AR Sponsor
Posted: 7/2/2009 3:45:27 PM EDT
|
I just finished building my first AR and I won't be able to take it out to the range for a couple weeks. I got a couple .223 snap cap dummies to see if the gun will dry-cycle. The dummies load fine, but will not extract at all. They just end up stuck in the chamber. I actually tried extracting with two different bolts (both new) and both of them fail to extract 100% of the time.
Any thoughts on what I'm doing wrong? |
|
The snap cap dummies (A-Zoom brand) appear to be anodized aluminum. I don't have any calipers to measure them compared to live rounds, but the company boasts that they are precision made to be the same dimensions as real rounds (whatever that is worth). Obviously they are a considerable amount lighter.
The bolt is well lubed, however it does feel a little stiff when I move it in the carrier by hand. I'm unsure of just how freely it should move around in there. When I pull the charging handle back after dry firing with the snap cap dummy, the bolt is fully extended out. The dummy round fits into the bolt and the extractor seems to get a firm grip on the lip or the casing when I try it disassembled, but I have no idea how well it's connecting when the gun is put together and the dummy round is in the chamber. I'll look into the #60 O-ring thing. Is it common to have problems ejecting unfired rounds? I'm confused about how much of the blowback force aids in the ejecting process. |
|
Quoted:
The snap cap dummies (A-Zoom brand) appear to be anodized aluminum. I don't have any calipers to measure them compared to live rounds, but the company boasts that they are precision made to be the same dimensions as real rounds (whatever that is worth). Obviously they are a considerable amount lighter. The bolt is well lubed, however it does feel a little stiff when I move it in the carrier by hand. I'm unsure of just how freely it should move around in there. When I pull the charging handle back after dry firing with the snap cap dummy, the bolt is fully extended out. The dummy round fits into the bolt and the extractor seems to get a firm grip on the lip or the casing when I try it disassembled, but I have no idea how well it's connecting when the gun is put together and the dummy round is in the chamber. I'll look into the #60 O-ring thing. Is it common to have problems ejecting unfired rounds? I'm confused about how much of the blowback force aids in the ejecting process. When there is pressure in the barrel the case expands and actually holds tighter to the walls of the chamber. Annodized aluminum has less lubricity than brass. May try a light coat of oil on the snap caps. Make sure the carrier is lubed as well as the bolt, but this sould not affect hand cycling or ejection appreciably. The bullet portion of the snap cap may actually be grabbing a bit of the rifling if it is too long. Same with the shoulder of the snap cap. The O ring increases the grip of the extractor claw. |
|
I installed the #60 O-ring and that failed to solve the problem. I drove out to an isolated area in the country and tried dry cycling some live Wolf .223 rounds instead of the dummies and everything worked flawlessly. So the problem was with the Snap Cap dummies (A-Zoom brand). Lesson learned.
|
AR Sponsor