Pre-2k spring questions

[glaman5266]

Hello. I couldn't find anything in a quick search on here, but according to Google it seems like pre-2k cockers take different springs than 2k+? Specifically the hammer spring? I don't know all the differences between pre/post 2k, and I'm trying to dial in my first pre-2k ('95 or '96). The one in my Slice kit review thread:
https://www.mcarterbrown.com/forum/p...ice-kit-review

Basically, it's shooting low 290s with the IVG backed out all the way, an overbore and crappy year-old paint. I'm guessing it'll be over 300 with proper sizing & fresh/good paint. I don't wanna mess with the HPR 'cuz it's preset. Re-threading the lower tube for a newer style IVG isn't a thing I want to do at this time.

So what springs do I need? I'm thinking I just need a weaker hammer spring...

Thanks for reading.

[Jonnydread]

I thought the springs were the same, that it was mostly the front block threading and bolt length that are different. Now I'm second guessing myself though...

[JonM]

I haven't been able to get my Cocker over a chrono yet, but I did notice that the Inception Designs hammer spring I installed is definitely longer than the stock spring. The gun cycles fine with it installed, but I expect I'll need to tear it down a couple times before it's ready for the field. I'd be interested to hear other people's experiences as well.

[NONOBLITUS]

https://autocockerparts.com/

Don’t mess with that Reg. Just play around with the springs and grab a kit from same place you got the slice kit.

[OpusX]

Very old school cockers could have been Sheridan sprung (would also have different hammer and ivg/cap). Most are Nelson sprung, and easily can be made so in any case. The valve chamber in pre-97 cockers I believe is also a bit more shallow typically requiring a shorter valve spring to get the best performance.

[glaman5266]

Very old school cockers could have been Sheridan sprung (would also have different hammer and ivg/cap).

That's what I was wondering, as I've seen that mentioned in my research. I don't want to buy a spring kit if the hammer spring isn't going to be the right one. Mine has a non-threaded IVG. Hmm...

[OpusX]

No issues running Nelson or Sheridan springs it is dependent on the hammer. The old Sheridan sprung hammers have a much smaller apature in the rear to only accept narrow "sheridan" style springs. More than likely you are using Nelson hammer springs.

EDIT: All currently available standard cocker hammer springs are Nelson. It is the assumed standard. Sheridan sprung stuff is the odd old man outlier here.

Pic of a Sheridan style hammer (from Bacci)

[August West]

I would take the IVG out and check what spring is in there, nelson or sheridan, and probably cut the spring down to get the velocity down. If it is a nelson spring you won't have any adjustability via the IVG, If it is a sheridan spring, cutting it down will allow you to increase the velocity with the IVG. Springs are cheap and I have been known to tune this way but it is not ideal, if you decide to cut, go slow, one coil at a time or less, and wear eye pro.

I know you already mentioned not wanting to mess with the reg but I will say that an adjustable reg is worth its weight in gold sometimes for fine-tuning.

[glaman5266]

Thank you for posting.
I'm a fan of "if it ain't broke, don't fix it." I like the preset HPRs and LPRs for that reason. They just work. Less to mess around with. And honestly, this thing shoots super good as it is. I probably won't need to tune it much, if at all, once I get the hammer spring how I want.

[glaman5266]

OpusX Thank you for posting the pictures!

Mine is Nelson then. Thank you all for posting & helping me out. I appreciate it.

[OpusX]

No prob. Cockers are always the naturally aspirated vintage hotrod tinkerboxes of the game. Fixing them until they're broke is pretty normal.

[glaman5266]

Well, I've rebuilt plenty of them, but never fully built one from scratch. So I don't know much about the springing, nor have I ever had to play around with them. I mainly just do rebuilds and they simply work with what's in them, lol.

I just ordered a spring kit from ACParts. We'll see what happens.

[2cBillB]

That's pretty cool. I didn't know the springs were so different.

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[Jonnydread]

What a fascinating thread

[Jordan]

That's pretty cool. I didn't know the springs were so different.

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Bud built the Sniper to be an aluminum copy of a Sheridan, just with a removable barrel. Early valves and possibly hammers were essentially cut down Sheridan components, so the springs were also Sheridan as well.

Once people figured out how to fit Nelson springs and compatible hammers into Cockers, Bud had to follow suit to stay current.

[gabe]

Unless it's been mentioned already, the 97 and earlier nelson spring guns had a valve spring that was much shorter than the 98+ spec so normal autococker valve springs will not work on those.