Early on at 308ar.com we did a page that referenced the the point that the Armalite AR-10 utilized a BOLT CATCH ROLL PIN same as the Armalite M-15 (AR15) rifle while the DPMS LR-308 308 AR and similar rifles utilize a BOLT CATCH SCREW. Well despite that page we still get many questions about this small part. Based on these messages I decided a simple picture might be easier to understand in this day of sort attention spans. While I believe there are a small minority of 308 AR manufacturers using BOLT CATCH ROLL PINS just as there is an AR-15 manufacturer or two have adopted the BOLT CATCH SCREW feature. This post is meant to make folks aware of the differences.
AERO PRECISION BOLT CATCH SCREW – Aero Precision refers to this part as the M5 Threaded Roll Pin. Our threaded roll pin is used in multiple applications, including for the bolt catch on our M5 Lower Receivers and for the forward assist on our Upper Receivers. Made from stainless steel, it has a 6-32 thread pitch and is designed to be installed with a 1/16″ Hex Key Wrench.Note: This product is already included with our M4E1/M5E1 Enhanced Uppers, M4E1 Threaded Uppers, M5 Upper Receiver and our M5 Lower Receiver. It is not necessary to be purchased separately. This individual product is available for customers who have lost or damaged their existing threaded roll pin.
At this point I cannot definitively state what 308 AR rifle manufacturers use the threaded BOLT CATCH SCREW or the BOLT CATCH ROLL PIN. Feel free to contact us and let us know whether your lower utilizes a BOLT CATCH SCREW or BOLT CATCH ROLL PIN
308 AR AR-10 Manufacturers who utilize a BOLT CATCH ROLL PIN
Fulton Armory FAR 308AR Lower Parts Kit Without Trigger
Fulton Armory – FAR 308AR Lower Parts Kit Without Trigger
Back in 2008 or so there were far less manufacturers of 308AR parts and with the most anti-gun President in history there was suddenly a shortage of parts. Items like RIFE BARRELS, BOLT CARRIER GROUPS and LOWER PARTS KIT‘s. Fulton Armory was like my personal secret stash of gun parts.
308 AR AR-10 Bolt Catch Pin – The bolt catch pin, one of the smallest parts on the AR 308, AR-10 and AR-15 platform weapons is a part that can stop an AR-10 308AR build dead in it’s tracks if you didn’t purchase the correct one or the correct LOWER PARTS KIT for your STRIPPED LOWER RECEIVER. Here’s why. The AR-15 platform uses a roll pin and that’s taken for granted when shooters move up to the AR-10 and 308 AR platforms. Unfortunately this is where the topic gets muddy.
Armalite AR-10 rifles use a traditional roll pin setup in the AR-10 lower receiver so their Lower Parts Kits obviously include the pin. If you use an AR-10 LPK on your non Armalite 308 AR you will need to order the threaded “Bolt Catch Screw” seen elsewhere on this page. I typically keep the Armalite LPK’s on hand as well as a few of the bolt catch screws.
Armalite AR-10 and AR-15 EL0220 Bolt Catch Roll Pin
The Armalite AR-10 utilizes this roll pin, Armalite part number EL0220 which is the same as their M-15/AR15 rifles. Alternatively DPMS LR-308 based weapon utilize a proprietary hybrid pin/screw (mentioned above).
The DPMS 308 Bolt Catch Screw is essentially set screw who’s threads have been removed from one end creating a hybrid screw type pin. Now unfortunately though not all DPMS LR-308 platform based LOWER RECEIVERS utilize the hybrid BOLT CATCH PIN. Some manufacturers utilize the roll pin method identical to the Armalite AR-10.
The process of installing the Bolt Catch Pin is probably one of the most difficult tasks for the inexperienced to perform. Not done properly it’s easy to damage the finish of your lower or worse, break something. Fortunately a little grease, a roll of masking tape and some special roll pin punch make it easy. Visit our AR-10, 308 AR Roll Pin Tools Page.
Aero Precision M5 Extended Magazine Catch Button -The Extended Magazine Catch Button is a drop-in replacement for the standard lower receiver magazine catch button. This extended button is longer, allowing it to protrude the proper distance when used with our M5 Lower Receiver.