I just finished a beowulf build and last time I went to the range it was having issues.

It load the first round fine, after firing it would eject the shell and then 50-75% of the time it would TRY to load another round, but it would hang up and feed it at and akward angle. Then on the last round the bolt would not lock back...... It will lock back if I pull the charging handle back on an empty mag. And it seems to load the first round fine when i drop the bolt.

What can I look at. I changed the trigger/stock and put on a FF tube (2 peice didn't dissasemble the barrel.), so what can I look at to fix this problem. I put in an LMT trigger and PRS stock. Those are the only two things I can think of that would affect it.

Josh

If it does not lock back on an empty mag when firing the last round, then it is definitely short stroking.

Sources of short stroking are not enough energy delivered to the carrier, too much energy sucked off by drag in the mechanism, too much energy taken up by extraction, too much energy taken up by the springs.

Not enough energy delivered to the carrier - Obstructed barrel port or front sight base, poor fit of the carrier key to the carrier, carrier key screws not tight, gas tube end or carrier key opening worn and leaky, carrier gas path obstructed, gas tube obstructed, gas rings gone, large clearance between tail of bolt and carrier;

Too much energy sucked off by drag in the mechanism - Binding or rubbing carrier, binding recoil spring, carrier and hammer binding on each other or inadequate lube on reciprocating parts. You can feel this during manual cycling, both with the trigger released and with the trigger pulled;

Too much energy taken up by extraction - Rough, sticky, or out-of-shape chamber, as evidenced by marks on cases and bent extraction rims. Ammo/chamber that make excess pressure, as evidenced by pierced, cratered, flattened, or lost primers, buttons of case metal extruded into the ejector plunger hole, case head growth in firing. Dirty chamber - clean with gun solvent, then lacquer thinner;

Too much energy taken up by the springs - Extra power recoil springs and hammer springs can be too much to allow full cycling. Start with GI, and if they work OK, then play with stronger ones.

Notice how many sources there are. Eliminate the gas path problems by checking them all, put in GI springs, and clean and lube everything.

Just to ad one thing to the above trouble-shooting by M4Madness does your bolt lock back all the way?
I noticed you said you changed the stock.
What I mean is one time I changed my stock for a SP1 type and used the A2 stock screw.
It would not lock back after last shot fired and double feed, all kinds of bad things. The longer screw wouldn't let the bolt carrier go all the way back.
The bolt should be all the way locked to the rear almost out of sight looking through the ejection port.
Just a thought.
Good luck.

What kink of ammo were you using?

Alexander Arms 334 Grain HP same thing I used before the changes, im leaning towards the long screw..... The gas system shouldn't affect it as it worked before.

Quoted: Alexander Arms 334 Grain HP same thing I used before the changes, im leaning towards the long screw..... The gas system shouldn't affect it as it worked before.

The long screw issue only comes into play when using the longer A2 screw with the shorter A1 stock. What are you using for a stock?

Is the buffer retainer installed correctly UNDER the buffer tube?

Acording to his post this is the stock he is using:



A PRS stock. Never seen one in real life.

Quoted: Acording to his post this is the stock he is using: img335.imageshack.us/img335/2740/stock350x2084nm.th.jpg A PRS stock. Never seen one in real life.

That is correct i used the screw that came with it.

Josh