S.O.S. Having a problem with hammer spring in…
…my latest build. This pistol may become my one and only FT pistol, or it may not. One thing is for certain, I need to figure out this hammer/hammer spring issue.
What it is:
Don Cothran 2260 pcp tube (stainless)
RJ machine Riser breech
10.1″ .177 LW barrel
Various hammer springs, and power adjusters (the reason I say various is because I eliminated the possibility of it being any specific spring or power adjuster, or end cap by trying four different ones.
What happens is I cannot cock the hammer with any kind of preload on the spring. If I put no preload on the spring, I can cock it back, but this is not strong enough to open the valve (360 fps with 7.9 gr) I wanted to see how everything was flowing so I cocked the hammer back on no preload, then I screwed in the Charles Mellon power adjuster to max preload, minus one turn out and I hit 980fps. But if I attempt to cock it back while on this preload setting I can’t even get it to move at all 🙁
My spider senses tell me the problem lies with the tube. I had a similar problem with my last DC tube and I opened it up a bit with some bore compound and polish. I tried the same thing this time but I don’t think it was enough.
I plan to hit Home depot tonight, so if anyone knows the best thing to use to open it up (dowel size, grit, etc.) please let me know.
If anyone has any other ideas on what it might be (although if I were a betting man, I’d bet the house that the hammer is galling, I see a slight gall mark in the tube…)
How much should I take off the I.D.???? Thanks guys.
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Viewing 9 replies - 1 through 9 (of 9 total)
Yeah, to get 1 bad product can happen to anyone, but if this is the 2nd problem you’ve had with same part, then I’d definitely be PO’ed..I suggest ya call Don, tell him what’s going on and ask his advice..The fix could be something simple you can do at home, or maybe you’ll have to send it back to him to get it corrrected.. IIRC, Don offers a custom hammer that has teflon(???) strips rinning the length of the hammer to reduce friction..ask him about that, I’m almost positive that’s where I saw it 😀 HTH……-Rodger
Yeah, I have a tube of locktite screaming to be used on the bolt handle. But I have another bolt coming in a few days and don’t wnat to screw with getting it appart.
Lazy!
Roachcreek
So if anyone has any advice on the best way to open my stainless D.C. tube up a bit, please feel free…(keep in mind I am working with crude tools…no lathes 😥 ). Thanks.
send it back to him and have him make it right.
Don is touted as such a great craftsman you know. Maybe he is unaware of how SST galls up.
I was having the same problem yesterday, and tweaking my bolt handle, I had no extra 22 bolt when I built my last one up, so I disassembled the Crosman bolt and threaded the hole, but there is no stop on the threads so it is loose all the time.
Roachcreek
Try using just a dab of blue Locktite on the threads to keep it from loosening. I had the same problem and the Locktite fixed it.
Carl
It is definitly the tube. Man, I have no luck with my D.C. tubes. This is the second one that had a hammer galling problem. The way I was able to deduce is I tried a few shorter springs and still had the same problem. Then I just replaced the stainless tube with a crosman 2250 tube to see if that was it and sure enough, cocks a smooth as a babies butt with the crosman tube.
So if anyone has any advice on the best way to open my stainless D.C. tube up a bit, please feel free…(keep in mind I am working with crude tools…no lathes 😥 ). Thanks.
Joe,
That was what was going thru my mind.
I was having the same problem yesterday, and tweaking my bolt handle, I had no extra 22 bolt when I built my last one up, so I disassembled the Crosman bolt and threaded the hole, but there is no stop on the threads so it is loose all the time.
I ordered another bolt from Mellon, but he got swamped this weekend, so I just put a weaker spring in and solved my problem and bolt handle flex at the same time. I will revisit the stronger spring when I get the new bolt from Mellon.
Worked good enough this morning to make kill with it, but it is only running 450.
Waiting for my Boss valve from B&A, it is supposed to ship with my Crosman 101 they are rebuilding. I should get here about the time the rains and 45 degree weather start, so velocity will be in the toilet unless I set up the chrony and run out to shoot between warmups 🙄
I’m thinking a shortened/carbine stainless steel Discovery style tube and valve from TKO and a fill probe for HPA for the winter months.
Roachcreek
Gotta do the math and figure out how many coils of spring you have room for.
check the hammer pin if it is bent/worn it reduces hammer stroke for cockingg.
Walter…
Walt,
Thanks once again. I will cut down a spring and try it out. The pin is not bent at all. I was worried about it bending as it is a very long pin (RJ riser breech).
My only concern is if I do get it to cock smoothly with a shorter spring will it still provide enough energy to get my fps up high? And don’t tell me to do any math, I was never good at that..remember, I am an artist 😕
Thanks Walt 😀
too many spring coils for the room you have.
Gotta do the math and figure out how many coils of spring you have room for.
check the hammer pin if it is bent/worn it reduces hammer stroke for cockingg.
Walter…
Viewing 9 replies - 1 through 9 (of 9 total)
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The first tube I got from Don…he offered to fix it for me, but it was an easy enough fix. Once I sanded it out a bit and polished it up, the galling issue was resolved.
I would imagine this one will be fixable as well. I like to avoid shipping back and forth when at all possible.
A smaller diameter hammer with a teflon sleeve tube insert…that would be a nice combo.
I also discovered another problem that I was all excited about thinking that it was the main cause, but it was not 😥 But it is worth mentioning just in case anyone else ever experiences any kind of galling with a custom build. It seems my bolt probe handle—when seated in my bolt probe—was protruding out ever so slighltly past the face of the probe causing the handle to gall on the inside of my RJ machine breech. I grinded it down and resolved that…but the issue with the hammer galling the tube still exists.
Before I set upon “opening it up” I would appreciate the suggestions for the best “tool for the job”. A dowel with some sand paper glued to it makes sense, but I defer to the more experienced as always. Thanks.