Which Tightbore and Hop Rubber for a G&P Sentry?

[Longshot]

Right, I've been a silly boy here. I was thinking about getting a TB for my Sentry but had read conflicting reports about the barrel length online so I decided to open it up and take a measurement for myself. I also thought I'd give the barrel a clean while I was at it. This led to two problems:

1, I've found out that the barrel is 275mm long, but there doesn't seem to be any TB barrels for sale in this length. In fact, some American reviews suggested that the standard barrel in the Sentry is a TB - anyone know if this is the case, or if it's not what TB barrel suits (or will fit) the Sentry?

2, I ripped my hop rubber. Stupid thing to do, but that damn rubber was just jammed in there all to hell and would not come out. I'm pretty sure I ripped it when it 'bunched up' on the way out, but I could well have ripped it when I tried (delicately, I swear) to reinsert it and it once again just jammed to crap (one thing I read online said to oil the oustide of the rubber when putting it in, but I'm sure that's a bad idea for some reason, isn't it?).

I know there are plenty of threads I could read on this, but would someone please recommend me a good hop rubber for a nice bit of range. I'm currently thinking either 'Madbull Shark 60 Degree Accelerator Hop Rubber (Red)' or 'Madbull 60 Degree Hop Rubber (Blue)' because I'm sure I've read good things on here about Madbull rubbers. I'm honestly not up on these things, so I just want something that is effective and easy to reinstall. The hop unit is standard G&P, if that makes any difference.

Any and all help is much appreciated.

[dantwnn]

Re: Which Tightbore and Hop Rubber for a G&P Sentry?

couldnt tell you the tightbore of right length.but id use the closest prommy one with firefly rubber or laylax purple one. Or tm ones hav always been good and dead cheap

[Puddzzz]

Re: Which Tightbore and Hop Rubber for a G&P Sentry?

Just measured my Systema TB at 275mm (give or take a few mm as it is still in the Hop Up) if that helps.

I use a Fire Fly rubber in my G&P M4 and achieve awesome ranges along with a Fire Fly Bucking and achieve excellent accuracy through a JG barrel Definitely recommend Fire Fly. I used the Madbull Blue rubber but found better performance with Fire Fly rubber. Heard that TM Rubbers are very good.

[HuntR]

Re: Which Tightbore and Hop Rubber for a G&P Sentry?

On a budget, Vanaras tightbore and TM rubber.

Decent budget, Madbull tightbore and Systema rubber.

Feeling flush, Prometheus tightbore and firefly rubber set.



I've also had a great experience from the SHS rubbers. The clear ones. But that was paired with an SCS hop nub. The SCS (Shredders concave spacer) is brilliant. However it does take quite abit of fiddling to get it set up properly.

Personally though i'd go down the Prometheus route with a firefly soft rubber set. For 2 reasons. The firefly rubber set easier is easier to source than the SCS. And it's also far easier to get it set up properly

[CK]

Re: Which Tightbore and Hop Rubber for a G&P Sentry?

CQBr length M4's I have always used 285mm Madbull Black Python ver II's in. with a madbull hop unit, and a TM rubber, works a dream.

My old Sopmod though had a Prometheus TB and Firefly hop rubber, and that was the dogs danglers.

CK

[BringOnThunder]

Slight hijack but what sort of fps increase will a tbb give?

Sent from my HTC Desire using Tapatalk

[joe123]

Re: Which Tightbore and Hop Rubber for a G&P Sentry?

Roughly 10-15 fps for 6.03

[Longshot]

Re: Which Tightbore and Hop Rubber for a G&P Sentry?

I've got a standard TM rubber coming my way now, I'll see how that goes. Anyone know what 'degree' the standard TM rubber is?

As to the tightbore, tomorrow I'm going to have my learned scientific friend work out what the current barrel in there is right now. If it's any bigger than 6.05 I'll probably opt for a Madbull V2 285mm and make do with the extra 10mm jutting out - should be easily hidden by the flash hider anyway. I'll check the FPS at my next game in two weeks first though, the guy I bought teh Sentry from stated it was about 325, so not much room to play with there is a TB ups the FPS by too much...

[Longshot]

Re: Which Tightbore and Hop Rubber for a G&P Sentry?

Right new problem.

Electric calipers tell me that the standard barrel is actually a 6.04mm TB, so I'm going to leave that in there (though probably get a Madbull down the line for the superior quality.

Took the hop up unit apart too to see what the nub was like. Turns out it's the 'H' type, but I've got no other type to hand to change it for right now so I'm leaving it in there despite hearing that Hs can be a God send or a curse, depending on who you ask - and your overall setup, presumably).

Now to the problem: stuck the new TM rubber in when I got it this afternoon. Got it in nice and gently using a little silicon grease on the outside sides, well away from the nub area. Refitted the unit back in, closed everything up and went for a test fire. Now I'm having major feeding issues! Tried three different brand midcap types and all are causing problems.

G&P mid is firing a couple of shots then nothing unless I eject and replace the mag, then just does the same again.

MAG mid is firing every round at about 100FPS.

CA mid is the best, but it's firing randomly, sometimes you get a BB, sometimes you don't.

The piston seems to be firing fine. If I remove the mags and look up the hop from the bottom it's doing its thing. And with the exception of the MAG mid (which is admittedly a tight fit in the receiver) the BBs are all either firing properly or not at all - not 'dribbling out' which I assume would indicate a hop rubber issue. In fact, I've turned the hop right off and still experiencing the same issues.

What the hell have I done now and how do I proceed?

[SOBandy]

Re: Which Tightbore and Hop Rubber for a G&P Sentry?

Yo dude i have a g and p and run a prom barrell with prom hop unit and i absolutly stand by it, so much so that half of the team now run this set up. Prom hops are the best around and the barrells are airsoft porn

[North West Outpost]

Re: Which Tightbore and Hop Rubber for a G&P Sentry?

Split the gun down again and make sure the hop rubber is sitting evenly inside the hop up. Don't worry if it takes many attempts to get it right, just keep doing it untill it sits right.

Then make sure you didnt get any lube inside the hop rubber on the nub. Having lube outside is good as it seals things up.

[Longshot]

Re: Which Tightbore and Hop Rubber for a G&P Sentry?

Been playing around for the best part of an hour and I'm just getting no joy here. I really can't work out the problem.

I assumed it was hop rubber related at first, but any which way I look at it the whole hop unit and rubber look sound (it is in there nice and round, not eliptical looking, and the c-clamp and everything else is sitting flush). The piston is firing fine as well (observed both dry firing with gun apart and by looking up through the hop unit).

Everything looks good until you get some mags in and she just doesn't want to know. Fires one or two and then is just feeding nothing through. It's not like they're dribbling out or coming out wrong, they're just not getting from the mags and into the hop by the feel of it.

I've got some time off next week so I'll have to get serious and start swapping parts around from my different M4s to establish what is and isn't working as it should.

[North West Outpost]

Re: Which Tightbore and Hop Rubber for a G&P Sentry?

Do you hear any different sounds. Like there is a distinct dry fire sound, can be quite loud. Then there is the sound when a bb is jammed in the hop rubber, a kind of quietish dull sound.

[Longshot]

Re: Which Tightbore and Hop Rubber for a G&P Sentry?

It's the distinct dry fire sound that I get. Fires one or two rounds and then it's essentially dry firing without any BB feeding going on.

[North West Outpost]

Re: Which Tightbore and Hop Rubber for a G&P Sentry?

That's quite strange as you have only changed the hop rubber.

I got caught out like that recently. A new M16 everything tight, said to a mate after a rebuild, bloody thing only feeds now and again. Need to sort that out....He slapped the bottom of the mag and it was fine...lol. Sometimes it's the simplest of things.

I had already pushed and wriggled them, obviously not hard enough.

I have also had hop rubbers where they protrude just slightly into the feed tube. Only a tiny bit but enough to stop feeding.