Thursday, August 5, 2010

Brass Barrel Slide Breech - Build Guide!

For users of modified or custom-built single-shot blasters that require manual reloading, the usual basic methods of loading foam darts is to either use "speedloaders" (a cluster of individual barrels attached together) or using a stick to ram-rod individual foam darts into a barrel... both being rather slow and tedious procedures.

A popular alternative is to use slide breeches.

Many slide breech designs have been created by various modders over the years and slide breeches are usually installed into single-shot manual-reload blasters to offer a quicker (and more elegant) dart reload solution.

I've tinkered with a few slide breech designs and eventually came up with a customised design which uses 9/16" brass tubes (my favourite barrel material and dimension of choice, as it fits the custom foam darts i use perfectly) nested within 13mm locally-sourced PVC pipe (which allows wide compatibility with all my modded and custom built blasters).

In addition, i have also designed an in-built brass barrel "secure-join" system which ensures a 100% air-tight seal.

Here is how i built my custom Brass Barrel Slide Breech:

Step 1: Prepare 1ft length of 9/16" brass tube (Brand: K&S Engineering) and 40cm length of 13mm SingaPlastics PVC pipe.

The 9/16" brass tube nests within the 13mm SingaPlastics PVC pipe.

Note that the PVC pipe internal diameters (ID) can vary depending on production batch and sometimes it can be too tight or too loose for the brass tube (even within the same length of pipe), therefore you'll need to test the nesting fit using different sections of pipe beforehand to get the best fit combination for smooth breech operation.

Step 2: Use a Dremel with a cutting disc designed for cutting plastic, along with a grinding bit to cut and trim a suitable sized breech channel in the 13mm PVC pipe, make sure the channel is long and wide enough to fit foam darts.

Include a semi-circle cut at the back of the breech channel for the breech locking tab.

Step 3: Put aside the PVC breech for now. We shall move on to the brass barrel section.

To create the brass barrel "secure-join" system, cut 3 x 2cm sections of 1/2", 17/32" and 9/16" brass tubes.

Nest all 3 brass tube sections within each other with the 1/2" and 17/32" sections positioned forward slightly. Glue the sections together with strong 2-part epoxy glue.

The 1/2" section will help push the foam dart forward into the barrel and the 17/32" section will sleeve with the 9/16" brass barrel. This forms the basis of the brass barrel "secure-join" system.

In the photo below, you can see how the system works. When the breech is closed, the 9/16" brass barrel will sleeve onto the nested brass tube assembly to create a 100% air seal.

Step 4: Install the brass tube assembly into the back of the breech channel, position it so that the brass barrel can sleeve on it when the breech is closed. Use 2-part epoxy glue to permanently attach it.

Done properly, a nice audible "click" can be heard when the brass barrel and tube assembly connect.

Step 5: Attach a breech locking tab onto the brass barrel.

In my example, i simply used 2 x hex nuts stacked up and epoxy glued onto the brass barrel. I use Selleys Super Strength 2-part epoxy glue (properly clamped with 72 hour curing time), as i've found that its the only epoxy glue strong enough to still hold the locking tab permanently even after repeated heavy-duty usage.

The breech locking tab is important because it prevents the brass barrel from slipping out of the PVC breech casing, and when the breech is closed, it ensures a secure air-tight connection and seal.

In the photo below, it shows the breech open (top), breech closed (middle) and breech locking tab engaged (bottom).

Step 6: Attach the completed Brass Barrel Slide Breech to your blaster of choice.

Here is an example of how i attached it to my +bow.

I customised a 13mm PVC adapter with PETG tube rings to match the +bow coupler.

Then i joined the Brass Barrel Slide Breech with the custom 13mm PVC adapter using a straight 13mm PVC pipe connector.

Great performance and a much smoother (and cooler looking) foam dart reloading procedure. :)


  1. So... This makes the blaster hold more than one dart? If so, do they all shoot in one trigger pull?

  2. Will you post a guide to make your Customized darts?

  3. John,

    Yup, i've posted up a Custom Calibrated Foam Dart Conversion Guide, here is the link:

  4. Shnowman,

    Nope, the slide breech still only fires 1 foam dart at a time, but the loading procedure is using a breech system (instead of using multiple individual barrels or ram-rodding foam darts down the barrel).

  5. 9/16 fits very tightly in 13mm pvc so much that if you dont use it for awhile it will get stuck so i would sand out the pvc abit by wrapping something in sand paper and then just manually sand it out

  6. Hey SGNerf,
    May I ask how you glue nicely nested pipes together?
    I've tried applying adhesive on the inner or outer pipes, but sliding them together would just cause the adhesive to be pushed out and I'm not sure whether the contact surfaces have been properly glued.
    I've been using tape and friction to secure my pipes, but it hasn't been working out =P

  7. VersatileChicken,

    It actually depends on the particular batch of 13mm SingaPlastics PVC pipe being used.

    PVC pipe internal diameters (ID) can vary slightly depending on production batch and sometimes it can be too tight or too loose for the brass tube (even within the same length of pipe), therefore you'll need to test the nesting fit using different sections of pipe beforehand to get the perfect fit combination for smooth breech operation.

    Good reminder, i've updated the guide with this additional note.

  8. ZENN™,

    Just apply a layer of 2-part epoxy glue to the surface of each brass tube section and nest them within each other, simply wipe off any excess glue that gets pushed out, let it cure completely for maximum bond.

    The thin layer of glue on and around the brass surfaces will be sufficient to hold them together properly.

    Btw, i use Selleys Super Strength 2-part Epoxy glue for all my modding works nowadays, as it is the strongest adhesive i've tested so far and an excellent gap filler, which ensures 100% air-tight seals.

  9. Thanks for this guide, sir. I'm trying to fix mine, and I wonder... Do I need to use some brass rods for this? I already ordered the materials from the brass suppliers in Brooklyn, and I'm ready to start working.

  10. Lawrence,

    Brass rods? There isn't any brass rods used in this brass breech build guide.

    Btw, i use brass tubes from the brand K&S Engineering (which most brass breeches for Nerf blasters are made with), so i'm not sure if you got the same brass tube dimensions with your brass tube supplier. I guess you could just adapt it to your own dart specifications and pvc breech casings.

  11. The brass bolt tube runs the full length of the PVC correct? What is a decent barrel length to have for good accuracy and range?

  12. Blink680,

    The brass tube for the barrel runs the full length of the PVC pipe.

    Longer barrels will enhance range and accuracy, but it also depends on the power of the blaster, the foam darts used and the overall maneuverability required during games.

    For my +bows, i currently use both 12" and 18" brass barrels, depending on the game scenarios and setups.

  13. Thanx Sg nerf for the design.
    I am going to make a R55l so, could you suggest me any better barrel(brass barrel slide breech) length for my gun. And how much would it cost? Please.

  14. Amarsingh,

    The R55L has a very large plunger air volume, so for optimal performance, a longer barrel should be used to match the barrel-to-plunger volume ratio. I use a 2ft length brass barrel slide breech for my R55L (double the length shown in this guide).

    Note that a R55L with a 2ft length barrel totals up to more than 6ft+ in overall length so it's quite cumbersome to carry and not a practical blaster at all to use in actual games, i use it mainly just to showcase and test out variations in different plunger designs. :)

  15. Hi SGNerf, care to share where you get your brass pipes from? Those that I can get my hands on are pretty short....

  16. Maurice,

    I get mine from local hobby shops or online from eBay sellers.

    They usually come in 1ft lengths, though i have seen some in 3ft lengths too.

  17. SG,when you open the breech does the brass stick out the end of the barrel?

  18. VersatileChicken,

    Nope, the 13mm PVC pipe section is 40cm length while the 9/16" brass barrel is 30cm (1ft) length, the difference in lengths are designed so that there is extra space for the brass barrel to move within the PVC pipe.

    So even when the breech is open, the brass barrel will never protrude from the PVC pipe section.

  19. Hi SG Nerf, how much will all the pipe cost?

  20. nikhilk,

    In Singapore, K&S brand brass tubes usually cost around SGD$5-$6 per ft. The SingaPlastics PVC pipes are around a few dollars a metre. You can find the local places to buy these materials posted at the NerfSG forum.

  21. Hey SG! What barrel length would you suggest for a modified titan?

  22. Itsover9000,

    For modded air tank blasters, longer barrels are preferable (ie. 1.5ft or 2ft... i've even seen modders use up to 3ft lengths) to achieve optimal ranges.

    The main issue with such long barrels is that they can to be quite cumbersome to use and tend to flex abit due to the overall barrel weight.

    So most modders usually just stick to 1ft length barrels, 'cos its alot less cumbersome to use.

  23. Hey, I'm trying to fix my Longstrike CS-6. My internal barrel is cracked and the air wont be able to push the bullet out. Can you do a barrel breach INSIDE the barrel/chamber?

  24. Gunblastz,

    Just refer to my Nerf Recon "Brass Breech" Mod Guide, the modding procedures for the Longstrike will be similiar too:

  25. Wow SGnerf! you are the best! Thank you for the link, now I have much more confidence in fixing my longstrike. :D

  26. Can these fit clip system/elite/streamlined darts.

    1. Anonymous,

      Its possible to use full length foam darts with this breech design, you'll just have to cut out a longer breech channel. :)

  27. Hi SG,

    I'm in the process of making my slide breech, but I can't decide if I should use tightening rings at the bottom of the 9/16'' barrel. What do you think?

    1. T da B,

      It all depends on the foam darts or stefans that you plan to use... test their fit in the 9/16" brass barrel first, if they have a snug fit (easy to load in but does not drop out when the barrel is tipped downwards), then you don't have to put any tightening rings.

      If you mainly use loose fit ammo, then you could just add tightening rings to a depth that suit the diameters of those ammo... though i would recommend using snug fit ammo from the start instead so that you don't need to restrict yourself to only loose fit ammo.

    2. Right now my darts have a "snug" fit in my 9/16'' brass, but shouldn't it be a tight fit? From my experience, the tighter the fit, the more muzzle velocity, since the dart is held in place friction while the pressure builds up behind it.

    3. T da B,

      It depends on the power of your blaster, tight fit is okay for higher powered blasters, but for lower powered ones, tight fit stefans can sometimes result in reduced performance (or might just get stuck in the barrel). You'll have to test and see.

      Tight fit stefans also tend to be abit more difficult to rear load into barrels. In addition, they also tend to get jammed when used in converted N-Strike stefan clips (due to the wider foam getting stuck within the clip).

      I usually prefer a snug fit for all my stefans in 9/16" brass or 0.528" ID PETG barrels, so that i can use them in most of my modded blasters and are easier to load... saves the hassle of having to make different stefans for different blasters too. :)

    4. Thanks for the info. I try to design my barrels and breeches around my stefans to avoid dedicating darts to blasters. Do you think my stefans will have problems loading into the slide breech if I use tightening rings?

    5. T da B,

      Depends on the dart fit of your particular stefans in the barrel, it'll be best to test fit them first beforehand.

      If they already fit well, then no need to put tightening rings.

    6. Just finished! Tightening rings were definitely the way to go. Loading is still smooth and ranges are slightly better than without tightening rings. I also cut two slots in the PVC instead of one so you can lock the slide on either side!