Anybody here remember the PWA (PacWestArms) lowers? I believe they were the forerunner to Olympic. Anyway, at the shop where I work, a fellow came in with a box or AR parts, enough to build 2 rifles, a 20" HBAR and a 16" carbine. The only things missing from 2 complete guns was the 20" bbl gas tube and a buffer retainer and spring. Both lowers were PWA, uppers are un marked, one w/ A2 sights and 1 w/ A1, barrels pre-ban w/ bayo lugs and threaded. I know the PWAs are pre-ban. The carbine has the old style 3-position aluminum stock, and its barrel is heavy out to the FSB and thin from there to the muzzle (pre-M4). I put them both together, using tha A2 sighted upper for the 20" gun. The 20" gun needed a new extractor spring and buffer and then worked flawlessly, even not properly lubed. I started lurking around here shortly after that so now I know it wasn’t properly lubed, thank you Pat Rogers. The 16" gun has been a PITA. the upper is obviously no to spec. It needed filing on the rear tab just to close all the way, and the barrel locating notch is off. One of the triggers was too wide, so I don’t believe the FCG is spec either. I got the shorty together and it has been one thing after another, it is just about working. The shop owner wanted to sell both rifles, but after so much tinkering to get the short one to work, he’s not selling that one. It is basically the AR I have wanted for awhile (I don’t currently have any), with the barrel profile and A1 sights and such, so I think I can get it on the cheap. I figure then I can upgrade parts to maybe end up with something worth having. I’m sure there are opinions, so I’d like to hear them. I know I can either listen or ignore, so either way I’ll read them. Thanks in advance.
I’ve owned two PWA lowers, one preban that I owned for years but traded away (very fairly) to a guy living in a ban state and one postban that I still own. I’m no expert but I remember reading PWA had some association with LMT, not Olympic. Judging by the looks of the logo & serial number engraving I would say this is correct because they look identical to my LMT lowers in every way. The two companies were also located in the same city in Illinois.
- Both of the PWA lowers I have experience with where perfect and neither gave me any issues.
That could be. Info I could find was sketchy at best, so it could be wrong. From what I hear, LMT makes good stuff, better than Olympic (?). While I am familiar with the AR system and how it works, I’m not into them so much that I know all the best manufacturers. I had a parts gun built on an EA (Essential Arms) receiver way back in the 80s, but had sold it. I had bought it complete. I just recently decided I wanted another, but kind of old school, with the carry handle, A1 sights, and skinny barrel. I’m just wondering if the receiver is any good and if my build could be a reliable piece. I know, no one here knows exactly what I’m doing, so this is more a question about the possibility of this conglomeration of parts.
PWA were/are (?) made by LMT. I may be wrong on this, so don’t take it as gospel but originally the PWA name was owned by LMT.
Look into the gas port diameter in the barrel.
It should be 0.062" to 0.067" maximum on a 16" carbine barrel.
If this is an un-marked barrel, it’s heritage is instantly suspect.
I find that most un-marked barrels have oversized gas ports.
Plugging and re-drilling makes a HUGE difference in how they perform.
If the port is indeed oversized, there are other solutions instead of plugging and drilling.
You can run a really heavy buffer, an adjustable gas tube or an increased-volume gas tube like the PRI fatboy.
Reading through my how it works thread might be helpful to your understanding of the AR.
Some years ago there were a lot of PWA lowers and guns built on them at the gunshows down here. The only issue I ever saw or heard about concerning the lowers was mag wells being undersized on some. I saw a few people try a lot of GI mags in them and all very tight, so I know it wasn’t the mags. Obviuosly an easy thing to check. By the time you get it running you will have gained a lot of practical experience, so if it is really cheap, why not! Good luck.
Billy
I read the link you provided and it explained about the gas inside the bolt carrier, but I pretty much knew the rest. I knew about case expansion and the inability to extract a case still under pressure. The barrel is not totally unmarked, it has something stamped into it on the top just in front of the FSB, I will see what it is. I only work in this shop on weekends, so I won’t be there again until Sat. I will also check port size. In reading around, I see about the carbines having more issues than rifles with gas amounts and pressures. I think it’s getting too much gas. It was recoiling kinda hard and overriding the next round in the mag, as if the mag couldn’t keep up. I saw in Brownells this “pigtail tube” which was longer and supposed to help out with pistols and carbines. I made my own from stainless tubing (didn’t want to spend $80). Theirs had 2 coils, mine had 4. It wouldn’t even eject. I shortened it to 2 coils. It ejected but wouldn’t pick up the next round or lock back. This to me confirms my belief that it was getting too much gas. The tubing I have is slightly thicker than the original, having an ID about .008" smaller and an OD about .01" larger. I believe it is acting like a restricter, so I have just made a straight one and will try it Sat. No, I haven’t altered the FSB or the gas key, I am turning the tube to fit, and turning the gas key end to match the original. And I can run a lathe, I’ve been a machinist for 20 yrs. I guess at least the lower is good (maybe the only thing), but it needs a better FCG. Oh, well, I’ve got my FAL where I want it, I guess I need something else to play with.
Stay away from pigtail gas tubes.
They move around as they heat up and cause all sorts of problems.
Go back to a regular gas tube.
Remove the front sight base.
Drill down about 0.15" to 0.175" with a #43 drill bit.
Tap this top 2/3 of the barrel wall thickness 4-40.
Install a 4-40 x 1/8 setscrew firmly into the port until it stops against the shoulder you left at the bottom.
Verify that the setscrew is about 0.025" to 0.050" below flush from the surface of the gas block seat.
Peen the top of the setscrew so it’s locked into place.
Drill down through the setscrew with a 1/16" drill bit.
Re-assemble the barrel.
All your problems will likely be solved.
Let us know what those markings on the barrel said.
Yeah, I noticed when aligning the pigtail tube that if it binds at all the coils just let it spring in and out and would probably stop the BCG in its tracks. I will note the markings on the barrel and check the hole size. I can do the 4-40 thing quite easily, especially if that will simply remedy the problem. I do appreciate this help greatly. Is there somewhere to get the specs for things like the gas hole sizes for various length barrels and such? Also, what is the recommended torque for the barrel nut? I know to grease the threads. I staked the gas key, it wasn’t staked at all.
There is no reliable list published that I have seen.
There are lists floating around the internet, this site even has one in a tacked thread.
All of those lists show port sizes that are oversized in my opinion.
I have measured literally hundreds of barrels while documenting what the different makers use.
I have my own list, but I don’t give it out freely due to the effort I have put into aquiring the info.
Torque spec is 30ft-lbs to 80 ft-lbs as required to index.
Grease the threads.
Bring it to about 35 ft-lbs.
Break the nut loose.
Bring it to about 35 ft-lbs.
Break the nut loose.
Tighten it to proper alignment.
Thanks again. No problem on the hole sizes, I understand about that. I don’t know why I didn’t think of just plugging and redrilling the hole. Had to do something similar for a friend with a Carbon-15 pistol (pre-Bushmaster) that wouldn’t work. Ended up closing the hole off almost completely and taking it to the range. Fired a shot, removed FSB, filed hole open some, removed filings from bore reinstalled FSB held on w/ set screw, repeat as necessary until working. I guess it was too simple; couldn’t see the forest for the trees. Like I said, I know basically how it works, but haven’t messed with a whole lot of them, and certainly not the varied manufacturers of parts as you guys here have. Most people around here buy an Olympic or Bushmaster and call it good. I’ll let you know Sat. nite what markings are on the barrel. I know all this stuff was laying in a closet since the 80s or early 90s.
I’ve always thought LMT bought what was PWA. They seem so similar. Here’s my LMT and PWA lowers.
Got m4, I see the LMT has the antiwalk pins for the FCG. Having watched the lower when the hammer was moving, I can see the hammer pin is turning in the receiver, and being the receiver is aluminum, it could open the hole if not lubed well, but is it that big of a problem? I understand you shoot them a lot, have you had any wear out the holes?
They do protect the lower from the pins going out of round. I know a couple of people w/registered full auto lowers where the pins holes got very large (occurs really bad in 9mm full autos), on precious registered auto lowers it’s a very expensive job to repair them.
I don’t use them to protect the lower. I like how they make the trigger pull consistent for each shot (since the pins don’t move). I run a very smooth stock trigger, stock springs but with the KNS pins in my LMT.
Well I plan on running stock parts in the FCG w/ stock springs but I plan on some smoothing, so maybe I might want a set of those also. First I’ll see how the trigger ends up. Thanks.
Well, I got home quite late last night, and didn’t get on the computer, but I got the rifle yesterday and brought it home. I looked at the gas port hole and it was large, .078", much larger than the .062" you recommended. I drilled and tapped it for the set screw and drilled that .055", then .062", so the hole wouldn’t be oversize from an off-center dill point. I can always open it up if necessary. I put the factory tube back in, but haven’t gotten to test fire it yet. The markings on the receiver are just like the ones on Gotm4s pic.
In this pic is the only marking on the upper I could find. It’s not visible in this poor pic, but there is a “K” in raised format in the depression below the rear sight.
In this pic, which is just as poor, are the markings on the BC and bolt. On the carrier are the letters “SE” inside a rectangular border with scalloped corners. On the bolt are the letters “MPSE” in a white ink-like printing. The bore of the carrier is hard chromed. It looks like the gas key bore is hard chromed as well.
The only markings on the barrel are in front of the FSB, read with the muzzle pointing to the right. “SS1X9LM”
I hope somebody can Identify some of these parts markings. Thanks in advance.
None of the pictures worked for me so I am going on your descriptions alone…
Smith Enterprises carrier.
Smith Enterprises bolt that’s MP tested as well.
Both are good parts.
The only markings on the barrel are in front of the FSB, read with the muzzle pointing to the right. “SS1X9LM”
That sure sounds like an Olympic Stainless Steel 1x9 twist barrel.
Are you sure the last two letters are not UM instead of LM?
The UM stamp is Olympic’s “Ultra Match” designation.
Look at the top of the front sight base where the front sight post is at.
Are the letters “<-UP” raised or stamped into the flat?
If it has raised letters, that’s a cast front sight base which is another big Olympic Arms hint.
Pictures are working now and they are not much help.
Nice toe.
That’s good to hear on the BCG, I was hoping they would be good parts. The barrel is definately marked with “LM” not “UM”. The FSB does have <- STAMPED INTO it directly above the “UP”. Yeah, the pics turned out bad. I’m kinda partial to that toe, as well as the rest. It’s happened a couple of times, as it doesn’t show on the camera screen and then there it is. Oh, well, I’m not a photographer by trade. It doesn’t appear to be chrome-lined bore on the barrel. If this is an Oly barrel, is it ok? Is a 1 in 9 twist ok for general shooting w/ regular ball-type ammo? It is a heavy barrel under the handguards and .625" under the FSB and on to the muzzle.
Edited to add: BTW, the FSB is held on with roll pins. Since I’ve had it off a few times, it goes on however it wants, maybe crooked,maybe straight. What crap. I’m going to line it up and drill it out OS and fit solid pins and be done with it.
Also, if it’s an Oly barrel, would it have a .223 chamber or 5.56? If .223, I need to fix it to be safe with 5.56, right?
That’s a “gun show special” barrel if it had roll pins holding the FSB.
Good news is that you have a forged front sight base.
Align your FSB like this before you drill it for solid pins:
Use a removable carry handle and a 1/2" diameter piece of drill rod to make the tool.
If the barrel is heavy under the handguards, I’ll bet you 10:1 that the barrel is 3/4" at the front sight base, not 5/8".
If it was 5/8", it would be lightweight under the handguards as well as out front.
I can’t use a removeable carry handle as it’s an A1 upper, not a flattop. But I can make a rod like that to align the FSB with. I just now removed one of the handguards and checked the barrel with calipers. It measures .875" at the handguard side of the plate that holds them (handguards) in, and .625" under the FSB.
