Corsair hammer springs

[lloyd-ss]

Tom,
Is the cone spring damaged or weak?  That could be making the tank dump worse.

You can try this and possibly get the spring with the .047 wire to work.  Check the length and number of coils in your original spring. Stretch a piece of the new spring out so that you get a spring of the original length, but with 2 or 3 fewer coils.  Cut the stretched spring to about 1/8" longer than the original spring.  That should give you a stiffer spring than original. 

It might seem counterintuitive, but if you have 2 springs of the same dia and wire and length, but with a different number of coils, the spring with the fewest coils will have the highest "Spring  Rate" in pounds per inch. 
Lloyd

[melloroadman]

Tom the first rifles out had no spring at all from what I have been told . The rifle on full power with that small tank will bump at shot 5 every time . You only have 155 cc of air and a 308 is a big bore . The spring was installed so the rifle can be hand pumped . Prior to that you could not get the valve to seal with a empty tank and a hand pump . With the set up that that rifle has I have been told by Dan who makes them that a stronger return spring will reduce the power . But since you are wanting to do that any way you might use a different spring to control the energy but not the dump .Marvin

[tkerrigan]

The cone spring went toasty in reply #15.  I ordered the slugs below last night from hunters-supply.com to try out.  They don't cost that much more than the round ball if you buy 500 at a time, around a dime a shot.  I hope they shoot decent, that would be easy.  I will take a pic of the new air stem spring arrangement tonight or tomorrow and attempt to post it.               Tom

1 x 30 Cal .308 076 FP: Box of 100 (100) = $15.50
1 x 30 Cal .308 079 gr. FP Soft: Box of 100 (0130807941) = $18.00
1 x 30 Cal .308 118 gr FP Soft: Box of 100 (0130811841) = $18.00

 The 76gr and 118gr are 45.75 for 500 and I think the freight is free.
 The 79gr are 59.00 for 500.

[melloroadman]

Tom I have the same new spring retainer here on my work bench . Dan sent me one a while back . Which I have not installed at this time . He sent it to me because he knew both my rifles were early production rifles . He also knew that I was installing the lighter hammer springs . And his words to me at that time were . You will lose some energy when you install this but since your are using a lighter hammer spring you probably will not care . He built this rifle to get the max out of it which I believe he did .
As far as the bullets go let us know how they work . Do you have any pictures of them ? And if I get a chance to go to OHS do you want me to see if they have any springs ? Or are you ok now . Marvin

[melloroadman]

Tom with the stock hammer spring it was not possible to use a adjuster . The spring was so close to bind that there was no way to compress it anymore . Now that you have taken 2 coils off of it you have that much room for adjustment . JAT Marvin

[tkerrigan]

When the bullets show up I'll shoot all three weights and experiment with some hammer spring shims if necessary. It only takes a few seconds to get at the spring anyway. The bullets are the first three on this page. 
http://www.hunters-supply.com/shop/index.php?cPath=27&osCsid=f86e0cfd6327501acbc8958c5e3e7cdf
I'm wondering if my difficulties getting chrony readings before I shortened the hammer spring may have been due to supersonic speeds.  The only reasonable readings were 3 that were over 1200, all the rest were about 300 or 6000.  It did sound like a jet plane.    Tom

[melloroadman]

The link is good enough for the bullets . Do let us know how they group for you . It sounds like you were to close to the chrony . 10 feet or better is needed on a BB . I use 10 feet and tied a string to my chrony so I set it up at the same distance every time . Marvin

[tkerrigan]

I worked my way up to 18 yards away and didn't get readings until I shortened the hammer spring, remember I had to resurface the sealing edge of the valve stem, The stem had a square corner, by the time I got the spring grooves out of it, about a 1/64" radius, therefore it opens a little more than usual. The hammer spring was shortened enough that when putting the screw through the end cap, you don't have to push against the spring.  I'll measure the free length next time it is out.          Tom

[melloroadman]

I'm sure you will figure out the chrony . That string I use gives me a guide to center my barrel with as well . The only concern I have about the spring is if it gets to short then you have no pressure on the hammer and hammer bounce takes place . You need to keep pressure on that hammer .Marvin

[tkerrigan]

I wouldn't say that the spring is loose, that's just where it stops.  With eight shots starting at 3300# 921,  1000,  1058,  1075,  1067,  1048,  1001,  924, with round ball the hammer can't be bouncing too much?  I have fond hopes of just having different thickness shims for various bullet weights. I've grown tired of removing the safety to disassemble and have just been leaving it out.  I think I will cut a groove in the stock so it can just stay in.    Tom