Former RPB employees?

[Emeritus Liber Eremiticus]

"...Mine has a barrel shroud with small holes in it in groups of 3s, with the hooded Williams front sight and a checkered wood forearm. ..."

What is the height above bore of your front and rear sights?
Calculating sight heights for an open bolt gun surely differs from methods for locked breach guns. My MP40 was dead on in offhand shooting after the bolt slammed forward, and I never bothered to measure sights while I still had it so as to get to the secret formula the German geniuses used to make those jackhammers accurate.

 

[MitchWerbellsGhost87]

My carbine is Cobray stamped, RPB marked, and has the collapsing stock you refer to as the Commando stock in the GB sale 1028397461. Like that anyway. Has two position notches, the shortest unavailable due the the semi-auto assy frame stopping forward travel. Has stock adjust block. My stock block may have been added, the welds through the frame are not parkerized, but I doubt the installation was aftermarket because the work was very nicely done. Sure looks like an experienced factory welder did the install. At minimum an experienced gunsmith installed it.

The upper on mine has that large, welded on rear sight that overhangs the rear of the upper. Peep centered .507" above the top of the steel sheet it is bent from and a teeny square notch at the very top.

Front sight on the upper looks like the standard 45 pistol version front to me.

As I said, my barrel is aftermarket, so I can provide no info about the original barrel or the sight it carried. I will have to fabricate a sight for my barrel or, hopefully, find an OEM barrel and make it correct.

I had no experience inside an Igram before I was given this, and didn't even know this one was a carbine version until I bought the Mac Man book . I spent the fifty bucks for that to get thorough inside views and assure the setup was proper, unaltered semi auto. 99% of online info deals with the SMG or methods of conversion. Info on proper examples is rare indeed. Mine is legal. I know nothing of this gun's history.

I have seen pictures of two kinds of RPB 45 bolts. One has a 1/4" or so radius cut on leading edge of the bottom on trip side and the other has a less cam-like meager radius there. Mine has the large radius. That is all I know about the bolt variations.

I don't believe I am yet authorized to post pictures.

You can post pics I think, I don’t believe that feature is restricted at first but I could be wrong.

So yes the gun should have the Cobray on the right side of the lower receiver, I should have been more specific. These RPB guns wouldn’t have the logo on the top of the upper like the later SWD uppers. Just one “serpent” logo on the side of the gun with no circle around it and no “Cobray” under it.

The “commando” style wire srock is indeed the “alternate type”, so it sounds like you also have an early one with the collapsing stock hardware installed. Interesting that the semi auto carriage blocks the stock from closing on yours. Mine has an extremely short legged wire stock, shorter than all the others I’ve seen, as a result, it closes all the way on the semi auto gun. They may have remedied this with the shorter legs after the first few stocks wouldn’t lock closed. I never even considered that the stock may be so short because it was built to accommodate the open bolt semi sear carriage.

When I try to install any other standard length wire stock it does what you describe and bottoms out on the sear carriage before the notches can reach the locking block. The majority of these guns didn’t have the collapsible stock hardware and just had the legs welded into the frame..

Interesting that your stock block hardware isn’t finished on the inside and sounds as though the steps were done in a different order with the installation of the stock block hardware. The way you describe the welds is odd, as the stock block hardware is normally welded on the bottom of the gun. Maybe it is also welded on the inside and I simply haven’t noticed since it’s all blued on the inside of mine.

There would have originally been 3 holes on the bottom of the rear of the stripped frame, one hole for the stock button and then a smaller hole on each side of it (these holes are visible on the semi auto pistols with no stock hardware). The smaller holes would have been for 2 studs on the stock block that interface with the holes and get welded in on the bottom and smoothed down. I don’t believe I’ve seen them welded from the inside but anything is possible in the early days of RPB. Hell, mine had the wooden forearm attached to the barrel shroud with wood glue, no screws!

With the open bolt semi guns, they would weld in the FCG components and then apparently hot blue the guns. I used to think they were parkerized but was corrected by this board, the semi autos are matte blue. The reason for this is because they have to be finished after welding, and the FCG components get welded in, springs and all. The phosphate solution used in parkerizing is acidic and will break down and weaken the springs, so a matte blue finish was used on the semi autos instead of parkerizing. Parkerizing was used on the SMG frames that had the FCG installed after the frame had been welded and parkerized.

Your upper most likely was originally a MAC barrel and shroud. The MAC barrel assembly had the Williams hooded front sight, it was maybe one inch above the barrel shroud, if that. The front sight post on the RPB manufactured carbine uppers is about 2” high but that’s just an estimate, I’ll try to get you an exact measurement.

Damn, I just sold a mint condition new old stock RPB 9mm 18.5” factory carbine upper assembly on gunbroker last week…. It would have been perfect to replace your aftermarket barrel.

Sounds like yours has the factory carbine rear sight. Not all of them had this. Mine does not. Not sure if there was any rhyme or reason involved with the carbine rear sight or if some just got it and some didn’t. I have seen factory RPB Carbines both with and without that rear peep sight. (It’s an M1A1 Thompson rear sight stamping welded to the receiver)

I’d love to see pics of the gun. PM me and I’ll help you get them posted here.

 

[Emeritus Liber Eremiticus]

I will take some pictures.

You misunderstood. The stock block hardware DOES have the usual park/blue finish, but the two weld points, the stud attaching welds themselves, on the bottom of the upper, show no blue. The welds are nicely done though, which makes me think it was not a garage weld job but that the factory may have installed the stock block when necessary based on customer option requests. Further, the three holes for the stock block were certainly present when the upper had the finish applied - I can see the inner edge of of the stock unlock button hole has been blued and matches. By way of comparison, the semi auto assembly in the lower was welded in, then the weld was smoothed perfectly flush, and then the lower was blued - you can see the welded spot only because it is ever so slightly off color. The upper seems to have been finished before the stock lock was welded in.

I feel badly for hijacking the RPB Employees thread. But I sure appreciate the help and info. I fired Ingrams in all the calibers many times back when Mitch Werbell was hawking them and when the gun with a can cost way less than the stamps. But I never owned one and never went inside them except to clean them and did not make a study of the internal machinery. Therefore, I am a novice where the details are concerned. The Mac Man book is the only expert I have consulted, and it proves by omission that keeping up with all the variations is impossible. Because, in addition to the plain vanilla SMG and semi auto guns, the assembly lines seem to now and then have cobbled together whatever they thought of just to see if anyone wanted a gun like that.

 

[MitchWerbellsGhost87]

I will take some pictures.

You misunderstood. The stock block hardware DOES have the usual park/blue finish, but the two weld points, the stud attaching welds themselves, on the bottom of the upper, show no blue. The welds are nicely done though, which makes me think it was not a garage weld job but that the factory may have installed the stock block when necessary based on customer option requests. Further, the three holes for the stock block were certainly present when the upper had the finish applied - I can see the inner edge of of the stock unlock button hole has been blued and matches. By way of comparison, the semi auto assembly in the lower was welded in, then the weld was smoothed perfectly flush, and then the lower was blued - you can see the welded spot only because it is ever so slightly off color. The upper seems to have been finished before the stock lock was welded in.

I feel badly for hijacking the RPB Employees thread. But I sure appreciate the help and info. I fired Ingrams in all the calibers many times back when Mitch Werbell was hawking them and when the gun with a can cost way less than the stamps. But I never owned one and never went inside them except to clean them and did not make a study of the internal machinery. Therefore, I am a novice where the details are concerned. The Mac Man book is the only expert I have consulted, and it proves by omission that keeping up with all the variations is impossible. Because, in addition to the plain vanilla SMG and semi auto guns, the assembly lines seem to now and then have cobbled together whatever they thought of just to see if anyone wanted a gun like that.

The upper and the lower were not built at the same time or even in the same place with these early RPB carbines. In fact, mine has a parkerized MAC upper. They were using up the leftover MAC parts. The lower receiver itself was built and completed by RPB, but the uppers, bolts, FCG parts, stocks etc etc were all MAC parts still during this early stage of production.

The 3 holes in the bottom of the frame are present from the beginning of its life as a frame flat. Those holes are punched into the flat before it’s even folded I believe, either that or right after it’s folded, before it’s welded together. All of the guns have the 3 holes, even the later closed bolt semi auto cobrays had those holes, because they used the same frame flats for the semi autos that they used for the SMGs. The only frames I’ve ever seen that didn’t have those holes were the Texas MAC frames, which only had the hole for the button because they used a stamped stock block that was welded on the inside of the receiver instead of studs on the bottom.

What you are describing with the stock almost makes me think it was not done at the factory. I have never seen any factory RPB guns with the block welded in after the fact with visible welds in the white. The only time I’ve seen welds in the white on a factory finished gun is the Mk760 front trunnion weld, and it’s because they used stainless rod so the parkerizing wouldn’t take on the weld. The stock block welds are never even remotely visible on the bottom of the gun. They did it in a way that it appears there are no welds there at all (see attached pics). So what you are describing is definitely not common or typical of a factory RPB gun (or any MAC). That said, I’ve learned to never say never in this hobby, but it seems highly unlikely that they would have deviated so drastically from their standard construction practice on just one gun, unless maybe the collapsible stock was an afterthought for whatever reason on that one. These may be early semi autos, but RPB was in the MAC machine gun business for a couple years before they decided to build these semi autos. So it’s not like they were still experimenting with construction techniques. It would be odd for a gun to have been welded differently at this stage in the game.

No worries about derailing the thread. Happens all the time on this board.


Look how short the stock is from the SAC! the legs are actually the same length but they extend about an inch into the buttplate of the SAC stock and the notches are milled in different locations.

 

[Emeritus Liber Eremiticus]

The mag release is aftermarket, but the original came with the gun. No other prior changes were present internally .
Collapsed, the stock makes the gun 26 1/2" OAL with an 16 1/2' barrel, and that is with stock stopped against the semi auto FCG (and not locked in any notch). Extended it locks in only one position, which is at about 30" OAL, with about 8" of visible stock.
The barrel on this is a Velocity Firearms VMAC45 carbine barrel with their shroud. I read several uncomplimentary comments about Velocity, but nobody else seems to have this length available, so I risked it and I bought this so I could shoot the gun. My opinion of Velocity is: No complaints. Service was fast and packing was solid. The barrel looks OK (rifling is shallow) and the shroud looks great. The web site says the barrel is manganese phosphate treated but it looks smooth blue to me. Sadly, the barrel is threaded 5/8-18, so I am paying TROS to custom make a 3 lug for it.
When I find a real barrel, I'll buy it.

Here are a couple shots of the exterior.

 

[brenbuilds]

I would surmise that either the "R" indicates rifle, or-for some reason- it is a proof mark of some type. The "R" overstamp on the magazine does remind me of a armorer's proof mark or initial, or even a re-arsenal mark; granted there really isn't a history of that being done in the MAC world to the best of my knowledge.

I have an early J.A.W.S./Hatton Avenger Commando with the original blued upper that bears a hand scribed "A" beneath the upper that is an utter mystery. Given how scant information is on those guns, it's difficult to know if it was done at the factory, or by a previous owner adding an identifier to their upper.

 

[Emeritus Liber Eremiticus]

The stock arms do look very short in your picture. The length of the arms on my stock is about 8 3/8" and the spacing of the notches is about 7 1/4". How does that compare to yours?
The butt plates are different as well, mine being crescent with no recurve. I have seen many pictures of both types and get the impression that your version was the earlier.

Look how short the stock is from the SAC!

 

[MitchWerbellsGhost87]

The stock arms do look very short in your picture. The length of the arms on my stock is about 8 3/8" and the spacing of the notches is about 7 1/4". How does that compare to yours?
The butt plates are different as well, mine being crescent with no recurve. I have seen many pictures of both types and get the impression that your version was the earlier.

I have seen at least 4 different styles of the “alternate” stock. The earliest type has a large buttplate that’s curved in or out at the bottom. The later RPB version of the stock used the smaller M11 sized buttplate, attached to M10 legs. The legs themselves on that short SAC stock (not pictured in these photos) are the exact same length as the normal wire folding stock legs, they just continue into the butt plate about an inch or so and have the locking notches in different locations.

Here’s a few examples of the different types of stocks.




A = SWD alternate stock, made from either leftover MAC M10 buttplates or on the same tooling, late 80s, buttplate has flares on the side from having been stamped onto rounded legs for the Cobray terminator shotguns and then later again repurposed for the SWD Jersey Arms Avenger Commando M10.

B = MAC alternate stock, this is the earliest type, 1972-75. The bent in curved buttplate has different variations, some are bent differently than others. It also has a hole to clip a sling on the butt plate.

C = RPB Alternate M10 stock, 1980-83, these had a smaller M11 sized buttplate welded to M10 legs. This is the standard size that came on the RPB M10 SAC carbines, typically welded in place with no stock hardware installed the receiver. Also sold as an aftermarket upgrade

D = RPB M11 Alternate stock. 1980-83, same as C but with legs for the M11 small frame gun.


Bonus pic of a very rare RPB Type C stock as sold by SWD (post 1983) with the “Cobray” trademark stamp

I would surmise that either the "R" indicates rifle, or-for some reason- it is a proof mark of some type. The "R" overstamp on the magazine does remind me of a armorer's proof mark or initial, or even a re-arsenal mark; granted there really isn't a history of that being done in the MAC world to the best of my knowledge.

I have an early J.A.W.S./Hatton Avenger Commando with the original blued upper that bears a hand scribed "A" beneath the upper that is an utter mystery. Given how scant information is on those guns, it's difficult to know if it was done at the factory, or by a previous owner adding an identifier to their upper.

EARLY Powder Springs MAC is known for proof marking their parts. The bolts all have different letters on the top, barrels have numbers and letter stamped on them, the front trunnions as well. The “MAC” Cobray logo stamp on the magazines always had a number underneath it. I have seen MAC 4,MAC 6 and MAC 7, but I know others exist.

The “R” stamp also features these numbers. I have seen it with MAC 6 and MAC 7. I have very early MAC walther manufactured MP9 magazines that have a letter “Q” and a letter “G” proof marked above and below the usual MAC Cobray logo stamp.

 

[MitchWerbellsGhost87]

The mag release is aftermarket, but the original came with the gun. No other prior changes were present internally .
Collapsed, the stock makes the gun 26 1/2" OAL with an 16 1/2' barrel, and that is with stock stopped against the semi auto FCG (and not locked in any notch). Extended it locks in only one position, which is at about 30" OAL, with about 8" of visible stock.
The barrel on this is a Velocity Firearms VMAC45 carbine barrel with their shroud. I read several uncomplimentary comments about Velocity, but nobody else seems to have this length available, so I risked it and I bought this so I could shoot the gun. My opinion of Velocity is: No complaints. Service was fast and packing was solid. The barrel looks OK (rifling is shallow) and the shroud looks great. The web site says the barrel is manganese phosphate treated but it looks smooth blue to me. Sadly, the barrel is threaded 5/8-18, so I am paying TROS to custom make a 3 lug for it.
When I find a real barrel, I'll buy it.

Here are a couple shots of the exterior.

View attachment 39200View attachment 39202View attachment 39203

Nice gun! interesting how it’s such an early number but seemingly built later than the one I have. The takedown pin on that gun is the last style they used, 81-82. All of the components on that gun, including the upper receiver with the “SAFE FIRE” markings are later generation RPB parts from 81-82, but the serial number places its manufacture in 1979, same as mine, 6 guns before mine… yet somehow mine is made entirely 100% from leftover MAC M10LR SMG carbine parts, including the early trigger with the bumper on the back of it and the MAC upper/barrel and MAC stock. it seems like right when I think I’ve got it figured it out, another curveball like this one comes around. Only thing I can think of is that the frame was numbered early on but wasn’t completed and shipped out until a year or 2 later when those later RPB parts would have been used to assemble it. This is a common occurrence with SWD guns, as I often see very early M11/9 components slapped together on guns that didn’t leave the “factory“ until a year or 2 after those parts had been phased out. I highly doubt your carbine was repaired or rebuilt with those early 80s RPB parts. As far as I can tell, RPB didn’t sell those 2 piece screw takedown pins as a replacement part for very long, if at all.

very cool that you were able to find a velocity carbine barrel in 45 for it! Even those are hard to find these days (unless they can still be ordered direct from velocity and I was simply unaware) If you ever wanted to run 9mm in that gun I have a spare MINT condition 9mm RPB 18.5” carbine upper, all you would need is the 45 to 9mm conversion sleeve insert. They are still available for about 50 bucks.

 

[Emeritus Liber Eremiticus]

The pictures I have seen of the genuine screw type takedown use a long shaft screw on that end. But on mine the screw is maybe 1/2" long and threaded full length. Both the pieces have a driver slot.


The Velocity barrel was an in stock item. I thought $180 for an immediately available barrel for a fairly uncommon gun, and with nice shroud with it, was a decent price.

 

[MitchWerbellsGhost87]

The pictures I have seen of the genuine screw type takedown use a long shaft screw on that end. But on mine the screw is maybe 1/2" long and threaded full length. Both the pieces have a driver slot.
View attachment 39209

The Velocity barrel was an in stock item. I thought $180 for an immediately available barrel for a fairly uncommon gun, and with nice shroud with it, was a decent price.

great deal on the barrel, the originals are a LOT more expensive these days.

that pin is the standard 2 piece flathead screw style takedown pin that was used by RPB on the semi autos and SMGs in the early 80s. I believe that is the final pin design offered by RPB before they closed their doors. Early pin designs were “push pins” that were hollow with a spring detent. The earliest variety was made by MAC and left over from the Marietta,GA era guns, these had a solid head on one side and then an open hollow end on the other with the spring steel detent visible inside the pin. The second type was the same design but it was open on both ends. The large headed end had a hole in it as well as the opposite narrow end, same spring detent on the inside. Then there was the 2-piece flathead takedown pin in question. This was ultimately replaced for good by SWD in 1983 with the 2 piece M60 style pin that snaps together.

 

[Emeritus Liber Eremiticus]

Regarding the R stamp: For what it is worth, this image of a trunnion stamped R makes it look to me like the "MAC 6" QC stamp was doubled exactly like the R it shares space with. Further the double stamping of both the R and the QC are about identical.
I wonder whether it was a single QC stamping incorporating both the R and the MAC 6.
It is open for debate.

 

[MitchWerbellsGhost87]

Regarding the R stamp: For what it is worth, this image of a trunnion stamped R makes it look to me like the "MAC 6" QC stamp was doubled exactly like the R it shares space with. Further the double stamping of both the R and the QC are about identical.
I wonder whether it was a single QC stamping incorporating both the R and the MAC 6.
It is open for debate.
View attachment 39437

It’s one stamp. The “MAC #” is on all of them, and the number varies, I know of MAC 4,6, and 7 with the “R” stamp. It always has the Cobray symbol inside the loop of the R and “MAC #” underneath it. It is present on some of the M10 45 30rd mags, in place of the the normal Cobray logo, same location. I have a “MAC 6” example that I traded for a “mac 7” to another collector.

I also have at least one carbine upper where the R stamp looks like it bounced, like it does on yours, but not as many times on mine, it is only doubled. Both of the carbine uppers that I have with the R stamp on the bottom also have Cobray stamps on the top of the upper and shroud.

One of them is a very rare and early SWD M11/9 carbine upper that was made using the 18” carbine barrel from the RPB M11 .380 LR carbine upper. It has been rechambered in 9mm and attached to an M11/9 upper.

The upper has the R on the bottom of the front trunnion, so it is absolutely a carbine thing with the uppers. I have never seen it on a non-carbine upper, though I have seen it on totally different parts altogether.

 

[MitchWerbellsGhost87]

Here is a .45 carbine upper that was just listed on GB, this one has the later style RPB upper that has “SAFE SAFE FIRE” stamped around the slot, it has the Cobray logo on the barrel shroud which leads me to believe it was likely leftover RPB sold by SWD, as I don’t think RPB ever stamped the shroud with the Cobray trademark. This is the only one I’ve seen that has the RPB upper with those safety stamps paired with a Cobray marked shroud, it is a transitional parts gun.

This one also has the standard Cobray trademark on the bottom of the trunnion instead of the “R”. The usage of the standard Cobray logo in that spot on some of these uppers leads me to believe that the “R” stamp was simply being used as a logo for branding, since these uppers were sold on their own as upgrades through the catalog. It appears as though the “R” marking is used interchangeably with the “Cobray” marking in this instance.

So far the earliest carbine uppers I’ve seen have no stamp on the bottom of the trunnion. All of the “R” stamped uppers that I have come across have been very late RPB stuff that was presumably distributed by SWD. I do know of one SSM11 single shot pistol that has the R stamp inside the frame, and I believe those were sold by RPB at the very end, in an effort to get around the new ATF ruling that banned their open bolts. So it seems that the R stamp may have come into use at some point in 1982-83, though it is highly likely that it existed before then and was not being used for the same purpose.

The “MAC #” makes me think this stamp dates back as far as the early MAC days, as RPB did not utilize the “MAC” name and even went as far as removing it from their standard magazine stamps. That said, I have personally only encountered it on items that could have all been sold by SWD with the exception of that single shot M11, which was only months before SWD was incorporated in 1983.

 

[MitchWerbellsGhost87]

For anyone else who may have been curious about this stamp. I asked Shane from Excalibur about this. Shane is Sylvia Daniel’s son and he was there for all of the SWD era. He confirmed that this is an “RPB hand stamp”. So basically it’s like a proof mark or an inspection mark on the bottom of the upper done with a hammer by hand. This doesn’t explain the stamp on the magazines, but it explains the stamps on the bottom of the rifle uppers that appear to have been done with multiple smacks from a gunsmith hammer. It also doesn’t explain the numbers on the bottom of the stamp, but I can only assume those numbers were used for different batches or possibly different employees.

 

[SecondAmend]

I find it somewhat ironic that we know more about the markings on the Chinese crossbows and their bolts that were made in 245-228 BCE and buried with the Terracotta Soldiers than we know about the markings on the SWD and RPB firearms.

 

[MitchWerbellsGhost87]

I find it somewhat ironic that we know more about the markings on the Chinese crossbows and their bolts that were made in 245-228 BCE and buried with the Terracotta Soldiers than we know about the markings on the SWD and RPB firearms.

100%. I have always found it odd just how little was documented about these guns from the RPB/SWD days. The bound book only has the SN and caliber, so there is no way to date or authenticate all of those special edition blue steel guns and hard Chrome guns. They used so many different variations of parts and components in the manufacture of these guns as well yet there really is absolutely no documentation out there regarding any of the testing or materials used, subcontractors that manufactured the stuff etc etc… I have an 1876 Colt single action army pistol in .45LC. it is an original from 1876, it belonged to my grandfather, it is gold and blue steel engraved with mammoth ivory grips. I had it authenticated by colt, they sent me a really nice packet on high-end stationary with information pertaining to my gun. They were able to tell me exactly what store it shipped to on what date, and that it shipped as a blue steel pistol with a wooden grip. They even included a photograph of the hardware store in Colorado from 1876 the year that my gun was shipped there… but I can’t find out what a whole damn marking means on a gun that is only 40 years old. Go figure.