Bolt Carrier Group recoil dynamics

[Casey Simpson]

Watch this video and decide whether a high mass bcg is better than a low mass one.
Because of its heavier weight requiring more energy to move (F=MC2), the breach of semi-automatic rifle with a high mass bcg will by nature remain closed longer than one with a low mass one. And because of recoil produced by the bcg stopping, bouncing off the buffer and changing direction, the shooter experiences the second recoil of an Ar rifle. The second recoil may be softened with an improved buffer spring or buffer device tending towards improved deceleration of the bcg. The delayed, later opening of the breach, allowing the bullet to be farther down the barrel upon opening seems better to me since the muzzle will be closer to the called shot than an earlier and sooner opening of the breach.
A third reaction happens upon closing of the breach, and in the video notice how the bcg bounces off the chamber! Lots of vibrations going on. The right buffer spring can diminish this movement too by not over-powering the bcg forward.

Seems to me a lighter bcg gets slammed around too much. What do y'all think?

High speed vedio bcg

 

[Hellbender]

Re: Bolt Carrier Group recoil dynamics

The bullet has left the barrel before the bolt carrier moves, on a properly operating rifle. Adding a long suppressor can sometimes change these dynamics.

Here's some discussion on the subject...

http://www.snipershide.com/forum/ubbthre...177#Post1818177

I should have this gun going in the next 3-5 days, as the barrel is FINALLY here.

 

[Casey Simpson]

Re: Bolt Carrier Group recoil dynamics

Hmmmmm; i'd try a lighter carrier if I had one. Maybe you're right. I'll look into that.

 

[hrfunk]

Re: Bolt Carrier Group recoil dynamics

After better than a dozen years driving a Remington 700P, I recently started working with an AR15 based Sniper System. While I'm no stranger to the AR platform, using it in a mid-range (0-300 yards), precision shooting capacity has required more "get acquainted" time than I anticipated. One of the big reasons for that is the difference in recoil impulse (or impulses). The video does a good job of showing exactly what my shooting shoulder has been telling me for the past 3 or 4 months. Basically I like the AR system and I think it has a lot going for it, but there is definately a learning curve for us turn-bolt veterans.

HRF