I have learned not to panic, and I tried to evaluate what I was doing wrong. There was nothing obvious. But I think what happened is that complacency had set in and I was no longer concentrating. So my accomplishment had the seeds of its own destruction built in. Knife throwing is so much more complicated than shooting guns that any lapse in attention will show up. The missing part was an *intention* to land the knife. Then I understood this character named Goodnight Rabidoux in the most recent Magnificent Seven film (which I recommend). Rabidoux was a famous Confederate sniper who got his name for shooting a large number of people at Antietam. He is attempting to train some townspeople in marksmanship, and they are failing miserably. In exasperation, he cries out, “You have to hate what you shoot at!” I didn’t make much of that at the time except that it sounded dramatic, but I now think that he was referring to that extra bit of intention that made him a great shot. The trouble with him is that under the pressure of war, he got this mixed up in his mind with the intensity of hatred and this rebounded on him to cause a severe case of PTSD. Anyway, the pure intention, without any hatred of the plywood, is bringing me back.

        Matt61


        • Matt61,

          Yea,… a barn spike is just a really big nail. It takes something on the order of a 3# mini-sledge to drive them. As for throwing them,.. my brother in-law which is in law enforcement mentioned it. Supposedly he can throw most anything and make it stick. He is a lot like you in many regards in that he pursues varied interest and strives to excel at them. Weapons of all types and hand to hand combat that include the martial arts.

          As for my limited knife throwing experience,.. I found the best results when totally relaxed,…. not unlike air guns. The biggest obstacle was only having 3,.. and trying to find that rhythm again after picking them up or unsticking them. I remember well,.. wishing that I had like 24 or so. For me,… I think that would be key to quick learning. Having a trained spotter at the side would be nice as well. Someone to watch the release and the stick, near stick or missed landing. Chris


        • Matt61,

          The other obvious benefit to the spike is that once the head has been removed and both ends are sharpened very well is that now you have a 2 sharp ends,….. which in (theory) should double your chances of landing a “stick”. Chris


    • Matt61
      Thought you was talking about the ultimate accuracy in air guns in your end statement.

      “You get the differences down to an insignificant amount and then sort the rounds to shoot the most similar ammo together.”

      Hmm maybe ultimate accuracy in firearms and air guns is similar. And how do you really know the results but to shoot and see. 🙂


    • Matt,

      You are getting into this too deep! A lot of that stuff has been debunked over the years. Like primer pocket uniforming is now known to have no effect on accuracy.

      Neck turning works, but even better is what Harvey Donaldson recommended a half-century ago. Shoot large groups, like 10 shots, with your best load and set aside all the cases that group well. Then load them only and see how great your groups are!

      B.B.


      • Okay, B.B., you have created the giant golem, and only you can stop him. 🙂 It sounds like the Donaldson method doesn’t go against the principles of neck turning. There must be some individuality to the cases. But it is a clever workaround that gets the results faster.

        Matt61


  16. I was a bit baffled by the guy who overloaded the .22RF ammo to make a “.22 magnum”.

    Why try to re-invent something that is already commercially available? And safer?

    Les


    • Desertdweller,

      How much space IS available between the back of the bullet and the top of the powder? IS there any space? If so,…. is that space vital to the cartridge’s performance?


  17. BB,
    Without going through the whole commentary, I totally agree with your results with the flaky accuracy phenom of “pellet adapters” you mention. I should mention, however, acceptable, even quite good accuracy wiith some center-fire sub-caliber rounds in “full-sized” chambers. Specifically I’ve had good results with .32 ACP in .308 Win/7.63 NATO .and .32 ACP is a heck-of-a-lot more quiet than a Full-Hoo-Haa main battle rifle round. Realistically, if one is just trying to pot a bunny for dinner there are logical reasons to keep a lower profile.
    And the there are the “wax bullets” that work pretty well, at least in shortish barreled revolvers. They have the advantage of reasonable accuracy and being quick and easy to make at home. (Not wanting a lawsuit, you’re on your own tor research on that one, but just as a tip, neither your girlfriend nor your housecat will react benevolently to playfully getting shot in the butt with a primer-only propelled wax bullet. Either one, or both, will walk over to you and beat the absolute living besnockers out of you…and you’ll take it because you’ll,deserve it.
    In any case, be aware that any which way you do it, they”ll not shoot to the same place.


  18. Wyss made primer driven training kits for the swiss GP 90 cartridge:

    https://www.swisswaffen.com/?W=WTE90&LP=ST2
    The GP90 is very similar to the .223 Remington.

    Wyss also made it for the GP11 with a insert for the 7,5 mm barrel:
    https://shop.indoorswiss.ch/de/ordonnanz/4769-wyss-trainingseinsatz-te-31-57.html

    I´ve tried to fire a .22 pellet from a .22 lr chambered rifle loading a 6 mm Flobert behind it. It´s a very short cartridge for gas-alarm guns which has only primer and no powder. It ripped the head of the of the pellet and pressed the skirt in the form of a cylinder, which remained in the chamber.

    Andrew


  19. Mendoza still makes primer powered guns, but of course they would be firearms if imported into the US. Look on their website for “rifles de salva”. The ones that list a velocity actually fire a pellet – with no velocity listed they’re starter guns for sporting events.


  20. Hi BB, noticed you made reference to your Mosin Nagant in the recent Umarex Throttle blog. I’ve developed an interest in this Russian firearm over the last couple of months. Although this is an airgun blog, do you have any write-ups on this vintage rifle? Which model do you have? I am keenly anticipating part 2 as it relates to the Mosin.

    Regards,
    Peter



      • Hi BB, very nice pictures and a handsome rifle it is….well, the man too 🙂 You are lucky in getting one with a new barrel. The ones I’ve seen are covered with cosmoline and can’t tell if the bore is any good. I’m interested in a 91/30 sniper with the original scope….still looking for that good deal. The look and feel of history really appeals to me! In your opinion, is the hex 91/30’s crafted better than the ones with a round receiver? Apparently there is a lot of debate over this.

        Can hardly wait to read about the adaptor for this rifle! Until now, I didn’t realize you can even shoot pellets out of a cartridge rifle. Thanks this write-up BB.

        Regards,
        Peter


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