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Discussion Starter · #1 · (Edited)
I'm collecting parts for at least one build of a 1917a1 and had a question about semi-auto parts/configurations. It seems that there are more than one design of the semi-auto sideplate denial island and parts, and that the parts may not be compatible between designs. So far, from what I have learned there are the following side plate manufacturers that *may* or *may not* have their own designs:

KMP

TNW

Ohio Ordnance Works

Rogue Island Arsenal

RPB

From what I have learned, the following companies produce (past or present) sideplates and milled or modified bolt/lock frame/barrel extension/sear/trigger for one or the other of the above designs.

KMP
TNW
Rogue Island Arsenal
Halo
Ohio Ordnance Works
Lee Tool and Machine​


Am I on the right track here? I'm trying to get a better understanding of what is out there and what to watch out for.

LSP Only:
Iron Creations​
 

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I prefer the Rogue Island denial island design since it does not weaken the finger on the lock frame. They all have differences but the main players are Halo, Rogue Island and KMP. Iron creations only makes LSP no rights and OOW's design is a three denial island and while I like their trigger set up I don't care for the RSP's personally since you have to do some pretty heavy milling. I have no experience with Lee tool so I can't help there but call if you have more questions and we can get into more detail of each if you wish.
 

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Discussion Starter · #3 · (Edited)
Rogue Island Arsenal (Rollin) has its own denial island design too?

Hmm... (if there is already a thread on this somewhere please feel free to link me to that so I'm not reinventing the wheel here).

Are the differences just in the location of the denial island on the RSP? Sounds like triggers are/can be different too (between manufacturers). Is that correct? You mentioned that you like OOW's trigger.

OOW RSP has a three denial island or three islands?
 

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Easier to go through this over the phone since I would be typing all night lol. 585-7Four9-8880
 

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PhD in Over-Engineering
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Yes, I have an in-house design for my builds. Now I do not sell plates, so it is not a simple matter of me providing you one. My plates are custom made for my builds by Halo, but he does not sell plates with that design with certain, rare exceptions. (Like the 1928 plates, in deference to rare, nickel plated Colt internals.) Russ can give you the skinny on the phone. If you decided you wanted a plate with my island, then get hold of me and we'll talk.

By the way, credit where credit belongs: the denial island design I use was developed by a old member of the forum here, machinehead2. He helped me with the initial prototyping on the Dual Feed guns, as well as the M37s we were doing before mondragoon had his kits on the market. I was trying to reach him, Gary LaVarnway, a year or two ago, and could not get any response from either e-mails or phone calls. I don't know what became of him, but he was a good friend and business associate to whom I owe much. He gave me authority over the denial island design, so long as he was given his due should any dispute come up on the design. I wish I knew what happened to him, but the Rogue Island design is what Gary came up with, so he gets all the credit.
 

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Discussion Starter · #6 ·
Thanks Lucky and it is interesting to note that you also use a different denial island than the others, thanks for the note on that.

QUESTION: are the difference in various denial island designs intended to make proprietary the parts needed to service the firearms like semi-auto milled bolts, lock frames, and barrel extensions, or is it because one is truly a better design for some reason?


(I PM'd Russ to check his availability, I don't want to disturb the man's dinnertime :D )
 

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PhD in Over-Engineering
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I can't speak for the old line builders, but they may have just drawn up their own design for no particular reason other than it is what they came up with to get an approval letter. I know Mark at Black Bear had a nice, slim three island design. He even sold blue prints for it, if you wanted to roll your own. But OOW, US Ordnance, TNW all had, I think, their own unique design. In contrast, the companies that sold plates mainly for the home building market- Ohio Rapid Fire, T&S KMP, Lee Tool, Halo and others- primarily used the common design with the large, single island.

When Gary was making our M37 plates, back in the mid 2000s, he wanted to avoid the lock frame depressor finger. He also made my pre production Dual Feed plates and, as he didn't have time to make the production stuff, he simply gave me permission to use his design as needed. He mainly didn't want anyone to see one of his and think it was a copy of what I was doing, rather than the correct attribution. It's his design, and I always give him the credit. But I don't have carte blanche to give it out willy nilly. Besides, it is something of an advantage for me to use on my builds, which I have no interest in diluting by making plates available for general sale. I see it as a competitive advantage, at least in my own demented mind! :confused: :D
 

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Discussion Starter · #8 ·
Ah, I get it. At least from your perspective, Gary's (and now your) design goal was to maintain the integrity and strength of the parts being machined, while still comfortably meeting the ATF specification for a semi-auto denial island(s) designed into the RSP. That makes sense.

Are trigger/sear/accelerator changes essentially the same or substantially similar between the various builders or are they largely different?



* Interesting to note that I can only find pictures online of the inside of Halo, T&S Manufacturing, and Thompson Machine RSPs. I'd love to see the inside of an OOW plate to understand what a three island design looks like.
 
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