Former RPB employees?

[MitchWerbellsGhost87]

I seem to recall that we have at least one former employee of RPB industries here on the board. I’m hoping maybe someone who was involved in the original 1978-82 operation can chime in here and share some knowledge regarding this stamp.

The stamp in question is the letter “R” with a Cobray symbol and “MAC x” (x = a number) inside the letter R. I have speculated that the “R” is likely for “RPB”, being as I have seen this stamp on various RPB parts now, including the bottom of the front trunnion on many of the carbine upper receivers, M10/45 30rd mags, and on the receiver reinforcement tab in an SSM11 single shot pistol (I did not see this one personally but a fellow collector has).

I have a friend who is close with Wayne Daniel so I had him inquire about it, but Wayne is in his 80s now and certainly doesn’t recall every little detail from 50 years ago, so he didn’t have much input on that stamp. I think he was under the impression that my buddy was asking him what the magazine itself was, not the stamp, as he simply said it was a grease gun mag that was done by MAC.

I initially thought it may have been a MAC thing, being as it has “MAC” on it, and the stamp may have originally been something RPB acquired through the MAC auction, but at this point I can confidently say I have only seen it on gun parts that were at the very least assembled by RPB. That said, it is totally possible that the R stamped parts were leftovers from the MAC era… but given the fact that they seem to be almost exclusively present on the bottom of the RPB carbine uppers, I have my doubts about them being done by MAC (at least the items I’ve seen bearing the stamp).

I have been told that it might stand for “reject” but that just doesn’t seem to be the case. None of the items I have seen with this stamp have had any issues or shown any indications of being a reject or factory second, and if they were “rejects” then why would they complete them and then let them get out onto the market?

I personally suspect that RPB was stamping the bottom of the carbine uppers with this logo because those uppers were sold on their own as aftermarket upgrade parts. I would love to have a positive answer on this mystery but I fear that may never happen with so much time having passed and very little having been documented about this stuff.

Oh and to add to the mystery, I recently acquired an RPB M10/9mm carbine upper receiver that has the letter “P” stamped on the bottom of the trunnion, but no Cobray or “MAC”… the plot thickens ¯\_(ツ)_/¯

 

[root]

The GL is for guide lamp.
WWII gg mag as you know.

Was gonna bust yer chops and say reject but ya already adressed that aspect.

As far as 2nds and rejects they are still put out today accept they cal them blems now.
PSA is real good at selling them.
Colt just released blem Pythons over the summer to the public market so it's not just the lower quality companies that do it.

May be possible they were rejects or blems everything went to the action right?
That would create a very easy way to market.
Cheaper the part faster it sells and blems are always the cheapest price wise.

Having a reject guide lamp gg mag would be no surprise to me the demensions on them are all over the place.
Most of us that run the surplus mags know to buy a dozen go through them keep what works and pass along the rest.

Doesn't mean the mag is bad just means it doesn't work in a particular gun.

Same with uppers what fits one lower may not fit another due to the way they were made by different companies.

Lage fixed that issue with grub screw adjustments on the uppers.
But I could see where someone labeled a upper as no good cause it didn't fit a lower right off the factory line.

 

[skiboatsp]

The GL is for guide lamp.
WWII gg mag as you know.

Was gonna bust yer chops and say reject but ya already adressed that aspect.

As far as 2nds and rejects they are still put out today accept they cal them blems now.
PSA is real good at selling them.
Colt just released blem Pythons over the summer to the public market so it's not just the lower quality companies that do it.

May be possible they were rejects or blems everything went to the action right?
That would create a very easy way to market.
Cheaper the part faster it sells and blems are always the cheapest price wise.

Having a reject guide lamp gg mag would be no surprise to me the,demensions on them are all over the place.
Most of us,that run the surplus mags know to buy a dozen go through them keep what works and pass along the rest.

Doesn't mean the mag is bad just means it doesn't work,in a particular gun.

Same with uppers what fits one lower may not fit another due to the way they were made by different companies.

Lage fixed that issue with grub screw adjustments on the uppers.
But I could,see where someone,labeled a upper as no good cause it didn't fit a lower right ofc the factory line.

It's called tolerance stack up. It is what it is. Thanks for the post. Very informative. Good post.

 

[MitchWerbellsGhost87]

The GL is for guide lamp.
WWII gg mag as you know.

Was gonna bust yer chops and say reject but ya already adressed that aspect.

As far as 2nds and rejects they are still put out today accept they cal them blems now.
PSA is real good at selling them.
Colt just released blem Pythons over the summer to the public market so it's not just the lower quality companies that do it.

May be possible they were rejects or blems everything went to the action right?
That would create a very easy way to market.
Cheaper the part faster it sells and blems are always the cheapest price wise.

Having a reject guide lamp gg mag would be no surprise to me the demensions on them are all over the place.
Most of us that run the surplus mags know to buy a dozen go through them keep what works and pass along the rest.

Doesn't mean the mag is bad just means it doesn't work in a particular gun.

Same with uppers what fits one lower may not fit another due to the way they were made by different companies.

Lage fixed that issue with grub screw adjustments on the uppers.
But I could see where someone labeled a upper as no good cause it didn't fit a lower right off the factory line.

Warning: long post ahead!!

Thanks for the reply. You would think if they were marked “R” for reject just for the purpose of in-house identification and sorting that they wouldn’t bother putting their logo into the stamp. The use of the logo in the stamp could imply that it was intended to make it out to the public.

I am aware that the GL is guide lamp etc, the original contractor markings from WWII. Another reason I doubt that the “R” is an indicator of a factory second or “reject” is because it is on parts that are seemingly perfect, in spec, and given the level of QC that they had at RPB, I can’t imagine they would even nitpick the parts to that extent (slight finish flaws and an extra .01 here or there were par for the course with these parts).

With these guns it’s not uncommon to have to fit replacement parts to a gun with some filing or grinding. Uppers have a tendency to work differently from gun to gun, because of very slight differences in front trunnion height as a result of different batches produced years apart by various different manufacturers.

Even uppers produced by the same manufacturer seem to vary in their tolerances and spec from batch to batch (SWD in particular) so I just can’t imagine they would label any of these items as a reject or factory second.. nor have I ever seen them advertising factory seconds, or blem items. If there is anything wrong with the items I’ve seen with the R stamp, its nothing more than any other typical RPB or SWD Ingram component.

I have been thinking that maybe the “R” was simply for “RPB”? The “MAC” letters underneath it are odd though because RPB went out of their way to remove the “MAC” letters from the stamps that they used for their magazines, but they left it on the “R” stamp? this is what makes me think that the stamp almost definitely had to have at least started its life with MAC, even if it ended up being used by RPB.

There is also the possibility that these parts were already marked with that stamp by MAC and RPB just went ahead and utilized the “R” stamped trunnions on the carbine uppers exclusively, though that seems like a bit of a reach. that would imply that the “R” stamped trunnions may possibly have been MAC rejects (MAC had better QC and much tighter tolerances), and RPB went ahead and picked out the usable ones and installed them on the carbine uppers in particular. I’ve never seen it on the bottom of a standard upper, but that doesn’t mean they aren’t out there. I’ve learned to never say never with this old Cobray stuff.

The “R” marked magazines I’ve seen were seemingly perfect, though one of them does indeed have a flawed finish, looks like the bluing got a little messed up and came out with a bit of a rainbow hue, like an oil slick, but I see worse factory flaws on RPB items that were not marked as rejects or seconds on a regular basis (I sell vintage MAC parts and accessories on GB as a side business) so I find it hard to believe that RPB would go out of their way to stamp parts as “rejects” but then complete and sell them anyway as normal inventory.

I know of an RPB SSM11 single shot pistol with the R stamp on the receiver reinforcement tab in the lower receiver. What could have even possibly been wrong with the takedown pin reinforcement tab in an M11 for it to be considered a “reject”? A receiver reinforcement tab either fits and the holes line up or it doesn’t, and since it was installed in a gun, it clearly fit and lined up. So it likely wasn’t a “reject”.

Also kinda interesting that the stamp was on the receiver reinforcement tab in the lower, which corresponds directly with the bottom of the front trunnion of the upper, where I have seen the stamp utilized the most consistently. So this may have just been a location on the guns that they preferred to mark with their logo, like the top of an SWD upper with the “cobray” logo on it.

Maybe it was just another stamp they used to brand their products, before they began stamping every single part with the SWD “Cobray” trademark? Wayne Daniel was very adamant that all of his parts have the Cobray logo, and often touted in his advertising that anything without the logo was a cheap knock off. The “R” stamp seems to pop up on RPB items from fairly late in the game, like 81-82. I have some RPB carbine uppers as well as an SWD carbine upper that have both the “R” stamp on the bottom, and the later SWD “Cobray” logo stamp on the top, added by SWD.

It’s possible they were simply marking the stuff with the “R” stamp just to mark it like they did with the normal Cobray stamp, after all it does have the Cobray logo in it. Wayne purchased the rights to the Cobray logo at the 82 RPB auction and began using it extensively on all parts sold by SWD. If the “R” stood for “RPB” then it would make sense that they stopped using that stamp when “RPB” was replaced by “SWD”.

This is all just speculation and theories… this is the biggest mystery to me as far as the old MAC/cobray collectibles are concerned, and I would love to find the answer, but it seems like anyone that would have known for sure has likely forgotten or they have passed away by now unfortunately. ¯\_(ツ)_/¯

 

[root]

Like I said you had addressed the R already.

If you look at the rejects, blems, 2nds, today they don't even mark them.
They only mention blem in the ad.
Leaving you the buyer to figure it out if you do chance the purchase.

Same with bullets that are 2nds
I'm talking reloading component projectiles not loaded ammo.
Other then the ad they are not marked.

Back then America had a lot more pride in Mfg and you knew if something was a 2nd or reject because they did take the time to sort & mark it as not top tier to their company standards.

During the 90's they had major issued with anodizing it was so bad they didn't even call them blems,or 2nds, ya just got a purple Bushmaster AR15 NIB.
Colt had the finish issue also same deal bought a NIB rifle back then the the upper & lower colors might have been off like one darker then the other making it look like two different guns had their uppers swappped around.

The public complained but neither company ever once said a word about it. You either wanted a new Colt or Bushmaster or you didn't.

Are those R stamped parts blems?
Who knows probably not.

Maybe the proof R is for "Ready" or "Right"

Best way to tell would see if they fit and run on lowers.
Or mic them out to a set of factory prints that has the +/- tolerances stated on it.

Only way any of us would know for sure though would be to stumble onto a old materials ledger or inventory ledger that had the info with a pic of the R stamp indicating its usage.

And if they really are rejects that would make them pretty rare since they were to never leave the property to be used by the public.
Most people today wouldn't even care so long as it works.

It is a interesting stamp and this thread is the 1st I have ever seen it or discussed it.
It's not covered in the MACMAN BOOK.


Look @ PSA they just dump them out there.
They might have more blems in circulation then built right parts.
13 pages of blems lol

https://palmettostatearmory.com/blem-guns.html

 

[MitchWerbellsGhost87]

Like I said you had addressed the R already.

If you look at the rejects, blems, 2nds, today they don't even mark them.
They only mention blem in the ad.
Leaving you the buyer to figure it out if you do chance the purchase.

Same with bullets that are 2nds
I'm talking reloading component projectiles not loaded ammo.
Other then the ad they are not marked.

Back then America had a lot more pride in Mfg and you knew if something was a 2nd or reject because they did take the time to sort & mark it as not top tier to their company standards.

During the 90's they had major issued with anodizing it was so bad they didn't even call them blems,or 2nds, ya just got a purple Bushmaster AR15 NIB.
Colt had the finish issue also same deal bought a NIB rifle back then the the upper & lower colors might have been off like one darker then the other making it look like two different guns had their uppers swappped around.

The public complained but neither company ever once said a word about it. You either wanted a new Colt or Bushmaster or you didn't.

Are those R stamped parts blems?
Who knows probably not.

Maybe the proof R is for "Ready" or "Right"

Best way to tell would see if they fit and run on lowers.
Or mic them out to a set of factory prints that has the +/- tolerances stated on it.

Only way any of us would know for sure though would be to stumble onto a old materials ledger or inventory ledger that had the info with a pic of the R stamp indicating its usage.

And if they really are rejects that would make them pretty rare since they were to never leave the property to be used by the public.
Most people today wouldn't even care so long as it works.

It is a interesting stamp and this thread is the 1st I have ever seen it or discussed it.
It's not covered in the MACMAN BOOK.


Look @ PSA they just dump them out there.
They might have more blems in circulation then built right parts.
13 pages of blems lol

https://palmettostatearmory.com/blem-guns.html

The notorious purple 90s bushmaster anodizing… yikes! I have seen a few SWD 2 stage suppressors from the 80s with purple anodized first stages as well.

The “R” stamp is shown in the MACMAN book in the section regarding magazines I believe. It shows an R stamped 45 magazine. The “R” stamped carbine upper receivers do indeed function just fine, no issues whatsoever. One of them is an SWD M11/9 carbine upper that is made with an RPB m11 380 SAC carbine barrel assembly that was rechambered in 9mm.

There is a picture of it advertised as the M11/9 carbine top in the back of the 1984 or 85 M11/9 semi auto manual, at some point they must have ran out of the leftover M11 380 RPB parts and starting making those standard production 16” 11/9 carbine barrels with the shorter shroud.

That SWD/RPB carbine upper has the “R” on the bottom of the trunnion. So they either used a pre existing RPB m11 trunnion with the R on it, along with the pre existing RPB barrel assembly, or they stamped it after it was assembled prior to distribution for whatever purpose. This upper also has the Cobray markings on the upper and the barrel shroud.

I have also seen an RPB M10/9 carbine upper that was sold by SWD that had the “Cobray” stamp on the bottom of the trunnion. This leads me to believe it was just meant to be branding and nothing more, since it was used interchangeably with the standard Cobray stamp in the same location on both the upper receivers as well as the magazines.

I think it was for “RPB”… my best guess. Now that I found one with a “P” on the bottom, maybe there is a “B” out there as well.

 

[root]

What if it was not a R at all?

What if it was put there just to mess with later generations?

Marking that make ya go Hmmmm.

 

[BlackBelt]

What if it was not a R at all?

I was thinking that maybe the R didnt stand for a word, but maybe was code nomenclature for a either a period of time or maybe a category of inventory, or perhaps a proof marking of some kind

 

[MitchWerbellsGhost87]

Here are both of my “R” stamped carbine uppers. I believe both of them were sold by SWD. I know the 11/9 was of course sold by SWD, in 1983, but it is made from RPB m11 380 carbine components.

I also suspect the M10/9 upper to have been sold by SWD because of the “Cobray” stamps on the top. It is an RPB manufactured upper and barrel assembly, but SWD apparently inherited a handful of these at the 82 RPB auction.

I have an early SWD sales sheet that features these leftover RPB M10 carbine uppers for sale. This leads me to believe the “Cobray” marked examples are leftovers that were sold by SWD. Being as RPB were not stamping the top of their uppers with the Cobray logo, it would make sense that they stamped the bottom for this purpose, which would also explain the RPB carbine upper I’ve seen with the “Cobray” on the bottom of the trunnion in the same spot as the “R”, so it seems it was used interchangeably.

I have thoroughly convinced myself at this point that the “RPB” was simply a branding mark that representing “RPB”. I believe it was used close to the end, around 81-82.. which would explain the presence of the stamp on the leftover carbine parts that SWD ended up with, as most of the earlier carbine parts had probably been sold by that point.

 

[thumpy]

Maybe it stands for rifle? Idk why you’d mark a mag that way but maybe they had different tolerances for the carbine “rifle” uppers? I’m reaching here no clue just figured I’d trow the thought out there.

 

[Gaujo]

Registered? Like registered trademark?

 

[MitchWerbellsGhost87]

Maybe it stands for rifle? Idk why you’d mark a mag that way but maybe they had different tolerances for the carbine “rifle” uppers? I’m reaching here no clue just figured I’d trow the thought out there.

If it was only on the carbine uppers then you would possibly be onto something, but it’s printed on 45 magazines also, as well as the receiver reinforcement tab on a SSM11 single shot pistol inside the frame…

 

[MitchWerbellsGhost87]

Registered? Like registered trademark?

When they started stamping the “Cobray” logo on everything, they always made sure to follow it with the little registered trademark “r” in a circle. I believe it was in place during the RPB era as well, but Wayne Daniel obtained the rights to the Cobray trademark at the 82 RPB auction, and he used the hell out of that trademark with SWD, stamping it anywhere it would fit, and using smaller stamps for the places where it wouldn’t.

That said, I don’t think the “R” represents “registered trademark”, but I have no real way of knowing what it means and can’t say anybody is right or wrong in their speculation… I just don’t personally think that’s what it was for.

 

[Gaujo]

I don't think it makes much sense either, but it's all I can think of

 

[Emeritus Liber Eremiticus]

I have a very early sac carbine with no "R" anywhere and the cobray mark only on the right side rear of the receiver.

 

[MitchWerbellsGhost87]

I have a very early sac carbine with no "R" anywhere and the cobray mark only on the right side rear of the receiver.

They don’t all have the R. I have a very early SAC (SN #010) that is built with all leftover MAC M10LR SMG parts and it has no R anywhere either and no other markings on the upper at all. The uppers with the R marking seem to be from 82-83, I believe both of my “R” marked uppers were actually Sold by SWD but both are built using RPB leftovers

 

[Emeritus Liber Eremiticus]

They don’t all have the R. I have a very early SAC (SN #010) that is built with all leftover MAC M10LR SMG parts and it has no R anywhere either and no other markings on the upper at all. The uppers with the R marking seem to be from 82-83, I believe both of my “R” marked uppers were actually Sold by SWD but both are built using RPB leftovers

Mine is 6 lower than yours. Wish I had an original barrel and one of those OEM wooden buttstocks

 

[MitchWerbellsGhost87]

Mine is 6 lower than yours. Wish I had an original barrel and one of those OEM wooden buttstocks

Does yours have the sliding stock hardware built into the frame? With the alternate style MAC flat butt wire stock? I think at some point they started welding the wire stocks in the open position with no hardware in the gun, but this SN 010 gun has stock block hardware factory installed and a collapsible wire stock. I have never seen another RPB semi auto with the stock block hardware and a collapsible stock. I’ve only seen the standard carbines with the welded wire stock or the deluxe model with the welded wooden stock.

I wonder if they were required at some point to weld the stocks in place for one reason or another by the AFT. 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. It is a MAC “M10 LR upper” , the early RPB carbines were made from leftover MAC m10LR SMG parts.

The carbine uppers that were made by RPB when the MAC leftovers ran out were different. A bit more crude. They had an M11 front sight welded to the top of a riser for the front sight. Barrel was not notched for the m1 carbine flash suppressor like the M10LR barrel. Like MAC, some of the RPB cooling jackets had slots, some had holes. So far I have only seen one of these early MAC leftover rifle uppers in person to examine, but it was not marked on the front trunnion.

The only ones I’ve seen that are marked on the front trunnion are the early 80s RPB and SWD manufactured 18” carbine uppers.

The SSM11 pistol with the “R” stamp on the receiver reinforcement tab would have been from 1982-83 (I personally did not see this one, but it comes from a very reputable source) In the very early days of SWD they converted the leftover SSM11 frames into SMGs and marked them with “SWD” on the bottom of the frame under the plastic grip piece… but I digress.

My non-Cobray stamped RPB carbine upper (pre-SWD) only has a letter “P” stamped on the bottom of the trunnion. The 2 “Cobray” marked carbine uppers i have are both “R” stamped on the bottom of the trunnion, they are both RPB leftovers that were sold by SWD, as I don’t believe RPB ever sold uppers with the “Cobray” registered trademark stamp on them.

It seems SWD is starting to pop up quite a bit in the “R” stamp mystery, but the “R” stamp has to be older than that, it has “MAC 6” (or another number) which is an early powder springs MAC stamp. It drives me nuts knowing I’ll probably never find out what the hell that “R” stamp was all about! I will have to just keep on assuming it stood for “RPB”. 🤷🏻‍♂️

 

[KickStand]

I’m guessing they welded the wire stocks in the extended position because they can’t fully collapse in a SAP/SAC.

 

[Emeritus Liber Eremiticus]

Does yours have the sliding stock hardware built into the frame? With the alternate style MAC flat butt wire stock? I think at some point they started welding the wire stocks in the open position with no hardware in the gun, but this SN 010 gun has stock block hardware factory installed and a collapsible wire stock. I have never seen another RPB semi auto with the stock block hardware and a collapsible stock. I’ve only seen the standard carbines with the welded wire stock or the deluxe model with the welded wooden stock.

I wonder if they were required at some point to weld the stocks in place for one reason or another by the AFT. 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. It is a MAC “M10 LR upper” , the early RPB carbines were made from leftover MAC m10LR SMG parts.

The carbine uppers that were made by RPB when the MAC leftovers ran out were different. A bit more crude. They had an M11 front sight welded to the top of a riser for the front sight. Barrel was not notched for the m1 carbine flash suppressor like the M10LR barrel. Like MAC, some of the RPB cooling jackets had slots, some had holes. So far I have only seen one of these early MAC leftover rifle uppers in person to examine, but it was not marked on the front trunnion.

The only ones I’ve seen that are marked on the front trunnion are the early 80s RPB and SWD manufactured 18” carbine uppers.

The SSM11 pistol with the “R” stamp on the receiver reinforcement tab would have been from 1982-83 (I personally did not see this one, but it comes from a very reputable source) In the very early days of SWD they converted the leftover SSM11 frames into SMGs and marked them with “SWD” on the bottom of the frame under the plastic grip piece… but I digress.

My non-Cobray stamped RPB carbine upper (pre-SWD) only has a letter “P” stamped on the bottom of the trunnion. The 2 “Cobray” marked carbine uppers i have are both “R” stamped on the bottom of the trunnion, they are both RPB leftovers that were sold by SWD, as I don’t believe RPB ever sold uppers with the “Cobray” registered trademark stamp on them.

It seems SWD is starting to pop up quite a bit in the “R” stamp mystery, but the “R” stamp has to be older than that, it has “MAC 6” (or another number) which is an early powder springs MAC stamp. It drives me nuts knowing I’ll probably never find out what the hell that “R” stamp was all about! I will have to just keep on assuming it stood for “RPB”. 🤷🏻‍♂️

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.