I am in need of finding a few different weights of recoil springs for my Serbu .50BMG.
Long story short, I am having short stroke issues due to lightly loaded PMC ammo that short cycles the firearm. I love this gun, and have no intentions of selling it, but I want to solve this problem, and getting a response from the manufacturer has not happened at the time of this writing. Their website notes clearly that they are very busy for responding to emails (They list a multi week wait period for emails) but they have not responded to calls yet either. Nothing against them for this, I understand that it is a small company and people are not always near a phone to answer it. I will keep trying to contact them, but for the meantime, I want to work towards a fix.
The firearms action is very slick after a workover, but the bolt still short strokes upon. At first I though that the Hydraulic buffer was the culprit, but after close review of high definition video, frame by frame, has determined that the bolt consistantly does not clear the magazine, and does not come close to hitting the start of the hydraulic buffer.
If it was just me, I would be a bit skeptical that the ammo was at fault, but would lean towards the gas system. This however, is not the case, as two other Serbu owners on CGN have privately contacted me stating the same issues with PMC ammo. None of these issues have been mentioned in the US to my knowledge.
I also know that my 2009 manufacture 660 Grain PMC is notably slower then what the website lists for 2011 manufacure and up PMC.
Out of my 33" barrel Steyr HS-50, it chronographed 2805 fps average. The manufacturer claims nearly 3100 fps, unspecified barrel length. One can only imagine that the 26" barreled Serbu would be noticably slower while using the same ammo.
I am not interested at the current time in reloading for .50BMG, it simply is not in the cards right now, so I want to adjust the gun to work with the ammo available by changing the recoil spring to a slightly lighter spring, much like you do with competition pistols. I figure if I can purchase 2-4 different springs, all gradually lighter then the factory spring, I can swap them out until I find the one that operates 100% reliably without going too light.
I do not want to cut my current spring. I need it as a fallback in case I can not sort out the spring problems.
The main question first off, is are there any potential downsides/ dangers to introducing a ligher recoil spring to achieve reliable cycling?
Next off, is where can I source the springs, or have them made?
I have the length while under pressure on the guide rod, as well as uncompressed length, and coils per inch of both as measured by a tape measure. I can't find my calipers, but when I do I will get the wire gauge. Anything else I need?
Here is a photo showing the extent of the short stroking, and how far I need to adjust the springs.
Here you can see that the bolt does not even start to contact the hydraulic buffer until the bolt has already cleared the magazine.
Springs, both compressed at full length on guide rod, and full length uncompressed removed from the guide rod.
Uncompressed.
Video of the short stroking. It just barely catches the first round, but fails to catch all subsequent rounds. The bolt stopped at the exact same spot, just shy of clearing the magazine, for the following 9 shots.
Thanks for taking the time to read, and thanks in advance for any help or suggestions that come my way to solving the problem or sourcing a new spring.
Long story short, I am having short stroke issues due to lightly loaded PMC ammo that short cycles the firearm. I love this gun, and have no intentions of selling it, but I want to solve this problem, and getting a response from the manufacturer has not happened at the time of this writing. Their website notes clearly that they are very busy for responding to emails (They list a multi week wait period for emails) but they have not responded to calls yet either. Nothing against them for this, I understand that it is a small company and people are not always near a phone to answer it. I will keep trying to contact them, but for the meantime, I want to work towards a fix.
The firearms action is very slick after a workover, but the bolt still short strokes upon. At first I though that the Hydraulic buffer was the culprit, but after close review of high definition video, frame by frame, has determined that the bolt consistantly does not clear the magazine, and does not come close to hitting the start of the hydraulic buffer.
If it was just me, I would be a bit skeptical that the ammo was at fault, but would lean towards the gas system. This however, is not the case, as two other Serbu owners on CGN have privately contacted me stating the same issues with PMC ammo. None of these issues have been mentioned in the US to my knowledge.
I also know that my 2009 manufacture 660 Grain PMC is notably slower then what the website lists for 2011 manufacure and up PMC.
Out of my 33" barrel Steyr HS-50, it chronographed 2805 fps average. The manufacturer claims nearly 3100 fps, unspecified barrel length. One can only imagine that the 26" barreled Serbu would be noticably slower while using the same ammo.
I am not interested at the current time in reloading for .50BMG, it simply is not in the cards right now, so I want to adjust the gun to work with the ammo available by changing the recoil spring to a slightly lighter spring, much like you do with competition pistols. I figure if I can purchase 2-4 different springs, all gradually lighter then the factory spring, I can swap them out until I find the one that operates 100% reliably without going too light.
I do not want to cut my current spring. I need it as a fallback in case I can not sort out the spring problems.
The main question first off, is are there any potential downsides/ dangers to introducing a ligher recoil spring to achieve reliable cycling?
Next off, is where can I source the springs, or have them made?
I have the length while under pressure on the guide rod, as well as uncompressed length, and coils per inch of both as measured by a tape measure. I can't find my calipers, but when I do I will get the wire gauge. Anything else I need?
Here is a photo showing the extent of the short stroking, and how far I need to adjust the springs.
Here you can see that the bolt does not even start to contact the hydraulic buffer until the bolt has already cleared the magazine.
Springs, both compressed at full length on guide rod, and full length uncompressed removed from the guide rod.
Uncompressed.
Video of the short stroking. It just barely catches the first round, but fails to catch all subsequent rounds. The bolt stopped at the exact same spot, just shy of clearing the magazine, for the following 9 shots.
Thanks for taking the time to read, and thanks in advance for any help or suggestions that come my way to solving the problem or sourcing a new spring.
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