How important is this feature in a rotating bolt?


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Evil Monkey
January 9, 2009, 05:56 AM
I once asked why a multi lugged bolt like the ar15/ar18 bolt would be used over a typical heavy duty 2 or 3 lug bolt and the answer was because the multi lugged bolts rotate/lock sooner.

After thinking about it for a while, I thought maybe I was missing the point. Why is it neccessary for a bolt to have the least amount of rotation as possible?

I try and rationalize why a mutli lugged bolt is desirable but I'm not satisfied.

With 2 lug bolts, they need a longer rotation period to lock in place. So the carrier is machined with a long cam track. The reason it must be long is because if the angle of the track is too sharp, the carrier may have a hard time rotating the bolt into its locking position. The only "problem" I can see is that this makes the bolt face-to-carrier rear length long, thus needing a longer receiver for proper cycling. But this is hardly a big deal.

The 7 lug bolt has a very short cam track with hardly an angle, thus allowing the carrier to be short and allow for a shorter receiver.

What the hell!? This can't be it! It's too simple! There has to be more that I don't know. There's a reason why the AR18 is the most copied system with the same old 7 lug bolt and I can't figure it out.:banghead:

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everallm
January 9, 2009, 07:30 AM
It's copied because it's there nor because it's necessarily better.....

Here's a shot comparing an XCR, AK, AR-10, AA Grendel, AR-15, Kel Tec PLR bolt

http://www.65grendel.com/forum/attachment.php?attachmentid=723&stc=1

My personal opinion is that greater number, smaller, thinner, weaker lugs is a worse idea both mechanically as well as for effective cleaning.

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