Short stroke

[77bawls]

Could a loose fit in the gas tube roll pin cause a short stroke? The store was out of them and I had to improvise. I have the pin in there now, but what are some other things I can look for?

Is this the correct length?

[kendog4570]

Based on your pictures, the first place I would look is the buffer tube. Do you have as much grease in there as on the bolt, carrier, and in the upper receiver? If so, it can hydraulically dampen the buffer movement, and cause short stroking, especially if there is no vent in the upper butt stock screw. It should have a hole in it. There are many causes of it, but I would look there first.
Lube is important, but you have about a tube and a half too much there.

[Ryan in SD]

Yeah was thinking the same thing, lol so much grease!

[BisDak]

get this...

http://www.brownells.com/.aspx/pid=18722/Product/AR_15_MCFARLAND_trade__BOLT_GAS_RING

[dieselpower]

Based on your pictures, the first place I would look is the buffer tube. Do you have as much grease in there as on the bolt, carrier, and in the upper receiver? If so, it can hydraulically dampen the buffer movement, and cause short stroking, especially if there is no vent in the upper butt stock screw. It should have a hole in it. There are many causes of it, but I would look there first.
Lube is important, but you have about a tube and a half too much there.

Yeah was thinking the same thing, lol so much grease!

bam! good call. There is a difference between wet and goop. Is the gas key filled with that goop too?

The pin should hold the tube in place, if the tube moves around the hole in the gas block may be the problem. The gases maybe able to push the tube out of the way allowing some of the gases to escape leading to low pressure. Does the tube wiggle at the gas block? If yes...that could be a major problem. Start with a new tube and a new REAL pin. The Gas key side looks good, but you are correct the gas block side may be a problem.

[killshot44]

And despite all that grease the bolt-lugs look worn........odd.

You only need to lube the back of the bolt lugs and a little on the carrier skids. Do as the above posters recommend, clean off ALL of that heavy grease, relube and try again.

PS: Best lube I've ever used was recommended by one of my builders, it's called "Phil's Tenacious Oil" and is sold at high-end bicycle stores. Very "sticky" with good viscosity.

[dvsdev]

I'm not sure, but from the first picture the gas key does not look properly staked. The fasteners may have gotten loose.

[77bawls]

Okay I forgot to mention, round count is about 30. Before I put any lube on the outside of the bolt I ran it dry and it did the same thing. No there is no grease in the gas key and there is no grease at all in the buffer tube. The pic was just after I put grease on it usually I use lubriplate but I forgot it at home.

The store was out of gas tube roll pins and the clerk told me I could use a trim nail. I got a 1/16" nail but apparently the hole is 3/32". I went back to the store and they had the roll pins in stock 3/32"x5/16". That roll pin fits the low profile gas block perfectly but I have a picatinny rail gas block. It needs to be 3/32"x5/8". I used the small roll pin and just made sure it was centered in the block.

I'm going to go to Sac Valley in a few minutes to see how it does.

[kendog4570]

Okay I forgot to mention, round count is about 30....

Shoot 50 or 100 rounds of good ammo through it and then see how it does. And lose the grease pit!

[Outta Control]

Based on your pictures, the first place I would look is the buffer tube. Do you have as much grease in there as on the bolt, carrier, and in the upper receiver? If so, it can hydraulically dampen the buffer movement, and cause short stroking, especially if there is no vent in the upper butt stock screw. It should have a hole in it. There are many causes of it, but I would look there first.
Lube is important, but you have about a tube and a half too much there.

What you guys are just too much. Y'all always say Lube this , Lube that, and keep it lube. Now y'all say too much lube.

[kendog4570]

What you guys are just too much. Y'all always say Lube this , Lube that, and keep it lube. Now y'all say too much lube.

Not me, baby. Use good lube sparingly, try to wipe most of it off, and change it often.

[THT]

Lube the races of the carrier. ONE drop of lube on the bolt, spread with finger, wipe excess off. GREASE the upper receiver where the charging handle latch contacts it. That's all I do and I have very few stoppages.

[Sgt. Slaughter]

I usually take a grease gun and put the nozzle into the ejection port and fill it until grease comes out the seam inbetween the recievers, lucas oil red and tacky works for me.

[luckystrike]

less earwax and more oil, try different ammo

[TRAP55]

One that gave me a real headache trying to figure out, was the bolt carrier key fit to the gas tube.