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Discussion Starter · #1 ·
With all the flurry about LRBs that abounds lately I thought I'd pass on what I know and understand about the technology that I've researched in the last couple of years.



The pro's of the stystem.... If done correctly they will provide a fair amount of range, using heavier ammo for a given fps, making the weapon slightly more a accurate due to the heavier ammo you can now use.

The cons.... there is a law of diminishing returns, basically the more power you use the heavier the ammo you should be using in any case, for weapons over 450ish fps that should be using .36 bbs and above anyway the best you can hope to see is a slight increase in range, and I do mean slight, there will be no noticeable increase in accuracy and you may well find it actually decreases.



The first thing we must understand is that the LRB has been about for a very long time, infact it was the only real option at hop effect pre TM hop designs that we know and love today.

They are only really effective in lower power weapon systems, or rather the effects will be more noticeable in lower power systems.

The original LRB system Incorporated a fixed or stepped or off-set barrel at the point where we now find a modern day TM hop. These varied from .8mm to 1.7mm. This was done to provide an element of back spin to the bb to aid its lift to the top of the barrel. This varied from barrel to barrel, gun to gun dependent on barrel length and curve in the barrel.

Original LRBs where made from 10mm brass stock, as opposed to the 8 or 9mm barrels we're used to now which reduced vibration that we know makes a normal barrel less accurate.



The LRB is a very finicky system and is in no way a thing your average noob, and for that matter your not so average vet, can just plonk in and forget. The original barrels where mostly cast with the curve in them, along with the off-set, this then had to be matched to the fps being used and the bb being used, even to the point that it could be ammo brand and weight specific, if the manufacturer pulled that ammo you were screwed :-/



Now we shall move onto the systems we are trying to create within our modern weapons.

If you are interested in trying to fabricate an LRB system within your system, if indeed its at all possible, these are just some of the things to bare in mind as you go about it.



Consider the fps you are using, you may well end up cutting and shutting large parts of your gun and gain no benefit over your original hop, so where possible always keep in mind 'can I return it to how it was?'

The cylinder volume still matters to the barrel length, try and incorporate the 'ideal' length barrel for your cylinder.

Try to make your system adjustable, it will increase the ammo you can use no end and it'll be more user friendly.

Don't worry you can use your nub style hop unit, its used to hold the bb in place, and it stands in the place of the off-set in the original style barrels to provide lift(back-spin) to the bb. Then nub does add an amount of lateral as well as vertical stability, so you could use any style of nub combo, but results will vary and alot of experimentation is required to get the best results.

Consider the slippyness of the barrel, the system by its very nature relies on how 'grippy' your barrel is, teflon coatings and stainless steel are nicely slippy for you standard system but wont provide much grip for an LRB, un-polished brass on the other hand will grip very nicely and increase the amount of back-spin put on by the barrel.

Try to use coarse surfaced bbs for the same reason as above.



I think thats about it, if anyone has any other questions just pop'em up and I'll add the best answer I can give in here ;)
 

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So what would be the upper limit for FPS with an LRB would you say.

What if you had a 500 fps rifle, would you see any real improvements in the range and accuracy department, or not so much?
 

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Discussion Starter · #3 ·
woogie said:
So what would be the upper limit for FPS with an LRB would you say.

What if you had a 500 fps rifle, would you see any real improvements in the range and accuracy department, or not so much?
For a 500+ rifle you'd get some extra range, but not alot.

Its one of those 'the effort in might not be worth results out' things at that power.

The system more or less relies on you needing to use heavier ammo at a lower power to aid with accuracy, and as I said in the OP, at 500+ you should already be using the heaviest bb weights comercialy available, which sort of defeats the object.

Its more a system that aids DMR and BA users that are limited in power, like us over here and in the Eire, that are in search of that extra bit of accuracy and hitting power that the high power users already enjoy ;)

One benefit a high power user, and low power users, will get is that more of the power available is used to propel the bb, rather than wasting some of it by forcing the bb past a 'normal' hop nub, so could reduce the time to target by a small amount..... food for thought ;)
 

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Heres something that just came to me: how much of a difference does barrel ID play with LRBs? Like, what was the normal ID for classic LRBs, and how much of an effect does it play on LRB modified builds with todays barrels? Is 6.03-6.08 still the optimal size?
 

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I really don't see the point of this because, yes you have range but the bb's has very lottle poweer at this range. You wouldn't even feel it. I can hop .43 with my PDI chamber to about 150ft (328fps w/.2g) and I can hop .3g 200ft quite easy too. Then I can get a .25 nearly 240ft. But there is not point because if you hit someone that far away the bb will have no energy and it will be like having a butterfly land on you. They won't feel nor call their hits.

So yeah it works, but IMO pointless.
 

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Discussion Starter · #10 ·
@Bob..... All normal provisoes still apply to an LRB as to a 'normal' straight barrel, as the same effects are still happening inside ;)

@Inthetallgrass.... Thats very much the point in a low power system, it sends a heavier bb, carrying more kinetic energy out to a further range, its got nothing to do with how fast it gets there, and that is all feet per second measures, its Joules that measures the hitting power, and heavier bbs carry more joules. Also, as I said above, a properly set up LRB is more efficient as it enables you to use pretty much all of the fps available as it doesn't use a hop nub in the same way as a normal system, which wastes more and more power the heavier the bb you try to use. With an LRB the nub setting stays the same you just dial in more curve, this ofcoarse isn't limitless as you can only ever push the laws of physics so far.... and the curve of your barrel ;) and as your using heavier bbs the accuracy is still there with a bit more range.... whats not to like??
 

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Trust me I know the difference between fps and joules. I also know that heavier BB's have more kinetic energy etc. (I do do physics you know) but I really don't see the point as abosuloutely everything loses energy after it's source is depleted. So the Bb' will still slow down and lose it's joules too. I don't see how the Bb will keep it's kinetic energy at a high level for any longer than a conventional barrel if they both leave the barrel at the same time. Infact if you had to have it to a set fps (328 etc.) the Bb would be forced out with more power with a normal hop up because of the decrease factor from the nub while it would have less power with this barrel. Also with the Bb bouncing incraments being larger because of the larger barrel I imagine it would be less accurate.

I just don't think the effort is worth it when I can already get .3g Bb's farther than my effective range (when the bb has too litlle power for people to be able to feel they are hit) Things don't deaccelerate at a different rate if they are of the same weight and travelling at the same speed.

Still it is good idea and I encourage people who have the time and he money to do it.
 

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I really hate to be that guy, but my biggest problem I am not privy to the acronym LRB. what would that stand for?
 

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Discussion Starter · #14 ·
Its all about using heavier ammo, for a given fps, that under normal circumstances would be concidered not powerful enough to support that weight of ammo, this is the advantage of an LRB over a normal system ;)

inthetallgrass said:
as abosuloutely everything loses energy after it's source is depleted. So the Bb' will still slow down and lose it's joules too. I don't see how the Bb will keep it's kinetic energy at a high level for any longer than a conventional barrel if they both leave the barrel at the same time.
It wont, if you are using the same weight of ammo, the objective is to get a bb with more mass out to the same range as a lighter bb, therefore carrying more hitting power to the same range as something with less hitting power, while not using any more power.

inthetallgrass said:
Infact if you had to have it to a set fps (328 etc.) the Bb would be forced out with more power with a normal hop up because of the decrease factor from the nub while it would have less power with this barrel. Also with the Bb bouncing incraments being larger because of the larger barrel I imagine it would be less accurate.
I'm not really sure what you mean here, but its common knowledge that a conventional system hop uses power to produce its effect, the 2 exceptions to this are the VSR hop which is odd in the fact it actually gains fps the more hop you add and if you are allowed to do your site fps checkes with the hop set and not returned to zero as alot of sites I play at insist on :-/ As for the bb bouncing along the barrel, and barrel bore size (larger bores are actualy more accurate) this has been a long time source of confrontation on many websites and is a discussion for another thread, but for the purposes of this thread.... has been disproved, and has been confirmed b clear barrel experiments to show the bb only bounces once or twice then due to magnus effect of the hop then skids along the top of the barrel, without this the LRB as a system would not work in any way.

inthetallgrass said:
I just don't think the effort is worth it when I can already get .3g Bb's farther than my effective range (when the bb has too litlle power for people to be able to feel they are hit) Things don't deaccelerate at a different rate if they are of the same weight and travelling at the same speed.
Ah, but wouldn't you like to send a .4 out to the same range your now sending a .3, with the resultant extra hit power that would come from a heavier mass hitting the target, reducing the 'butterfly landing' problem you mention ;)
 

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Is there the possibility that custom made barrel spaces imprint an unwanted LRB-like effect on the BB? I use custom made ones which are supposedly round and create the same amount of spacing homogeneously around the inner barrel..but I did not conaider the roundness factor of the outer barrels.

Variables, they have a way of getting between you and cake.
 
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