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m102404 · September 25th, 2008, 10:24

This is a winter project rifle...and my first in-depth into airsoft bolt actions. It's used, with at least one previous owner.

Background (Skip this if you want to...questions are at the end):
When disassembling the barrel assembly and checking things out, I noticed that the hopup rubber seemed to protrude A LOT down into the inner barrel, even with the hopup turned all the way off. There was a little ball bearing under the hopup lever arm. No big deal that it's a ball bearing.

After disassembling the hopup unit, I noticed that the inside surface of the hopup rubber seems very rough (like it's been torn/worn), which is not surprising considering the soft rubber, ball bearing and amount of protrusion into the barrel.

I swapped the ball bearing with a regular hopup nub. It still protrudes a lot into the barrel (hopup off) but it at least has some give. Since the slot/molding of the barrel/hopup rubber is fairly minimal, I rotated the hopup rubber 180deg so there'd be a not-roughed-up section of rubber protruding into the barrel. It reinstalled smoothly and everything seems to sit right.

Reassembled, the rubber still protrudes a lot, hopup off. Shots fire reliably (they used to jam with the ball bearing installed), but way too much hopup is applied. Groupings are consistent...just way up in the sky and not on target.

Yes. I know I can get a PDI hopup and use regular AEG barrels and rubbers. I'll do that eventually when Jugglez finds one in stock.

FPS is 380fps with 0.30g BBs (spilled my BBbastard on the ground...so they're KSC perfects)...yes, I know...too hot for local games...that's not the point.

My questions are:
1. For those with bolt actions...when your hopup is off, do you get any protrusion of the rubber into the barrel? I.e. on most AEGs, when the hopup is off, the barrel is clear....is it different for bolt actions?

2. It's not really the most measurable question...but how much of the rubber is pushed down into your barrel (i.e. 1/10th, 1/5th, etc...) when your hopup is set normally. I realize that this depends on the rubber hardness, fps, etc...but just to get a general sense.

3. I'm not the best parts searcher kind of guy...I've looked, but haven't found stock hopup rubber parts listed on WGC, Redwolf, Unco...I'm "assuming" that the Well L96 parts are the same as Maruzen Type 96 parts...but no sign of stock replacement hopup rubbers...can someone point me to the right spot?

4. Are there any DIY/homebrew remedies to try to remedy this?
- I'm thinking of either grinding down the cup of the hopup arm so that the nub sits higher out of the barrel. Similar to PDI's "low" arm. But this will be a permanent mod, unless I fabricate another arm (and I'm not that bored yet).
- I'm also considering bodging something together to replace the hopup nub that will be "flatter" and not push down so much on the rubber...but with the amount that it pushes down, I'm not sure that it'll help.

Any help is appreciated. It's very nice that bolt actions are so simple with few parts vs. AEG/GBB's.

September 25th, 2008, 10:24	#1
m102404 Tys Trader rating Join Date: Apr 2006 Location: Toronto	Well L96 Hopup rubber This is a winter project rifle...and my first in-depth into airsoft bolt actions. It's used, with at least one previous owner. Background (Skip this if you want to...questions are at the end): When disassembling the barrel assembly and checking things out, I noticed that the hopup rubber seemed to protrude A LOT down into the inner barrel, even with the hopup turned all the way off. There was a little ball bearing under the hopup lever arm. No big deal that it's a ball bearing. After disassembling the hopup unit, I noticed that the inside surface of the hopup rubber seems very rough (like it's been torn/worn), which is not surprising considering the soft rubber, ball bearing and amount of protrusion into the barrel. I swapped the ball bearing with a regular hopup nub. It still protrudes a lot into the barrel (hopup off) but it at least has some give. Since the slot/molding of the barrel/hopup rubber is fairly minimal, I rotated the hopup rubber 180deg so there'd be a not-roughed-up section of rubber protruding into the barrel. It reinstalled smoothly and everything seems to sit right. Reassembled, the rubber still protrudes a lot, hopup off. Shots fire reliably (they used to jam with the ball bearing installed), but way too much hopup is applied. Groupings are consistent...just way up in the sky and not on target. Yes. I know I can get a PDI hopup and use regular AEG barrels and rubbers. I'll do that eventually when Jugglez finds one in stock. FPS is 380fps with 0.30g BBs (spilled my BBbastard on the ground...so they're KSC perfects)...yes, I know...too hot for local games...that's not the point. My questions are: 1. For those with bolt actions...when your hopup is off, do you get any protrusion of the rubber into the barrel? I.e. on most AEGs, when the hopup is off, the barrel is clear....is it different for bolt actions? 2. It's not really the most measurable question...but how much of the rubber is pushed down into your barrel (i.e. 1/10th, 1/5th, etc...) when your hopup is set normally. I realize that this depends on the rubber hardness, fps, etc...but just to get a general sense. 3. I'm not the best parts searcher kind of guy...I've looked, but haven't found stock hopup rubber parts listed on WGC, Redwolf, Unco...I'm "assuming" that the Well L96 parts are the same as Maruzen Type 96 parts...but no sign of stock replacement hopup rubbers...can someone point me to the right spot? 4. Are there any DIY/homebrew remedies to try to remedy this? - I'm thinking of either grinding down the cup of the hopup arm so that the nub sits higher out of the barrel. Similar to PDI's "low" arm. But this will be a permanent mod, unless I fabricate another arm (and I'm not that bored yet). - I'm also considering bodging something together to replace the hopup nub that will be "flatter" and not push down so much on the rubber...but with the amount that it pushes down, I'm not sure that it'll help. Any help is appreciated. It's very nice that bolt actions are so simple with few parts vs. AEG/GBB's.