localangler
Well-Known Fanatic
- Joined
- Dec 26, 2009
- Messages
- 53
Okay here is the short version. My dad called and is having issues getting the bolt into battery on his new build. When I got involved everything was together and was supposed to be at spec. When I slide the BCG into the upper it will go up and stop about 1/8" to 3/16" shy of going in all the way. That is about how far the rear of the BCG hangs out the back of the upper.
Trouble shooting attempts:
1. I dropped a 5.56 complete BCG into the upper and it slid in just fine with out a problem.
2. Swapped out the bolt from the 6.8 into the 5.56 BCG that worked and the issue reappeared.
3. Both bolts were removed from carriers and inserted into the upper by hand. The 5.56 would slid in freely by hand and could easlily be rotated over like it was going into batter like the BCG would rotate as it slid home if it was pushing it. When I tried it with the 6.8 bolt it would not rotate at all. I tried the same test in an existing Bushmaster 5.56 upper with the same result.
4. I also tried letting the BCG go forward slowly and wathced it from below with a flashlight. The 5.56 rotated over smoothly. The 6.8 started to and then bound up.
My initial thought is the bolt might have be out of spec just enough to cause a bind? Maybe the lugs on the bolt are just long enough that they are catching as the bolt tries to rotate. I'm not certain.
Basic Specs:
Upper is a YHM
BCG I'm not certain
Barrel is AR 15 Performance
Bolt is AR 15 Performance also
As a quick side note I am not saying it is the bolt. It could very well be a builder error and that is why I am posting here to try and figure out if it was a mistake on our end. If I was certain it was the bolt I would wait until Monday and have him call the company because they are stand up guys and I have no doubt that they would make it right if it was them. That is why we used their parts in the build after the research was completed.
Any suggestions feel free to throw them out there. My next step is to take it apart and start over again checking torque on everything.
Trouble shooting attempts:
1. I dropped a 5.56 complete BCG into the upper and it slid in just fine with out a problem.
2. Swapped out the bolt from the 6.8 into the 5.56 BCG that worked and the issue reappeared.
3. Both bolts were removed from carriers and inserted into the upper by hand. The 5.56 would slid in freely by hand and could easlily be rotated over like it was going into batter like the BCG would rotate as it slid home if it was pushing it. When I tried it with the 6.8 bolt it would not rotate at all. I tried the same test in an existing Bushmaster 5.56 upper with the same result.
4. I also tried letting the BCG go forward slowly and wathced it from below with a flashlight. The 5.56 rotated over smoothly. The 6.8 started to and then bound up.
My initial thought is the bolt might have be out of spec just enough to cause a bind? Maybe the lugs on the bolt are just long enough that they are catching as the bolt tries to rotate. I'm not certain.
Basic Specs:
Upper is a YHM
BCG I'm not certain
Barrel is AR 15 Performance
Bolt is AR 15 Performance also
As a quick side note I am not saying it is the bolt. It could very well be a builder error and that is why I am posting here to try and figure out if it was a mistake on our end. If I was certain it was the bolt I would wait until Monday and have him call the company because they are stand up guys and I have no doubt that they would make it right if it was them. That is why we used their parts in the build after the research was completed.
Any suggestions feel free to throw them out there. My next step is to take it apart and start over again checking torque on everything.
