Schuster MFG M1A Nut Overbored and vented This plug is vented and bored to 58% greater volume. Greater volume and venting produces 2600 psi less pressure on the Op-Rod. This modification is Service Rifle Legal. Includes cleaning drill with handle and tip cleaning wire. Made in the USA. Lifetime factory warranty. Technical Information Material: Parkerized Hardened Tool Steel Notes: M1A gas plug is vented and bored to 58 percent greater volume in plug area. This modification is Service Rifle Legal. 1/64" hole per CMP rules - 4th Edition 3-13-B-b Greater volume and vented equals 2600 PSI less pressure, on average, on the Op-Rod. This set includes cleaning drill with handle and tip cleaning wire. $45.00