Re: My SBR Build Adventure
You are on the right track with a different buffer. A different bolt may be in order as well. Since we don't live to far apart maybe I could loan you a few different buffers and bolts. Swapping in and out some parts may help you dial in on the problem.
Re: My SBR Build Adventure
Does your extractor have an o-ring? Had similar issues and that $.50 fixed it.
Re: My SBR Build Adventure
Daycrawler, I never considered the bolt. Would you be referring to the bolt only, or the carrier as well?
Esh, not sure about the o-ring, unless you are referring to the small rubber piece under the extractor spring? My extractor does effectively grip the rim, just does not seem to cycle back far enough to eject. It appears I misspoke in my original post above...
Re: My SBR Build Adventure
Quote:
Originally Posted by
marstev
Daycrawler, I never considered the bolt. Would you be referring to the bolt only, or the carrier as well?
Esh, not sure about the o-ring, unless you are referring to the small rubber piece under the extractor spring? My extractor does effectively grip the rim, just does not seem to cycle back far enough to eject. It appears I misspoke in my original post above...
The bolt and bolt carrier along with the buffer and spring. I have several that could be tried out. I am in the 19512.
Re: My SBR Build Adventure
A heavier buffer is not going to make the carrier travel back further.
Re: My SBR Build Adventure
Quote:
Originally Posted by
marstev
Daycrawler, I never considered the bolt. Would you be referring to the bolt only, or the carrier as well?
Esh, not sure about the o-ring, unless you are referring to the small rubber piece under the extractor spring? My extractor does effectively grip the rim, just does not seem to cycle back far enough to eject. It appears I misspoke in my original post above...
I believe we are on the same page: https://www.bravocompanyusa.com/BCM-...exspring-1.htm
Though AAC says to not use the heavier spring with the o-ring:
EXTRACTOR SPRINGS
We have 5.56mm test data for the Bushmaster ‘4 coil’ extractor spring with a blue insert and an o-ring. Four uppers
completed a 12,000 round test with no extractor spring related failures. Two uppers completed an 18,000 round test
with no extractor spring related failures.
We do not recommend using extra-power extractor springs because they are under higher stress and will likely
break sooner. The included o-ring adds the desired extra extractor force without requiring a spring which would
have more force and hence more stress. Also, extra-power springs, when combined with an o-ring, may make the
extractor harder to snap over the case rim and may lead to function problems. If you do use such a spring, please
don’t use an o-ring and change the spring every 1500 rounds for mission-critical use.
Note that, again per our spring discussion, Chrome Silicon springs do not resist taking a set better than ASTM A228
certified music wire when used at temperatures below 250 degrees F.
Taken from https://www.advanced-armament.com/Manuals_ep_45-1.html
300 BO AAC Upper manual.pdf
It's tough to diagnose. There might be a chance the extractor is just slipping before reaching the point of ejection. I had this issue and most people said gas and buffers. One person mentioned the o-ring. I bought that kit and tried the o-ring and the heavier spring (but not both). Both worked, but the AAC article convinced me to use the o-ring.. May not be your issue, but cheap enough to try.
Re: My SBR Build Adventure
Quote:
Originally Posted by
marinville
A heavier buffer is not going to make the carrier travel back further.
I even tried a buffer with all the weights removed and most still said it was a gas problem. After the o-ring/peg upgrade I could run with any buffer weight.
Re: My SBR Build Adventure
Quote:
Originally Posted by
marinville
A heavier buffer is not going to make the carrier travel back further.
The buffer will not affect the distance of travel, but heavier buffers will slow the cyclic rate. I have been told that if it is too fast, then it may not allow the next round to be picked up from the magazine.
On the flip side, I could also have a gas issue that might require removing the gas block and reaming the hole in the barrel.
I have both feeding and ejecting failures, depending on the ammo.
Hope to make it out to the range this weekend so I can at least try out my buffer. If I can at least get one kind of ammo to work, it will be a start, and I can have some fun! I was quite impressed that firing single shot, I was still able to keep it on the paper at 100yds. Not bad for a 10" barrel.
Daycrawler, I might take you up on that offer one weekend. Thank you!
Re: My SBR Build Adventure
Quote:
Originally Posted by
marstev
The buffer will not affect the distance of travel, but heavier buffers will slow the cyclic rate. I have been told that if it is too fast, then it may not allow the next round to be picked up from the magazine.
On the flip side, I could also have a gas issue that might require removing the gas block and reaming the hole in the barrel.
I have both feeding and ejecting failures, depending on the ammo.
Hope to make it out to the range this weekend so I can at least try out my buffer. If I can at least get one kind of ammo to work, it will be a start, and I can have some fun! I was quite impressed that firing single shot, I was still able to keep it on the paper at 100yds. Not bad for a 10" barrel.
Daycrawler, I might take you up on that offer one weekend. Thank you!
Take note of your ejection pattern, when it does eject. That should give you a clue about how much gas you're getting.
What length gas system does your barrel use?
ETA: I still don't think you're overgassed. An overgassed rifle should not have ejection problems with any ammo.