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Posted: 2/1/2009 4:56:16 PM EDT
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New guy here. I did a search and came up empty handed. I am looking at buying a preban ar with a DMPS Dissipator Upper. What is the purpose and if any pros and cons of this style upper. From the info that I have found it seems to have something to do with the length of the gas system. Where can I read/learn more about how the gas system works and what the pros/cons and reasons for different length gas systems are.
Thanks, Kevin |
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I had a DPMS "Dissy" for several years. It's different from a true Dissipator (Bushmaster) setup in that the DPMS barrel uses a rifle length gas system. The Bushmaster uses a carbine length gas system with a low profile gas block under the handguards. My DPMS was very reliable and made it through two Thunder Ranch carbine classes with no problems. However, others have had issues related to the gas port being so close to the muzzle. They sometimes require a bit of "tuning" (gas port enlargement) to run reliably with all types of ammo.
A couple of the advantages of this setup are: Long sight radius if you're using the iron sights. No real advantage here if you use optics. Less exposed barrel to melt your gun case foam if you're an idiot and put a hot rifle in your Pelican (DAMHIK). :) However, the DPMS has the HBAR profile under the handguards and it's a front-heavy pig of a carbine compared to a 16" M4 or pencil barrel. I had mine turned down to A1 spec and was much happier. |
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