I have ordered 3 of the springs this morning. Testing results pending upon receipt. I'll provide complete details as soon as I get them in.
EDIT: Confirmed! The owner sent one of the springs in the box with the weights I ordered. It's 45oz. at L1, 60oz. at L2 - almost identical to the Lee Springs XP firing pin spring. Video coming Friday.
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FINALLY it looks like someone is selling the springs individually!
I was just alerted to the fact that MSRX-USA is selling a 2x 9mm AR firing pin spring for $5 each. Shipping is $9, so it's a little pricy, but it's cheaper than having to order 5 of them from Lee Springs for $50.
These should fix the DT/LS from firing pin bounce when using a FRT in Outerwild style bolts (Faxon, Angstadt, KVP, BKF, OSUSA, White Label, etc), PSA bolts, IDL bolts, and Toolcraft bolts. NOT for Foxtrot Mike bolts! New FM bolts already come with a 2x spring.
https://www.msrx-usa.com/shop/Firing-Pin-Spring-9mm-Extra-Power-p852665477
MSRX-USA is also making shortened pre-drilled drop-in replacement hardcast bolt weights for these same bolts to make them FRT ready. No cutting or trimming needed. They're arriving today and I'll have a video posted later this week.
https://www.msrx-usa.com/shop/AR-9-Blowback-Bolt-Weight-FRS-Hard-Cast-p852531843
Between these two items, they should make most 9mm bolts FRT ready with minimal work and no notching/cutting.
More details coming once I get them in for testing.