MistWolf
08-13-15, 19:44
In the beginning, there was the Wolf Pup- and it was good. Or so the Big Bad Wolf thought...
http://i115.photobucket.com/albums/n289/SgtSongDog/Lil%20Wolf%20Pup/WolfCub008_zpsfa095b46.jpg
As you learn, so you evolve and as shooters evolve so do their ARs. It's been a year since I built the AR shortie I dubbed the "Wolf Pup" and it has not been idle. I don't know how many hundreds of rounds I've put through it but it's been quite a few. There have been teething problems, I've gotten an education and the Wolf Pup has had a few changes along the way. It was built around an Odin Works 10.5 inch stainless steel barrel, an unknown brand BCG, STS stripped lower built up with a standard LPK & standard FCG from another AR. Finally, the controversial Sig Arm Brace- all before the BATF whacked it with the shoulder ban hammer.
GAS BLOCKS and GAS PORTS
The first buffer tried was the standard carbine buffer. With the .082" port, the carrier was hitting and resetting the hammer hard enough to sting the trigger ginger through the trigger bow. I don't a little sting, I mean a "HOLY ----, THAT HURT!" A heavier buffer went a long way to taming the beast, but it was obvious more needed to be done. First, I swapped the pistol RE for a rifle RE. (I wanted to use an A5, but there was no way to fit the Sig brace to the A5.) The heavier rifle buffer and rifle length spring helped smooth out the recoil, but I knew it could be better.
http://i115.photobucket.com/albums/n289/SgtSongDog/Lil%20Wolf%20Pup/RE002_zps41b32d71.jpg
http://i115.photobucket.com/albums/n289/SgtSongDog/Lil%20Wolf%20Pup/RE005_zpsdc5ab440.jpg
I took a job in Pennsylvania for the summer and while there, I met Cory and we became good friends. He builds some very nice ARs to order and hooked me up with some good parts. One of them was an SLR adjustable gas block.
With the new LR opened all the way, there was some short stroking. The gas block that came with the barrel worked fine so I figured it had to be the new part. I was wrong. Turns out that the shoulder of the barrel was too far forward and both blocks were covering part of the gas port. I was luckey either gas block worked at all. After giving the problem some thought, I trimmed the SLR to fit the barrel.
LESSON 1) Look at a problem from ALL angles. Because I didn't take time to verify what dimension were out of spec, it doubled the time it took to discover what the problem really was. I thought it was the new SLR. Instead, it was the barrel
LESSON 2) Verify parts align as they should. Checking to see if the port on the barrel & block would have saved me a lot of time and ammo
Once we had the SLR fitted to the barrel, it was off to the range for testing. Grant mentioned in his Best Suppressed SBR Ever???? thread that he was able to find a gas port diameter that let his AR eject without locking back on his unsuppressed shorty. I figured if he could do it by gradually stepping up the gas port diameter, I could easily do it with with the SLR.
No joy. With the standard BCG (remember I mentioned it was an unknown brand BCG? Keep that in mind.) the best I could do was full ejection and the bolt locked back, or the empty would not eject and I'd get a bolt over, jamming an empty and a fresh round from the mag into the action. Classic signs of short stroking. Or so I thought.
Let's take another look at the problem. At first glance, it appears that this problem is due to the bolt not coming to the rear enough to let the empty eject but just enough to catch the body of the next round and shove it out of the magazine. That was my thought, anyway. Of course, it could also happen if the extractor wasn't holding the rim very well, but I figured that would leave the empty in the chamber.
Bottom line- I could not replicate a bolt over coupled with a failure to eject with a good extractor and a good ejector. While testing the SLR adjustments with an LMT enhanced carrier, I discovered the bolt from the unknown brand BCG had gone flat. I swapped it out for a bolt known to be good and the problems with the bolt overs went away. Now, the AR could be adjusted so the empty would eject and not lock back. One click closed simply meant the action short stroked and simply partially extracted the case then shoved it back into the chamber without picking up the next round from the mag
LESSSON 3) If you have a failure to eject and the bolt attempts to strip the next round from the mag, jamming both into the action, you have a problem either with the extractor or the ejector
LESSON 4) Be wary of unknown brand BCGs
LESSON 5) Do not assume you know what the problem is. Verify your troubleshooting before proceeding with a fix
The bad extractor spring skewed my testing of a standard carrier compared to an LMT enhanced carrier. At first, I could not adjust the gas so that the standard carrier would reliably eject without locking back. Once I installed a bolt with a good ejector in the standard carrier, ejection without locking back was achievable. The difference is that with the lot of ammo used for the test, the LMT carrier required that the SLR be closed one more click for the same.
The reason for tuning the Wolf Pup to eject without locking back is to find the very least amount of gas needed for the system to run reliably. Once that point was found, opening the SLR just one more click allowed it to lock back, Cycle speed feels slow at this setting. Opening it another click gave a little sharper recoil- just a little- and faster cycling.
LESSON 6) Check the condition of everything before beginning testing. Just one small detail can throw off your findings and ruin your work
When I started on this project, I thought my problems with an empty case and a round from the mag being jammed into the chamber were due to short stroking from using weak ammo/improperly adjusted gas block, or because the lubed dried out. Opeing the gas block, adding lube and switching to full power ammo made the problem go away. Mis-diagnosing the problem just made fixing it that much harder, wasting time and ammo. The upside is, I learned something from the experience and hopefully others will learn from it too.
Further testing of the two carriers will be done when I can get my mitts on a suppressor
NEXT: MAGPUL- MOE vs SLIMLINE
http://i115.photobucket.com/albums/n289/SgtSongDog/Lil%20Wolf%20Pup/WolfCub008_zpsfa095b46.jpg
As you learn, so you evolve and as shooters evolve so do their ARs. It's been a year since I built the AR shortie I dubbed the "Wolf Pup" and it has not been idle. I don't know how many hundreds of rounds I've put through it but it's been quite a few. There have been teething problems, I've gotten an education and the Wolf Pup has had a few changes along the way. It was built around an Odin Works 10.5 inch stainless steel barrel, an unknown brand BCG, STS stripped lower built up with a standard LPK & standard FCG from another AR. Finally, the controversial Sig Arm Brace- all before the BATF whacked it with the shoulder ban hammer.
GAS BLOCKS and GAS PORTS
The first buffer tried was the standard carbine buffer. With the .082" port, the carrier was hitting and resetting the hammer hard enough to sting the trigger ginger through the trigger bow. I don't a little sting, I mean a "HOLY ----, THAT HURT!" A heavier buffer went a long way to taming the beast, but it was obvious more needed to be done. First, I swapped the pistol RE for a rifle RE. (I wanted to use an A5, but there was no way to fit the Sig brace to the A5.) The heavier rifle buffer and rifle length spring helped smooth out the recoil, but I knew it could be better.
http://i115.photobucket.com/albums/n289/SgtSongDog/Lil%20Wolf%20Pup/RE002_zps41b32d71.jpg
http://i115.photobucket.com/albums/n289/SgtSongDog/Lil%20Wolf%20Pup/RE005_zpsdc5ab440.jpg
I took a job in Pennsylvania for the summer and while there, I met Cory and we became good friends. He builds some very nice ARs to order and hooked me up with some good parts. One of them was an SLR adjustable gas block.
With the new LR opened all the way, there was some short stroking. The gas block that came with the barrel worked fine so I figured it had to be the new part. I was wrong. Turns out that the shoulder of the barrel was too far forward and both blocks were covering part of the gas port. I was luckey either gas block worked at all. After giving the problem some thought, I trimmed the SLR to fit the barrel.
LESSON 1) Look at a problem from ALL angles. Because I didn't take time to verify what dimension were out of spec, it doubled the time it took to discover what the problem really was. I thought it was the new SLR. Instead, it was the barrel
LESSON 2) Verify parts align as they should. Checking to see if the port on the barrel & block would have saved me a lot of time and ammo
Once we had the SLR fitted to the barrel, it was off to the range for testing. Grant mentioned in his Best Suppressed SBR Ever???? thread that he was able to find a gas port diameter that let his AR eject without locking back on his unsuppressed shorty. I figured if he could do it by gradually stepping up the gas port diameter, I could easily do it with with the SLR.
No joy. With the standard BCG (remember I mentioned it was an unknown brand BCG? Keep that in mind.) the best I could do was full ejection and the bolt locked back, or the empty would not eject and I'd get a bolt over, jamming an empty and a fresh round from the mag into the action. Classic signs of short stroking. Or so I thought.
Let's take another look at the problem. At first glance, it appears that this problem is due to the bolt not coming to the rear enough to let the empty eject but just enough to catch the body of the next round and shove it out of the magazine. That was my thought, anyway. Of course, it could also happen if the extractor wasn't holding the rim very well, but I figured that would leave the empty in the chamber.
Bottom line- I could not replicate a bolt over coupled with a failure to eject with a good extractor and a good ejector. While testing the SLR adjustments with an LMT enhanced carrier, I discovered the bolt from the unknown brand BCG had gone flat. I swapped it out for a bolt known to be good and the problems with the bolt overs went away. Now, the AR could be adjusted so the empty would eject and not lock back. One click closed simply meant the action short stroked and simply partially extracted the case then shoved it back into the chamber without picking up the next round from the mag
LESSSON 3) If you have a failure to eject and the bolt attempts to strip the next round from the mag, jamming both into the action, you have a problem either with the extractor or the ejector
LESSON 4) Be wary of unknown brand BCGs
LESSON 5) Do not assume you know what the problem is. Verify your troubleshooting before proceeding with a fix
The bad extractor spring skewed my testing of a standard carrier compared to an LMT enhanced carrier. At first, I could not adjust the gas so that the standard carrier would reliably eject without locking back. Once I installed a bolt with a good ejector in the standard carrier, ejection without locking back was achievable. The difference is that with the lot of ammo used for the test, the LMT carrier required that the SLR be closed one more click for the same.
The reason for tuning the Wolf Pup to eject without locking back is to find the very least amount of gas needed for the system to run reliably. Once that point was found, opening the SLR just one more click allowed it to lock back, Cycle speed feels slow at this setting. Opening it another click gave a little sharper recoil- just a little- and faster cycling.
LESSON 6) Check the condition of everything before beginning testing. Just one small detail can throw off your findings and ruin your work
When I started on this project, I thought my problems with an empty case and a round from the mag being jammed into the chamber were due to short stroking from using weak ammo/improperly adjusted gas block, or because the lubed dried out. Opeing the gas block, adding lube and switching to full power ammo made the problem go away. Mis-diagnosing the problem just made fixing it that much harder, wasting time and ammo. The upside is, I learned something from the experience and hopefully others will learn from it too.
Further testing of the two carriers will be done when I can get my mitts on a suppressor
NEXT: MAGPUL- MOE vs SLIMLINE