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The Sprinco Lucky 13 Black Extractor Insert & Viton O-Ring pack gives you a stash of two of the smallest and easiest-to-lose parts in your AR-15 bolt. You get 13 black extractor spring inserts and 13 Viton CRANE O-rings, so whether you're building lowers, rebuilding bolts, or just topping off the parts bin, you've got backups ready to go. These little bits tend to disappear during cleaning, and having a dozen-plus on hand means you're never stuck waiting on a part to get a rifle back in service.
Both of these parts live under the extractor spring and do the same basic job from different angles: adding tension so the extractor grabs the case rim reliably. The black insert seats inside the coils of the spring for a firmer, more consistent bite, while the Viton O-ring slips around the spring to boost tension, a trick that traces back to solving extraction hiccups on short-barreled carbines and the Mk18. Worth knowing that Sprinco recommends running their 5-coil extractor spring with either the insert or the O-ring, not both at once.
Sprinco spent years supplying inserts and O-rings to OEM builders, and when they couldn't find a consistent Mil-Spec source, they bought their own molds and started producing to true military standards. The black extractor spring inserts are made per MIL-PRF-6855-REV G and the Viton O-rings are CRANE spec per MIL-R-83248C. Viton is the material you want here since it handles heat and holds up far better than cheap buna or plain rubber rings that break down after heavy mag dumps.
A good insert should feel pliable rather than hard when you install it, and the O-ring is a wear item that's smart to swap out now and then, especially if you run your rifle hot. At this price, keeping a full 13-pack in the range bag or toolbox is just good insurance. Everything here is made in the USA from quality base material.
Sprinco recommends using their extractor spring with either the black insert or the Viton O-ring, not both at the same time. Both parts add tension to the extractor, so stacking them can over-tension the setup. Pick one based on your build and how your rifle runs.
The insert seats inside the extractor spring coils to boost tension from within, while the O-ring wraps around the spring to add tension from the outside. The O-ring trick came from fixing extraction issues on short-barreled carbines. Both aim to keep the extractor gripping the case rim consistently.
Viton handles heat and holds its shape far better than plain rubber or buna material that tends to degrade during heavy shooting. Since the O-ring is a wear item that gets swapped periodically, starting with the right material means fewer replacements. These are CRANE spec, which is the standard you want for a 5.56 bolt.
These are two of the tiniest and easiest-to-lose parts in the whole bolt, and they walk off during cleaning all the time. Having 13 of each means you always have spares for the bench, the range bag, or your next build. At this price, it's cheap insurance to keep a full pack on hand.
| UPC | 657780261130 |
|---|---|
| Manufacturer | |
| Manufacturer Part Number | 26113 |
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