The magic of the outside lock: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

A history of airguns

The magic of the outside lock: Part 1

This report covers:

  • Breakbarrel
  • Loading
  • Spring break!
  • Performance
  • Trigger
  • Accuracy
  • The end

I said last time I would show you more of the details of the outside lock airgun in the next report, so let’s get started.

Gary Barnes made the gun a rifle, by boring a 36-inch long brass tube for .25 caliber and then rifling it with a left-hand twist. I don’t know the rate of the twist. He shaped the outside of the tube with 8 flats to resemble the octagon barrels of the past. But he left the breech portion round, so the barrel transitions from round to octagon, just like the finer makers used to do it.

Breakbarrel

He also made the gun a breakbarrel, which no originals were, as far as I know. The original guns were smoothbores that were in the great majority of what was being made at the time the outside lock was popular (1700-1775 — give or take a quarter century, either way — no one really knows). They were loaded from the muzzle with either close-fitting lead balls called bullets or else shot. But this gun would be shooting .25-caliber diabolo pellets and those don’t load from the muzzle! So it had to load from the breech.

outside lock barrel lock
Looking down on the top of the action and barrel we see the barrel lock. Swing that latch (arrow) to the left and the barrel opens for loading.

outside lock barrel open
Looking from the underside, the barrel is now open for loading. It doesn’t open far.

Loading

Once the barrel is open you insert a pellet into the breech, but it doesn’t stop there. Gary made a custom breech-seating tool that forces the pellet into the bore by a certain amount. He made it from the tip of a discarded deer antler and it is a work of art by itself. It certainly belongs with the rifle.

outside lock pellet loader
Gary Barnes also made this pellet loader from the tip of a discarded deer antler. It’s a work of art by itself and compliments the rifle.

You load the pellet first, then use the loader to push it deep into the breech. The white tip limits how deep it can go for consistent results.

Spring break!

When Gary delivered the rifle is came with a spare mainspring. He told me all the problems he had making the mainspring and then hardening it after it was shaped. In case you haven’t guessed yet, the reason the outside lock looks like it does is because most of the action parts are mounted to the outside of the lockplate, rather than being inside, where they are hidden. The mainspring has to be outside because there is no room for it under the lock.

Gary’s tale of the difficulties was so intriguing, in fact, that it inspired me to write a fictional short story about the making of the outside lock. I titled it The wind gun of Prostl, and it is now the last chapter in my book, BB Guns Remembered. I found it fascinating that an airgun made in 1730 could still be working (Gary had an original outside lock to examine) and evenย challenge a 20th century craftsman to recreate.

He was so concerned about the mainspring that he made a second one. The first one that came on the rifle was less powerful, so the rifle operated on a fill to just 600 psi. But after several dozen shots it did break like Gary had feared. He installed the second one and it operated all the time I owned the gun. As far as I know, it is still on the rifle today. This spring is more powerful than the first one and could operate with a fill pressure of 800 psi.

outside lock mainspring
This is the replacement mainspring that was installed when the original broke. After shaping, all surfaces had to be polished smooth to eliminate any scratches that would be weak points. Then the entire spring was heated until it turned dark blue. It is now both hard and resilient, and may last for centuries.

outside lock detail
Here you can see the detail of the mainspring acting upon the hammer.

Performance

Now see how well the outside lock rifle works. It’s filled with air through a hidden port in the butt. Although the air pressure doesn’t go that high, Gary did make the reservoir from multiple tubes to provide a generous volume. This is hidden inside the leather-covered butt that looks like a homogenous container to most people. In the olden days when outside locks were being made the butt would be made from sheet iron, folded into a triangle butt shape and mechanically locked along the bottom seam that was then brazed along its entire length. A reservoir made this way would hold up to 800 psi of air, but not much more. Gary used seamless hydraulic tubing that will hold much higher pressures, though it won’t be asked to.

The first mainspring produced up to 22 foot-pounds of energy with a lightย .25-caliber pellet on just 600 psi of air. It got many shots, but it broke before it was thoroughly tested.

The second mainspring could handle air pressurized to 800 psi and developed over 28 foot-pounds with a lighweight 20-grain Diana Magnum .25 caliber pellet. It almost certainly would have topped 30 foot-pounds with a heavier pellet.

Here is a string of shots I got from a single fill.

Shot…………….Velocity (f.p.s.)
1………………………713
2………………………792
3………………………795
4………………………664
5………………………635
6………………………606
7………………………581
8………………………557
9………………………539
10…………………….518
11…………………….495
12…………………….462

As you see, the velocity did decline after shot 3, and I just kept shooting and recording until shot 12. I probably could have gone a couple shots more.

In ancient times the shooter would have no idea of what velocity he was getting, but he would develop a sense of greater or lesser power from each shot. They shot balls against metal plates to determine the relative force their guns were producing. I think getting 12 shots or even a third that number (depending on where you stop shooting) is very good for only 800 psi.

Trigger

The trigger is weird, to say the least. You don’t pull it back — you pull it up to fire the gun! It’s a strange feeling that resembles a crossbow more than it does a gun.

Accuracy

I didn’t shoot the rifle for accuracy that much. It was more of a combined historical objectย and science experiment than a real pellet rifle. But the one time I did record a group I put 5 shots into 3/4-inch at 10 meters. That was shooting rested.

The end

I let the outside lock go because as I have pointed out before, I can’t own them all. It’s one I wish I had back, but I’ve lost track of it, so I suppose it will live in someone else’s fantasy from now on. I’m glad I had a chance to get to know it when I did.

64 thoughts on “The magic of the outside lock: Part 2

  1. I hope I see this gun in person some day! I’ll try to get you back in the loop on it if I do.
    But who am I kidding?
    Fact is I’ll be lucky to get back to the Texas show next year! You think Gary would be willing to tackle another one?
    That’s for you Ridgerunner.


    • As far as I know, Gary is still making air rifles. He has a forum called Airgun Rendezvous where you can get in touch with him. I think he has changed his business model to be similar to Dennis’. He will introduce a model and build a certain number of them, say ten. How often he takes orders I cannot say.

      If you are considering one of his air rifles, you had better have a VERY thick wallet. Gary is not an airgunsmith, he is an artist that uses air rifles as his medium to express his artistic talents. I have had the pleasure of admiring several of his works and have fondled and drooled over the particular one in question today. Who knows, maybe one day…


  2. BB
    The old low pressure pcp guns always amaze me.

    Everything you mention about this gun still applies one way or another to the modern pcp gun. You still need to map out the pcp’s shots where they fall on the target for what pressure you still have in the gun.

    But the way that old outside lock system works is just fabulous. If a person knew what they were doing they could have different outside cam locks made and you could change the guns performance by having more or less opening of the valve or how long the valve was held open.

    The camshaft in a engine works for he same way. It’s all about how you control the air flow.

    Very cool gun. To bad somebody doesn’t try to reproduce it again in modern technology. And yes Lloyd’s dual solenoid electronic system is pretty much it.

    I do appreciate the people that try to advance the technology in the air gun world. And glad that people back in history found a need to advance air guns back in their time.


  3. BBB or Bruce had a comment posted here also as well as one from me where I replied to him.
    Kinda freaked me out when I noticed only two comments when I pulled it back up.
    Wonder what’s up with that?



  4. Off topic. Airgun on board gauges are not all that accurate. My tow fill adapters with one inch gauges and my Discovery and Marauder never agree on the pressure. I fill to the pressure shown on the guns. However, just received my Omega Super Charger and now have another gauge that reads somewhat different than all the others.

    How accurate do you think the Omega gauge is?


    • Jonah,

      Without question the large oil-filled gauge on your compressor is more accurate than the small gauges on your airguns. This has always been the case. The trick is to use a chronograph and learn where each rifle likes to be filled. Then fill to0 that level regardless of what the numbers say.

      B.B.



  5. B.B.,

    Of course I reread the first installment before reading this one, and I was reminded by just how long the barrel of this one is, in order to allow the air to expand fully. That ultra-long barrel also made me recall the Modoc from Air Ordnance. Does that employ any of the same valve and lock concepts that this does?

    Michael


    • Michael,

      Not even close. The first Modoc cartridges failed, so they send me a whole second gun and new set of cartridges. They are simple blow-open shells that dump what ever is in them. They are as far as it is possible to be from the timed valve of the outside lock.

      B.B.



  6. Michael just mentioned the long barrel and I understand the principal of making maximum use of air that is available but I am a bit fuzzy on how it applies in modern pcp’s. For example- Ben. Bulldog has 28in. barrel but Evanix tactical .357 generates almost same velocity out of 20 in. barrel. Both fill to approx. 3000 psi. What is going on here, is it a matter of potential accuracy?


    • BBB,

      Let’s get specific. If we are going to do comparisons, we need actual data, not approximations. The difference between 700 and 750 f.p.s for a 100 grain bullets is 16 foot pounds.

      So the question is, what velocity for both guns shoot the same bullet on the same day at the same place (elevation, weather etc.)?

      B.B.


      • B.B.
        Ahhh,but only for a chrony and the guns to shoot across it! I guess need to find some tests that shows each gun and put them side by side and compare. I’m beginning to understand the basics of things , like a metered valve versus nonmetered and other things and I think I sometimes forget that you have to plug in all the available data before you can work your your equation to an accurate result.
        Thanks,BB, you just forced me to go do more digging. ๐Ÿ™‚
        Bruce



        • B B B,

          You asked some interesting questions. Are you looking to buy your first airgun? (or) Are you looking to add to what you are already shooting? Your questions lean toward PCP’s. Just curious.

          As for a chrony, you will find it nice. They are pretty reasonable $. If you do PCP’s you will want one. If you do gas piston, spring piston, single or multi pump pneuamatic or Co2, maybe not right away.

          What are your goals, needs and wants? Chris ( looks like you got the whole posting thing figured out! ๐Ÿ˜‰


          • Chris
            I think I’ve got a start on the blog thing ,thanks. Now if I could only find the things I sent to never never land and repost them.
            I’m 66 yrs. old and have been a powder burning hunter all my life. Only air gun use was for taking cottontails and such around grainbins at 10 or 20 ft. Not what you would call precision shooting! About 6 or8 mos. I had to stop working was just sitting around being bored and decided to drag out my 2 old(10 yr+)Gamo 1000 Shadow. Had 15yds in the backyard to shoot in – and 5000 rounds later I have broken springs in both and have had one repaired and working with that one now.it is scoped. Also have an RWS Diana Model 5 pistol but can’t shoot it because my old eyes and open sites don’t work well together any more. I would really like to get into pcp’s but my budget won’t allow it right now. I will have to stay with spring guns for awhile but that’s not a bad thing. Shooting a springer consistently is a challenge and I like it!
            (I believe that the trigger on that Gamo has a serated edge on its sear and pulls about 6 ins.!) I’ve been thinking I would like to try a gas piston gun – Ben. NP2 or ?
            Anyone have a suggestion?


            • B B B,

              It is great to hear some background. You are already well on your way. With Kevin, this site, and the people here, you are in good hands. Plus with your powder experience, you are starting way ahead of when I started. There is lot’s of offerings out there. Consider Pyramid before hitting Wally World. Wally’s sell the same ones, but PA sells a whole lot more. A descent scope is nice. Plus good pellets. I’ll leave it to you to do the research and ask the questions. Lot’s to learn. I think you will have no trouble occupying your time! ๐Ÿ˜‰ Chris


              • Chris
                Have been off line for a few days, my android phone has been on the blink so my wife is letting me take over her tablet. Its different so I have to adjust (learn) to something different.
                I had mentioned to you that I would probably stay with springers for awhile due to budget constraints. Well, I have been doing some more research and have come to the conclusion that that a decent Springer costs about the same as Ben. DISCOVERY and pump with it!
                So what do you think? If I do a little tiny bit of stretching on my budget( poor thing!) I can swing it.
                What say you?

                Bruce


                • Bruce,

                  Was off yesterday myself so sorry for a slow reply. The Discovery has been recommended several times to me. I have yet to go PCP. If I do, it will be a good automatic pump, tank and gun. I do not want to pump a pump to shoot. Lower fill pressures and smaller reservoirs can help with that. As for the price, 419 is not bad. I have a LGU and a TX, both springers, at 570 and 629$ each, (my TX is a left in walnut @ 755$). As for fps,…900, 625, 755 (in .22) speak for themselves. Keep in mind that advertised fps are often with lighter pellets. 590 and 630 actual are with JSB 15.89’s in each.

                  With a springer, there is more control issues,…with a PCP, not so much. I think that a chrony is needed with a PCP in order to find the best shot curve and fill pressure so keep that in mind.

                  Plus there are some pumps that are better than others so keep that in mind as well. You may want to consider pump options, not only the offered one.

                  That is about the best advice I can offer. Honest. Do research. Here is a good start.

                  Thanks for asking my opinion. Chris


                  • Chris,
                    Don’t be intimidated by a hand pump!
                    You saw the picture of me, I’m only5’4″ & 130# after a big meal and have no problem going to 2250 on my 2400.
                    I could go higher but don’t want to cause any problems with seals blowing.
                    Had I known how much easier it is to do all the pumping at once I would have given up the multi-pumps a long time ago!
                    Already started my second with the 2240 I’m working on now.
                    A hand pump is only about$150 as opposed to$600-$1000.
                    It’s a little work but it usually amounts to 15-20 minutes of moderate exercise.


                    • Reb,

                      Surprised you saw that. You may be right,….however I have a hard enough time getting up the “gumption” to shoot after a hard week at work,…let alone pump a pump. If I go PCP, it will be “all the way”. Until I hit the Lotto,….I may be waiting awhile…..or,….just go for it!



                • If you’re buying a brand new one you’ll be glad you did it early in! If you’re going the used route just be sure the person you deal with is reputable and you may even wind up with a better deal.


          • Chris
            Tom got me hooked up with Kevin Klentz. He lives about10 blks from me! He invited me over to his place after the 1st of the year to meet some other airgunners and get a chance to check out some different guns.I’m looking forward to that!


          • Before I finally got a chrony I built a ballistic pendulum on several occasions, its as simple as weighing a piece of 4×4 pressure treated block, cutting it to weigh one pound, minus the weight of two screws. Weigh the screws and subtract from the one pound block. Screw the screws into the top of the block evenly spaced. Use thin wire to suspend the block from a rod, bingo, pendulum. Draw a line every 1/8″ along a board, cardboard, whatever, of the back edge of the blocks swing going back and the full arc up with the bottom edge. Set up a camera to record making sure its perspective is aligned with the swing markings, especially the rested position. Record, shoot, review. With the footage you can find the maximum height achieved from the blocks reaction to being shot. Dont neglect the back swing, the first return swing is exactly the same height as the reactionary and sometimes, not perfectly centered shots, can make a wobble in the first up shot, though bad enough I would reshoot. Using the equarions to solve for energy using your chosen pellets weight by the height it moves one pound up, you can find velocity. Its not easy math, the pendulum build might take a while to perfect, but it is not that difficult really, once you spend 3 days figuring out the math and getting your shots evaluated, later attempts can be accomplished in about 3 hours, build, shoot, math. Dont forget to account for pellet build up weight if you are using it for more then one shot subtract for each pellets weight from the block. Its a fun experiment and can be built to be a permanent functioning ballistics pendulum, if desired, pvc tube and replaceable inserts instead of a wood block. I got results that, when later chronyed, were around 25 fps accurate. Good luck!


            • I just discovered that I can buy a chrony for a little more than 100$ and if I don’t shoot it like I read of Tom doing I might be better off. I don’t think my phone is capable of the computations and to get a bigger phone would cost the price3or4 chronys. I bet it was a lot of fun figuring it thru! The Challenge!


              • All the math could be done on a calculator, as long as it can parenthesis and square root…a-fi. Lol. It was the most math I have EVER done, and it took 3 days to turn the height the one pound swung into the energy of the pellet the first time. Besides being desperately curious what my guns were shooting at, the subject was obviously very interesting, and the challenge of doing what prechronyers did to know their velocities was definitely there. Im proud I accomplished doing it, and that it was surprisingly accurate, but if I was to do it again I would want to make a permanent fixture and have the equation set up in a way that punching and in the numbers was quicker. There is a ballistics pendulum calculator and instructions on a .edu site, ill have to find the link. Chronys are definitely easier! I got the green alpha and once the lights are correct it was worth every penny, imagine trying to tune a gun with a pendulum! ?, no way.


                • I like your final conclusion !
                  The task must have pushed you just a bit to follow thru to your finish. A week ago or so l posed a question to Tom about how to calculate potential accuracy between 2 different rifles. Obviously I didn’t think my question thru. Tom’s response made me realize that, and the quest was on! After 4 or 5 days, numerous web sites, untold numbers of ” plug in the number” calculators I have come to realize that there is no real way to calculate potential accuracy. There are way too many variables! The best way to find potential accuracy is one very good shooter with 2 guns on the range and may the best gun win !
                  The hunt was great. I learned a lot of new things .


                  • Thats one of the best parts of airguns and ballistics in general, there are set laws of physics that apply to the projectiles motion AFTER the circumstances of internal ballistics that are, essentially, full relativity and dynamics that are completely unique, even from one pellet to the next at molecular level. Every gun offers thousands of variable factors affecting its motion, all playing out to the end game of how the pellet flies. Intriguing is now a mild word. It certainly has kept me coming back, and I think the airgun “journey” is progressing through these understandings, investigating them, grasping them and manipulating them through different platforms, eventually finding guns or a gun that hits all the sweet spots of these physics to our liking. And even how our perspective of how these things should go, the sweet spot, changes and how we want to use them changes, making absolutely sure that there are infinite variables, without question. How do you calculate that? ๐Ÿ™‚


                    • I sometimes have problem when I get so caught up in all the swirling goodies in my head. I just remember why I am doing all of it and walk out in the back yard and put 50 or 100 pellets out said barrel! All is right with the world!




            • RR,

              That was very interesting. It all makes sense. It would seem that a indicator that could slide with little effort, that would holds it’s max. movement, next to a scale, could be employed. Re-set after each shot. Very cool stuff. I’ll stick to the chrony though……. ๐Ÿ˜‰



  7. B.B.

    Now that’s what I call art in airguns! The craftsmanship is totally amazing.

    I wonder if the lock mechanism works with spring being tensioned only on working cycle and relaxed all the other time. This way it might be like revolver – can be stored loaded indefinitely with only one finger move to activate it. I think, made with modern materials it could be a good thing for airgun hunters and that hammer principle is a good thing to check the rifle’s safety and de-cock if needed.

    The more I’m thinking about my own PCP design, the more I like open hammer schematics (or striker with de-cocker handle/cocking indicator).

    duskwight


    • duskwight,

      The mainspring is under tension when the gun is uncocked. A spring compressor is used to install it. The one from 1730 was still good in the 1990s, though I don’t know whether it had ever been replaced.

      This gun cannot be decocked. When the hammer goes forward to rest, its cam opens the firing valve. Later locks did have a decocking mechanism, but not this one.

      B.B.


    • Duskwight,

      In the Philippines, particularly in Luzon, the open hammer type is popular to actuate the knock-open valves of CO2 and PCP airguns. Hunters like them as that they can visually see that the hammer is cocked or by feel alone. They also like the fact that the design allows easy visualization if the airgun is loaded or not.

      The USFT is also an open hammer type.


  8. Kevin– kutna hora (hura?) is in the Czech republic. It is near silver mines and had a mint making coins ( 1500- 1600 @). When I was there in 1989, the mint was a tourist attraction. they were still making coins , but out of aluminium for the tourists. They used a hammer and die method to strike the metal blanks by hand. Ed PS if you like cathedrals, put Kutna Hora on your list.


  9. Just did a trial run on the HIPac site and it just keeps loading the picture of that squirrel with no product listings, no phone number or anything else but that dang squirrel.
    I’ll be getting paid on the first and will be ready to order one for my 2240 but I’m stuck.
    Can anyone please help?


  10. A belated Happy Thanksgiving to all. I was traveling. And while the food was much better than normal, I did miss shooting and the blog. So nice to see that B.B.’s new book will be available for Christmas. I think the forays into fiction are most interesting. Once, I told someone that I was interested in airgunning, and she said, “That’s just like the villain in the book/film No Country for Old Men.” The villain uses some sort of air-powered gun that is commonly used for slaughtering cattle. We could use a better image, I think.

    Matt61


  11. Hallelujah, it’s Monday!
    Well, that’s what I said this morning anyway.
    Then the Monday part kicked in :/
    Been on the phone trying to get one doctor talking to the other, spoke to a collection agency about a bill that shoulda been paid by my insurance company back when it first kicked in, was informed the fax hadn’t been received, setup a follow-up appointment for the ER trip I made yesterday and trying to get a ride for some groceries.
    It’s wonderful to be alive!


    • Guess I jumped the gun about the fax anyway.
      They just called to let me know they received the doctor’s orders from my neurosurgeon stating that my blood pressure is supposed to stay between 140-160 systolic and I’m to remain as physically active as possible.
      Been trying to get that done well over six months now.


      • Reb,

        Hang in there……..you mentioned you like fishing. What kind? My favorite was/is Catfishing. Been a few years though. My best was a 35 1/4″ 24# Flathead pulled out of a smaller river full of snags. Had to pull him in quick. Had a buddy that net landed him.




          • Reb,

            Well, since you are a “night owl”,…and I am not,…some fishing thoughts to ponder,……

            Ugly Sticks, Shimano,..”Baitrunner”,…slip rigs, 50# braided line, 30# mono, roller tips, 20oz. bottles for bobbers, live bait,………….got ya’ thinkin’ there? ๐Ÿ˜‰ Out’a here,…Chris


        • Forgot about the fishing part,
          My favorite is also catfish with crappie running a close second mainly because of the difference in temperature but to be truthful I like to eat em so I’m more into trotlines and limblines. Those were tricks I learned from my Step father, my biggest on rod and reel was a 7.75# blue from lake o’ the Ozarks.
          Felt like pulling a cinder block through the water!
          My step dad and his brother were loading up the 12′ John boat with the battery and trolling motor about 5:00 am and suggested I toss a line in and about a minute later I had bent the coupling on my Shakespeare while setting the hook. They both swore I didn’t deserve the catch as they usually did when I caught something bigger than they were gonna but we dropped everything and went straight back to camp to clean it.


          • Reb,

            Yea, the smaller ones are the best to eat. I grew up fishing the neighbor’s pond with lots of Bass, Bluegill, a few Crappie and of course the Yellow belly cats. Lot’s of fish frys! You guys have some real big cats down your way.


    • Unbelievable!
      Got back from the grocery run and had two boyfriends fighting in the middle of the sidewalk.
      Apparently one saw a text on the others phone that led to a lover’s quarrel.
      Biggest problem was Mom was in a hurry to get the groceries unloaded so she could get back to my brothers and fix them dinner. I told her mom don’t go up there yet then told them they were just about to get somebody kicked out.



        • No, this was after the Wal-Mart run in front of my apartment. Mom never slowed down just showed them her cellphone and said she was dialing 911 still have yet to see a cruiser and they’re under a half mile away, over 2hrs later no fuzz.



            • You’re right, Mom didn’t call em however my neighbor heard her and did and gave them my apartment number so I stayed up until midnight waiting for them to show.
              I woke up at 3:30 this morning after dreaming I was being evicted for the checklist from my last mandatory inspection.
              The demerits including;
              Drop pans in need of cleaning as well as oven and too much clutter
              These are considered fire hazards by the management although any one would have to be much worse in order to be one.
              In the comments section below I wrote 3:30 am;
              This marks the beginning of the end of our relationship!
              Something’s gotta give!
              I’m supposed to acknowledge receipt by 5:00 at which time I will be handing it back to the management complete with my comments.


  12. Got it turned in.
    The office on my side of the complex was closed requiring a 300yd hike to the other side, it also had a sign indicating they were out on property so I called.
    Upper management is in town and going through records but I handed it to the one who opened the door and she handed it to my manager who promptly called me before I was back across to explain that it wasn’t a write-up but rather implementation of a new policy… Crawfishin’ all the way!


Leave a Reply