How Does a Straight-Pull Bolt work?

[andrewdl007]

I've wondered this before, and never found a good explanation. How does a straight-pull rifle like the K31 work? Without the turning bolt, how does the bolt stay locked when the gun is fired? Anyone out there have a way of explaining that I would understand...Thanks.

 

[dubya450]

I've been curious as well

 

[Cal-gun Fan]

I believe it works just like a semi-auto without a gas system. That is, it uses a rotating bolt within the bolt carrier?

 

[Sam1911]

There are several systems, but they all do lock the action.

The K-31s have a rotating portion of the bolt that turns on the inner portion of the bolt. As you retract the bolt handle, a lug rides in a cam slot to turn and unlock the bolt head.

If no one else posts first, I'll snap some pics.

Other systems, like the Blaser rifles from Germany, use a very different system of locking tabs (almost like ball bearings) which are forced out into recesses in the receiver when you close the bolt. When you retract the bolt, they drop back inside the bolt.

 

[breacher]

I was playing with a used T-bolt 22 (Remington I think) at the LGS recently. It didn't look all that complicated but that was just a .22 cal rifle. It was a much faster bolt system than a rotating bolt. Too bad they are so expensive.

 

[Carl N. Brown]

Another variation uses a tilting bolt system.

Think of it as working like a FN FAL semi-auto without a gas piston or return spring.

Pulling back on the bolt handle raises the bolt out of its recess in the receiver and slides it open; pushing the bolt handle forward slides the bolt forward and tips into its locking recess.

 

[Sam1911]

Here are a few pics of the K-31 bolt.

 

[DM~]

I was playing with a used T-bolt 22 (Remington I think) at the LGS recently. It didn't look all that complicated but that was just a .22 cal rifle. It was a much faster bolt system than a rotating bolt. Too bad they are so expensive.

T-bolts were/are Brownings,



DM

 

[NG VI]

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