50 Beowulf, short stroking?

SwwPlayboy

New member
Please keep in mind, I am not AR savvy at all. So if I call something by the incorrect name, please just work with me on this. I'm writing this thread for help. Thank you.

Few months back, I invested in an Alexander Arms 50 beowulf. Beast of a round, crazy damage. Finally took it out to a friends ranch so I could see what it could really do. After a couple rounds, the bolt seemed like it picked up the round but caught it half way up the casing and wedged it. So I'd pull the charge handle back so the bolt would grab the rear and the round would go in just fine. I was having to do this every couple of rounds or so. Thought maybe something was wrong with the metal mag Alexander arms sent with the AR so I tried my buddies plastic 223 clip. (If you'r not familiar with the 50 beowulf, the rounds, although being casing in a 50 AE, the primer is the same size as a 223. This allows them to be shot in a ar-15 platform. The rounds fit in any 223 mag for an ar.) That seemed to feed a little better, but even after a time the bolt would do the same or not pick up the next round at all. It would discharge the case but not pick up the next round causing me to pull the charge handle back to grab the next round. Some times it would cycle 6 out of 7 in the clip, some times 3 out of 7. It wasn't consistent. Thought maybe the gun just needed to be broken in a bit. Ran 100 rounds through it, issue continued.

So, did a little digging online, the only similar issue people were having with the 50 beowulf were mag related. We had already ruled that out by trying 3 different mags. Decided to pull the bolt carrier out and have a look. We worked the bolt head back and forth. My buddies said it seemed a bit stiff compared to theirs. They pulled theirs out and showed it slid back an forth much easier. Suggested maybe it just needed to be broke in, hence the 100 rounds that went through it. loosened up a little but still not as much as theirs and was still having the same issue. Cleaned it and lubed it real good, no improvement. We did not take the bolt carrier completely apart. just cleaned it as is and worked the head back and forth while dropping lube in. Thought about trying a different bolt from one of their AR-15s. Although the BCG are the same, the face on the bolt head has a bit less meat than the the one for a 223.

I plan on calling Alexander arms tomorrow to see what they think about it. Till then, I'd like to see what others think.

I asked my buddies if they thought maybe the weights in the buffer tube were possibly to heavy and causing the bolt to short stroke, (this is something that had happened to a friend and his 300 black out). The rifle came as is from alexander arms, I have change nothing. They didnt believe this was the problem. So, is it possibe the bolt head is to stiff, or could the buffer tube weights be off? Could there be an issue with the gas block or gas line?
 
There are a few things that can cause a bolt to short stroke, and one is a gas leak. Another is a gas port that's not the correct diameter, or a bent/dented gas tube. Most of the time, it is a leak.

However, you said your bolt was tight when pulled apart? I would check the fit of everything, as the gas has to push the two pieces of the bolt apart to unlock it, before it ever moves back into the receiver. A little polishing of the inside of the bolt carriers cylinder with steel wool might help, then apply some thin oil. Also check the rings on the bolt, and check to see if there are any burrs in the cam slot.

Last, if the above does not cure the problem, then look for gas leaks around the bolt key, and the front sight housing, where the gas tube goes in.
 
There's not much you can do, but try to see if there is any residue from the gas on the metal. I would look for it around the bottom of the bolt key, where it fits on top of the bolt, and where the gas tube goes into the front sight housing.

They can also leak around the bolt rings, but since yours fits tightly, I doubt it's there.
 
Let's do a quick subsystem replacement check:
If you have another AR-lower available (or can borrow), switch it out and report back the results.
 
Thanks again Dixie. I called Alexander Arms today and they agree with what you have said, they believe it to be a gas issue. They ask for me to send it back to them so they may fix the issue. I plan to do this.

We tried a different lower, fired just fine, but was still short stroking. Tried a 2 different mags, same result. Considered changing bolts, but no one else I knew had a 50 Beowulf and I couldn't substitute it with a standard 223 bolt. Same bolt but bolt face is a different size. Seems gas is the next possible issue.
 
If it ain't the lower (Check), it's the upper.

A stiff[[er]/tight[er] bolt is par for the course w/ an AA upper
...and no big deal w/ my AA Grendel ...so probably not that.

Bill Alexander is good people -- so they'll fix the only other likely thing, gas.

(Hope so, as my own AA Beowulf is due any day now.)




Film at Eleven... ;)
 
mehavey, they were real easy to deal with and even offered to pay shipping. Was really impressed with their customer service so far. If everything comes back alright, ill be getting a Grendel from them next. You enjoying yours?
 
First thing I would have tried:fire single rounds with an empty mag in place. If the bolt locks back 100%, you're getting full bolt travel. If not, you have a gas leak/shortage or serious drag somewhere.
 
Film at Eleven.

Got the Alexander OverMatch Upper yesterday afternoon; dropped it onto the lower
I'd deliberately had built* for it at the Nation's Gunshow/Chantilly two months ago;
headed out to the range with some 335gr RainerHPs (loaded by Alexander);
set up at 25 to get on paper before adjusting the iron sights ......

...and it promptly short-stroked.

Bummer.

Thinking through it though, the guys who built the lower had said
"... for a Beowulf ? Oh boy. gotta put a heavy buffer on it...."

So I went home, pulled the stock carbine lower off my Armarlite Sporter and went back out
to the range ...worked fine, each time, every time.

Then I loaded up some Lyman#2 cast, Accurate Molds 370B/GC (that I also use in my 500S&W
over 32gr Lil`Gun for 30,500psi); double-checked it against QuickLoad for a predicted 24,500psi,
went back out to range -- where it again worked perfectly against the 8" gong at 50 yards

142eu1c.jpg


* Reminder: Make sure that the buffer/recoil system is stock -- heavy-duty systems will screw it up.



postscript#1: Predicted velocity was 1,686fps. Actual was 1,725. Calculated pressure (cubed ratio) was right at 30,000
postscript#2: Unaltered PMAG 5.56 magazines work just fine w/ the Beowulf
postscript#3: Absolutely clean burn. Not even a hint of leading. Bolt cleanup was totally unremarkable after a dozen cast rounds
 
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