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Dannn

BB weight, hop lift fps drops

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Since r hoping and tight boring my g63 I can get .25 bbs doing an awesome upwards curve with a small amount of hop so I've now got .28's and I can still get stupid amounts of lift on those so without having to spend d fortunes in buying increasingly heavier bbs does anyone have any graphs or charts or any info on hop/weight/ fps ratios

Also any info on the spring power increase to weight of bb fps loss as at this rate I'll be able to use .32's or more and so looking at the relationship between weight and kinetic energy...

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With .25s you can get a flat trajectory from R-Hopping - it's possible you've installed the patch too low and it's making too much contact. R-Hopping is all about minor adjustment until it's just right so this is to be expected.

If you have the easy install kit from HSA then take the barrel out, press it against the patch and see how much it protrudes into the barrel - that's how much hop you're getting with it completely turned off. You should be able to drop a BB down the barrel or by gently blowing on it - the patch should generally not protrude into the barrel at all on a standard bore width - so between 6.01 and 6.08 (wide bores are a slightly different story). If neither of these things gets the BB past the patch then it's seated too low. If you don't have the install kit then simply try using something flat (bit of wood or a hardback book) and press it against the patch to see how much it goes down into the barrel. Obviously don't push it too far in like the nub in your hop would - you're just trying to see what the patch looks like in the hop 'off' state.

Basically there are two solutions, and because of window sizes I can't be sure for yours, but the HSA patches sometimes don't have enough material and you need to build up the edges of your hop window with RTV before placing the patch on so that it sits higher. The other solution is to simply sand that thing down (as I'm sure you have already) once it's installed in the window so that your bucking alone does not push it further into the barrel in the 'off' position.

That said though, R-hops work best with .28s, .30s and above - that's when you get your 50m+ ranges, so it may be worth investing if possible. I feel your pain though - I'm looking at £13 per 3000 for my 249 and that thing is going to be shooting close to 30rps when broken in.

As far as FPS loss goes: Remember remember, FPS =/= energy. By-and-large (and Joule creep aside) your power is going to remain the same regardless of the weight of BB, and this is what sites really try to measure at the crono when they get everyone using the same weight. If you're using heavier BBs then you must still be around 1.05 - 1.15J if it's an AEG (335 - 350fps with a .20 respectively) as this is generally the site standard in the UK. With a .30, that's going to be roughly between 270 - 300fps. Obviously this means the BB takes longer to get there, but it'll actually get there and not drop off early.

Edit: Added a bit more detail and added to FPS bit too.

This may be of interest to anyone not following:


airsoft-fps-chart.gif

 

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It's possible, but do be sure as you should be able to get a flat trajectory out of a .25 if it's turns on a very, very small amount. Looks like it might be .28s or .30s from here on in though, eh!

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I had a similar difficulty with an R hop patch. I spent a day on a site with some sandpaper/dremel/tools just further tweaking the patch until I got it shooting straight with 0.28g BBs. I never bothered to get the 0.25g BBs working, I can't see any intrusion in the barrel at all its flush but they still just overhop and I think its from just the patch itself on the top without it being pushed down. Even though 0.28g BBs are nice and straight I find 0.30g BBs are better accuracy and range so that is what I now use.

 

It so vastly improves the amount of hop you can apply that it does indeed increase the weight your gun can effectively hop, but as a result it also could and in my case did mean 0.25g was impossible to use anymore.

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Using hsa n nub and clear r hop.

I think it's just the fact I've set it up so that the smallest amount of hop creates lift as its maybe a 'thou of an inside the barrel window if you know what I mean,?

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I had a similar difficulty with an R hop patch. I spent a day on a site with some sandpaper/dremel/tools just further tweaking the patch until I got it shooting straight with 0.28g BBs. I never bothered to get the 0.25g BBs working, I can't see any intrusion in the barrel at all its flush but they still just overhop and I think its from just the patch itself on the top without it being pushed down. Even though 0.28g BBs are nice and straight I find 0.30g BBs are better accuracy and range so that is what I now use.

 

It so vastly improves the amount of hop you can apply that it does indeed increase the weight your gun can effectively hop, but as a result it also could and in my case did mean 0.25g was impossible to use anymore.

I think 25's are gonna be useless too, I'll have to buy a box of heavier bbs to make sure I don't get caught without them as the local sites just stock 20 and 25's

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