Author Topic: Spring guide and top hat?  (Read 5400 times)

Offline donderkop

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Spring guide and top hat?
« on: June 20, 2010, 06:26:06 AM »
Spring guide and top hat[ in a springer] made of light weight material [delrin] l and before mentioned made of heavy material [s/steel]\
Which one would enhance higher velocity/better performence?
Is there any rule of thumb concerning the above mentioned?
 :0

Offline JimL911

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RE: Spring guide and top hat?
« Reply #1 on: June 20, 2010, 09:43:28 AM »
Heavier piston = higher velocity.
Higher velocity = harsher shot cycle which can effect accuracy.
It is a game of trial and error unless you tune a lot of guns and know whereto start.

Offline CharlieDaTuna

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RE: Spring guide and top hat?
« Reply #2 on: June 20, 2010, 11:29:12 AM »
A heavier piston does not always mean a higher velocity will be obtained unless detonation occurs and in some cases a heavier piston will reduce the velocity and at the same time create a harsher shot cycle. What does happen is the heavier piston hits the bottom of the cylinder harder and the cushion of air does not absorb some of the shock of the piston hitting the bottom of the chamber. Also, the weight of the piston increases the compression ratio and can cause unwanted premature detonation rather than combustion desired, especially if excessive fuel comes into play.

Also, higher velocity does not necessarily mean a harsher shot cycle. If properly tuned, many guns can have a higher velocity and will also have a far better firing cycle. Both the loss and the improvement of the velocity and firing cycle depend on several factors including the seal and chamber sealing properties, the lubes used where, how and how much, the spring and guide as well as tophat fit. Also, what method used in reducing the torque on what gun impacts the firing cycle.  
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Offline donderkop

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Re: Spring guide and top hat?
« Reply #3 on: June 21, 2010, 09:41:19 PM »
Thanks for the above mentioned. Does your answer implies that lighter materials like delrin will give lower velocities?  Also if the piston head [in a BSA Meteor MkV] were to be made of delrin, thus a lighter piston, will we have lower velocities?

Offline bobbyjim

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RE: Spring guide and top hat?
« Reply #4 on: June 22, 2010, 02:15:25 AM »
I always see that materials used for a top hat are Delrin, brass & steel. What about 6061 aluminum? Seems that should work also. Like to see some opinions on aluminum.