Thoughts on the k31?

"I like the cartridge and think it was a better military design than the 30-06 for two reasons: It is shorter and the rim is thick. Both of these are advantages for automatic weapons, which would hardly been a consideration for the designers of the M1903 and the 30-06, but, in time, these two factors became primary reasons for going to the 7.62 Nato. If we had simply copied the 7.5 X 55 Swiss we could have avoided the conversion."
I built a STGW57, and can attest the cartridge works great in an autoloader. The other feature that isn't state enough is that GP11 is significantly lower pressure than 30-06 or 308, being a mere 45,500psi vs. 60,000psi for the other two. It's case volume is nearly identical to 30-06, however. The only real problem with the cartridge is that double-stack magazines for it are huge, though they require hardly any curve.

Supposedly, GP11 actually inspired the performance sought from 308 during its development. The Swiss have supposedly retired the GP11, but I don't honestly see how they could have, unless they are now using NATO ammo or have abandoned the concept of snipers or heavy machine gunners (and none of those things seem likely). I rather imagine there is just no need for the state to make the ammo, since the sporting usage of the round seems high enough to sustain the rounds existence both there and here (and apparently everywhere the Swiss have settled in numbers)

TCB
 
I think it's a cool, accurate rifle but the cost of shells are prety high for it. Still not a bad gun for all kinds of disciplines though, with an interesting history to boot.

All in all, I'd say if you want one, but it!
 
The other feature that isn't state enough is that GP11 is significantly lower pressure than 30-06 or 308, being a mere 45,500psi vs. 60,000psi for the other two.
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That is a very good point. Lower pressures are more desirable for a number of very good reasons. Higher pressures always cause more problems than they solve.

For example, I predict we shall be hearing more and more problems with the new lead free M855A1. Stoners rifle was designed around a 50,000 psia round. To keep ammunition manufacturer's happy, the Army bumped that up in the 60's, and now, they are bumping the pressures up to 58,000 psia. (a guess based on the attached article) The rifle lugs are still sized for a 50,000 psia load, so expect lots of failures to extract, lug cracks, and jamming.

Testing The Army’s M855A1 Standard Ball Cartridge

http://www.americanrifleman.org/articles/testing-army-m855a1-standard-ball-cartridge

In 1984, the USMC conducted a test comparing the Vietnam-era, 55-grain, M193 round to the then-new 62-grain, green-tipped M855, which had boosted chamber pressure from 50,000 p.s.i. to 53,000 p.s.i. Side-by-side, 6,000 rounds each were fired through M16A1s and M16A2s with the green-tip’s hotter load. While the M16A1s saw virtually no accuracy decline, the M16A2s saw their groups more than double in size—the sole variable was chamber pressure. And the new cartridge generates even greater pressure, perhaps 3,000 to 5,000 p.s.i.
 
The rifle lugs are still sized for a 50,000 psia load, so expect lots of failures to extract, lug cracks, and jamming.
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I honestly don't know if I'd go so far as to say all that, since the design does have a good bit of head room in its safety factor; but that said, it's doubtful the number of failures would go down from increasing the pressure. 60,000psi is supposed to be the abso-posi-lutely-ist you can push a brass case before the whole thing liquefies and blows out, so they really are knocking on heaven's door if the new round is getting that high. I agree that extraction will likely be the issue. Well, that, and loose primers getting lodged in the FCG/BCG and tying up guns at the most inopportune moments.

As far as accuracy, it's certainly true that the hottest loads seem to rarely if ever be the best ones, but tweaking the chamber pressure variable spreads the groups, perhaps one need merely tweak the bullet variables to dial them back in. I certainly hope we're not sacrificing accuracy --which is supposed to be the chief emphasis besides modularity in the new generation of rifles-- for the inconsequential-by-comparison goal of going green (I assume they'll be halving tank/MRAP fuel tanks and armor plate, next :rolleyes:).

I truly do find it troubling how much effort our military insists on putting into squeezing more blood from the Stoner turnip. It was originally designed with aerospace methods and practices in mind, and those by definition have a lot less headroom built into them than most; it's doing a set job with as little as you can. But when you subsequently demand more from the design, you start out much closer to the margin of what it can take than usual; we very rarely upgrade load ratings of aircraft components for this exact reason. They were designed to meet a certain requirement, but we can guarantee no more.

Especially when you compare how much the modern M4 has changed from the original M16, you do have to question the wisdom in how we've gotten this far by changing so little when it was a borderline design in the first place. History has shown we should at least consider resizing the bolt head a few mills larger so the lug-fracture phenomenon is non-existent, just like in practically every other design. Even .05" larger diameter would vastly improve the bolt strength, and as AR10's have shown, without noticeably changing the weapon size or weight (for that matter, why not use AR10 size bolts for everything?)

Back to the 7.5 Swiss, I really do think at this point it is the ultimate or pen-ultimate main-rifle cartridge. If you want a 30 caliber +150gr round that can work out to 1000 yards (or so) I'm not sure there's much else that is as efficient. All the various 303's, -06's, x54Rs, 7.5 Frenches, and even 8mm all kinda do the same thing, but all have major drawbacks (rim, length, rim/taper, too light, too big) that the Swiss seems to have optimized. The worst "sin" in the 7.5 is how wide the case head is; but this 1/16" or so increase allows the case to shorten a good 1/2" without losing capacity over -06 --a much more efficient geometry in terms of weapon and magazine size. 308 does a good job at this, but at the price of enormous bolt thrust and loss of bullet weight/case volume. Put it this way; I may be rechambering my 1902 Remington Rolling Block to 7.5mm from 7mm Mauser because the bolt thrust is surprisingly close to the original --I doubt any of the main battle rifle cartridges could say the same.

The big screw up by the Swiss was packaging all their ammo in 10 round crayon boxes, when every single last one of the guns that used 7.5x55 used 6 round-multiples (except the WA2000, possibly --no wait, Wikipedia says it had a 6 round mag, too :banghead:). The logistics of all the ammo packaging had to have been bad enough in a real war scenario, but to have the whole hot dogs/buns mismatch thing in the middle of it (and for 50+ years, no less) was just retarded. Not sure what the thinking was, there.

Be sure to load up on stripper clips, or find a way to make them yourself; the rifle is the most expensive bolt action ever fielded, the ammo the highest quality ever fielded, and the stripper clips are the best design I've ever used. The Swiss could have probably beaten the Germans and taken over Europe (and Russia) if they weren't so focused on banking and gadgets. I suppose one could say the same for the Czechs and Finns, minus the banking part :p

TCB
 
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I don't know if the boxed/clipped ammo could be considered "shooting themselves in the foot". the US issued a few million M1917s during the great war with 6 round mags and only issued 5 round clips. there's nothing stopping the guys from single feeding with the K31 is there?
 
I truly do find it troubling how much effort our military insists on putting into squeezing more blood from the Stoner turnip. It was originally designed with aerospace methods and practices in mind, and those by definition have a lot less headroom built into them than most; it's doing a set job with as little as you can. But when you subsequently demand more from the design, you start out much closer to the margin of what it can take than usual; we very rarely upgrade load ratings of aircraft components for this exact reason. They were designed to meet a certain requirement, but we can guarantee no more.
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The basic problem with the Army Ordnance Department is that they are primarily experts in government contracting and they have lost their core technical competency in firearm design. The Army had designers and lost them all when Springfield Armory was shut down in the 60’s. While there are Mechanical Engineers, they tend to be the low achievers who could not find an industry job, and Government pay reflects this. Government engineers are paid about 25% less than industry. You will run into EEO types running programs who are clearly incompetent, people promoted because they fit into socioeconomic categories. Government employees are “managers”, not “doers”: they don’t do design work. For one thing, Security would not let them install design software programs on Government computers for fear of “viruses”. Instead these “Technical Experts” are ultimately Technical Contract Experts, very knowledgeable about contract changes, CDRLs’, forms, Wide Area Flow, the color of money, the Economy Act, the Anti Deficiency Act (very well trained on that one!) but it turns out, they are basically clueless about firearm design, firearm design history, and the technical aspects of firearm design. When they need someone who can think, they hire Support Contractors, and it is Support Contractors who do all the real technical work, such as mechanical modeling. Remember the movie “Sand Pebbles”?. Government employees are the crew, sitting on their butts, not wanting to take the rice bowl away from the coolies doing the work.


Especially when you compare how much the modern M4 has changed from the original M16, you do have to question the wisdom in how we've gotten this far by changing so little when it was a borderline design in the first place. History has shown we should at least consider resizing the bolt head a few mills larger so the lug-fracture phenomenon is non-existent, just like in practically every other design. Even .05" larger diameter would vastly improve the bolt strength, and as AR10's have shown, without noticeably changing the weapon size or weight (for that matter, why not use AR10 size bolts for everything?)
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These guys are not changing anything ahead of time. They don’t fix things till they are broke and it has to be very broke for them to figure out they have a problem. This is due primarily to the lack of expertise within the management chain and the total inertia within the system. They don’t recognize problems until the tire tracks are on the back of their suits. Any one remember all the up armoring of HMMWV's? The Army was loading HMMWV’s around 8,000 pounds over gross and only then did they figure out they had a ball joint problem?

The Army bought the M16 , they did not design it, they don’t know the design margins, and don’t know how to come up with the design margins. I can assure you after reviewing enough DTIC reports, around the middle 70's it becomes apparent that the Government was sliding down the stupid slope at an increasing rapid pace. The technical quality of the reports and the work really show a dummying down over time. Ever read the book “Canticle for Leibowitz”? Remember the Blessed Blueprint, the Sacred Shopping List, and the Holy Fall out Shelter? The current crew is as clueless about firearm technical details as those fictional characters were about technology before the fictional nuclear holocaust.
 
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I have a K-11 (which the model before the K31) and just love it, shoots accurate as hell and a recoil that is very manageable. Here's mine:

osv7.jpg

All matching numbers (including bayo)

62cj.jpg


With pig-sticker:
p5w2.jpg
 
"As mentioned above, dont cycle with your head on the stock. Especially if you are left handed..."
If you keep telling them, they'll never learn :D. FWIW, my posture is such that I have no such issues; if your cheek bones prefer you to lean forward vs. to the side, you won't be so lucky.

TCB
 
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