BHI Enhanced M4 SOPMOD Bolt Upgrade Kit

Through exhaustive testing and end user operator input, SOCOM/Crane-NSWC created a kit that helps to remedy extraction problems experienced by end users of M4A1 carbines. Most extraction problems have been traced back to the doubling of peak gas port pressure and 20% shorter dwell time on the carbine length gas system over the standard full length gas system on the M16A1/A2 rifles. This causes faster bolt speeds, and more violent extraction. The BHI M4 SOPMOD kit includes all the upgrades of the Crane version with the addition of a rate reducing heavy buffer, and an extreme duty Sprinco buffer spring.

The kit includes:

Extractor (milspec) - This is the most important part of the bolt as related to extraction and ejection.

Gas rings (3) (milspec) - replacement will ensure that gas is reliably trapped in the carrier, and used to operate the bolt carrier at the proper speeds. Bad gas rings can cause failures to completely cycle and lock to the rear on the last shot as well as failure to eject.

Extractor spring (Wolff 5 coil extra power) - Along with the extractor, the extractor spring is crucial to proper extraction and ejection of the M4 series rifles.

Black Buffer (milspec) - this has replaced the older soft blue rifle extractor spring buffer. It helps fight against extractor bounce. (Springs with the blue buffer are considered unserviceable in all current rifles in the U.S. Army.)

Crane O-ring (SOPMOD specific) - This O-ring nearly eliminates extractor bounce and adds 4 times the extractor tension. It is the insurance policy on the upgraded spring and buffer. When you life depends on it, a back up is always nice to have.

Sprinco Extreme Duty Buffer Spring - This heavy spring will last 4 -5 times longer than a standard spring, and adds additional tension to absorb recoil; energy, and ensure reliable feeding, chambering and locking.

DPMS rate reducing buffer - This buffer, along with the upgraded buffer spring will absorb more energy as the bolt cycles to the rear, slowing the bolt velocity and giving the shooter a much more manageable recoil impulse, and a decreased rate of fire on full-auto carbines. The heavier buffer will also ensure that feeding chambering, and locking on even a dry dirty chamber is positive and reliable.

Add this together and it equals an M4 that will run like a Timex and handle like a Porsche! Only from BHI

NOTICE: This kit was designed for 14.5 and 16" carbines with stock carbine length gas system. May not be compatible with some carbine and midlength gas tube models with custom gas blocks.

This kit does not work with the Rock River Arms AR-15 Rifles.

 

Shipping Restrictions

Shipments allowed to USA only. Export of the commodities described herein is strictly prohibited without a valid export license issued by the U.S. Department of State, Office of Defense Trade Controls, prescribed in the International Traffic in Arms Regulation (ITAR)