Why were the Irwin Pedersen carbines not accepted?

I figured someone would have answered by now, I am no expert but I will give it a shot.

Making interchangeable parts is something that has to be meticulously planned for, with production processes established, and the use of go/no go gauges, with master gauges to measure the gauges used on the line, among many other factors. I am not certain this was the issue with IP, but if they were old school gunsmiths/manufacturers as Lupus Dei mentions above, it is likely they had a failure to fully indoctrinate interchangeability into their culture, since it may have been predisposed to hand fit parts. Management would have been an issue if they allowed this, and didn't have the proper tolerance checks in place. The result was probably a bunch of individually functional M1 Carbines that wouldn't work if you mixed up the parts.

Incidentally, this happened with another WWII firearm, but not in the same manner. When the Reising Model 50 Submachine Gun was adopted by the USMC in 1941, they were under pressure to get their hands on a submachine gun, because the Thompson was in limited production, and almost all the output went to Britain, and the U.S. Army. The USMC could not get many Thompsons, so they contracted with H&R to build the Reising Model 50, which was already in production for civilian use. (Mostly law enforcement)

The Model 50 did great in tests by Russia, performed at H&R, and in other tests. It performed exceptionally, but the parts were hand fitted. The USMC knew this, but wanted a submachine gun fast. They decided to go with the gun produced as it was, because gearing up to produce fully interchangeable parts would have taken many months. The problem was, this fact was not communicated well through the Marine Corps ranks. So, in 1942, the USMC found themselves at Guadalcanal with the Reising, and began to clean the weapons communally. This became a fatal error, since the parts were not fully interchangeable, and weapons without original parts subsequently failed in combat. The Reising Model 50 got an underserved bad rap as a result. There were some other issues with the blued finish of the early guns rusting in the jungle conditions, but again, the issues were not the fault of H&R, but rather the fault of the USMC in its haste to field a submachine gun under pressure. When all this occurred on Guadalcanal, a Colonel weighed his options, and, knowing he had other shipments of Reisings inbound to him, and that he could change the cleaning processes used with them going forward, he gave an order to dispose of the Reisings that had parts switched out into a river. The bad taste for the Reising never really left the USMC grunt, because regardless of how it all came down, many thought the weapon itself failed them.

So, this gives you an idea of what could happen had hand-fitted M1 Carbines been accepted from IP, assuming that hand fitting was the issue in the first place.

David Albert
dalbert@sturmgewehr.com

To answer the OP's question:

According to Ruth War Baby, Irwin Pedersen failed to qualify a single carbine. At Aberdeen they had fractured receivers from tests.  Page 156 says that IP was going to lose their contract for failure to preform.

painter777,

I appreciate you passing along the info, particularly the political details, which sound like they proved significant, and probably deserve additional discussion.

When I said "school me," I meant it to mean that I'm definitely open to further input on the subject. I probably should have expressed that differently.

It's been so long since I've seen a cost plus contract that I forgot about them...

I understand your point about the money, but I see it as a secondary factor. The main reason that IP Carbines were not accepted was that they didn't meet quality standards, even if politics may have influenced their acceptance. The history and professional makeup of the company at the time support the assertion that problems existed with product consistency. If IP had met the standards, even if they had been more expensive than other Carbine manufacturers, I believe they would have been accepted, if that remained consistent with the contractual language. The government was ultra-influential in driving down supplier costs in WWII, and I bet that a good deal of pressure would have been placed on IP to reduce their costs, and the learnings of other Carbine manufacturers would have become applied. At no other time in our history did companies share their knowledge and learned efficiencies that in peacetime were vehemently protected as competitive advantages.

David Albert
dalbert@sturmgewehr.com

painter777 wrote: To answer the OP's question:   - "why the 3542 carbines that Irwin Pedersen produced, were not accepted by government? What was the main reason, ? "   Cost per carbine was too high. War Dept realized they had entered a bad contract agreement.   That's the main reason. Nothing to do with Quality,  interchangeability or production.   Regards Charlie-painter777

It can also been said about NPM. There Carbine were coming in around or over 63.00 that was way over what the Government wanted to spend. I think if I'm not mistaken it was in the 30 to 35.00 range. If anyone knows for sure Please feel free to correct this. The quality of NPM was one of the best. It's the only Carbine that passed the Rain Teat and they tried to get the other Manufacturers to follow this, but couldn't.