M&P10, functions 100% without suppressor. Long ago, gas port was opened slightly (.068 to .073 I think) in order for it to function reliably with surplus ammo. Currently, I’m using an H2 buffer.
With the suppressor mounted, I get stovepipes/brass obstructions every 3-5 shots. Sometimes sticking out like a regular stovepipe, sometimes facing forward like a double feed, but one is empty brass. Rifle seems to feed the next round every time though, it’s just that the brass is in the way.
Rifle is very gassy.
Thoughts? Try H3 buffer?
My gas block is pinned, so I don’t really want to swap that.
Thanks
If you don’t want to use an adjustable gas block then your other option is a heavier buffer. I would try Clint’s XH buffer.
If that still doesn’t work you might end up swapping gas blocks.
I’ve had excellent results using XH buffers in 7.62 AR’s with the Omega suppressor. I experienced the same issues as you when shooting suppressed but a ~10 oz buffer was the cure. I have one on my LE901 currently and that thing is still a little over-gassed.
Will that type of heavy buffer still function fine without the suppressor?
If it works suppressed, it should be fine unsuppressed. I would pair it with one of the Wolff springs. Send him an email, he’s quick to respond and can usually get your issues like those solved.
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Mine do, especially the Colt, but I’ve never shot an M&P so I can only speculate. As I’m sure you know, you’ll need enough ammo pressure to overcome the weight of the buffer without the added back pressure from the suppressor. I shoot handloads consisting of 155 gr AMAX’s and 44.0 grains of Varget or TAC.
Over gassed.
Dan
I think that could be the better name… I’m running a SpringCo orange and 9mm buffer and still have some of the same with SpecWar 7.62 or Omega with included impact marks on receiver extension, receiver and substantially felt recoil. I don’t have as much using steel case ammo but. Only fix will be adjustable gas block, I’m debating a insert or that.
I experienced the same thing with a 308AR (PSA Gen 1). An adjustable gas block solved all my reliability issues. I went with a Syrac Ordnance and it was easy to tune for both suppressed/unsuppressed on one setting. I recommend you go a similar route.
Unfortunately, it is not uncommon to see many base 7.62 ARs over gassed. Many manufactures and individuals choose to increase the port size to the lowest port pressure ammunition as a band aid in a permanent way without choosing other alternatives that are not permanent, i.e. reduced action mass. That band aid reduces function when some other combinations get involved, especially cans.
It is not that difficult to tailor action masses for most for uses in a non permanent way. When the base port gets opened to the point that regular action masses are towards the heaviest side, then you have reduced options when variables, like a can for example get involved. There are other negatives associated with this, as a larger base port diameter will erode into a larger tear drop shape much faster and in length than a smaller one. Restricting the gas outside the base port does not reduce that, the erosion is from the base region exposed to the gas seal provided by the projectile as it passes that.
S&W ported the MP-10 to be properly gassed with commercial pressure ammo. With the Omega in place, it’s likely over gassed. However, the rifle in question is also exhibiting extraction problems. Change the extractor spring
As others have said, it’s over-gassed. You can try an H3 buffer, but that will affect your non-suppressed cycling as well (which isn’t ideal if it’s already functioning 100% non-suppressed). An adjustable gas block would be the better solution, as you can set it for both suppressed and non-suppressed shooting.
Tried the H3 buffer today, got this after 4 rounds, basically the same thing as before. Sometimes it’s just like this, but the spent brass is facing forwards as a double feed.
So, overgassed. What exactly is happening? Is the bolt moving so fast that it’s trapping the brass before it has time to escape?
My options are:
1- try an even heavier buffer and/or spring to slow the action
2- get an adjustable gas block to replace my current one (BCM set screw, that was also pinned through the barrel)
3- do nothing. This rifle is primarily for unsuppressed use anyway.
Thoughts on the gas block type since mine is pinned?
I’d be curious what the result would be if you did this. ^^^^
I don’t believe that it’s having extraction issues, if anything it’s ejection. But the rifle isn’t old enough to have those go bad, and both are great unsuppressed.
I believe that is exactly what’s happening (bolt carrier speed). I again suggest a heavier buffer.
Personally, I want my .30 caliber suppressor to work with my .30 caliber should I have the desire to use both in conjunction even thought I, like you, shoot my AR10 primarily unsuppressed.
I don’t use adjustable gas blocks so can’t comment. I’ve never had a problem removing pinned low-pro blocks in general
Or BCM blocks in particular so I don’t think it’ll be a problem for you.
This pic looks like the rifle is overgassed which is causing the action to move violently enough to allow the extractor to lose control of the empty casing during extraction. A stronger extractor design/spring/o-ring may help but its just a band-aid (unless of course your extractor spring is actually weak/worn).
I still vote AGB. If you use the rear, already existing barrel dimple and thread locker you’ll be good to go.
An H3 is something like 5.5oz, right? The XH buffer mentioned earlier is almost 10oz. If I recall. It should be enough mass to slow your bolt down enough for proper extraction. Since you said you’d want to avoid replacing the GB - I’d try that first. If that doesn’t work then I’d add the adjustable gas block.
What about a SpringCo orange spring? That was also recommended to me, and confirmed through SpringCo.
Less cycling mass, more resistance. Thoughts?
A stronger extractor spring might help you
A heavier buffer might help you
A stronger buffer spring might help you
An adjustable gas block will almost certainly help you
I battled an overgas condition in my 308AR with a variety of extractor springs, buffers, buffer springs. They helped. But when I installed (and tuned) an AGB all my feed, extraction, ejection issues went away. YMMV