Issues with 300 blackout subsonic.

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Norskie
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Issues with 300 blackout subsonic.

Post by Norskie » Thu Jul 16, 2015 6:32 am

My pistol setup consists if a 9"aac barrel anderson mfg upper cmmg bcg. Anderson lower and standard lpk. Sig brace. Spikes t2 buffer. Carbine spring. Shoots factory supers just fine. Factory subs and hand load subs I have failure to feed issues. With both types the next round stove pipes. The rounds fire and eject properly. Could the problem be that a carbine spring is to much for the tube on the sig brace and sub loads don't have the snot to push it back?

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Re: Issues with 300 blackout subsonic.

Post by edzz » Thu Jul 16, 2015 9:04 am

It is probably short stroking, however the question is why?

Could be lack of lubrication, try running it on the wet side.

Could be lack of back pressure, try a Noveske flaming pig, a sound suppressor or other muzzle device designed to increase back pressure.

Could be short stroking due to the combined weight of the buffer and bolt.

Could be the recoil spring rate.

Could be the magazine. Try different brand. Lancers have a good reputation with 300 blk. Some people have had problems with the ribs inside the magazines pressing on the heaver bullets used in the subsonic causing miss feeds. PMags aren't always the best choice for 300blk.

If you chamber only one round and insert an empty magazine will the bolt lock open after firing?

How many rounds have been fired in this pistol, is it broken in yet.

When I built my 300 I initially had cycling issued that I overcame.

Many variables hopefully others will chime in with the correct answer.

I would start with lubrication and one round with the empty magazine to find out if your getting enough bolt travel for last round lock-up.
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Norskie
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Re: Issues with 300 blackout subsonic.

Post by Norskie » Thu Jul 16, 2015 10:14 am

Pistol has less then 100rds down the barrel. I am using pmags will try gi mags next. And the one round at a time. And go from there.

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Re: Issues with 300 blackout subsonic.

Post by Nievo » Thu Jul 16, 2015 6:17 pm

I'm using a 9.5" barrel along with a pmag, Spikes T2 buffer and standard carbine spring and have no problem cycling subs.

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Re: Issues with 300 blackout subsonic.

Post by WickedWillis » Fri Jul 17, 2015 7:55 am

Nievo wrote:I'm using a 9.5" barrel along with a pmag, Spikes T2 buffer and standard carbine spring and have no problem cycling subs.
I think the OP needs to increase the buffer weight like you have Nievo, honestly.
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Re: Issues with 300 blackout subsonic.

Post by Nievo » Fri Jul 17, 2015 6:32 pm

He already said he was using a Spikes T2 I believe.

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Re: Issues with 300 blackout subsonic.

Post by Norskie » Sat Jul 18, 2015 11:37 am

Yes I currently have a spikes t2. Just test fired with pmags and gi mags bolt would not lock open on empty with either. I will beef up my hand loads a little and go from there

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Re: Issues with 300 blackout subsonic.

Post by Nievo » Sat Jul 18, 2015 4:19 pm

Have you tried factory subs? I've been using Remington 220gr OTM's and haven't had a issue yet with those.

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Re: Issues with 300 blackout subsonic.

Post by Kolat » Fri Dec 01, 2017 11:02 am

Add a silencer.

If you aren't using a can then you're shooting pointy 45acp that doesn't expand and is expensive.

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