Problems With my 10.5in Ruger556 in 300blk

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Oncewas
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Problems With my 10.5in Ruger556 in 300blk

Post by Oncewas »

Hello
New to the board and new to 300Blackout. A couple of months ago before everything got too crazy I thought I'd buy a 300blk to run suppressed for home protection. So I bought a Ruger 556 10.5in barrel in 300blk and a DeadAir Sandman Ti. I purchased 250 rounds of Stryker 200gr and 200 rounds of Sellier&Bellot 147gr rounds. I shot it unsuppressed with both rounds and everything went well. I
The suppressor came in and off to the range. Shot 20 rounds of the S&B supersonics and still everything was fine. I used a Magpul 300blk mag. I then switched to the metal Duramag that came with the Ruger loaded with 20 rounds of the Stryker subsonic. Second round failed to load, six shots then seventh failed to load, five shots sixth failed to load, five shot sixth failed to load then last four okay. Cleaned the gun really well and took it back out a few days later with only the subs first mag was a Magpul 5.56 mag all 28 rounds shot with out a problem. Next mag was a Magpul 300blk mag and I could shoot a few then failure to cycle through the whole mag. Slo mo video shows the BCG is not going back far enough to load the next round.
The gas port is 0.094.
The buffer is 3.0oz.
I've been told it's under gassed and I should open up the port to 0.1010. I can do that but I'm afraid of over over gassing but I do have a Seekins Adjustable Gas Block coming.
I do have an Odin Works Heavy adjustable buffer coming. I've already concluded my buffer is too light.
Any advice or other pointers.
Thanks Rex
Oncewas
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Re: Problems With my 10.5in Ruger556 in 300blk

Post by Oncewas »

Really. Nothing.
BJK
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Re: Problems With my 10.5in Ruger556 in 300blk

Post by BJK »

I'm just guessing with what follows because you only state that it failed to load, and that can mean so many things. Heck, anytime I've had a malfunction it failed to load. But I'm trying to figure out what you were trying to say, yeah, guessing.

Everything was OK until you switched to a different mag? If you go back to the mag that was working do the problems stop?

The mag spring is trying to lift much heavier cartridges with their much heavier bullets than if it was 5.56 in the mag. A lot has to happen in a short amount of time and in a specific order with a semi-auto and a mag not intended for 300BLK could be at fault. Before you change things that are more difficult and costly to change I'd change the simple and less expensive stuff first. Someone at Ruger may have realized that,"Heck yeah, this mag fits in that hole, so we're good!". Maybe yes, maybe no. Then again, maybe it isn't the mag. Too, look inside the mag when it's loaded. 5.56/.223 mags can interfere with the nose of the bullet. 300BLK specific mags don't, or at least the ones I own don't

FWIW, if your gas port is undersized putting an adjustable gas block on it won't make it bigger. You'd need to open it up, as you stated. But I try to simplify things first, and only if that fails then make changes that I might not actually want if they also fail. It's an old axiom that one works on less expensive and easier to replace parts first. In a HD gun I want 100% reliablity and to me that means no parts that I have to keep in tune to make it run. Maybe you think differently. But to me "adjustable" means tuneable to a specific load and that also means it can go out of adjustment. That goes against my philosophy of simplifying.
Oncewas
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Joined: Sat Nov 07, 2020 3:50 am

Re: Problems With my 10.5in Ruger556 in 300blk

Post by Oncewas »

BJK
Thanks for the response. The two different mags I've had the failure with were both 300blkj mags. The first time it was with the metal Duramag that came with the Ruger that is stamped 300blk then the next time with the MAgpul 300blk mag that worked fine the last time. While I had hoped it was the mags I don't think it is.
I can open up the gas port but it's already at 0.094 ands going up to 0.110 which is what's been recommended just seems like a big step. But that is why the adjustable gas block. For when/if I open up the gas port.
Everything I've read says my buffer is too small at 3oz so I've got an Odin Works Heavy adjustable coming to try to work out if that is the problem. Once it gets here I'm going to try and see if that helps or I have a set of lighter KAK buffers I can also try.
You are right I don't want a gun that every time I shoot it I have to adjust it for the different rounds I'm shooting. I just to get it fixed.
BJK
Silent But Deadly
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Joined: Thu Jun 18, 2020 8:30 am

Re: Problems With my 10.5in Ruger556 in 300blk

Post by BJK »

Good luck with it. Please let us know what the solution was after you figure it out.

Did you happen to change buffer springs? That's also part of the equation. I ask because I change things out lots of times, then forget as time passes then I get to shoot it, and have to figure out what I did. I claim old fart status to justify that behavior.

Reading your post again you changed ammo from S&B super and went to Stryker subs and it started to malfunction. Correct? Well, this isn't going to make you feel any better about your malfunctions, but S&B supers ran and still do in mine. But their subs went from running initially to not running 100% after a time. Never did figure it out but I also didn't spend any time on it. I'll make my loads and sell the S&Bs. That's my solution. :D

Again, good luck!
Oncewas
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Re: Problems With my 10.5in Ruger556 in 300blk

Post by Oncewas »

I'm thinking of first trying different ammo. I will look into loading my own but I don't think that is something I can just say "oh let's do this now" without first having a clue what I'm doing and purchasing the equipment.
I thought about changing buffer springs but that's a whole different animal and I wouldn't know where to begin. Stronger, lighter? More coils, less coils?
I could just shoot supers they seem to work fine and that's about all I'm finding online anyway.
At 70 I too suffer from old fart status. just trying to stay ahead of the game (or the reaper)
I'm post back here once (if I do)what I find out.
Again Thanks.
Rex
Oncewas
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Re: Problems With my 10.5in Ruger556 in 300blk

Post by Oncewas »

Okay an update. I changed out the buffer to an H1 and it seemed to help. A mag of supers went fine. Mag of subs went fine until I had a dud on the seventeenth round. ejected it next two rounds okay but it didn't lock back on last round. I added weights to the Odin Works buffer (just guessed didn't take the scale with me.) Loaded up a mag of supers everything went fine. Loaded up a mag of subs everything went fine until the last round when it didn't lock back the bolt on an empty mag. Now this is all with the suppressor. I did not open up the gas port yet. I have an adjustable gas block but have not installed it yet.

I am now going to run an H2 buffer and see how things go.

Still need to find out why the bolt won't lock back on an empty mag.
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