I have two different 350 legend AR’s and neither will cycle with Hornady 250 grain suppressed ammo. Both guns have carbine length gas systems. Both cycle fine with supersonic ammo. I have tried several different weight buffer weights. No luck.
What is the actual malfunction?
Will it lock back with one round in the mag?
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No the bolt doesn’t come back far enough to even eject a round. Ejects at 2 o’clock with supersonic ammo.
Gas port too small for the ammo?
Bit of a silly question but just for clarity: when you say “suppressed”, you’re talking about a traditional high backpressure silencer, correct?
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Yes, there is a little confusion about the post. Do you mean not cycling with subsonic ammo? If so, is a suppressor being used with this ammo?
I have two AR’s in 350 legend. One is a 16” barrel and the other is a 18” barrel. The barrels are different manufacturers both function properly with 350 legend supersonic ammo. Both function with supersonic ammo and my suppressor installed which is a griffin armament 36 bushwhacker. Neither gun will function with Hornady 250 grain subsonic ammo. Have tried different weight buffers, different springs, different bcg’s, tried everything I know to try. Got some Winchester 255 grain ammo I am going to try this weekend.
My guess is that your combination isn’t going to run subsonic stuff no matter what you try. The pressure generated by the subsonic is never going to achieve reliable cycling of the action.
Thanks for clearing that up. I don’t think the Bushy is the highest backpressure can, but it should be plenty.
I think most of the subsonic cartridges only work with pistol length gas. Hopefully you’ve got a straightforward setup. I haven’t messed with this cartridge in real life, but Quickload implies that it needs a short gas system. The pressure drops off faster than BLK, and some of the silencers tend to vent to atm faster, too.
Check your gas keys by trying to turn the screws clockwise gently. If they turn at all you’ve found the problem. Unlikely that both have broken or loose screws, but maybe. (Edit: I see you already ruled this out)
You could try dumping the weights out of the buffers and testing it with them hollow/empty with the lightest spring you have on hand. Sometimes that’ll give a clue that things are borderline.
I suspect your solution will eventually involve a drill, either your own, or the manufacturers’. Test that Winchester before going that drastic.
I already tried taking a carbine buffer apart and removing the weights one at a time until I got to just one weight. Still no luck. No luck with the Winchester ammo today either . Got it to cycle one time then second round it wouldn’t lock back. I guess if I want to run this caliber I will have to get a barrel custom made with pistol length gas system or build a pistol with shorter barrel.
I’m sure you’ve also already checked that the barrel gas block or FSB is tight and straight.
I did a brief search, and the first 3 manufacturers I checked showed carbine length gas systems for 16” barrels, but pistol length for shorter. So, perhaps I’m wrong that it should use a shorter gas system for subs, and just needs a larger port.
Odd that this is a problem, given that the Winchester subs were part of the original release. I would’ve expected the rifles to be designed with them in mind for suppressed use.
What manufacturer(s) on these AR’s out of curiosity?
I built both rifles one barrel is satern the other is ballistic advantage. Contacted Ballistic advantage they offered to help me figure it out. I think at this point I am going to drill out the gas port. I have wasted over $100 in ammo trying to get both guns to cycle.
I really wanted these guns to cycle with subsonic ammo so I could use them for hog hunting.
Open up the gas port. You can always install an adjustable gas block if you open it up too far.
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