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DIY LRB mod with one piece barrel spacer

42034 Views 38 Replies 19 Participants Last post by  De Ober
Most of use have heard of a a LRB or long range barrel, and a fair number know what it actually does. For those of you who don't know, a LRB is a barrel that has slight down ward bend in it, so as the BB is propelled out of the barrel, it rides along the top. It improves the range and accuracy by helping to stabilize the BB's backspin and reduce the BB bouncing in the barrel.
Doing a little bit of research, there is a EZ LRB kit by Hunterseeker5 for sale on Shapeways, but it required that you only have one barrel spacer in the first third of the barrel, not the many most of us use for accuracy. Looking at it closely, the main piece is just a wedge with a grove cut in the center for the barrel, I began wondering if you could get the wedge in place to bend the barrel, then pour wax between the inner barrel and outer barrel so the inner barrel will hold its shape, then remove the wedge. This would give you the combined effect of a LRB mod and a wax one piece barrel spacer. So with out further ado, here is my guide for a DIY Long range barrel AND one piece barrel spacer done on a VSR-10 clone, a TSD sd700.

Dowel the same outside diameter as the inside diameter as your outer barrel. If your barrel is tapered (like mine) use a dowel the same diameter as the tip of the barrel.

Paraffin wax, a candle will do, but you will half to remove the wick after it has melted.

Electrical tape

Teflon tape

Barrel spacer that you can drill holes in (I used my the stock one that came in my gun when I first bought it)


Band saw


Belt sander

Stove and pot

*** note these are the tools that I used, there are many different ways to do this mod ***
The first step is to make the wedge that will bend/flex the barrel and holds it while the wax is cooling. The rough shape was cut out with a band saw, using a clamp on strait edge and a tree felling wedge as a guide. This could just be free cut. I apologize for the poor quality pictures. They were the best I could take

My set up

Note that both the dowel and the wedge have to slide in order to cut the wedge shape in the dowel.

The next step is to sand the barrel wedge smooth so that is is strait. I used a belt sander for this.

Now that the wedge has been cut and is now smooth, it is time to cut the groove in it using a router. The outside diameter of a airsoft barrel is usually between 8mm and 9mm because I live where we use English system, so a 5/16'' bit was just slightly undersized, and because it was undersized only the two edges would contact the barrel when it was in use, so I used a square rather than rounded bit. If an undersized bit is used, almost any shape groove can be used. I used square out of convince, it is more important to have the grove in the center of the flat side of the dowel, than have the groove be round.

The depth of the router was set to be slightly over 5/16'' so the barrel would not touch the bottom of the groove, only the edges.

Next the router table was adjusted so that bit was in the center of the guides. I clamped on a second guide so there was no chance of the groove being off. Be sure that the setup here is all 100% square and centered. Any error here will make the barrel bend not perfectly downward.

After the dowel has been run through the router. Be sure to make a pusher stick to push the dowel through, but make sure you hold it down as well. Trust me, its not with loosing a finger over (or the last 1/8 inch of your finger like friend did : /)

Finally trim the edges off the wedge with the groove in it and the wedge is done. Be sure to check the groove is in the center.

Next it is time to prepare the barrel for the bend. The EZ LRB instructions state to place a barrel spacer in the first third of the barrel, but first you need to ensure that it will allow the liquid wax to flow through it it. you can do this by drilling holes in an old barrel spacer.

Next you can wrap electrical tape around the spacer to ensure that it will not be pushed by the wax, and will stay in the place in the barrel that you placed it.

Assemble the barrel and the hop up unit. Be sure any tinkering done to the hop up/barrel are done because your about to cast it in wax. I recommend the dental floss mod with Teflon between the barrel and bucking, a anti blow by ring on the nozzle end of the bucking, an ER-hop, EM nub, and Top dead center mod. Wrap some more electrical tape around the barrel as close to the hop up unit as possible with out interfering with the hop up. The goal is to create a seal so that no wax can get into the hop up. After you have a tight fit, wrap Teflon tape around the electrical tape to get a even tighter seal.

Now put the barrel/hop/spacer up back into the outer barrel, ensuring that everything is in its proper place and screwed down, keeping the barrel end cap off. Use the wedge you just made to add the desired downward flex, testing if needed. Temporarily glue the wedge in place to the outer barrel with a drop of super glue if it slips/moves around.

Melt the wax by placing it in a appropriate container, then placing the container in a pot with an inch or two of water in in. Boil the water on the stove and wait for the wax to melt.

Plug your barrel with a drop of hot glue to ensure no wax gets down your barrel. If wax does enter your barrel, flushing the barrel with boiling water remove it, but it is still better to have done the plug correctly. Carefully pour the wax between the outer and inner barrel, using a small funnel. It is easier to fill the bulk of the barrel with the first pour, and then do a second pour after the first has hardened to get the wax closer to the top of the barrel, keeping the wedge in for both pours. Make sure you pour at least up to the drilled out barrel spacer before the wax hardens, or you risk the holes your drilled clogging up, and having to restart the wax process. Be sure you leave enough room in the top of the barrels for your barrel cap. You will need to drill out the cap wider to accommodate the bend you placed in it.

Wait for the wax to COMPLETELY cool to room temperature before removing the wedge. If the bend in your barrel is off or needs to be adjusted, you can reheat the wax with a heat gun. Remember wax expands when it melts.

An alternative method is to do the wax spacer with out the wedge, then heat the wax with a heat gun and then place the wedge.

Congratulations you have successfully made a long range barrel, AND made a wax one-piece barrel spacer. If you need to remove the barrel, you can hit the outer barrel with a heat gun or hair dryer to melt the of the outside edge of the wax enough to pull the whole barrel and wax spacer out. You can then you can cut off the wax and recast the barrel.

Pictures of targets before and after coming soon.
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Very nice guide, I might do this eventually. One thing I will say though is that makeshift chronograph guide I posted that you used to chrono your rifle is not at all accurate because it slows down the bb quite a lot. It seems consistent enough so if we can somehow compare the makeshift's results to a real chrono's results we can make a chart, but that's another post.

P.S. I haven't posted in a while because I went on a camping trip that I forgot to mention beforehand.
I have stuffed my front portion of my outer barrel with paper, in such a way that the inner barrel has a downward bend. I have yet to test if it all works as i want it to, but it should be work.

Note that I do measure with a caliper, so I know that i'm dead straight.

And yes, i know this is the uber poor man's solution to this.
Anyone know a good way to remove the wax from a barrel? Its a bit difficult to get the barrel out of the wax, so, i need a way to get it out without removing it :p
Still not really got my head around how to do this. I need to properly read it haha!
When I get round to giving it a go though I'll try and make a tutorial.

How difficult is it?
Anyone know a good way to remove the wax from a barrel? Its a bit difficult to get the barrel out of the wax, so, i need a way to get it out without removing it :p
You need to remove it without removing it? Am I missing something?
without removing the barrel from the outer/wax ;)
torch lighter. nothing beats wax like a pocket blow torch. buddy of mine broke his 4 burner using when he had to use it as a makeshift welder when he was out rock crawling one time.
How do you know what angle to get the wedge at?
Testing. Cheese has posted it on here somewhere... Not very much from what I understand. Start with 1-2mm maybe?
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I think he means what angle should he cut the actual wedge at. Make it a very slight angle so you can push in in or out and make small adjustments. There is no real set angle.
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Is there any guide for doing it with a screw in the barell? I feel like this could be done kinda like a TDC mod except the screw would push down on the barrel?
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Not a guide, but i believe Cheeseman does his LRB like this. Except, he uses two screws to adjust, and center the innerbarrel. (I could be mistaken though)
How many millimeters down do you need to bend the barrel for optimal performance?
I think that I have read that a gap of 2mm is about all you need. Your milage may vary depending on FPS, bb weight, barrel quality, etc.

There is my attempt at LRB'ing my CA G3, its not a guide but it'll give you a better idea on how I got it done!


I will note, that this system could do with two screws either side to make sure the barrel is centered! But it works, so :shrug: what you gonna do?
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I just want to throw out there some physics

so you are bending the tip of your barrel, right? if you have barrel spacers along the length of your barrel /and/ bend the tip, one of those spacers, if not flexible, will be a fulcrum and end up bending the barrel in the opposite direction farther down.

If you chose to do this, you either want a barrel spacer mid-barrel that is very wide and strong enough to resist this effect like tanaka ones (not those weird door stopper shaped ones made of rubber) or none at all and just put one near the hopup, and one near the end of the barrel.

so: tanaka style UHMW barrel spacers = good
electrical tape or O ring spacers = bad (for this purpose)
Can LRB (by whatever method) be done with a stainless barrel? Alum & brass are relatively flexible by comparison.
The point would be to arc the barrel, not bend. to do this you need to secure the barrel in 2 places, one at the hop up unit and one farther down the inner barrel. then when you apply pressure with however method you choose the last unsupported section of the inner barrel well bend down, but the section between the hop up and the and spacer will be strait. I have heard that you can do SS barrels but is easier to do on aluminum and brass.
I didn't see it mentioned, but what type of wax did you use, and is there a concern with wax inside metal on a warm day? I feel like the wax would get soft and the load of the barrel bend would straighten as the wax softened. I like the idea of a solid material between the barrels like wax though.

With this type of mod, is there a preferred barrel size? You're using 6.03 you mentioned, but I read 6.01 would improve accuracy and distance. Do you need something a little bigger than 6.01 for this mod to be more effective?
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