5.7 MMJ Carbine PMC
Printed From: The Carbine Collector's Club
Category: The Club
Forum Name: Carbines of the Collectors
Forum Description: Share Your Carbine
URL: http://www.uscarbinecal30.com/forum/forum_posts.asp?TID=6061
Printed Date: Apr 24 2024 at 1:32am
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com
Topic: 5.7 MMJ Carbine PMC
Posted By: mjholden57
Subject: 5.7 MMJ Carbine PMC
Date Posted: Feb 24 2022 at 2:20pm
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Hi All, So I purchased a M1 carbine in 5.7 MMJ a few years ago and really enjoyed the history of the cartridge and of Melvin Johnson. The carbine I purchased was not an original made by Johnson Arms, but rather by someone who wanted a tribute rifle to the man. So I finally found and purchased a real 5.7 MMJ carbine on a PMC receiver with a correct "A" marking serial number, but the serial number it's self falls outside the range of what has been published as Johnson 5.7 carbines...anyone have any additional information or history on these rifles? Thanks in advance.
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Replies:
Posted By: floydthecat
Date Posted: Feb 24 2022 at 3:08pm
| Just to be sure, is the receiver ring correctly marked as 5.7? |
Posted By: mjholden57
Date Posted: Feb 24 2022 at 7:14pm
| No it is not marked in any caliber. The serial is A844 which denotes it was a Johnson carbine and it's definitely 5.7 MJ. |
Posted By: floydthecat
Date Posted: Feb 24 2022 at 7:23pm
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You might have just identified a new highest serial number?
Sleeplessnashadow will likely notice this and be interested.
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Posted By: sleeplessnashadow
Date Posted: Feb 25 2022 at 10:33am
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Welcome Michael (and thanks for the heads up Roger) I have info on six of the Plainfield Machine 5.7mm caliber models with not so great photos of three of them as examples. With a seventh serial numbered as 5.7mm but marked and chambered for caliber .30 carbine. So I held off on showing the receiver markings. Serial numbers range from X A002 (the 1st below) to A356. S/N A711 is a .30 cal. carbine marked M1 (4th below).     Any chance you could share some photos of yours and its markings? Melvin Johnson (Johnson Arms) had Plainfield make carbines for him. Some in .30 carbine, some in 5.7mm. But the markings and serial numbers were different than what Plainfield used. Also not consistent with the Johnson Arms carbines I have info on. I've held off on the page(s) for Johnson Arms due to a lack of photos and info. Canfield did a book on Johnson Arms with info on and pics of their carbines. But their not the same markings as those made by Plainfield. Jim |
Posted By: mjholden57
Date Posted: Feb 26 2022 at 2:17pm
| I will post pictures tomorrow. PMC is stamped behind the rear sight on the receiver but there is no caliber marking on the front receiver ring.. |
Posted By: mjholden57
Date Posted: Feb 27 2022 at 11:35am
Front receiver ring  Rear of receiver  Serial #  |
Posted By: floydthecat
Date Posted: Feb 27 2022 at 12:16pm
| I believe that some PMC carbines never were rolled on the receiver ring. Jim will be able to expand on this. |
Posted By: sleeplessnashadow
Date Posted: Feb 27 2022 at 11:55pm
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Michael, The markings and lack thereof on your Plainfield carbine are different than the rest of their 5.7mm carbines. First up, a few questions for you... This is Plainfield s/n B311. Notice the markings and lack thereof match yours. It has a couple unique things I'd like you to check your carbine for.     Does yours have the thin web on the front of the trigger housing lug? If not, is the front of the lug curved or straight?  Is your recoil plate tang wide like this one or the normal recoil plate tang width? One more question. How many lands/grooves does your barrel have? The two fellas who started Plainfield Machine had not intended on getting into the carbine manufacturing business. They were machinists contracted to produce receivers and various parts for Millville Ordnance. When the owner of Millville was indicted they were left with a bunch of receivers and parts, unpaid for a bunch of the work they did. They started as H&S to try to recoop some of their losses. When they saw the profits involved they decided to start manufacturing carbines as Plainfield Machine. Initially, they were literally a mom and pop operation. With their kids joining in with various employees over the years. Their first 1100 or so carbines they used a letter prefix with three numbers for their serial numbers. The markings and features of the letter prefix carbines evolved as they progressed from B thru Z and until they standardized their markings and features at about s/n 1500. You can see this on the page devoted to Plainfield's markings: http://www.m1carbinesinc.com/carbine_Plainfield04.html" rel="nofollow - http://www.m1carbinesinc.com/carbine_Plainfield04.html There were two exceptions. Occasionally they serial numbered and assembled a carbine using a left over receiver made earlier in time. Something done by most commercial manufacturers. Occasionally they deviated from the norm either intentionally or unintentionally. This is the most common receiver ring marking on the Plainfield 5.7mm carbines ...  Your receiver markings were used much earlier than these. I suspect it was a left over receiver serial numbered later in time. The answers to the questions above will help narrow down what was done and possibly when. I don't think the 5.7mm carbines were made in one run. I suspect they were made occasionally 1966-1970 or so. Jim |
Posted By: mjholden57
Date Posted: Feb 28 2022 at 6:47am
| Wow, such history is amazing. I haven't broken the rifle down yet, but I will and take photos to show you what the receiver looks like. |
Posted By: mjholden57
Date Posted: Mar 05 2022 at 2:44pm
No additional markings,     |
Posted By: sleeplessnashadow
Date Posted: Mar 06 2022 at 3:58am
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I think your receiver may be one of the receivers left over when MOCO went out of business. Then later used by Plainfield Machine. Regarding yours having s/n A844... MOCO s/n's I have info on are A107 - A361. H&S s/n's I have info on are A423 - A615. I suspect Plainfield continued this sequence when they started using the Plainfield Machine name. Plainfield s/n A129 and A164 are M2 .30 cal. carbines with the Plainfield Machine marking on the receiver ring along with the Cal. .30 M2 model number. Plainfield's first M2's used the A as a suffix (164A, 208A, etc), not as a prefix. Both of these M2's are consistent with all other M2's having the A as a suffix. During a time when Plainfield switched from the Z series to the numbers only and hadn't become consistent with their markings. Plainfield s/n A711 is a .30 cal. carbine with the PMC markings like yours. Plainfield Machine Cal. .30 M1 was hand stamped a letter at a time on the receiver ring. I suspect this was one of the first Plainfield carbines. But one alone isn't enough to call it as the earliest Plainfield s/n versus a 5.7mm s/n used on a .30 cal. carbine.. I suspect yours may have been s/n'd as a .30 cal. carbine then later assembled as a 5.7mm. This would explain why it's a higher s/n than all the other 5.7mm carbines (X A002 - A356). It also fits the PMC markings and the machining of the receiver that is like the first hundred or so Plainfield carbines and unlike any of the other 5.7mm receivers. Keep in mind yours is consistent with a leftover MOCO receiver during a time when Haas and Storck were just getting started as Plainfield Machine. Take a look at the sides of your barrel in the area of the gas piston housing. The MOCO carbines had their initials there.   The initials were present or sometimes removed on some of the barrels used with the H&S carbines.   MOCO carbine barrels had 4 lands and grooves. Some of the H&S barrels were also 4 lands and grooves. Some H&S barrels were two lands and grooves (cut down 1903A3 barrels). This continued with the early Plainfield barrels then switched to 12 lands and grooves before they finally settled on 6 lands and grooves. Hope this makes sense. I'm not ready to call yours a new high s/n for the 5.7mm carbines as I think it very likely it was initially numbered as a .30 cal. carbine. Jim Jim |
Posted By: sleeplessnashadow
Date Posted: Mar 06 2022 at 4:02am
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A P.S. ... Whatever the case, your carbine is over 55 years old. I highly recommend getting it inspected and safety checked by a competent gunsmith. Jim |
Posted By: mjholden57
Date Posted: Mar 06 2022 at 10:07am
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Jim, Thank you for the information. I did have a local gunsmith inspect the receiver and barrel and he gives it a thumbs up. Exciting to have such a piece of history and I'll just leave it in the safe and shoot the tribute rifle I have. Not sure what type of value it holds other than being an interesting part of history and the Plainfield Machine Company. I will check the initials location and post a reply. Mike Holden
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Posted By: mjholden57
Date Posted: Mar 06 2022 at 6:19pm
| So I have no initials on either side of the gas block and no evidence of grinding off or attempting to remove an markings. |
Posted By: sleeplessnashadow
Date Posted: Mar 06 2022 at 7:28pm
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For the majority of people the commercial carbines haven't had the collectable values like the GI carbines have had. Their value has been as affordable shooters. While history adds interest I don't foresee the history of the commercial manufacturers upping the value of their carbines, making them collectable, or worth preserving. I think their real value has been and will be as providing people with affordable shooters and helping to fuel and sustain the interest in the .30 cal carbines. While at the same time they can be great for self defense and beginners. If you're interested, here are some examples of the lands and grooves found on carbine barrels. Two Lands & Grooves  These were surplus GI 1903A3 barrels made by Remington cut down to carbine dimensions. They were inserted into the rear half of a demilled GI carbine barrel or a replicated replacement. Gas piston housings were integral if a demilled GI barrel was used. If a replica of the rear half of the GI barrel was used, each of the commercial manufacturers had their own gas piston housing design and means of attaching it. These were very common with the early commercial manufacturers in the 60's. Erma's Mfg used them with all their carbines. Four Lands & Grooves  Six Lands & Grooves  Plainfield Machine made these their standard in the mid 1960's thru end of production. Continued by Iver Johnson after they bought Plainfield and operated out of the NJ location. Used by Iver Johnson in AR thru 1985. IJ switched to 4 lands and grooves in 1986. Twelve Lands & Grooves  These were made for a couple years in the mid 1960's by Small Arms Manufacturing Co. in Bridgeville, PA. They didn't add the gas piston housing. Each commercial carbine manufacturer had their own design and means of attaching it. 12 groove barrels were used early by Plainfield, Universal, National Ordnance, and Alpine. Jim |
Posted By: mjholden57
Date Posted: Mar 08 2022 at 6:47pm
| Working on pictures of the rifling to confirm my carbines barrel configuration. |
Posted By: mjholden57
Date Posted: Mar 08 2022 at 7:12pm
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Posted By: adam lee
Date Posted: Mar 12 2022 at 1:57pm
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That looks like a 6-groove barrel, FWIW. I've been enjoying this 5.7 PMC history detective lesson! Adam ------------- Yesterday, it worked. Today it is not working. Windows is like that. |
Posted By: sleeplessnashadow
Date Posted: Mar 13 2022 at 1:44am
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Yup, 6 lands & grooves. Maybe someone more familiar than I am with the 5.7mm cartridge can comment on the number of lands & grooves recommended for it. Jim |
Posted By: mjholden57
Date Posted: Mar 16 2022 at 2:48pm
| Not sure if that is good or not, 6 lands and grooves, but at least it meets the criteria of the barrels that came standard. Really just want to confirm it's an original MMJ 5.7 carbine. |
Posted By: sleeplessnashadow
Date Posted: Mar 16 2022 at 11:02pm
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While I can say for certain that Plainfield's standard became the 6 lands and grooves it applies only to their .30 cal. carbines. They may or may not have used the same for their 5.7mm Johnson caliber carbines. The few in 5.7mm Johnson I have info on do not include the number of lands and grooves. I don't know of anyone who can tell the difference with the accuracy the 2, 4, 6, or 12 groove barrels with the .30 cal. carbine cartridge. Testing would need to be done with new carbines/barrels as used ones may have other contributing factors to performance and accuracy. I haven't seen anything on the best number of lands and grooves for the 5.7mm cartridge. But someone somewhere may have. Since the 5.7mm cartridge uses a neck downed .30 carbine casing the only difference between the carbines chambered for the 5.7mm and those chambered in .30 carbine is the barrel. All things considered, I think yours was probably originally assembled as a 5.7mm carbine but there is no way to determine if someone later swapped a .30 carbine barrel out for a 5.7mm barrel. The past 4+ years I haven't continued buying commercial carbines for evaluation due to the amount of work I'm doing on the GI carbines and the USCarbineCal30.com website. I update and correct the M1CarbinesInc.com pages as more info becomes known. I bought and paid for a Plaifield 5.7mm carbine about 7 or 8 years ago.   The seller failed to follow the laws so the deal fell thru. An exercise in frustration and a big disappointment. Hope this helps. Jim |
Posted By: mjholden57
Date Posted: Mar 18 2022 at 3:00pm
| Thanks for all the info and your time. All in all I'm okay with the rifle and at a minimum it's in a awesome caliber and at best it's a legitimate MMJ carbine. |
Posted By: sleeplessnashadow
Date Posted: Mar 29 2022 at 5:47am
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An update on the number of lands and grooves for the 5.7mm Johnson barrels. I'm working on a web page for the Johnson Arms carbines. Found info the 5.7mm barrels used by Plainfield Machine and for the Johnson Arms carbines were 6 lands and grooves. Jim |
Posted By: sleeplessnashadow
Date Posted: Apr 12 2022 at 9:12am
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A web page devoted to Johnson Arms is now online for those interested in the 5.7mm Johnson cartridge and carbines that shoot them. http://www.m1carbinesinc.com/carbine_Johnson.html" rel="nofollow - http://www.m1carbinesinc.com/carbine_Johnson.html |
Posted By: sleeplessnashadow
Date Posted: Apr 12 2022 at 4:01pm
Also found a better pic of the Plainfield receiver markings. Forgot I took this one.
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Posted By: eb in oregon
Date Posted: Jul 13 2022 at 10:22am
If the receiver is marked with any other name than Johnson Arms it is not an original, unless it was made by another company after Johnson Arms folded. As far as I can determine (as I've not examined a specimen of all manufacturers) the Johnson Arms receiver was originally a modified unmarked Plainfield receiver and then became a special order receiver with a modified ramp. I'm pretty sure that the company's that made carbines in 5.7 used the original M1 ramp profile. The one Johnson used will feed anything from 35 grain Hornady's to 40 grain open tipped match style bullets. The standard M1 carbine ramp (in my experience) will feed semi-spitzers only. The company's I know of that made 5.7 carbines would be Johnson Arms, IAI, Iver Johnson, and Fulton Armory for a short time. I've never seen a different type of ramp (outside of Johnson Arms) that used a feed ramp other than standard.   ------------- "You are what you do when it counts." |
mjholden57 wrote: