AR newb question here....

[BigtimeAub]

I've got a carbine and am going to put the Magpul MOE fixed stock on it. Will the gas block on my rifle allow for enough gas to cycle properly with a full size buffer and buffer and buffer spring or can I just stick with the carbine length buffer and spring?

Would it be advantageous to change the gas block to an adjustable gas block for any reason?

Any advice and explanations would be greatly appreciated.

Thanks

 

[ORD]

Re: AR newb question here....

DO NOT RUN A CARBINE BUFFER/SPRING IN A RIFLE-LENGTH BUFFER TUBE!

You'll need to swap out the carbine receiver extension/buffer tube, as well as go to the longer rifle-length A2 receiver extension, buffer and spring for use with the MOE fixed/A2 type stock. You cannot safely run a carbine-length buffer/spring combo in the longer A2 receiver extension without cause damage to your rifle.

An adjustable gad block won't likely be necessary to ensure proper functioning of your setup under normal circumstances, but they are advantageous in terms of being able to fine-tune your rifle's cycling, reduce perceived recoil impulse to some degree, account for variations in ammo/shooting conditions (like if you'll be running full power stuff one time and subs or with a can at others), etc.

 

[BigtimeAub]

Re: AR newb question here....

Ok, so I went to the range today. I installed the full length extension tube, full length buffer and spring. I ran into some problems which I was anticipating. The bolt would blow back far enough to eject the shell but not far enough to pick up the next round. I was using P-mags so that shouldn't have been an issue. The feed ramps are fine but that wouldn't have mattered since the round wasn't being picked up by the bolt.

So, is this not an issue where the buffer is too heavy and/or the spring is too stiff? I'm not the smartest guy when it comes to this stuff and I don't pretend to be but I would assume that the gas block is too restrictive for the full size buffer and spring and is designed and tuned specifically for the smaller, lighter carbine buffer and spring. Is that not correct?

What will happen if I use the carbine buffer and spring in the full length stock? Will the shorter buffer recoil too far into the stock allowing the BCG to follow into the stock itself? Or is there enough tension in the spring that this would not be likely to happen since the rifle's gas system was in fact designed around the reciprocating mass that is the carbine length rifle?

Thanks for your help!

 

[Beef82]

Re: AR newb question here....

Low powered ammunition is the most likely culprit.

What length barrel and gas system? What ammo were you using?
Have you checked for gas leaks at the gas block? Gas blocks are not specific to carbine, mid, or rifle systems. Rifle is properly lubed of course? Did this happen every shot or just the first couple out a mag?

If you install a carbine buffer into a rifle extension it will allow the BCG to travel too far into the extension at a minimum damaging/breaking the retainer and is unlikely to properly return to battery, if it will even properly chamber to intially fire.

 

[BigtimeAub]

Re: AR newb question here....

The ammo used was 20rds of Remington UMC 55gr and 10rds of PMC Bronze 55gr. FTF was encountered for all 30rds.

The barrel length is 16" with the carbine length gas system. The rifle was properly lubed but I can try wetting it down a little more.

 

[Beef82]

Re: AR newb question here....

Well, probably not the ammo, that's not the hottest stuff out there but it should cycle fine on it. 16" w carbine rarely suffer being undergassed. No need to drown it in lube, only asked because its somehow often overlooked. Any indication of excess leakage around the gas block?

Another couple questions for clarification, the rifle functioned in it origional carbine configuration? You tried more than one Pmag?

I'm about out of ideas, the rifle buffer sys is generally about as reliable and forgiving as it gets, hopefully someone with more knowledge will be along, good luck.

 

[mt Al]

Re: AR newb question here....

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BigtimeAub</div><div class="ubbcode-body">
Would it be advantageous to change the gas block to an adjustable gas block for any reason?

</div></div>

I, too, an mew-ish to ARs so take this with a grain of salt. Heck, it might even be BS!

The guy who built mine put in an adjustable gas block after I shot quite a bit with stock (non-adjustable?) block. I made up a few hundred reloads with a "standard" recipe and we went out and shot. He adjusted the gas block and, could be just mental, but the rifle seems to cycle smoother than when it was not adjustable.