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Posted: 4/8/2014 6:42:17 PM EDT
[#1]
In the original drawing Augee posted, it looks like a sling swivel mounted to the rear of the FSB.
Question for the reloading guys - how does the .221 Fireball compare to the .224 BOZ? The latter is a more modern round, possibly more accessible. How do they compare size and ballistics -wise? |
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Posted: 4/8/2014 7:08:13 PM EDT
[#2]
What would everyone rather want a reproduction of the prototypes or a good guess of what a production MARS would be like?
I'd like to at least model one up. Making true 5.56x30 from cut down 5.56x45 cases is definitely the way to go. |
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Posted: 4/8/2014 7:15:46 PM EDT
[#3]
if you didn't want to cut and weld the lower to accommodate a shorter magwell, it might be easier to start from a 0% lower, cut it to size and then cut the magwell.
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Posted: 4/9/2014 1:11:56 AM EDT
[#4]
Can a mag well be cut without a broach?
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Posted: 4/9/2014 2:52:11 AM EDT
[#5]
Quote HistoryQuoted:
if you didn't want to cut and weld the lower to accommodate a shorter magwell, it might be easier to start from a 0% lower, cut it to size and then cut the magwell. That was my thought as well. The upper would still have to be chopped, which would definitely be easier with a flat top than carry handle though, and my main concern would be the final strength of an upper that has been cut in half in the middle of where the BCG reciprocates.  You could start with a 0% upper, but I don't see what advantage that would give you in the case of the upper because of lug position. You'd really need to CNC the whole thing to make it truly viable and not just be a test bed.
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Posted: 4/9/2014 4:01:31 AM EDT
[#6]
I agree a Zero lower would likely be the best route--but this could be done on an "old fashioned" vertical mill. That's how AR lowers have been done since the 1950s. Having worked a vertical mill, I would LOVE to try a CNC machine! For me, the cutting of the upper, mags & welding (TIG or MIG?) would be a PIA.
According to Wikipedia, the .224 Boz is a necked-down 10mm 50 gr at roughly 2,600fps. It was used in an HK MP5, which is a roller-delayed action--not gas operated. And I've seen pistol, which were modified Browning (1911--not blow back). While there may have been a run or 2 of 10mm Boz made--I doubt there's a great deal of cases to be had--so I'd rather use 5.56 NATO & cut it to make 5.56 x 30 rather than scrounge up 10mm. Of course, someone with a 10mm will feel differently, no doubt. In a quick internet search--the .224 Boz was a British cartridge & I couldn't readily dig up powders info for loading the .224 Boz. I suspect H110 or VV N 110 would work for the MARS round.....maybe the Boz, but some of the internet drivel is conflicting about the round, claiming a "fast powder" is needed. ETA: from what little I could find on the Boz, since it's a "non-sporting" round from the UK, little info for reloading is available from the original manufacturer ( DERA Fort Halstead, UK) and some allege that there are "intellectual property issues" if used in the USA, as the UK company would ONLY deal with mil or LEO. Not that the "range police" are going to freak--more that the Boz isn't out there in any great numbers.....I'd pass. |
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Posted: 4/9/2014 6:29:44 AM EDT
[#7]
Quote HistoryQuoted:
I don't mind making my own shortened .223 cases. With the amount of powder it uses, as a reloader this excites me. The parts are exclusive.. Its going to be costly. Good things cost money. Quote HistoryQuoted:
I don't mind making my own shortened .223 cases. With the amount of powder it uses, as a reloader this excites me. The parts are exclusive.. Its going to be costly. Good things cost money. Jhud: Given the dimensions of the 5.56x30mm, do you think you could make a case to those specs with the press and dies you have now? I know nothing about reloading so if you can confirm that the round can be made with common reloading knowledge and tools then I'd think the next step would be to get someone to ream and head space a barrel to a shortened 5.56 chamber. I'd go on the assumption that any company that can make a 5.56 chamber reamer can make one shorter (not saying it'd be cheap  ). At that point we could atleast try to make a full sized bolt carrier / lower version. Just for testing put a spacer in a 10 - 20 round mag to keep the rounds towards the front of the mag... I'm assuming with a standard carbine tube, buffer, and spring that would at least get us really close to what the port size on the barrel would need to be. From the pics it looks like the original had a carbine gas system.
Description of 5.56.times.30mm MARS Cartridge Caliber: 0.224 inches (5.56mm) Bullet: 55gr Full Metal Jacket Boat Tail Bullet length: 0.752 inches Load: 16.8gr of a commercially available ball propellant Primer: commercially available 71/2 Muzzle Velocity (11 inch barrel) 2600+fps Muzzle Energy (11 inch barrel) 825+ftlb Cartridge dimensions (inches): Outside diameter of neck 0.253 Outside diameter of case below shoulder 0.369 Outside diameter of case near base 0.376 Overall case length 1.2 Length to top of shoulder 1.05 Length to base of shoulder 0.95 Loaded cartridge overall length 1.7 |
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Posted: 4/9/2014 7:25:29 AM EDT
[#8]
MARS chamber and ammo would be easy and the parents aren't really a problem because of time elapsed without action.
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Posted: 4/9/2014 8:37:16 AM EDT
[#9]
Quote HistoryQuoted:
MARS chamber and ammo would be easy and the parents aren't really a problem because of time elapsed without action. I don't know, sometimes my Mom can be a pita. 
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Posted: 4/9/2014 8:54:52 AM EDT
[#10]
Quote HistoryQuoted:
I don't know, sometimes my Mom can be a pita.
Quote HistoryQuoted:
Quoted:
MARS chamber and ammo would be easy and the parents aren't really a problem because of time elapsed without action. I don't know, sometimes my Mom can be a pita.
that's b/c you track aluminum shavings all over her house. do you know how hard those are to get out of carpet. 
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Posted: 4/9/2014 9:45:31 AM EDT
[#11]
OK, back on track.
Here's a size comparison. pics stolen off of the web. 
If a custom short bolt has to be made, it might be better to use the 5.7x28 so it can be blowback. |
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Posted: 4/9/2014 9:53:52 AM EDT
[#12]
Quoted:
What would everyone rather want a reproduction of the prototypes or a good guess of what a production MARS would be like? I'd like to at least model one up. Making true 5.56x30 from cut down 5.56x45 cases is definitely the way to go. My opinion, ideally would be to work through what "production" would be like. It would look the same externally, but would eliminate the kludgy adaptations of the FCG in the prototypes. *IF* someone wanted to actually bring something like this to market, they would want to do some redesign of the bolt and bolt carrier so as to allow use of standard AR15 fire control components and geometry. The original MARS prototypes has altered FCG geometry so as to allow a standard BCG to be used, it was shortened at the back. Machining capabilities today are improved to the point where a properly configured BCG should be readily achievable. I mentioned years ago in a similar vein as this thread, that a "short action" AR15 in somewhat standardized form would open up interesting possibilities as a platform for various smaller cartridges, at the time I was thinking 7.62x25, 30 Carbine, 5.7x28 and pistol calibers. It would be interesting to see some reproductions of the MARS prototypes as well for their historic interest, but those are a dead-end as far as expanding the platform. Also with the current machining capabilities, it would be far easier to just make the receivers from billet instead of trying to alter forgings. Magazines would be the hardest part... if Colt actually had stamping dies made for them, perhaps they still exist. The handguards are standard Carbine length parts. |
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Posted: 4/9/2014 10:04:20 AM EDT
[#13]
Quote HistoryQuoted:
OK, back on track.
Here's a size comparison. pics stolen off of the web. http://www.hunt101.com/data/500/medium/5_7mm_Johnson_Spitfire.jpg http://www.hunt101.com/data/500/medium/57x28vs22-9mm-45acp-223-762_m.jpg If a custom short bolt has to be made, it might be better to use the 5.7x28 so it can be blowback. So a couple things to consider: 1) Ammo source -Commercially available -Load your own 2) Does tooling / blanks exist -Chamber reamers -Head space tools -Reload tools -Barrel blanks 3) Gas or Blow Back operated 4) Does it require changes to the BCG -Will the bolt need modification -Will the BCG need modification 5) Does the FCG need modification 6) Do magazines exist |
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Posted: 4/9/2014 10:12:10 AM EDT
[#14]
.22 TCM Sorry if this has already been mentioned. I saw the round at a LGS last week. It's a neat little round and shows promise. Looks like it would raise a welt. The following is copied from Wikepedia:
The .22 TCM (Tuason Craig Micromagnum)[2] is a proprietary cartridge developed by Fred Craig and Rock Island Armory.[3] Before the cartridge was commercialized, it was called the .22 Micro-Mag. The TCM is a bottlenecked cartridge, similar in case capacity, general shape, and performance to the 5.7x28 FN.[citation needed] Standard factory loads are 40-grain jacketed hollow-points. The .22 TCM is based on the .223 Remington case, shortened so that the shoulder is at approximately the same length as the case mouth of a 9x19mm cartridge. The maximum overall loaded length is the same as a .45 ACP. The cartridge is designed to feed from a Para-Ordnance style double column .38 Super or 9x19mm magazine.[2] Currently only Rock Island Armory catalogs firearms chambered in .22 TCM: a 1911 style semi-auto pistol (also available with optional additional 9mm barrel and recoil spring), and a bolt action rifle (which reportedly can use the same magazines as the pistols); and only Armscor (the parent company of Rock Island Armory) manufactures ammunition. |
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Posted: 4/9/2014 11:16:43 AM EDT
[#15]
Quote HistoryQuoted:
What would everyone rather want a reproduction of the prototypes or a good guess of what a production MARS would be like? I'd like to at least model one up. Making true 5.56x30 from cut down 5.56x45 cases is definitely the way to go. Even though it would require reloading I agree that 5.56x30mm would be the way to go. Using the LWRC shorty stock, a barrel chambered in 5.56x30mm, modified mags / mag block with new mags, and a standard lower / upper / BCG would get you the shortest route to a firing gun. From that point shortening the receiver, upper and BCG can happen. |
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Posted: 4/9/2014 11:41:10 AM EDT
[#16]
Two things that a mini micro AR15 receiver set, BCG, and magazine system address are:
* Youth shooters * PDW's I've been wanting to make one of these for a long time for both reasons, and my older daughter needs a small rifle/carbine to begin practicing with, as even my smaller carbines are over-sized for her, and will be for quite some time. I personally like the .221 Fireball cartridge, as you don't need to do anything to it as far as trimming, etc. and you get awesome performance from it. There are polymer airsoft mags on the market that could be modified with metal feed lips for proof of concept/prototype carbines, while the rest is machine work and coatings with the receivers, BCG, and recoil system. Mag width is the same as 5.56 AR15 mags. |
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Posted: 4/9/2014 12:00:10 PM EDT
[#17]
Making correct mags for 5.56x30 will be much more expensive than machining bolts, uppers, and lowers.
If you don't have the short mag there is no point in doing the project at all. All the other dimensions are reduced to match it. |
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Posted: 4/9/2014 12:25:49 PM EDT
[#18]
Getting mags made would be easy I you wanted to invest the money.
If have PMAGs made, but that's just me. Also the MARS round has less taper than 5.56x45 and needs a straighter mag. Existing mini cans would perform very well on 11" MARS rifles. I've thought about making them, using contracted shops to reduce risk but that's at least a million in startup costs if someone would make the ammo and I'm not sure about the Colt patents and the strength of demand for such a thing. |
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Posted: 4/9/2014 12:33:49 PM EDT
[#19]
Quote HistoryQuoted:
Making correct mags for 5.56x30 will be much more expensive than machining bolts, uppers, and lowers. If you don't have the short mag there is no point in doing the project at all. All the other dimensions are reduced to match it. I agree. Getting it done would be a historical event though (I am willing to help make it happen.. because I want one, but like original.. I don't mind making brass) |
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Posted: 4/9/2014 12:38:12 PM EDT
[#20]
The MARS cartridge is really a very straightforward wildcat which can be readily made from 223 cases. The performance was much higher than 5.7x28, 22 BOZ, 22TCM or other alternatives that have been suggested, with the exception of the 22 Johnson. Other than the Johnson, I doubt any of the others would have sufficient energy to operate the gas system.
I still contend there is an excellent market potential for a MARS-like rifle and cartridge for police patrol rifle and SWAT use as well as the theoretical military applications and obvious civilian/consumer market potential. |
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Posted: 4/9/2014 12:41:21 PM EDT
[#21]
Quote HistoryQuoted:
Making correct mags for 5.56x30 will be much more expensive than machining bolts, uppers, and lowers. If you don't have the short mag there is no point in doing the project at all. All the other dimensions are reduced to match it. 
The mag catch hole looks way too small, and I suspect that notch on the back may have something to do with it. Dunno.
The more I think about it the more I like the idea of 5.56x30mm despite the hurdles. Any caliber will need a new mag if you're trying to clone the look so why not 5.56x30? |
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Posted: 4/9/2014 12:44:20 PM EDT
[#22]
MARS would be the best police round extant. Only 6x35 could compete with it. However you'd have to have ATK or Olin or Hornady on board ensuring plentiful and cheap ammo to do it.
If it were my baby I'd have four ballistically matched 55gr projectiles. FMJ, TSX, lead free RRLP and TBBC. |
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Posted: 4/9/2014 12:45:15 PM EDT
[#23]
30 carbine mags in an AR has been done.
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Posted: 4/9/2014 12:58:00 PM EDT
[#24]
I wonder how the OAL of the 17 Winchester super mag compares to the 5.56x30.... an AR available in 17 WSM might be very interesting.
I'd also imagine that the performance of the 5.56x30 with some of the newer technology modified burn rate powders (like what's in the Mk318) would be pretty interesting. |
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Posted: 4/9/2014 1:39:06 PM EDT
[#25]
 What I've got so far, shortened the receivers and receiver extension, once I draw up a magazine I can figure out exactly how much the receivers need to be shortened, along with the exact BCG dimensions. |
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Posted: 4/9/2014 1:46:56 PM EDT
[#26]
Quote HistoryQuoted:
I wonder how the OAL of the 17 Winchester super mag compares to the 5.56x30.... an AR available in 17 WSM might be very interesting. I'd also imagine that the performance of the 5.56x30 with some of the newer technology modified burn rate powders (like what's in the Mk318) would be pretty interesting. Would you believe Franklin Armory has done a DI operated 17 WSM:Franklin Armory 17 WSM AR on Youtube Only problem I see is finding the ammo. I honestly would prefer the 5.56X30 since I like reloading and I have piles of brass and bullets. only problem is getting the dies and reamer done. |
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Posted: 4/9/2014 1:57:22 PM EDT
[#27]
Quote HistoryQuoted:
https://dl.dropboxusercontent.com/u/30126941/MARS1.JPG What I've got so far, shortened the receivers and receiver extension, once I draw up a magazine I can figure out exactly how much the receivers need to be shortened, along with the exact BCG dimensions. Amazing. Y'all have gone way further already than I imagined - and you've already gone beyond the level of my technical knowledge and ability. All I can add, is I hope that some of this comes to something and one day some of this can be a reality, I'd be in for one! I have long since thought that a "short action" AR would be a fantastic thing to exist and get produced, but the "apparent" lack of interest from KAC to develop their PDW any further, and the lack of anyone else really agitating for it led me to believe that I was one of the only ones - glad to see I was wrong.
~Augee |
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Posted: 4/9/2014 2:06:24 PM EDT
[#28]
Quote HistoryQuoted:
https://dl.dropboxusercontent.com/u/30126941/MARS1.JPG What I've got so far, shortened the receivers and receiver extension, once I draw up a magazine I can figure out exactly how much the receivers need to be shortened, along with the exact BCG dimensions. That's great. Your avatar illustrates a key point I have been trying to make in the variants sub forum, and that is that the weak link in the system when pushing pressures is the hoop stress right where the relief cut is ahead of the threads on the tennon of the barrel. In this discussion, we are talking about using the existing .222 Remington-based cartridge diameter, which the AR15 was built around, whereas the other discussion involved trying to stuff .30 Remington AR in there, with a .500" case diameter ahead of the extractor groove, and run 55,000psi average pressures. 
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Posted: 4/9/2014 4:51:23 PM EDT
[#29]
Quote HistoryQuoted:
http://i271.photobucket.com/albums/jj149/halpark/pix825141966_zpsfdddbdbc.jpg The mag catch hole looks way too small, and I suspect that notch on the back may have something to do with it. Dunno. Looks fine to me - just the angle I think.
The more I think about it the more I like the idea of 5.56x30mm despite the hurdles. Any caliber will need a new mag if you're trying to clone the look so why not 5.56x30? Quote HistoryQuoted:
Quoted:
Making correct mags for 5.56x30 will be much more expensive than machining bolts, uppers, and lowers. If you don't have the short mag there is no point in doing the project at all. All the other dimensions are reduced to match it. http://i271.photobucket.com/albums/jj149/halpark/pix825141966_zpsfdddbdbc.jpg The mag catch hole looks way too small, and I suspect that notch on the back may have something to do with it. Dunno. Looks fine to me - just the angle I think.
The more I think about it the more I like the idea of 5.56x30mm despite the hurdles. Any caliber will need a new mag if you're trying to clone the look so why not 5.56x30? It looks like an AR mag bent at the first rib - the main issue I see are the floorplate retaining tabs. You would lose the front two if modifying an existing mag, and re-swaging it would not be easy. I think it could be done though, maybe with a retainer made from another mag... building the swaging die would take some work, but it's reusable. I like the idea of the .22 TCM - it has some interesting ballistics, but if you are going to do a clone, I think the MARS cartridge seems the best bet after reading the discussion - it would mean someone handloading however. A CNC'd upper is a must IMO however, as I said. An 0% lower could be shortened acceptably I believe, by just moving the front of the receiver back into the magwell as well as the pivot point. |
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Posted: 4/9/2014 4:51:47 PM EDT
[#30]
Quote HistoryQuoted:
http://i271.photobucket.com/albums/jj149/halpark/pix825141966_zpsfdddbdbc.jpg The mag catch hole looks way too small, and I suspect that notch on the back may have something to do with it. Dunno. Looks fine to me - just the angle I think.
The more I think about it the more I like the idea of 5.56x30mm despite the hurdles. Any caliber will need a new mag if you're trying to clone the look so why not 5.56x30? Quote HistoryQuoted:
Quoted:
Making correct mags for 5.56x30 will be much more expensive than machining bolts, uppers, and lowers. If you don't have the short mag there is no point in doing the project at all. All the other dimensions are reduced to match it. http://i271.photobucket.com/albums/jj149/halpark/pix825141966_zpsfdddbdbc.jpg The mag catch hole looks way too small, and I suspect that notch on the back may have something to do with it. Dunno. Looks fine to me - just the angle I think.
The more I think about it the more I like the idea of 5.56x30mm despite the hurdles. Any caliber will need a new mag if you're trying to clone the look so why not 5.56x30? It looks like an AR mag bent at the first rib - the main issue I see are the floorplate retaining tabs. You would lose the front two if modifying an existing mag, and re-swaging it would not be easy. I think it could be done though, maybe with a retainer made from another mag... building the swaging die would take some work, but it's reusable. I like the idea of the .22 TCM - it has some interesting ballistics, but if you are going to do a clone, I think the MARS cartridge seems the best bet after reading the discussion - it would mean someone handloading however. A CNC'd upper is a must IMO however, as I said. An 0% lower could be shortened acceptably I believe, by just moving the front of the receiver back into the magwell as well as the pivot point. Great pic JBowles! |
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Posted: 4/9/2014 6:24:52 PM EDT
[#31]
Quote HistoryQuoted:
https://dl.dropboxusercontent.com/u/30126941/MARS1.JPG What I've got so far, shortened the receivers and receiver extension, once I draw up a magazine I can figure out exactly how much the receivers need to be shortened, along with the exact BCG dimensions. If someone actually makes this thing, do the world a favor and make the magwell a tiny bit wider so as to accommodate a double stack 45acp mag. Pistol caliber spinoffs would be the most natural and immediate progression of the "short action" concept. Also make sure that the Sig MPX magazine could be accommodated via a magblock or whatever. |
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Posted: 4/9/2014 6:29:23 PM EDT
[#32]
n/m
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Posted: 4/9/2014 6:29:44 PM EDT
[#33]
Quote HistoryQuoted:
I honestly would prefer the 5.56X30 since I like reloading and I have piles of brass and bullets. only problem is getting the dies and reamer done. What's his name Kiff [Greg?] at PTG [Pacific Tool & Gage could easily do the reamer off a decent drawing. They do it every day. There are any number of precision smiths who, in addition to chambering a barrel, could fabricate a set of dies using the chambering reamer. There is at least one vendor (Redding? Sinclair?] who can furnish blank dies to be used with chambering reamer. I really don't think the ammunition or the dies are anywhere near the three biggest hurdles. One is money, another is magazines, and the third is figuring out the receivers and bolt carrier group. I see the third one as being the most technically challenging. |
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Posted: 4/9/2014 6:35:03 PM EDT
[#34]
Quote HistoryQuoted:
google fu says india is making 5.56x30 Should I arrange an overseas trip to set up a contract? the retro forum could fund it. We can make this happen. The ammo availability could be really cool. I would be even cooler if the MSMC magazine was something that might be able to be compatible with an AR type lower, but it's an AK pattern polymer mag from the looks of it. |
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Posted: 4/9/2014 6:48:06 PM EDT
[#35]
Quote HistoryQuoted:
http://i271.photobucket.com/albums/jj149/halpark/pix825141966_zpsfdddbdbc.jpg The mag catch hole looks way too small, and I suspect that notch on the back may have something to do with it. Dunno.
The more I think about it the more I like the idea of 5.56x30mm despite the hurdles. Any caliber will need a new mag if you're trying to clone the look so why not 5.56x30? Something just occurred to me looking at that photo. That mag has a constant curve, and the notch on the back would be consistent with a rear tab-release style mag catch. Those are quite possibly magazines for some other kind of firearm which Colt adapted with the AR18 style mag catch slots for the prototypes. The question is, what would the original magazine have been? 10 years or so ago when I was talking about a "short action" AR, I know the Israelis has an interest in 30 Carbine and possibly 22 Johnson rifles... they made a 30 Carbine variant of the Galil but it was quite heavy and not really what they were looking for. They even set up that US company for a while that was making M1 Carbines including some in 22 Johnson. I don't know if that's still the case or not. The MARS I presume was intended possibly for that market as well as US SOCOM applications. |
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Posted: 4/9/2014 7:27:09 PM EDT
[#36]
Quote HistoryQuoted:
Something just occurred to me looking at that photo. That mag has a constant curve, and the notch on the back would be consistent with a rear tab-release style mag catch. Those are quite possibly magazines for some other kind of firearm which Colt adapted with the AR18 style mag catch slots for the prototypes. The question is, what would the original magazine have been? 10 years or so ago when I was talking about a "short action" AR, I know the Israelis has an interest in 30 Carbine and possibly 22 Johnson rifles... they made a 30 Carbine variant of the Galil but it was quite heavy and not really what they were looking for. They even set up that US company for a while that was making M1 Carbines including some in 22 Johnson. I don't know if that's still the case or not. The MARS I presume was intended possibly for that market as well as US SOCOM applications. Quote HistoryQuoted:
Quoted:
http://i271.photobucket.com/albums/jj149/halpark/pix825141966_zpsfdddbdbc.jpg The mag catch hole looks way too small, and I suspect that notch on the back may have something to do with it. Dunno.
The more I think about it the more I like the idea of 5.56x30mm despite the hurdles. Any caliber will need a new mag if you're trying to clone the look so why not 5.56x30? Something just occurred to me looking at that photo. That mag has a constant curve, and the notch on the back would be consistent with a rear tab-release style mag catch. Those are quite possibly magazines for some other kind of firearm which Colt adapted with the AR18 style mag catch slots for the prototypes. The question is, what would the original magazine have been? 10 years or so ago when I was talking about a "short action" AR, I know the Israelis has an interest in 30 Carbine and possibly 22 Johnson rifles... they made a 30 Carbine variant of the Galil but it was quite heavy and not really what they were looking for. They even set up that US company for a while that was making M1 Carbines including some in 22 Johnson. I don't know if that's still the case or not. The MARS I presume was intended possibly for that market as well as US SOCOM applications. It kind of reminds me of a PPSH-43 mag... jhud said: Did you even see the Mini-14 mags that have a derlin floorplate help in place by some springs and detents? It is a far superior design than the modern. It is an early design that gets rid of the Tabs that hold a sheet metal piece in place. Pretty much the mag can be cut flush and have 2 holes in each side for the detents Nope, but I'd (we'd) like to!
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Posted: 4/9/2014 7:38:24 PM EDT
[#37]
Quote HistoryQuoted: If someone actually makes this thing, do the world a favor and make the magwell a tiny bit wider so as to accommodate a double stack 45acp mag. Pistol caliber spinoffs would be the most natural and immediate progression of the "short action" concept. Also make sure that the Sig MPX magazine could be accommodated via a magblock or whatever. Quote HistoryQuoted: Quoted: https://dl.dropboxusercontent.com/u/30126941/MARS1.JPG What I've got so far, shortened the receivers and receiver extension, once I draw up a magazine I can figure out exactly how much the receivers need to be shortened, along with the exact BCG dimensions. If someone actually makes this thing, do the world a favor and make the magwell a tiny bit wider so as to accommodate a double stack 45acp mag. Pistol caliber spinoffs would be the most natural and immediate progression of the "short action" concept. Also make sure that the Sig MPX magazine could be accommodated via a magblock or whatever. I'm thinking the magazine will be more like a little Stoner63 magazine, it really addressed must of the 30rd M16 magazine's short comings. It's looking like the buffer is just a DPMS 308 carbine buffer, the receiver extension is a bit shorter than LWRCI's, the firing pin, hammer and carrier key are just modified M16 parts, uses a standard bolt and barrel. The carrier is a bit different, I won't be able to finalize the receivers until the magazine is done. I'm going to try to do a set of cartridge and chamber drawings by this weekend, I've got it figured out just need to get it on paper. Additionally it's should be a trivial change to make a version that uses M1 Carbine magazines and shoots 30 Carbine. |
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Posted: 4/9/2014 7:56:15 PM EDT
[#38]
Quote HistoryQuoted:
I was already thinking about making the mag wider to accommodate bigger corner radii on the magazine and magazine well so that it's easier to machine the magazine well and not have to broach or EDM the magazine well. This would also make much tougher plastic mag. I'm thinking the magazine will be more like a little Stoner63 magazine, it really addressed must of the 30rd M16 magazine's short comings. It's looking like the buffer is just a DPMS 308 carbine buffer, the receiver extension is a bit shorter than LWRCI's, the firing pin, hammer and carrier key are just modified M16 parts, uses a standard bolt and barrel. The carrier is a bit different, I won't be able to finalize the receivers until the magazine is done. I'm going to try to do a set of cartridge and chamber drawings by this weekend, I've got it figured out just need to get it on paper. Additionally it's should be a trivial change to make a version that uses M1 Carbine magazines and shoots 30 Carbine. Quote HistoryQuoted:
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https://dl.dropboxusercontent.com/u/30126941/MARS1.JPG What I've got so far, shortened the receivers and receiver extension, once I draw up a magazine I can figure out exactly how much the receivers need to be shortened, along with the exact BCG dimensions. If someone actually makes this thing, do the world a favor and make the magwell a tiny bit wider so as to accommodate a double stack 45acp mag. Pistol caliber spinoffs would be the most natural and immediate progression of the "short action" concept. Also make sure that the Sig MPX magazine could be accommodated via a magblock or whatever. I'm thinking the magazine will be more like a little Stoner63 magazine, it really addressed must of the 30rd M16 magazine's short comings. It's looking like the buffer is just a DPMS 308 carbine buffer, the receiver extension is a bit shorter than LWRCI's, the firing pin, hammer and carrier key are just modified M16 parts, uses a standard bolt and barrel. The carrier is a bit different, I won't be able to finalize the receivers until the magazine is done. I'm going to try to do a set of cartridge and chamber drawings by this weekend, I've got it figured out just need to get it on paper. Additionally it's should be a trivial change to make a version that uses M1 Carbine magazines and shoots 30 Carbine. I've seen Stoner mags, but would like to see a pic if you have one - I don't remember the difference. Using an existing mag like a .30 carbine would definitely make the project easier. I will pull one out tomm. for giggles. |
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Posted: 4/9/2014 8:35:45 PM EDT
[#39]
Quote HistoryQuoted:
I was already thinking about making the mag wider to accommodate bigger corner radii on the magazine and magazine well so that it's easier to machine the magazine well and not have to broach or EDM the magazine well. This would also make much tougher plastic mag. I'm thinking the magazine will be more like a little Stoner63 magazine, it really addressed must of the 30rd M16 magazine's short comings. It's looking like the buffer is just a DPMS 308 carbine buffer, the receiver extension is a bit shorter than LWRCI's, the firing pin, hammer and carrier key are just modified M16 parts, uses a standard bolt and barrel. The carrier is a bit different, I won't be able to finalize the receivers until the magazine is done. I'm going to try to do a set of cartridge and chamber drawings by this weekend, I've got it figured out just need to get it on paper. Additionally it's should be a trivial change to make a version that uses M1 Carbine magazines and shoots 30 Carbine. Quote HistoryQuoted:
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Quoted:
https://dl.dropboxusercontent.com/u/30126941/MARS1.JPG What I've got so far, shortened the receivers and receiver extension, once I draw up a magazine I can figure out exactly how much the receivers need to be shortened, along with the exact BCG dimensions. If someone actually makes this thing, do the world a favor and make the magwell a tiny bit wider so as to accommodate a double stack 45acp mag. Pistol caliber spinoffs would be the most natural and immediate progression of the "short action" concept. Also make sure that the Sig MPX magazine could be accommodated via a magblock or whatever. I'm thinking the magazine will be more like a little Stoner63 magazine, it really addressed must of the 30rd M16 magazine's short comings. It's looking like the buffer is just a DPMS 308 carbine buffer, the receiver extension is a bit shorter than LWRCI's, the firing pin, hammer and carrier key are just modified M16 parts, uses a standard bolt and barrel. The carrier is a bit different, I won't be able to finalize the receivers until the magazine is done. I'm going to try to do a set of cartridge and chamber drawings by this weekend, I've got it figured out just need to get it on paper. Additionally it's should be a trivial change to make a version that uses M1 Carbine magazines and shoots 30 Carbine. I'm a little concerned on the shorter-than-LWRCI receiver extension. The LWRCI stock at full extension is barely longer than a Sully stock, and I think that's too short for a a general purpose rifle especially with some of the markets I would envision for this kind of rifle. If this is anything beyond a completely theoretical exercise, I think it would be advisable to get the specs on the Indian 5.56x30 cartridge so that cartridge would be compatible with the rifle unless a compelling reason would present itself in opposition. I'm curious how you're getting a standard bolt to fit, IIRC the reason for the original MARS have the modified rearward-offset FCG was to accommodate the use of a longer standard bolt. |
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Posted: 4/9/2014 9:58:06 PM EDT
[#40]
Quote HistoryQuoted:
I'm a little concerned on the shorter-than-LWRCI receiver extension. The LWRCI stock at full extension is barely longer than a Sully stock, and I think that's too short for a a general purpose rifle especially with some of the markets I would envision for this kind of rifle. If this is anything beyond a completely theoretical exercise, I think it would be advisable to get the specs on the Indian 5.56x30 cartridge so that cartridge would be compatible with the rifle unless a compelling reason would present itself in opposition. I'm curious how you're getting a standard bolt to fit, IIRC the reason for the original MARS have the modified rearward-offset FCG was to accommodate the use of a longer standard bolt. Quote HistoryQuoted:
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Quoted:
https://dl.dropboxusercontent.com/u/30126941/MARS1.JPG What I've got so far, shortened the receivers and receiver extension, once I draw up a magazine I can figure out exactly how much the receivers need to be shortened, along with the exact BCG dimensions. If someone actually makes this thing, do the world a favor and make the magwell a tiny bit wider so as to accommodate a double stack 45acp mag. Pistol caliber spinoffs would be the most natural and immediate progression of the "short action" concept. Also make sure that the Sig MPX magazine could be accommodated via a magblock or whatever. I'm thinking the magazine will be more like a little Stoner63 magazine, it really addressed must of the 30rd M16 magazine's short comings. It's looking like the buffer is just a DPMS 308 carbine buffer, the receiver extension is a bit shorter than LWRCI's, the firing pin, hammer and carrier key are just modified M16 parts, uses a standard bolt and barrel. The carrier is a bit different, I won't be able to finalize the receivers until the magazine is done. I'm going to try to do a set of cartridge and chamber drawings by this weekend, I've got it figured out just need to get it on paper. Additionally it's should be a trivial change to make a version that uses M1 Carbine magazines and shoots 30 Carbine. I'm a little concerned on the shorter-than-LWRCI receiver extension. The LWRCI stock at full extension is barely longer than a Sully stock, and I think that's too short for a a general purpose rifle especially with some of the markets I would envision for this kind of rifle. If this is anything beyond a completely theoretical exercise, I think it would be advisable to get the specs on the Indian 5.56x30 cartridge so that cartridge would be compatible with the rifle unless a compelling reason would present itself in opposition. I'm curious how you're getting a standard bolt to fit, IIRC the reason for the original MARS have the modified rearward-offset FCG was to accommodate the use of a longer standard bolt. This. I am 5' 6" and the Sully was too short for me without additional pads. The ideal length for me is just about another 5/8" shorter than a standard A1. The 607 stock was way ahead of it's time. With today's technology, I don't know why someone hasn't jumped on a 4-pos or even 6 pos 607-ish modern stock. Why do we have to have rails and sharp edges on every damn thing to be effective? |
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Posted: 4/10/2014 12:48:00 AM EDT
[#41]
The stops on the RE should be designed to allow a standard stock to collapse fully. Then you can use a VLTOR or LMT stock when minimal collapsed length isn't critical.
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Posted: 4/10/2014 4:19:39 AM EDT
[#42]
If LOP is a real concern you can just swap the RE for a standard M4 and make a 4-5 weight buffer.
Swapping the stock will only net you an increase equal to the increased length of the stock compared to a standard CAR stock.  Worked up this layover, it looks like I'm right on track with what Colt intended. The set back FCG is certainly the path of least resistance vs shortening the bolt, it also serves its intended propose by making the rifle more small hand friendly. It appears Colt never really figured out the firing pin retainer it's going to take some tweaking or further hammer modifications to keep the hammer from hitting the firing pin retainer. |
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Posted: 4/10/2014 5:48:32 AM EDT
[#43]
Quote HistoryQuoted:
If LOP is a real concern you can just swap the RE for a standard M4 and make a 4-5 weight buffer. Swapping the stock will only net you an increase equal to the increased length of the stock compared to a standard CAR stock. https://dl.dropboxusercontent.com/u/1702248/ColtMARSspecs.jpg Worked up this layover, it looks like I'm right on track with what Colt intended. The set back FCG is certainly the path of least resistance vs shortening the bolt, it also serves its intended propose by making the rifle more small hand friendly. It appears Colt never really figured out the firing pin retainer it's going to take some tweaking or further hammer modifications to keep the hammer from hitting the firing pin retainer. Quote HistoryQuoted:
If LOP is a real concern you can just swap the RE for a standard M4 and make a 4-5 weight buffer. Swapping the stock will only net you an increase equal to the increased length of the stock compared to a standard CAR stock. https://dl.dropboxusercontent.com/u/1702248/ColtMARSspecs.jpg Worked up this layover, it looks like I'm right on track with what Colt intended. The set back FCG is certainly the path of least resistance vs shortening the bolt, it also serves its intended propose by making the rifle more small hand friendly. It appears Colt never really figured out the firing pin retainer it's going to take some tweaking or further hammer modifications to keep the hammer from hitting the firing pin retainer. 
With continued attention to FIGS. 3-8, the modified receiver assembly 22A as, noted, has a reduced length as compared with the receiver assembly 22 of its predecessor firearm. A modified hammer 44A, viewing especially FIGS. 3, 4, and 5 includes a hammer face 92 having a first recess 94 with a base surface 96 intended to squarely impact a firing base 98 (see FIG. 7) of a modified firing pin 50A. In this regard, it is noted that a butt end 100 of the firing pin 50 of the known design (FIG. 2) has been eliminated in order to expose the firing base 98 of the modified firing pin. By reason of these modifications, the hammer 44A continues to be pivotably mounted on the axis of its predecessor hammer 44 and still be able to squarely address the firing pin 50A.
The modified hammer 44A is also formed with a second transversely extending recess 102. In the known bolt assembly 26 (FIG. 2), a retaining pin 104 mounted on the bolt carrier 48 extends across the path of the firing pin 50 and is engageable with the annular flange 64 to thereby define the range of movement of the firing pin. In the modified construction of the invention, the retaining pin 104 continues to be engageable with the flange 64 of the modified firing pin 50A to define the limit of rearward motion of the firing pin 50A relative to the bolt carrier 48. Because of the shortened construction of receiver assembly 22A, the second transversely extending recess 102 is provided to clearingly receive (FIG. 4) the retaining pin 104 when the hammer 44A is at the limit of its travel in the clockwise direction (FIGS. 3 and 4) with firing base surface 96 engaged with the firing base 98 of the firing pin 50A. The recess 102 thus prevents an interference between retaining pin 104 that would otherwise be a consequence of the shortening of receiver 22. I haven't had a chance to measure some real parts and play around but it looks like they just put a groove in the hammer to clear the retaining pin. (102 circled on the hammer). I'd think the FCG set back is the balance of space they couldn't get from putting a pocket in the hammer and cutting off the nub of the firing pin. So FCG set back distance would be (.550" - (Depth of Hammer Pocket + Length of FP cut off)). If they wanted to keep automatic fire without doing any more modification then where the trip part of the bolt carrier group rests will give you the location of the auto sear, which should back up the math of where the selector and the rest of the FCG sits. Then the end of the BCG would be cut flush to fit the receiver. |
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Posted: 4/10/2014 5:49:34 AM EDT
[#44]
Quoted:
https://dl.dropboxusercontent.com/u/30126941/MARS1.JPG What I've got so far, shortened the receivers and receiver extension, once I draw up a magazine I can figure out exactly how much the receivers need to be shortened, along with the exact BCG dimensions. Was browsing the patents for the MARS rifle and found this: when compared to the shortest variant of the M16 in official service, namely, an M4 -type carbine. In similar fashion, the length of the barrel has been reduced by 3.5 inches to 11.0 inches for the new barrel, the receiver assembly has been shortened by 0.550 inches to a new length of 7.25 inches and the receiver extension has been shortened by 1.3 inches to 5.9 inches. At the same time, it is desired to retain, to the maximum extent possible, the components of the earlier version of the firearm and their relative placement in order to assure interchangeability not only in product but also on the battlefield. |
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Posted: 4/10/2014 5:54:40 AM EDT
[#45]
Also, will retract what I said about thinking it's a carbine system.
Patent shows carbine length, words make it seems pistol length. I'll stick carbine (again) for now. The novel cartridge required "tuning" the gas system to insure proper function, that is, ejection and feeding at the lowest possible cyclic rate, as the gas port is much closer to the chamber. |
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Posted: 4/10/2014 6:39:52 AM EDT
[#46]
I guess I should of read the patent more closely.
I'll have everything but the magazine sorted out tonight then. I'm going to also rework the lower forging to to give a bit more clearance for the trigger near the pistol grip, I'm also thinking of moving the the magazine catch back to keep it's relationship to the FCG the same (the "small hands" thing). The patent shows a standard looking gas system albeit one with a huge gas port. |
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Posted: 4/10/2014 9:23:52 AM EDT
[#47]
Found another thread with a picture of a MARS mag...
Seems like there's got to be some change to the mag catch system on a MARS gun. Also of interest was a note about the mag: "Has a Colt Part number 62665 on a stainless follower." |
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Posted: 4/10/2014 9:36:21 AM EDT
[#48]
So to sum it up so far:
There's a good understanding of the FCG, Bolt, BCG, detailed technical data on how the 5.56x30mm is built, measurements of the smaller receiver, measurements of the smaller extension, and we have the barrel length. Does anyone have a guess whether it's .625 or .750 at the gas block? Anyone has any way to find more information on how the magazine latched up? I saw AR18 was mentioned. Anyone think of any other stoner prototypes it might've come from? The patent even states they tried to do the MARS on the cheap during tight budgets so there's got to be some solution... |
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Posted: 4/10/2014 9:53:28 AM EDT
[#49]
Quote HistoryQuoted:
So to sum it up so far: There's a good understanding of the FCG, Bolt, BCG, detailed technical data on how the 5.56x30mm is built, measurements of the smaller receiver, measurements of the smaller extension, and we have the barrel length. Does anyone have a guess whether it's .625 or .750 at the gas block? Anyone has any way to find more information on how the magazine latched up? I saw AR18 was mentioned. Anyone think of any other stoner prototypes it might've come from? The patent even states they tried to do the MARS on the cheap during tight budgets so there's got to be some solution... Prototype photos look like it's .625 at the gas block - possibly 11" or a little shorter - but still looks a little longer than a 10.5"... though that could be the unfamiliar barrel weight. ~Augee |
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Posted: 4/10/2014 10:08:26 AM EDT
[#50]
Quote HistoryQuoted:
Prototype photos look like it's .625 at the gas block - possibly 11" or a little shorter - but still looks a little longer than a 10.5"... though that could be the unfamiliar barrel weight. ~Augee Quote HistoryQuoted:
Quoted:
So to sum it up so far: There's a good understanding of the FCG, Bolt, BCG, detailed technical data on how the 5.56x30mm is built, measurements of the smaller receiver, measurements of the smaller extension, and we have the barrel length. Does anyone have a guess whether it's .625 or .750 at the gas block? Anyone has any way to find more information on how the magazine latched up? I saw AR18 was mentioned. Anyone think of any other stoner prototypes it might've come from? The patent even states they tried to do the MARS on the cheap during tight budgets so there's got to be some solution... Prototype photos look like it's .625 at the gas block - possibly 11" or a little shorter - but still looks a little longer than a 10.5"... though that could be the unfamiliar barrel weight. ~Augee Patent states the barrel is 11" long. My eyes tell me .625 but I want to say it makes perfect sense to be .750. See how this hits you... If I were a Colt engineer on a budget I'd go pull a carbine barrel blank from the production floor to tinker with for my PDW. Late 90's that'd be an M4 carbine. Here's a picture (http://img.photobucket.com/albums/v204/kenc3/DSCN0813.jpg) from someone who cut a M4 barrel to 11.3" or 11.5"ish length. Seems to me if you were to go with 11" you'd bypass the taper of the M4 cut and have exactly what we see on the MARS PDW, an 11" carbine barrel. |
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