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The carrier looks ok. After a brief history read on the Rhino, that key may be of inferior metal anyway. You could get a new key, add a seal of permatex if you want, use some grade 8 screws and stake it down.

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Originally Posted by Splittiebus66

The carrier looks ok. After a brief history read on the Rhino, that key may be of inferior metal anyway. You could get a new key, add a seal of permatex if you want, use some grade 8 screws and stake it down.

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Yeah I thought I could use it. Too late now though, I followed the instructions from some ar15 website
abut torquing the screws (30lbs) well I got to 15lbs and snapped a screw. I need a good drill bit,
the ones I have are junk and wont drill it out. I'll put that one to the side and buy a mew BCG, screw it.

Came across this article regarding barrel selection and hoped it might help someone else as much as it has me.

https://everydaymarksman.wordpress.c...art-2-barrels/

https://youtu.be/pyYODtiohzQ

Long but good insight on the AR. I listened to it over a handful of work commutes.

Alright AR gurus. I put together a .300blk pistol. After the last round is fired, the BCG comes forward and overrides the bolt-hold-open part way. It is scraping the bottom of the BCG fairly significantly. The bolt slams home upon dropping the mag. I'm assuming it's a buffer/buffer spring weight issue. Thoughts?

Sounds over gassed for first guess.
Also check your bolt catch and spring, make sure they move freely and spring is working.

What spring, buffer, gas location, gas port size?
Subs or supers?
Can or no can?

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Originally Posted by Nate7667

Sounds over gassed for first guess.
Also check your bolt catch and spring, make sure they move freely and spring is working.

What spring, buffer, gas location, gas port size?
Subs or supers?
Can or no can?

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Pistol length gas system.
Carbine buffer/spring
supers
no can

If it's too much gas, it's an easy fix. It has an adjustable gas block.

This is my first .300blk, I guess it's designed for a wider range of gas. It's a preassembled Aero upper.

Thanks

Yup, start there.
Close the gas block settings. Open 1 or 2 clicks and fire away while adjusting it open until function and lock back.

Probably set to run subs right now. Much less pressure with those.

Getting ready for my first build. Please explain barrel twists to me. I see 1:7, 1:8 and 1:9 variants. What does it mean, why should I care, and what should I get?

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Originally Posted by alpacaheat

Getting ready for my first build. Please explain barrel twists to me. I see 1:7, 1:8 and 1:9 variants. What does it mean, why should I care, and what should I get?

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Bullet Weight Twist
40-Grain 1:12
55-Grain 1:9
62-Grain 1:8 or 1:7
77-Grain 1:7 or 1:8
80-Grain 1:7

1:8 is the go to barrel for the most versatility. If you're building for supreme accuracy, look for a barrel that is best for your chosen bullet grain.