Quote:
Originally Posted by Skruface
The problem with the spring being too long is probably because you have bearings on both the piston head and the spring guide. Sometimes a longer spring will fully compress and jam without the piston being all the way back. This can lead to the piston stripping or breaking. In all honesty, you only need bearings at one end. Usually, that should be the spring guide end...less weight in the piston head is a good thing.
As for comparable springs, our own Illusion made this excellent spring chart a few years ago:
http://www.airsoftcanada.com/SpringChart.php
I'd go with a Prometheus MS120 for your application. |
According to chart Prometheus MS120 is the same strangth as my PDI 170%. Where is the improvement?
If I remove bearings on piston side, I'll get extra 4 mm, but spring is still 175mm long. It would take a lot of struggle to fit it in. Is there any special way to do it? Not mentioning the possible jamming.
Quote:
Originally Posted by Skruface
The problems with mechboxes cracking, *ESPECIALLY* v2 mechboxes, tend to start when the cylinder is not matched to the barrel. When it holds too much air (such as an m4 cylinder, with an internal volume meant for a 363mm barrel, is used with a 285mm barrel). The bb will actually exit the barrel before the piston is fully forward...with no backpressure to slow it down, the piston slams HARD into the cylinder head, just as if you were dry firing. This is not good. I urge you to consider getting a cylinder that's matched to your barrel, otherwise be prepared to buy plenty of mechbox shells.
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Which cylinder would you recommend then?
Or maybe I can just drill a larger hole to the cylinder to lover total volume. No need to spend anotehr money...
The cylinder I have is recommended for 200-400 mm barrel, not sure if 100 mm will lmake any difference...
Quote:
Originally Posted by Skruface
If it's a bushing, it's a single solid piece of steel. It will look like this: http://redwolfairsoft.com/redwolf/ai...l?prodID=21829
Bearing bushings are usually a mutli-piece design. They have a metal bushing, some small metal ball bearings, and a metal race to keep the bearings inside the bushing. They look like this: http://redwolfairsoft.com/redwolf/ai...l?prodID=17813
The problem with bearings is their ability to handle the load of a high-powered spring. 6mm bearings and cheap 7mm bearings will fail under load, the race will break, and the ball bearings will end up shooting into you piston and gear teeth, increasing the chances are they will be ruined as well. If your bearing bushing fails, you may have to replace the piston and gears along with the bearing bushings themselves. The larger the bearing, the more stress they can handle....8mm can handle load better than 7mm, which is in turn better than 6mm. However, "bargain" bearing manufacturer will often use an oversized bushing bearing case and still use the same ball bearings as they use in 6mm bearings to make them cheap...so buy high quality bearing bushings if that is the route you want to go. Generally, bearings with ceramic ball bearings are better than those with steel, as ceramic is both smoother and stronger. Kanzen makes the best ceramic bearing buchings you can get for an airsoft gun....they run about $35 a set. |
Hm so I have ball bearings after all. I will buy new ceramic bushings then. (do they have any at redwolf?) Is 7mm enought?? Otherwise I would have to buy new gearbox with 8 mm holes or drill new holes to my current one to fit 8mm bushings.
Quote:
Originally Posted by Skruface
In this case, I would try to match the hopup rubber with the velocity you intend to shoot. A new (harder) rubber designed for higher FPS will give you more shot-to-shot consistency.
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New one added to the basket...
Quote:
Originally Posted by Skruface
Realize that the v2 mechbox has physical limitations based on it's design. It's not about "if" it will break...it's about "when". If you are using a version 2 mechbox at more than 280 fps, it will break. This probability is increased the higher the FPS. It is compounded when you do not match the cylinder and inner barrel, as stated above. After you have replaced 2 or 3 mechboxes, you may be wishing you spent that $45 after all.
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Ok, ok I will consider... Would you recommend any shop? I have found just one...
Quote:
Originally Posted by Skruface
A Systema red piston or a Systema black one? The red ones have had problems for as long as I have been playing....keep in mind that pistons are designed to be the replaceable part in your mechbox....it's the cheapest thing to fix, and when a plastic/nylon/POM piston fails and chunk go flying into your gear teeth, they're much less likely to do any damage to the gears. A good nylon piston with properly adjusted angle of engagement will work as good (if not better) than an all-steel (or titanium)-toothed piston at a fraction of the cost. But hey, it's your money.
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Black one, funny thing is I have shot about 100 bb with this brand new gun when the last nylon tooth broke off.