My new favorite 556 SBR

jimmyheadgear

jimmyheadgear

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This gun began life as a PSA 10.5" suppressed SBR. It was OK but there was a lot of recoil and gas in my face. At that time, I didn't want to try an adjustable gas block.

In stages I started to change things.
First was the barrel. I went with a SOT 9.2" carbine gas AGP barrel with .0625" gas port.

https://specialopstactical.com/prod...hon-agp-w-nickel-boron-carbine-length-barrel/

I noticed a difference. It shot a little smoother, but not anywhere close to what I was looking for.

Next, I added a Bootleg adjustable BCG. I set it to the 4th setting. This also made a difference.

After that, I swapped out the regular buffer tube for an A5, replaced my spring and H2 buffer with a Tubb AR15 flatwire spring and a Kynshot RB5007 AR9 buffer.

AR15 Forum member amphibian has a lot of great info on his site.

http://c3junkie.com/?page_id=654

This change seemed to really make a difference. It's much softer and shoots a lot flatter now. The Kynshot buffer weighs 161.5g and the H2 is 130.1g but as amphibian noted he believes the hydraulic action of the Kynshot makes a bigger difference vs the moving weights in the H2.

At this point the gun shoots a lot smoother than before but there is still a ton a gas coming from the ejection port.

So the last piece is an adjustable gas block. I got an SLR Sentry 7. Very nice gas block, I like the click to adjust gas metering.
It now shoots like an air rifle. I know I should've started with the adj. gas block in the first place but it was interesting to see the incremental differences all of the other parts made along the way.
1-DSC-7997-crop-adj.jpg

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Tagged.

My fav rifle is a 10.3" BA Hanson barrel with a Superlative AGB. I still fight with it to be reliable.
 
Really like these shorter ARs. A 16” feels clunky compared.

I, too, took the long way round with ARs, but that’s half the fun, and I prefer to learn the hard way!
 
jimmyheadgear said:
I switch between a Blitzkrieg and Slash's heavy buffer depending on whether it's suppressed or not.
Click to expand...

Unsuppressed- I also went the conventional route of heavy buffer....
It just made more moving mass and increased the already existing problem of dot dip.

Then I went off the reservation, lightened the bolt and used a JP SCS w/red spring.
5000+ rounds later, no problems at all.

Go lighter for unsuppressed. It will shoot flatter. 9mm AR Blow backs dont need nearly the weight that we have been lead to believe.
 
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Slacker said:
Unsuppressed- I also went the conventional route of heavy buffer....
It just made more moving mass and increased the already existing problem of dot dip.

Then I went off the reservation, lightened the bolt and used a JP SCS w/red spring.
5000+ rounds later, no problems at all.

Go lighter for unsuppressed. It will shoot flatter. 9mm AR Blow backs dont need nearly the weight that we have been lead to believe.
Click to expand...
Good to know. I'll give it a try. Thanks.

ETA: What did you do to lighten the bolt?
 
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OP would you mind telling me where you bought the Kynshot from? I've been waiting for them to go on sale but nothing so far, perhaps something on Black Friday will bring me joy.
 
Thanks - I've picked up a few things from them and you are right so far they've had the best price. No big hurry since I probably have another month or more before my stamp arrives.
 
11B CIB said:
How much gas are you bleeding off?
Click to expand...

too much. Ejection is around 1 o’clock

I just need to take off the hand guard and spend an afternoon messing with it
 
Tim said:
too much. Ejection is around 1 o’clock

I just need to take off the hand guard and spend an afternoon messing with it
Click to expand...

If you need any tips let me know; I run three of those
 
11B CIB said:
If you need any tips let me know; I run three of those
Click to expand...


Running an H3 buffer and blue Sprinco spring. Suppressed.

I get failure to lock open and fail trigger reset. Like I said, I just need to spend some dedicated time with it.
 
Slacker said:
You definitely went the long way around.
AGB, LW BCG and LW buffer seem to be the fastest and most effective mods to get a flat shooting gamer rifle.
Click to expand...
Granny's Christmas card money and Black Friday sales are getting me a new upper.

Anderson lightweight upper
https://aimsurplus.com/anderson-manufacturing-lightweight-sport-ar-upper-receiver/
Brownells lightweight BCG
https://www.brownells.com/rifle-par...=Avantlink&utm_content=NA&utm_campaign=Itwine
Radian Raptor LT lightweight charging handle
https://www.primaryarms.com/radian-raptor-lt-ambidextrous-ar15-charging-handle-black
SOT 12" AGP barrel
https://specialopstactical.com/prod...n-agp-w-nickel-boron-midlength-length-barrel/
SLR Sentry 7 adj. gas block
https://slrrifleworks.com/sentry-7-set-screw-adjustable-gas-block/
SLR HELIX 10.7" keymod handguard - F Model
https://slrrifleworks.com/helix-10-7-keymod-handguard-f-model/
Q Cherry Bomb muzzle break
https://hansohnbrothers.com/shop/q/accessories/muzzle-brakes/cherry-bomb/


This upper will go on an sbr lower that has a standard buffer tube, Sprinco Reduced Power carbine spring (Yellow) and a KAK lightweight buffer to start. I'll then be able to swap it out with the A5 sbr lower I have to see any differences.
I've got everything except the barrel. The wait is killing me.
 
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NKD said:
Do you use regular fixed gas blocks and standard buffers?
Click to expand...
I just switched over the 9" to an adjustable block. The 16" has a fixed gas block and the buffer is a regular A5. It runs fine with all kinds of ammo.

The barrels were made to work with stock setups not requiring any changes.
 
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