AR Shorty troubles- all fixed

hicaliber

hicaliber

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I just picked up a 10" upper for my AR and took it to the range today.
Unfortunately it didn`t work quite the way it`s supposed to.
When you fire a round the bolt comes back far enough to #### the hammer for the follow up round but not far enough to strip the next round from the mag.
I spoke to a friend who says he thinks the spring is too heavy and says to pick up a lighter spring or cut one coil from a spare spring (which I don`t have).
I would just like to get a second opinion from the AR gurus here before I buy another spring.
Thanks in advance for your help.
 
Called Short Stroking. Usually under 11.5" barrel have this problem, Not enough gas to cycle the bolt.

New gas tube - PRI or a Pigtail should solve it.

Drilling out the gas port is the last thing you want to do, becuase you cannot change it back.

Spring trick is the cheapest route to pick. It might work, might not. Now you could get a m16 bolt, heavier buffer. But $$$$
 
sxyglock17 said:
Drill the gas port a little larger...
Click to expand...

Jesus Christ STOP!!!!!!!!

Put away the drill and the Dremmel tool, go to your room, Repeat "I will not Bubba my gun" 1000 times in your best southern accent.

The gas port MAY need to be opened, but that step should be the absolute last thing he tries.

Most short stroking with the short barreled guns is caused by excessive pressure, not too little.

HiCaliber - try

1) If you've got access to one, try swapping out the AR-15 carrier for a M-16. While you are at it, make sure the gas rings are in good condition and not lined up.
2) If you are using a collapsable stock, try and get the heavy buffer for it.

Quite often, the additional mass works to tame the pressure peak, and cures the short stroking issue.

If this does nothing to solve your problem, or makes it worse, it may be time to look at the gas port.

1) Is this a "proven" upper that has worked on another gun, or is it a frankencolt assembly? Possibly the front sight housing isn't aligned with the gas port.
2) If the gas port needs to be opened up, be prepared to add on one of the adjustable gas tubes, just in case you go too big.
 
Thanks guys
There is a brand new pigtail in it, istalled by the previous owner.
I was using two types of factory ammo, Wolf and not sure of the other manufacuter.
Yes I am using a colapsallble stock and no I don`t have access to a m16 bolt, I am using the bolt and carrier from my Norinco CQ311.

I will try a heavier buffer and hope it works.
 
First thing you do is throw that Russian wolf ammo in the garbage.
My 11.5 problems cleared up 98% after I did.
Where are you located in Ontario? I have an m16 carrier asm you can try
 
If it is the Wolf Laquered case stuff -- clean the chamber a lot then try with decent ammo.

Short Stroking can be caused by several things, but with the pig tail that can be too little gas due to the large gas volume.

With a PigTail a heavier bolt and spring will not help - just compound the issue.
Keep in mind the spring and heavier buffer was designed to slow bolt velocity to combat bolt bounce where due to excessive velocity the bolt woudl unlock on a bounce

I'd recommend cleaning the chamber, as well as cleaning the bolt and carrier and trying some good M193 spec 55gr stuff.
IF that does not work.
Then we can get into part swaps and other stuff.
 
Kevin I have the original gas tube that the guy took out, should I go to the trouble of puttin it back in?
I will try cleaning it up and using some better ammo and report back what happens.
 
Get a 20 in barrel like the weapon was originall designed for. Also down range velocity will be better for a already midrange or more like it shortrange cartridge.
 
y2k said:
Get a 20 in barrel like the weapon was originall designed for. Also down range velocity will be better for a already midrange or more like it shortrange cartridge.
Click to expand...

The man bought a 2 seater roadster for a reason WTF are you talking minivans for? :?
 
hicalibre - while I dislike the pitails - odds are the guy put it in to fix something...

I'd clean it and see what happends with different ammo.

IN THEORY - the pigtails will do a similar thing to the PRI FAT BOY - in increase the gas volume in the tube ans slow thge recoil impulse to a longer softer on elike a rifle not a carbine - however in a lot of guns with small gasports they just reduce the recoil impulse (as the Fatboy can do as well) to not enough, and short stroke.
 
MPI said:
y2k said:
Get a 20 in barrel like the weapon was originall designed for. Also down range velocity will be better for a already midrange or more like it shortrange cartridge.
Click to expand...

The man bought a 2 seater roadster for a reason WTF are you talking minivans for? :?
Click to expand...


Amen! We all know why / when / who / where blah, blah, blah of original design. He's having trouble with a modified AR. No help in telling him to buy the original with a 20" barrel.

I would definitely recommend a good cleaning and use the Wolf ammo in an original setup or sell it to someone who can make better use of it. Low grade ammo in a shorty AR is a no no, as is light reloads. Full power, quality / clean factory ammo is the best way to go. It may alleviate you problem. Like others have said... drilling the gas port is the last option.

Regards,
 
Exactly, which led me to ask what ammo was being used.

If the front sight base has been modified or replaced, better make sure that the gas ports are lined up properly.
 
y2k said:
Get a 20 in barrel like the weapon was originall designed for. Also down range velocity will be better for a already midrange or more like it shortrange cartridge.
Click to expand...

Thanks for your insite, I have a 20" upper for the "weapon". I also have a 10" upper I would like to get functioning properly and these good people are trying to help me accomplish that.

I will try the less permanent fixes suggested before I do something as drastic as drill out the gas port. I appreciate all the positive input and I will let you know how I make out.

I have an offer to try an m16 carrier so that is one of the things I will try along with a good cleaning and some better ammo.
I would also like to check the alignment of the gas ports as suggested but I don`t know how, instructions please.
This is my first AR so be patient.
 
Using the proper spring and buffer for the short carbine stock is a useful thing and not expensive to do as a good starting point. Just to make sure you're working with the right combination of weight and force as a good place to work from.

As was pointed out take the thing all apart and clean it, especially the bolt/carrier assembly. While its apart make sure the splits in the gas rings are staggered about 120 degrees apart. This will ensure that what gas is getting there is actually doing the job its supposed to and not leaking out.
 
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