Category Archives: Factory Tours

Inside POF-USA

Recently, I contacted Frank DeSomma of Patriot Ordnance Factory with a request for a T&E upper to be used for an upcoming SPR comparison.

Noting that I was in Arizona, Frank invited me to take a tour of POF’s facility before I tested one of their uppers. It should go without saying that this was an offer I couldn’t refuse.

Located in an industrial park devoid of any indication that a world class manufacturing facility lurks within, POF is composed of a machine shop – two machine shops, really – an assembly area, a shipping area, and a small front office. I was impressed when I saw that no employee seemed to be idle for more than a few moments during the entirety of my visit, which lasted nearly 3 hours. Everyone was doing something, and they all seemed to be doing that “something” in a very efficient manner.

Frank spent a good deal of time explaining the function of various components of the POF system. I’ll cover those as best I can, but I may revise details over the next few days if I find that I misquoted him or made a technical error. I’ll also probably expand on certain items in the next few days, but I have a lot of ground to cover here, so the initial post won’t be as detailed as I’d prefer.

Frank came from the aerospace industry, and he had certain objectives when he set out to design his new system. His first objective was heat dissipation. To that end, every POF rifle and upper has a fluted barrel and an aluminum heat sink barrel nut – aluminum because it dissipates heat 5 times faster than steel. Even the shortest POF barrels are fluted, he said, because he doesn’t believe in cutting corners.

On the left is a 5.56mm barrel nut. On the right is a .308 barrel nut.
Fluted barrels on POF short barrel uppers.

Frank gave me a lot of impressive figures about heat dissipation after big round counts. I can’t remember them exactly (I should have been writing this stuff down). He did tell me something very interesting that I can remember, though – although he uses standard bolts in his 5.56 firearms, he’s never had a broken or cracked bolt come back for repair/replacement, nor has he had one break in his own testing.

I also was shown cutaways of upper receivers, both standard M4 and POF. I’m familiar with the phenomenon of receiver flex – when forces are exerted on a long handguard, especially with a vertical grip installed, the forward portion of the standard M4 receiver can deflect by a very small amount. This deflection, however, can cause premature wear and failure of bolts. To this end, companies such as Vltor have designed the MUR and VIS, LaRue Tactical has designed the Stealth as well as the OBR, and POF has designed its own upper receiver, seen below in cutout form next to a standard M4 receiver. Although they’re facing away from one another, note how thin the top of the M4 receiver is compared to the POF upper.

Comparison of POF and M4 upper receivers.
Not only is the receiver thicker, but the barrel is supported, for lack of a better term, by the massive barrel nut.

After this “system overview”, I was shown some new POF products – a 7.62×39 SBR was among them. Here, from the top, are 6.8, 7.62×51, and 7.62×39 POF SBRs.

More shots.

There were additional items discussed at that time, but I’ll cut ahead to the manufacturing portion and cover those later.

Frank is very proud –  as well he should be – that he manufactures most of the components for the P-415 and P-308 in house. We’ll start with receivers.

Each P-308 lower receiver starts as a 7 pound “billet” of 7075-T6 aluminum. By the time the lower receiver is finished, 6 1/4 pounds have been whittled away. P-415 lower receivers start and end at a reduced percentages of those weights.

This CNC milling machine is where lower receivers take shape.

Magazine wells are wire EDM cut to precise tolerances – .0001 – that’s one ten-thousandth of an inch.

Wire EDM machine
These are the unused magwell portions.
P-308 lowers waiting for the EDM process.

Upper receivers come to life in two different buildings, but for the sake of organization, I’ll describe it all at the same time.

5.56/6.8mm uppers start as 7075-T6 forgings. Note that multiple parts are being machined at one time – production was being maximized whenever possible.

Upper forgings are prepared for machining.
Inside this big machine, midgets with chainsaws carve POF upper receivers.
P-415 upper receiver forgings being machined.
POF P-308 upper receivers start as large aluminum rounds.
Bolt carrier “blank” compared with machined bolt carrier.
P-308 bolt carrier being machined
Birth of a POF rail/handguard system.
Disconnectors are wire EDM cut.
Charging handles are manufactured on site.
P-415 and P-308 barrels start as Rock Creek 5R barrel blanks.
Initial machining operations ensure barrel concentricity.
Barrels are then contoured.
Barrel extensions are manufactured in house. It costs POF more to grind the inside and outside of the barrel extensions than it would to simply buy off-the-shelf extensions.
Here, the single 1911-style feed ramp is machined into a barrel extension.
Closeup of feedramp machining.
Barrel extensions are attached and headspace is set. Gas ports are drilled after this step.
The next step involves barrel fluting.
12″ .308 barrel, left; 11.5″ 5.56 barrel, right.
Production costs for each gas block include a beautiful TIG weld. It’s probably unnecessary, but again, Frank doesn’t like to cut corners.
The inside of every gas block is honed at this station to ensure a precise barrel/gas block fit.
Barrels awaiting their gas blocks.
Before nitride, gas blocks and barrels are drilled for taper pins. The two parts are then serialized, separated, finished with a nitrocarburization process, and reassembled with their “siblings”.
Barrel nuts are torqued to at least 40 ft/lbs.
Assembled uppers awaiting handguards.
Handguards awaiting their uppers.
Assembled uppers being prepared for shipping.
P-415 rifles in the final stages of assembly.
Every POF upper and rifle is test fired with a variety of ammunition before it ships.
I’ll be writing follow-ups and more detailed explanations shortly, but I think they deserve their own posts.


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