Straight pull AR?
I have read some write ups of people pulling the gas system out of their AR's and making them into a straight pull bolt. I am curious how this works? Could it be done with an AR like the oly arms 25wssm?
Does anyone have a video or drawing that shows how the bolt locks when a round is fired but can still be pulled straight back by hand
I am curious as to why you would want to do this. It seems as this would negate a VERY big reason to have this type of rifle in the first place....
The bolt unlocks because you're actually retracting the bolt carrier, not the bolt itself. The bolt is cammed into the carrier to turn about 15 degrees counterclockwise when the carrier moves backwards, thus unlocking and moving freely.
Originally Posted by LuJon
That make perfect sense! Thanks
Originally Posted by Diesel Nut
Really I would prefer an ultralight bolt action upper in a standard cal for the AR10 lower or one in something like .300 olympic on the AR15. I have to think that w/ a thin profile barrel, carbon fore grip, a small upper reciever, and a skeleton stock a sub 5lb modular rifle could be crafted. Imagine being able to break your 5lb bolt action sheep rifle down into two pieces and toss it in your pack! W/ no buffer tube you could even have a side folding stock on it to make it even more compact though a bit heavier.
Originally Posted by hunt_ak
Ah...just to shed weight. I'm with ya now...
Or if you prefer not to hike up the mountain at all to shoot the sheep, they also make a single shot, bolt action .50 BMG that fits a standard AR lower.
Diesel nut is right, the bolt carrier group goes straight back and forth. The cam pin, which goes through the rear of the bolt itself, rotates within a slot in the bolt carrier group. On a normal AR the spring provides the power for this, but with a straight pull, the shooter would provide the power. This camming action is the reason you should not "ride the bolt" on an AR, as sometimes it will hang up and not rotate the bolt into battery as it should. This is at least partly why they added the forward assist to the M-16A1.
I installed a JP Industries adjustable gas block on my latest build, and when the gas is shut off, it must be cycled by hand every time, just like you've proposed, so the biggest 'hurdle' next up would be to seal off the gas port effectively without adding any additional weight. Perhaps the hole could be threaded in the barrel, and a plug fitted, or just an aluminum gas block turned 180 degrees to shut off the gas flow.
You'll likely want to leave your buffer and spring in the butt, as I've noticed that even with the gas shut off on my rifle, the bolt carrier still comes back about 3/8's of an inch, and in a gun with a bit more 'breaking in', could travel farther, coming clear out of battery. I've a couple of AR's that are 'slick' enough that if I put the carrier and bolt ass'y into the upper, and lock 'er up without a buffer and spring, the carrier ass'y will slide back, unlock the bolt, and slide fully back if I tip the rifle up. Also, remember that the bolt carrier extends into the buffer tube in recoil, so it's not likely that you could add a side-folding butt and block off the back of the upper, without cutting the carrier's length back so it doesn't extend out the back in operation, savvy?
Fulton Armory, and now a few others, offer right, left, and ambidextrous side-handle 'slick side' uppers that would shave a few more ounces off the weight, and you wouldn't have to have the charging handle, nor gas tube on the bolt carrier.
David Tubb has been building lift-handle bolt guns on AR's for awhile, might want to check out what he's doing with those, but it'd likely take yer next paycheck or two to get one.
With a really slender barrel, a lightweight ventilated free float tube, and compact scope, your rifle should be a real lightweight! With something like an A2, or 'entry' buttstock, recoil should be fairly straight back, so it'd be semi-comfortable to shoot with a good big-game round.
Interesting idea, let us know how it works out!
Last edited by Darreld Walton; 03-20-2010 at 05:32.
I fired an email off to David, we will see what he thinks.
Interested to see what he says...and if the wait on a reply is going to be before we grow old...