Thanks for using this forum If you think the built in forum search function sucks, Use Googles site search below
Thanks for using this forum If you think the built in forum search function sucks, Use Googles site search below
RidgeRunner05 wrote:When I first bottled my .25 using my stock/unmodified valve, stock hammer spring, and t port I was able to get 30-40 shots in the low 900's from a 3000 psi fill.
The passages through my adapter block are 7/16" and I have 6-7" from the adapter to the intake face of the valve. I also removed the gauge block from the air tube to allow more unrestricted airflow into the valve.
I just finished de tuning the rifle from experimenting with some heavier slugs. I now have the war valve,12.5# spring and the t port is opened up to .187". My current tune is 50 shots from 875-900-875 from a 2400 psi fill.
With proper porting of the stock valve, I see no reason you shouldn't be able to achieve the shot string you are looking for.
AlanMcD wrote:People ARE very helpful here, but even though this forum is dedicated to a single platform it has gotten so huge in terms of posts and topic areas that sometimes it is hard for people to find your thread. The best advice may come form someone that never even sees what you asked because of the different sections - for example, I was just looking in here even though I am not a .25 cal shooter, and here I am about to give you some (hopefully) useful advice days after you asked it . . .
The advantage of the Yellow is that practically every frequent user sees a new post, since they all flow in on top of each other - so if you check it every day you see all the posts on the first page or two and are caught up. But miss for several days and you never know what was posted - and you can pretty much forget about bothering going back to see what was added to a second or later page thread unless you were part of it unless you have some serious time to kill. I have taken the time there to go back and add stuff for "closure" to posts that I made in case somebody finds them through a search, but that is probably a waste of time in most cases as nobody ever ends up there - here that pulls it back up to the top of a section.
Here the recent stuff is always on top, but it can be a nightmare to find people that need do help - even more so because of the people that put the same thread in multiple places and create what amounts to trash and partial/redundant info to wade through. Sometimes we just don't have time for it, and I'll confess to times I can't be bothered to search out things. I do sometimes use the "unanswered posts" link to try to find people that have not been helped, but if any posts are made to that thread it is dropped from that path.
And when looking for things I can help with, I often forget where I was in the forum already . . . . none of this is meant as a criticism of the moderators and the site owner - nothing is perfect anywhere, and I do appreciate all I learned here and I do try to give back.
Anyways, I found this, and will try to help. I am a .22 shooter and don't have a .25, but I think I can help. First, several years ago all the modding was being done on our own and we shared what we learned. Then people that were giving out advice decided to make a go of taking what they know and turning a hobby into a small business. So yes, now the easiest and often best path is to buy what you want directly from somebody that can get you there without risk or experimentation. If you go it one your own, you will probably need a spare valve or two from Crosman, but you might get lucky and not mess up on your own.
Much of the knowledge you seek is buried in the past in the Mods section - search is your friend, but it turns up so much now that you do have to wade through a lot to get what you want.
If you go back into the past by digging several pages in, you will find things like this:
viewtopic.php?f=14&t=9392
and this:
viewtopic.php?f=24&t=9769
And here is one I posted on the additional mods I made to my already modified .25 cal valve (from Addicted2Airguns - but Dave is no longer selling parts): viewtopic.php?f=29&t=8270
Of course these can lead to other things that you will find too. I will say that all the mods I did to my valve were made with hand tools - I have no easy access to a drill press, lathe, or mill.
I did make a simple handy jig for holding the valve that helped a ton: I took a small section of 2x4 and drilled a 1" hole in it, and then cut the wood in half on my table saw right through the centerline of the hole - the allowed me to place my valve (and later my regulator) into it for secure work without damaging it at all.
Hopefully this helps!
FuzzyGrub wrote:Search for posts from RDSAIL. He did a number of valve mods, mainly for power, and then detuned latter for shot count. While he has posted some here, there will be more data on GTA. You would have to review his data to see if he had any strings at the power range you are seeking, and then extrapolate to what your new air volume will be. If you want to be cautious, just open the valve exhaust and TP a little larger than stock.
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