Strange ideas in gun designing

The contemporary discussions never specifically said "screw those .22 TCM guys" but I always thought tangentially approaches it by claiming the 9mm case is not big enough, so theirs is based on a 10 mm. 

Which is plausible enough, but there are not as many 10mm guns by a long shot so even if that extra case helps (and the MV seems to bear it out) it makes it that much less a drop-in for many. Not gonna get simple BOZ uppers for your AR, for example, since new bolt. Etc. 

The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life. – Theodore Roosevelt

 

Joined: 19NOV2004   Location: Mission, Kansas

Trajan Aurelius posted:

No photo description available.

I don't know what the hell this is but I want one.  Source document says homemade 12 gauge.

That buttstock looks... uncomfortable.

Tankersteve

In Yorktown, VA.          Joined August 2008

Gov't Civilian, after retiring from active duty in 2015. 

 

'One's own open sore never smells.'  - Haitian proverb

tankersteve posted:
Trajan Aurelius posted:

No photo description available.

I don't know what the hell this is but I want one.  Source document says homemade 12 gauge.

That buttstock looks... uncomfortable.

Tankersteve

It looks like a cross between a Thumper (M79) and a "street sweeper".  It also looks like something someone cooked up in their garage.  No, it doesn't look comfortable, but I still want one anyways...>LOL


If it's a Pain in the Ass....you're doing it WRONG

I don't make policy, only suggestions, take them as such.

 

Joined: 8/5/05    Location: 20 miles west of Gettysburg, PA

 

 

I've seen that "shotgun" show up on other forums. The story is it was made for a comic convention for someone dressed up from the Warhammer 40,000 universe. So not a real shotgun (actually based of the grenade launcher from the tabletop game) but certainly true to form for that sci-fi universe.

Gaunts Ghosts is good intro book series to the 40k Universe or Luetin09 on the YouTube for explanation to the lore if anyone is so inclined.

---------------------------------- 'My lot in life is to serve, to the best of my ability. To know my life was not a waste, that in the end I can look back from the gates and know I did my best and that it was enough"

I never understood the angle was to slow the bolt and am not sure I believe it even now. Mechanism seems sketchy for this; we don't normally see accounting for drag on guide rails as a way to reduce bolt velocity otherwise so... ??? 

It is just to get the bore inline with the web of the pistol grip for no muzzle rise, and shorten the gun. Also some vector physics; it's moving up and down as well as forward/back so can kick the gun down if you design it as such. 

Previously fielded in the MAS38. Maybe others? 

Jatimatic patent drawing

 

The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life. – Theodore Roosevelt

 

Joined: 19NOV2004   Location: Mission, Kansas

MrMurphy posted:

 

Most military SMGs have done well, and make sense, i.e Thompson, Uzi,  MP5, etc. Among the machine pistol crowd you get some more unusual stuff even today.. the ones that blur the lines have always made me scratch my head. 

 

technically the Thompson works in spite of it's designer's best efforts. The blish principle the gun was originally designed around turned out not to be a thing.

shoobe01 posted:

I never understood the angle was to slow the bolt and am not sure I believe it even now. Mechanism seems sketchy for this; we don't normally see accounting for drag on guide rails as a way to reduce bolt velocity otherwise so... ??? 

Without studying the issue at all, as well as being sleepy and full of lasagna, I'll offer the following theory of the design:

Any drag present isn't necessarily part of the theoretical workings. Imagine a nonsensical, extreme example where the bolt movement is nearly perpendicular to the bore...10 degrees shy of perpendicular. Whatever...number doesn't matter. It's just for a mental picture. Now, replace the recoil force vector with the sum of two vectors: one normal to the bolt axis and one along the bolt axis. The component of the recoil vector that acts in line with the bolt axis is pretty small. F=ma applies, as usual. A slick-as-snot action doesn't matter.

Of course, friction would be there at some level. As the bolt axis deviates more from the bore axis, the force vector pushing the bolt against its guiding surfaces grows. More friction, but I'd be surprised if the small increase in friction at small angles is something the designer really based the design on.

It would be interesting to build a simple spreadsheet to play with the angle and friction numbers. Or...the numbers might prove this theory of operation to be an urban legend. Perhaps, at small angles, the difference in timing is small enough that the vector shit is lost in the variability of friction. The real reason could be the lowered bore axis/ergonomics thing...or something else entirely.

 

Patent language is freaking impossible to read, so if anyone else can slog through it, this may help: 

https://patents.google.com/patent/US4569270A/en

Abstract
 
The invention concerns an automatic, mass-obturated hand firearm comprising a body (1) with handle (2), a barrel (3) joined to the body, a breech block (4) with guide (5) constituted by the body and with cocking and firing mechanism (7), the guide of the breech block ascending rearward so that the rearward path of motion of the breech block deviates upward from the center-line (8) of the barrel. The purpose is to eliminate the problem of automatic hand firearms that during shooting the barrel tends to rise upwards.
 
As taught by the invention, when the breech block (4) is in its forward position its center of gravity (9) is located forward of the handle (2). The breech block (4) is preferably disposed to have its major part forward of the rear end (10) of the barrel (3). Furthermore, the center of gravity (9) of the breech block (4) is preferably located forward of the rear end (10) of the barrel (3). The guide (5) of the breech block (4) forms a preferably obliquely forward and downward inclined surface, against which the breech block rests so that when the rearward directed recoil force acts on the breech block this plug moves rearward and the surface of the breech block hits against the surface of the guide, producing on the body (1) a moment turning downward the muzzle of the barrel (3).
 

Since, I am pretty sure you cannot hide anything in a patent. Not just the shape, but the reason for and results of operation of that machine have to be disclosed. So, probably as good as we'll ever get into the mind of the designers. 

Of course, the French famously keep everything arms-related secret, so they presumably killed the designer of the MAS 38 after he was done. We won't get much from that 

The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life. – Theodore Roosevelt

 

Joined: 19NOV2004   Location: Mission, Kansas

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It sure seems like a reduction in muzzle rise is the reason. I didn't read all of the patent, but I understand their intent to have a bolt with some mass really far out toward the muzzle and to push it upward with each shot. Equal and opposite reactions courtesy of Sir Isaac N.

 

 

Often the strangest stuff I find on a firearm while investigating is that simply I dunno what that part is. Sometimes, it is something lost to history, and not there now. 

This video had some stuff on the Lee Enfield I did not know. Or, at least, I knew in principle but seeing a real gun on video is different from reading or a diagram

It's a commercial version of the long Lee rifle, mostly for back in the day when officers were gentlemen, so you didn't get issued stuff, but bought nice versions. So, not being issue: never updated. When you find one, it's a time machine. Neat. 

I had an SMLE III* with the loop for the mag chain. Never knew what it was for until now. 

 

I am also reminded how much it is important to document stuff. Multi-part interview with someone at FN on the MAG58 a few years back, and one question to them was what is this funny little notch on the side of the gas block.

Answer: We have no idea. Reason is lost to the mists of time. BUT, so many of these are sold, for so long, to so many orgs, who use it in so many ways, they dare not remove it, even though it would save them (and their purchasers) a couple bucks. What if it has some very specific need? Or, it has been incidentally used for indexing to a mount or something, then your army buys new guns and... they don't work with the old gear. They have enough ethics they don't want to do that to any of their customers, who really need these things to work. 

The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life. – Theodore Roosevelt

 

Joined: 19NOV2004   Location: Mission, Kansas

shoobe01 posted:

Of course, the French famously keep everything arms-related secret, so they presumably killed the designer of the MAS 38 after he was done. We won't get much from that 

Hence the lack of good refernce material on French small arms.

Did you know they had an assault rifle program pre WW2?

I think I knew this, but have seen only tiny bits and pieces. 

I have Proud Promise on the bookshelf in the other room even. But even that sort of pretty deep research is so full of holes from their secrecy. 

ETA: Guess I need to read that again. Been too long. Just flipped through the relevant section for a minute while ostensibly watching the toddler for HH6 and there are some cool things MAS40 with the 20 round mag would have been amazing. Wish I had that in the basement instead of my (maybe-working-now) MAS49/56. 

The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life. – Theodore Roosevelt

 

Joined: 19NOV2004   Location: Mission, Kansas

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