Airsoft Canada - View Single Post - The amazing R-hop test project!

ThunderCactus · March 25th, 2013, 13:31

So I've been doing a lot of reading on other forums about this, and whenever someone bashes it, says it's not all it's cracked up to be, or says there's no gain, I'm not convinced they understand the physics behind the mod, or have proper test conditions.

So firstly, one HUGE misconception is that it makes a ridiculously huge difference in range and accuracy.
This is not false, but tends to be over exaggerated.
Why?
Well most often, someone has a STOCK gun, and upgrades it immediately to an R-hop. Obviously you're going to see a huge improvement.
But when you go from something already really good, like a firefly or PDI-W, then the gains aren't quite so drastic. Then we're talking about 5-10s of feet difference as opposed to an extra 120ft.

Second, applied hop
On an AEG, you don't have nearly as much initial pressure to drive that BB past the hop rubber with a lot of force. I haven't seen an AEG yet that doesn't jam before it gets to it's max hop setting. And the more hop you apply, the more force is lost trying to force the BB past the rubber, resulting in FPS losses. With heavy rounds and low FPS, you typically can't apply enough hop to a round to get it to fly straight.
There's a lot of complications comparing AEG performance to GBBR performance on heavy rounds, so I'll explain it in more common terms;
Most 300fps GBB pistols do REALLY well on .30s, whereas a 330fps AEG typically does not. If a low fps AEG and GBB pistol have the same muzzle velocity when shooting a .30(that means they're both shooting around 220fps on the chrono or whatever it comes out to), the pistol tends to achieve a flatter trajectory, and the AEG tends to jam from over-hop before you can get it shooting to it's max range.

So that's complicated stuff I'm not confident about with out testing.
How am I gonna prove that crap out?

WELL, what all that means is that the Rhop should allow you to use heavier rounds on AEG's that you normally wouldn't be able to use.
So as far as proving the rubber, it's pretty straight forward, so here's what I'm gonna do (and I'd LOVE to have some other gunsmiths test this out as well!)

Get a low FPS gun 300-330fps, start shooting with a high quality hop rubber, then install an Rhop and re-test
-Test with the .25g BB they would typically run at that FPS
-Then with .30s, which often fall short on low FPS platforms
-Then with .36s, which most definitely will jam anything under 350 before it will fly straight

THEN, repeat that test with a more common 380-400fps AEG
-Test with .28s as they would commonly run
-Then with .36s, that should still do alright
-Then with .43s which should outline a clear difference between the two!

EDIT: Also needs to be compared between longer and shorter barrels. Ideally testing with the same gun. Practically, I would accept a graph of results from various longer and shorter barreled guns.

Now the reason I'm upgrading the same AEG for both is to ensure the internals play no part on the test, since the mod only affects the hop/barrel end of things.

So, what we SHOULD see is the R-hop being same or slightly better with the common weight of BB, and then perform better with heavier ammo.

So of course not being a physicist myself, what I put forth could be totally ass backwards, but that's what the practical test is for. Once we get some factual results, we can figure out the science from that. If nothing else, this will prove if the R-hop is really a better rubber, or just being puffed up by people who just don't know any better.

We're building a measured range at two of our Mb fields this year (that's the pan anyway), so I'll have measured results. (Gonna do my PTW as well since google maps tells me I'm shooting stupid far)

So for any gunsmiths interested in partaking, make sure the mechbox is getting a REALLY good seal before testing. We want the AEG's to be in peak performance condition BEFORE getting the R-hop.
Measure out the distance you're shooting and please use a spotter to verify where they land.
I'm sure we'd all appreciate having detailed performance results on this

Also it's the end of march and we've still got a good 2ft of snow here in Mb, so it could take us a while to set up for this =/

I've currently got an R-hop in my G&P 249 at the moment, and preliminary testing looks good, but not mind-blowing (testing at 380 with .28s). Getting good range and accuracy, but certainly not an extra 60ft, maybe 20-30.

Buddy o mine has the same G&P, so I'm gonna borrow his barrel to quick swap between R-hop and standard rubber to do some real time comparison if I ever manage to get my ass out to a game sometime soon lol

March 25th, 2013, 13:31	#1
ThunderCactus Not Eye Safe, Pretty Boy Maximus on the field take his picture! Trader rating Join Date: Feb 2007	The amazing R-hop test project! So I've been doing a lot of reading on other forums about this, and whenever someone bashes it, says it's not all it's cracked up to be, or says there's no gain, I'm not convinced they understand the physics behind the mod, or have proper test conditions. So firstly, one HUGE misconception is that it makes a ridiculously huge difference in range and accuracy. This is not false, but tends to be over exaggerated. Why? Well most often, someone has a STOCK gun, and upgrades it immediately to an R-hop. Obviously you're going to see a huge improvement. But when you go from something already really good, like a firefly or PDI-W, then the gains aren't quite so drastic. Then we're talking about 5-10s of feet difference as opposed to an extra 120ft. Second, applied hop On an AEG, you don't have nearly as much initial pressure to drive that BB past the hop rubber with a lot of force. I haven't seen an AEG yet that doesn't jam before it gets to it's max hop setting. And the more hop you apply, the more force is lost trying to force the BB past the rubber, resulting in FPS losses. With heavy rounds and low FPS, you typically can't apply enough hop to a round to get it to fly straight. There's a lot of complications comparing AEG performance to GBBR performance on heavy rounds, so I'll explain it in more common terms; Most 300fps GBB pistols do REALLY well on .30s, whereas a 330fps AEG typically does not. If a low fps AEG and GBB pistol have the same muzzle velocity when shooting a .30(that means they're both shooting around 220fps on the chrono or whatever it comes out to), the pistol tends to achieve a flatter trajectory, and the AEG tends to jam from over-hop before you can get it shooting to it's max range. So that's complicated stuff I'm not confident about with out testing. How am I gonna prove that crap out? WELL, what all that means is that the Rhop should allow you to use heavier rounds on AEG's that you normally wouldn't be able to use. So as far as proving the rubber, it's pretty straight forward, so here's what I'm gonna do (and I'd LOVE to have some other gunsmiths test this out as well!) Get a low FPS gun 300-330fps, start shooting with a high quality hop rubber, then install an Rhop and re-test -Test with the .25g BB they would typically run at that FPS -Then with .30s, which often fall short on low FPS platforms -Then with .36s, which most definitely will jam anything under 350 before it will fly straight THEN, repeat that test with a more common 380-400fps AEG -Test with .28s as they would commonly run -Then with .36s, that should still do alright -Then with .43s which should outline a clear difference between the two! EDIT: Also needs to be compared between longer and shorter barrels. Ideally testing with the same gun. Practically, I would accept a graph of results from various longer and shorter barreled guns. Now the reason I'm upgrading the same AEG for both is to ensure the internals play no part on the test, since the mod only affects the hop/barrel end of things. So, what we SHOULD see is the R-hop being same or slightly better with the common weight of BB, and then perform better with heavier ammo. So of course not being a physicist myself, what I put forth could be totally ass backwards, but that's what the practical test is for. Once we get some factual results, we can figure out the science from that. If nothing else, this will prove if the R-hop is really a better rubber, or just being puffed up by people who just don't know any better. We're building a measured range at two of our Mb fields this year (that's the pan anyway), so I'll have measured results. (Gonna do my PTW as well since google maps tells me I'm shooting stupid far) So for any gunsmiths interested in partaking, make sure the mechbox is getting a REALLY good seal before testing. We want the AEG's to be in peak performance condition BEFORE getting the R-hop. Measure out the distance you're shooting and please use a spotter to verify where they land. I'm sure we'd all appreciate having detailed performance results on this Also it's the end of march and we've still got a good 2ft of snow here in Mb, so it could take us a while to set up for this =/ I've currently got an R-hop in my G&P 249 at the moment, and preliminary testing looks good, but not mind-blowing (testing at 380 with .28s). Getting good range and accuracy, but certainly not an extra 60ft, maybe 20-30. Buddy o mine has the same G&P, so I'm gonna borrow his barrel to quick swap between R-hop and standard rubber to do some real time comparison if I ever manage to get my ass out to a game sometime soon lol Last edited by ThunderCactus; March 25th, 2013 at 15:50..