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Posted: 1/6/2014 8:46:12 AM EDT
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I know changing the buffer will help. I want to put in an H3, but do I need to do anything else? Also what does changing the sprig to those Wolf XL(i think thats the name)springs do?
Thank you. BTW I usually run a 16" upper on my full auto. About 90% at 16" and 10% at 11.5" |
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These days, just about every barrel out there is over gassed since every manufacturer knows people are going to try to run the cheapest ammo they can find. Think about it. Cheap Russian surplus 223 ammo didn't exist 20 years ago. You can slow the ROF by determining the optimal port size your gun will run on. It is not as straight forward as you would think though. All 3 of the 10.5" barrels pictured below used 3 different port sizes to lock the bolt back on an empty mag. There differences were quite significant.  All fired with the same lower, ammo and BCG. All run dry since lube can vary the results. You can read more about it here: http://micromoa.com/?page_id=855 I tested a 11.5" upper recently which had a port size of .073" and it held the bolt back at .063". Below is the RoF results for that...again below are the RoF results running unsuppressed. .063" port 629 RPM .073" port 816 RPM Going to a stronger spring is going to INCREASE your RoF. Which I think you were referring to the Wolf XP spring. You only need an H2 buffer to stop bolt bounce for full auto. Any heavier and you are just adding more reciprocating mass...making the gun more bouncy. Heavy buffers also do not help in reducing the fouling that is coming from the gas system. Only controlling the gas will do that for you and if it does stop running on the optimal port size then you can always kick the regulator over to the larger port matching your barrels gas port. I think this makes more sense to just tune your uppers to run with your FA lower so you aren't changing buffers for every upper configuration. |
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Quoted:
These days, just about every barrel out there is over gassed since every manufacturer knows people are going to try to run the cheapest ammo they can find. ^^^ This, and the fact that 99.9% of the people who are buying that short upper will NOT be running it on a full auto, but a semi-auto SBR or pistol instead. Bolt bounce as a result of a too-large gas port is of no consequence on a semi-auto, no matter how fast they think they can yank on that trigger.  A too-large gas port on a semi-auto allows for function with a greater variety of ammunition, especially that cheap-o stuff. Of course, it would be better if the gas ports were properly-sized instead, or even "too small". It's a lot easier to enlarge a gas port than make one smaller!
ETA: If you really want to drop the cyclic rate, in addition to reducing the attendant muzzle climb, you should try one of the "specialty" buffers that are on the market. Two of the most popular are the Enidine hydraulic buffer and the MGI Rate Reducing Buffer (RRB). The MGI seems to affect the largest reduction in cyclic rate, while the Enidine is significantly lighter (about like an H2). As a result, the Enidine *might* work better with "weaker" ammo like Wolf. Both buffers have their fans and their detractors, but both work very well for their intended purpose. If you can regulate the gas port size, that is the best solution to the problem. In fact, that is the actual solution to the problem, while a special buffer is a fix of the symptom, albeit an effective fix. |
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Yep, I've been playing the buffer game for many years before I came up with my gas block design (http://micromoa.com). Below is a picture I took of some of my buffers. I also have the A5 setups for testing as well. On the Hydraulics, I've had inconsistent issues with them. I know they are sensitive to cold as well. I also find that it doesn't recover/bounce back fast enough for full auto usage. There is SWAT team that is currently evaluating my gas block and they were testing some guns with hydraulic buffers in full auto and both of them ruptured.. The MGI isn't bad. I did have the internal spring fail on me but I don't think the little spring did much so it didn't stop it from working. I've also had the pin that holds the AAC buffer together shear off. So that the pin was coming into the carrier. Also had issues in full auto with some of the tungsten powder buffers as well. NEVER had an issue with the good old regular H2 buffer. I figure if it is good enough for the military, it is good enough for me. Again, an H2 is all you need to kill bolt bounce which is why the military uses it even on the MK18. They also have H3's on hand when the gas port gets eroded and start to get overgassed (again it all comes back to the gas) but the barrel still groups. So an H2 is all I use these days in a carbine buffer tube. I also use the A5 system but haven't done as much testing with it. I like the fact that it does use a rifle spring for less spring 'preload'.  |
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Quoted: These days, just about every barrel out there is over gassed since every manufacturer knows people are going to try to run the cheapest ammo they can find. Think about it. Cheap Russian surplus 223 ammo didn't exist 20 years ago. You can slow the ROF by determining the optimal port size your gun will run on. It is not as straight forward as you would think though. All 3 of the 10.5" barrels pictured below used 3 different port sizes to lock the bolt back on an empty mag. There differences were quite significant. http://micromoa.com/wp-content/uploads/2013/11/3-10.5-barrels-1024x647.jpg All fired with the same lower, ammo and BCG. All run dry since lube can vary the results. You can read more about it here: http://micromoa.com/?page_id=855 I tested a 11.5" upper recently which had a port size of .073" and it held the bolt back at .063". Below is the RoF results for that...again below are the RoF results running unsuppressed. .063" port 629 RPM .073" port 816 RPM Going to a stronger spring is going to INCREASE your RoF. Which I think you were referring to the Wolf XP spring. You only need an H2 buffer to stop bolt bounce for full auto. Any heavier and you are just adding more reciprocating mass...making the gun more bouncy. Heavy buffers also do not help in reducing the fouling that is coming from the gas system. Only controlling the gas will do that for you and if it does stop running on the optimal port size then you can always kick the regulator over to the larger port matching your barrels gas port. I think this makes more sense to just tune your uppers to run with your FA lower so you aren't changing buffers for every upper configuration. Well said. Excellent post!
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Quoted: Tag. This govnah seems like the solution for my MRP 10.5" suppressed uppers. I'm in the Central FL area so contact me offline if you want a demo in person. You can also try before you buy as well. We can put one on any barrel you want so you can experience the difference yourself on your gun. Thanks! |
Another option not mentioned that really intrigues me is the FerFrans D.S.A.S. (Delayed Sear Activation System). I really wish they or someone else would come out with a bolt carrier they would sell that included this feature. They market their 7.5" guns to have a rate of fire in the 550-680s using this system.
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