Does anyone know anything about one of these devices ?

[Baddog0302]

There are devices made for the AR15 - carrier weights and some cycling rate reducers - that are designed to increase the dwell time - the time the bolt stays closed after ignition - that will alleviate some of the sooting and also help support the primers longer so they don't pierce or get unseated. There is also a redesigned AR15 carrier and bolt assembly that will do the same thing.

 

[sdbob]

Check out Tubb Precision, I use this carrier weight system in my .204 Ruger AR upper. My brass is staying in better shape because of it.....sdbob

 

[amlevin]

You can add "carrier weights" or just use an M-16 bolt carrier that hasn't had the rear of the slot milled out.

Legal to use as long as inserting it doesn't convert your AR to "full auto" (which actually requires a few more parts).

 

[Baddog0302]

Thank you both,
Tubbs sells his for $ 45.00 (+-) probably easier than trying to find a solid USGI bolt carrier, but I'll look

 

[mic2377]

The same thing can be accomplished by changing buffer weight to a H1, H2, or H3. A full-weight carrier helps as well but the difference is very small in comparison.

Also very important for high-pressure loading of the AR-15 is the correct gas setting. If an AR (or other semi auto, for that matter) has too much gas for running the action all sorts of nasty things happen to the brass. This includes ripped off rims, ejector swipes on the case head, and premature pressure signs on the primers. One of my AR's destroyed brass at what seemed to be mild loads. After tuning the gas and a heavier buffer, cases and primers looked much better for the same loads.