DI cant be that bad
- Thread starter trg42wraglefragle
- Start date
X2 My HK91 could go black in ten rounds, surplus, or straightup American made ammo made no difference at all.
Let's add to the understanding that DI is a PISTON gun, too. It's right there if the ignorant will bother to look - gas is ported into the carrier and expands in the gas cylinder - pushing against the gas rings that seal on the bolt tail. A piston gun doesn't need a flat head to pressurize a cylinder.
As that gas pressurizes the cylinder, it begins to move the carrier backward, camming the bolt open. The gas rings uncover the ports ON THE SIDE OF THE CARRIER AND EXHAUST OUT THE EJECTION PORT. Not into the action.
Let's look at another myth - dirty actions jam. Mike Pannone fired 2,500 rounds in a completely dry M4 milspec semi auto before experiencing malfunctions. Point being, that's about 10 basic loads of ammo for the soldier. About 7 days of intense combat - and every soldier would have wiped down and lubed his weapon daily in the lulls in combat, all part of 50% on watch between attacks. It's the combat ignorant who have no clue that assume gas residue would be any problem at all - which it isn't. Even for the Bundeswehr when they used the HK, one of the dirtiest guns I ever owned.
Then there's the argument about temperatures - which thermographic measurement has shown to be higher on a "piston" gun out on the barrel than the DI gun in the carrier - about 350 degrees higher. DI? You can fire a mag, shotgun it, and disassemble the carrier barehanded. Try that with a piston gun - disassemble the piston, expect serious burns.
Nothing much wrong with piston guns or DI, except neither works well as a bandaid application for the other. Piston guns almost always used bolts on rails to control carrier tilt, DI guns have force vectors that negate carrier tilt completely - the propulsion is nearly 100% coaxial. Genuine gun designers don't make mistakes like that, but gun merchandisers sure can sell them to the American shooter.
It's not a very good statement of what some of them think of us.
Let's add to the understanding that DI is a PISTON gun, too. It's right there if the ignorant will bother to look - gas is ported into the carrier and expands in the gas cylinder - pushing against the gas rings that seal on the bolt tail. A piston gun doesn't need a flat head to pressurize a cylinder.
As that gas pressurizes the cylinder, it begins to move the carrier backward, camming the bolt open. The gas rings uncover the ports ON THE SIDE OF THE CARRIER AND EXHAUST OUT THE EJECTION PORT. Not into the action.
Let's look at another myth - dirty actions jam. Mike Pannone fired 2,500 rounds in a completely dry M4 milspec semi auto before experiencing malfunctions. Point being, that's about 10 basic loads of ammo for the soldier. About 7 days of intense combat - and every soldier would have wiped down and lubed his weapon daily in the lulls in combat, all part of 50% on watch between attacks. It's the combat ignorant who have no clue that assume gas residue would be any problem at all - which it isn't. Even for the Bundeswehr when they used the HK, one of the dirtiest guns I ever owned.
Then there's the argument about temperatures - which thermographic measurement has shown to be higher on a "piston" gun out on the barrel than the DI gun in the carrier - about 350 degrees higher. DI? You can fire a mag, shotgun it, and disassemble the carrier barehanded. Try that with a piston gun - disassemble the piston, expect serious burns.
Nothing much wrong with piston guns or DI, except neither works well as a bandaid application for the other. Piston guns almost always used bolts on rails to control carrier tilt, DI guns have force vectors that negate carrier tilt completely - the propulsion is nearly 100% coaxial. Genuine gun designers don't make mistakes like that, but gun merchandisers sure can sell them to the American shooter.
It's not a very good statement of what some of them think of us.
I agree with you that most rifles have to get really dirty to jam, that including DI weapons. As for the HK, the roller delayed blowback tends to cycle when there's still a lot of pressure in the barrel, blowing (hot, dirty) gases back into the receiver and in the face of the left-hand user -.- (I'm cross dominant)
With the AR platforms I experienced the same issues, so I'd still say that a lot of gas is in the receiver, certainly more then with any gas piston designs. (This issue didn't completely disappear with the deflector, but it got better at least)
They don't have the same environmental issues, the Bundeswehr had to fix material faults on a 3000 rifles in Afghanistan. Most piston rifles seem to do fine, though controllability in automatic fire may be one of it's weak points. That being said, who uses full-auto anyway?
With the AR platforms I experienced the same issues, so I'd still say that a lot of gas is in the receiver, certainly more then with any gas piston designs. (This issue didn't completely disappear with the deflector, but it got better at least)
They don't have the same environmental issues, the Bundeswehr had to fix material faults on a 3000 rifles in Afghanistan. Most piston rifles seem to do fine, though controllability in automatic fire may be one of it's weak points. That being said, who uses full-auto anyway?
madcratebuilder
New member
tirod said:
+1000
I read about how dirty peoples DI rifles get, odds are it would be as dirty with a piston system. It's from the cheap ammo used in most cases.
You are kidding aren’t you: Ever hear of Vietnam, Grenada, Somalia, Gulf War’s I & II, Afghan, to name a few?
I have a bit of experience with both, DI’s and Piston guns. Mainly ARs (M16s) and M14/M1As. I went to basic & AIT in 1966 with the M14. Used M14s when I was in my short stay in the 82nd ABN Div. prior to going to SE Asia when I was given a M16A1.
Without getting into “War Stories”, I’ll say I shot the M16 quite a bit as an Infantryman with the 2/502 Inf, 101st Abn Div. To be honest I didn’t take the time to “count” the rounds I’ve fired, we carried a basic load of 460 rounds and it didn’t last long, we had the advantage of Huey’s kicking out cases of ammo as the situation went on. When we came out of the field, we expended what ammo we hand and re-supplied with fresh ammo, rather quickly (called it a Mad Minute). I’ve seen M-60s burn up a couple times, if you get on the trigger, shooting 100 round burst, it won’t last long at all. They’ll quit you in as little as 2-300 rounds (we didn’t carry extra barrels). It’s a piston gun.
The piston on the ’60 needs cleaned quite regularly. Not so the M16s. On a M16 you squirt a dab of oil on the bolt; it will keep going along time. Pistons have to be used dry so they will cause problems, Heat expands metal, without lubricant they will seize on you.
M14/M1As are issued with a wrench to take out the gas plug, allowing you to get to the piston. The piston is hollow inside and that fills up with carbon. You have a tool with a couple of drill bits used to clean the inside of the piston, if you don’t, it screws up. Now I’ve not fired the M14 on full auto a whole lot, not enough to make it quit, reason being it’s un-controllable on full auto.
Fast forward a few years. I was running a sniper school for the National Guard when I was approached by a RA Lt. requesting help disposing of some ammo. If he didn’t use it he would lose his ammo allocation for the next years. I agreed and he deposited 30K rounds of M193. To get rid of the ammo I sent one of my students (a young NCO named Tommy Kaktus, if you Google the name you‘ll see he is the present AG of the AK NG), to our unit to draw 10 M16a1s. I gave the class the day off to “dispose” of the ammo. They did, they turned the gas tubes on these guns red, and I believe burned up some barrels, but the ‘16s didn’t quit on us. Yeah, again we dabbed some oil on the bolt but that was it.
Don’t get me wrong, I love the M14/M1As, I’ve been shooting my M1A in competition since 1977. It’s never given me a problem but its not full auto, and I’ve been known to clean it, (including the piston). I’ve cleaned it a lot more then I clean my AR White Oak Service Rifle I use now.
I’m no scientist, but I know metal expands when it gets hot. Shooting makes metal get hot. The more moving parts you have, the more friction you’re gonna get. Friction need lubricant or it’s gonna seize. When you need to put a lot of rounds down range, you can squirt oil on to the bolt of an AR, but you can’t oil a piston.
It’s hard to say what a piston AR would do in Combat because they don’t have the usage that the DI ARs do. Closest we can come is the piston driven M-60. To be honest I don’t have much experience with the Piston ARs, I shoot service rifle, A10s aren’t allowed in Service Rifle matches, (NRA has started to allow them, but the CMP doesn’t).
The SA-80 is also a piston design based off of the AR-18. Ain't no magic in pistons.
The entire design of the AR-15 upper is based on DI operation: front sight, tube, bolt, carrier, and upper receiver. To go piston you ought to re-engineer the whole upper receiver assembly, not slap some sort of piston parts kit above the barrel.
Bartholomew Roberts
Moderator
Speaking of the SA80 and DI taking an unfair share of the blame for reliability issues in the M16, can anyone name one common part the SA80 and M16 share?
DI is fine for quality 5.56 ammo - arguably better than pistons because of some weight reduction and overall less weight moving back and forth.
I suppose that it doesn't hurt to make a gun designed to shoot 5.56 more like .380 rifles. In that same vein, why not make the receiver out of milled / forged steel? it will be more durable. Then make sure you add an ultra heavy barrel - that heavy barrel will hold up better to sustained full-auto fire. While you are at it, you really should replace those flimsy magazines with solid steel ones, like the AK.....better yet add a belt feed mechanism to it.
The point I'm making is that the AR was designed for clean factory 5.56 ammo. If you want to shoot Wolf, Chinese surplus, or .308 in full-auto, then go with a something that has a piston and not DI.
I suppose that it doesn't hurt to make a gun designed to shoot 5.56 more like .380 rifles. In that same vein, why not make the receiver out of milled / forged steel? it will be more durable. Then make sure you add an ultra heavy barrel - that heavy barrel will hold up better to sustained full-auto fire. While you are at it, you really should replace those flimsy magazines with solid steel ones, like the AK.....better yet add a belt feed mechanism to it.
The point I'm making is that the AR was designed for clean factory 5.56 ammo. If you want to shoot Wolf, Chinese surplus, or .308 in full-auto, then go with a something that has a piston and not DI.
Magazine.
Seriously, though, the SA80 is basically an AR18 derivative, and if I remember correctly, the AR18 had to be carefully designed to avoid infringing on the patents utilized in the M16.
That being said, there are some very similar looking parts, such as the bolt head and firing pin. I wonder just how different they really are.