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556 Patrol Spring Specifications

296 Views 8 Replies 7 Participants Last post by  GiterDunn
So 1 year ago I sold my 556 Swat Patrol essentially due, at the time, not realizing that 55x pattern rifles are still manufactured overseas and parts can still be imported and not wanting to keep a rifle I couldn't fix. Well yesterday, I happened to receive another 556 Swat Patrol as a gift/compensation for helping my neighbor with some home renovations before he sells and moves out of country. I loved my rifle and I am viewing this as a sign that I should probably keep this one. My only hold back is that, as far as I am aware, the short piston system was unique to the patrol and pistol models, and that sourcing replacement recoil springs is a little tough. However, I found a spring manufacturing website that offers over 100,00 springs of various sizes, strengths, metals, etc. I figure that before I decide to sell this gift, I'd see if I couldn't at least find some replacement springs there. If it works, yay! And if not, oh well. What I was hoping someone would have is the specifications of the short piston braided springs, or knows where I could get that information.

Specifically I need (in inches):

Outside diameter
Rod diameter
Free length
Rate (lb/inch)
Solid height (compressed length)
Wire Diameter

This particular rifle has the braided spring, but I don't see why a single core wouldn't work or be better. This is probably a shot in the dark, but I don't want to keep a rifle that I can't fix, no matter how bad a** it is, and the recoil spring is the 1 thing that I just can't find.
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So keep it and always be on the look out for spair parts. Or get a standard braided spring and cut to size.
Is this a part that frequently fails?
I haven't had one, nor shot one enough to have it fail. However I do know that the short rod springs of the patrol and P556/553's are more prone to fail compared to the standard long springs.
The springs are not hard to find, same as the SG 552. And those braided springs last forever.
Please post if you find another source for the springs and the specs needed. Thanks.
If it helps I can take some pictures and measurements of mine and post it here this weekend.
I have one. Just curious if you found a place with ready availability.
I'm interested in the dimensions as well, I'm building a quasi-552 with a patrol gas system, and maybe a custom milled KNS adjustable piston for an AK. BTW, you can just cut down 551/556 springs from wolf to fit the patrol piston, I've also been looking for a flatwire spring to do that with.
1 - 9 of 9 Posts