Jeremy2171
Member
Glad you are ok...but that example isn't really relevant here other than to say inspect your rifle before firing.
Warning from CMP
- Thread starter hso
- Start date
- Status
Garandimal
member
No, wait...
Ha!
Want more proof?
Watch it again.
"Because I Said So!"
- No one that understands Physics, ever -
GR
Jeremy2171
Member
Still waiting on yours...since you don't understand physics..
Garandimal
member
This - is Physics.
The M1 Garand and Commercial Ammunition
The M1 Garand Gas Cycle
To interpret the data provided, we will need to define the gas cycle. The gas cycle on the M1 Garand can be broken up into several distinct stages. Each stage affects how the pressure in the gas cylinder is changing. The Gas cylinder and operating rod assembly on the M1 are lossy. That is to say, gas is always flowing past the gas piston when the pressure in the gas cylinder is greater than the pressure outside of the gas cylinder. The following stages will deal with gas flowing into the gas cylinder. A graph of a typical gas cycle when using M2 ball (HXP) is shown in Figure 2.
Stage 0: The first stage consists of the bullet traveling up the barrel, compressing the air in front of it. The bullet moves up the barrel faster than the gas can escape from it. This causes the pressure to rises in the barrel. This stage ends when the bullet has moved up the barrel and is blocking the gas port. The compressive force of the bullet traveling up the barrel combined with gas blow-by will pressurize the gas cylinder to approximately 10psi. This initial pressure transient is what we use to start the data acquisition process.
Stage 1: This stage is defined as the bullet having moved forward of the gas port, but is still in the barrel. This stage is responsible for the highest rate of change of pressure over time (dp/dt). However, it is also the shortest of the stages, lasting approximately 46 microseconds.
Stage 2: The bulk of the gas transfer will occur during this stage. The bullet has left the barrel and the barrel is now rapidly depressurizing. However, the pressure in the barrel is still greater than that in the gas cylinder; therefore, gas continues to flow from the barrel into the gas cylinder.
Stage 3: Pressure equalization has occurred in this stage. It marks the point of peak pressure in the gas cylinder. From this point forward, gas will be flowing from the gas cylinder back into the barrel. Gas is also flowing past the piston and exiting the gas cylinder as previously mentioned.
Stage 4: The gas cylinder is depressurizing. This stage normally lasts approximately three milliseconds.
Stage 5: The M1 Gas cycle is now complete. The gas cylinder has depressurized. The operating rod has reached its peak momentum. At this point the operating rod has moved rearward approximately 3/8 of an inch. The operating rod will coast rearward using the kinetic energy it gained to perform functions such as: unlocking the bolt, extracting the empty cartridge case, cocking the hammer, and compressing the operating rod spring.
...and one of these:
Ported Gas Plug
... if you plan to shoot modern, high power hunting ammo out of it.
GR
Jeremy2171
Member
More cut and paste drivel that ignores the physics of the oprod interaction with with bolt lug. You know...where the actual bending comes from....
Oprods don't " bend" while supported in a steel tube and floating under spring pressure.
Address those physics or kindly stop the spam from your employer
Garandimal
member
Where is the mass on the Op-rod?
And where does the Op-rod bend in relation to it?
And by what force?
Speaking of bolt lugs...
You should find this enlightening.
Hatcher's Notebook (P. 206)
...In spite of the fact that there were over four million Garand M1
rifles made during World War II, there has never yet been a case
reported of a blown receiver or bolt on this rifle. It is true that as
a result of firing grenades, the rear wall where the bole is arrested
in its backward stroke has cracked out in a few instances, but there
has never at this writing, (June, 1947) been a case reported where
the receiver has failed at the front end where the locking is
accomplished.
In trying to determine the ultimate strength of the gun, Mr.
Garand built up progressively higher proof loads in increments
of 5000 pounds pressure, from the regular proof load of 70,000 lbs.
to the extreme figure of 120,000 lbs, per square inch. [em]
At this latter figure, cracked left lugs on the bolt began to be
encountered. A gun in which the bolt had the left lug cracked by
one of these excessive high pressure overloads was then fired an
endurance test of 5000 rounds of service ammunition, using the
cracked bolt, which showed no further deterioration. The U. S. M1
Rifle thus has perhaps the strongest action of any military shoulder
rifle in existence at this time.
GR
Last edited by a moderator:
Jeremy2171
Member
Lol now you are spamming Hatcher..lol
You still haven't addresses addressed the physics in relation to the oprod cam and unlocking of the bolt.
You still haven't addresses addressed the physics in relation to the oprod cam and unlocking of the bolt.
Garandimal
member
Where is the mass on the Op-rod?
And where does the Op-rod bend in relation to it?
And by what force?
GR
Last edited by a moderator:
Jeremy2171
Member
Please tell us oh annoying one....Where is the mass on the Op-rod?
And where does the Op-rod bend in relation to it?
And by what force?
Enjoy your crayons.
GR
MachIVshooter
Member
It is relevant, because it's an example of pretty much a best case scenario when you have a failure with a full power rifle round. The very same type of thing can happen with excessive headspace, which can result from overpressure loads hammering lugs & recesses, or just from improper assembly by Billy Bob who rebuilt or put together from parts some old military rifle. An out of battery firing would be similar at best, probably worse. A bolt or receiver failure would likely be worse. Much worse.
Very few people are going to closely inspect the critical components of these old rifles, much less have parts analyzed with XRF to ascertain alloy type, Rockwell tested for hardness, and magnafluxed to ensure integrity. On a 70-100+ year old gun of unknown history and possibly questionable manufacturing techniques, one should be cautious & conservative if the above material analysis is not done.
I'm not going to argue with you, no point. My posts aren't to convince you of anything, but to provide for other readers the perspective and caveats of someone who makes guns & gun parts for a living, and who has had failures that caused injury, knows all too well the stakes and that one shouldn't be cavalier about containing an explosion right in front of your face.
Swampman
Old Fart
Even Wikipedia won't accept original research and you expect people to risk damaging their rifles on the basis of yours?
Can you come up with something from a REPUTABLE source (i.e. not you) saying that current 220 grain factory ammo is OK for use in a Garand?
Jeremy2171
Member
No it's not relevant...other than to point out you fired a rifle that was not inspected and you fired a round it wasn't chambered for. You are lucky...I'm glad..but it was an easily avoidable mistake.
No..excess headspace doesn't cause things like what happened in your pics. OOB is different and usually very dangerous for firearm AND shooter.
No need to argue...your firing a rifle in an unknown chambering is warning enough.
Jeremy2171
Member
Sorry you don't like facts with supporting data. Can you come up with someone with the data that says firing it IS dangerous in a garand?
Let me comment that the rifle was built to shoot the 172-174 FMJBT bullet, and it did shoot a whole bunch of 148-150 FMJ's. There is no doubt the locking lugs and receiver seats will stand the load of a 50,000 psia cartridge, regardless of the bullet on top. The thing why no one ever fired bullets heavier than 175 SMK's is that the gas system will be over accelerated, and that will cause malfunctions. It is also hard on the rifle.
I purchased one of those vented gas cylinder lock screws and went out developed some heavy bullet loads, either 190 SMK's or 200 gr SMK's and IMR 4350. I played with the vent screws and found one that vented enough that the operating rod just latched. Should be good, right?
When I finally shot the thing slow fire prone in competition, accuracy was not as good as the regular bullets (168's at the time) and my rifle was bucking and slammed hard. That heavy bullet load was hard on the rifle and I did not want to bust loose the bedding, or anything else for that matter. So I went back to the regular bullets, which were mostly 168's and every thing was just fine.
If you don't have an adjustable gas system, you have to load the heavy bullets so far down, velocity wise, that it does not make sense to use them.
The primary damage to the operating rod that I saw was bending of the operating rod. When it rubbed against the stock at the upper ferrule accuracy goes to hell in a hand basket. And then, you have to completely disassemble the rifle, play with bending it back in the right direction, which given the three dimensionality of the operating rods, and all the bends and angles, takes a lot of thought in puzzling it out. I am spatially challenged, so it takes me time to figure it out.
I recommend use the ammunition that the rifle was designed to use, or reload and copy the bullet weights and velocities of the ammunition the rifle was issued with.
And, God save us all from rifles that some dork has reamed the chamber to a different cartridge, but did not stamp the barrel with the new cartridge designation. I do not regularly pour cerrosafe into a chamber, because I assume I am not dealing with a bobbie trap. Maybe I am too trusting. Guess I am lucky.
Anyone remember the 6.5 Arisaka that a home gunsmith rechambered with a 30-06 reamer? The NRA had an article on the thing in the 1950's. The home gunsmith assumed he had the 7.7 Arisaka, but he had the 6.5. He also ground the reamer pilot down, because the front of the reamer was 30 caliber, and was too large for a .264 bore. He shot a few rounds and too it to a real gunsmith because the rifle kicked too much. Then the story eventually made it to the NRA. Thirty caliber bullets fired in that rifle lengthened considerably. Everyone was amazed the rifle had not blown up.
Jeremy2171
Member
You mean 50,000 CUP not PSI there is a difference.
Over accelerated?
Which rifle below is shooting the garand safe ammo and which one is shooting Fed 220s?
I mean 50,000 psia. At the time the Garand was designed, CUP was assumed to be PSIA. They did not know that cartridges pressure tested at 50,000 CUP were higher pressure. So the structure of the rifle was designed to 50,000 psia, and because of powder technology advancements, issue ammunition was in the lower 40 kpsia.
Hey, go shoot your rifle with any load, any powder, any bullet you want. And shoot it a lot. I have to fix, repair my rifles. If my rifles loose their tune following your advice, you going to pay to fix them? I really doubt it. If you don't have any skin in the game, then don't attempt to give me any advice based on your opinions, or the wisdom of you tube.
Jeremy2171
Member
No opinions here...just facts.
Actual milsurp ammo at the time was mid 40k CUP to 50k CUP...FYI.
Garandimal
member
Op-rod speed - is a fraud - perpetrated by those ignorant of Physics.
"Garand Safe" ammo - produces Port Pressures in the M1 rifle w/in spec.
That's all.
Everything else - is religion.
The Church of the Speeding Op-rod.
GR
Jeremy2171
Member
If only you understood physics.....
Garandimal
member
More worthless gibberish from the Speeding Op-rod Druid.
Where is the mass on the Op-rod?
And where does the Op-rod bend in relation to it?
And by what force?
GR
Last edited by a moderator:
MachIVshooter
Member
Who said it wasn't inspected? Not I.
Chamber casting is not a normal part of used gun inspection unless there is a reason to believe it's no longer chambered as marked. Even a no-go gauge isn't bothered with by most unless they have a reason, like badly stretched cases or head separations after firing. There may be someone out there anal retentive enough to cast chambers in every used gun they buy, but I've never met or even heard of such an overly fastidious individual. I doubt you can honestly claim that you've never put rounds through a used gun you bought without verifying chamber dimensions.
And yes, excessive headspace can absolutely cause dangerous failures that send debris or gun parts into the shooter. Blown cases are one possibility, and it can also allow the case to accelerate into the bolt, greatly magnifying the forces acting on it. You should know this, given the level of expertise you're implying.
Jeremy2171
Member
Look you loaded a case that didn't properly fit the chamber... sorry about that.
And no excess headspace doesn't do what happened in your pic. THAT was improper cartridge/chamber fit. Excess headspace blows the shoulder forward "sometimes" causing incipient case head failure. Its really not as dangerous as you make it sound. I've shot brass that grew almost .019 in a chamber that was 2 thou over FIELD reject...zero issues and brass was intact.
MachIVshooter
Member
The very definition of excessive headspace is improper cartridge/chamber fit.
The safety vent in the receiver of many military rifles is there for a reason, and it's not because they just felt like poking an extra hole in it.
Your weapons and loads are yours to do with as you please, and I don't have a problem with people telling of their exceeding safety margins with good fortune, either, as long as they're clear on the fact that they did something which could end badly. @Clark is a perfect example of one who has pushed (and often exceeded) the limits of case and firearm design. But he knows what he's doing and acknowledges the risks when he posts about it. I will always take issue with and call out people stating that it's safe to exceed design parameters or that there's no risk in using weapons with problems like excessive headspace. THR posts come up frequently in search results, and people seeking to do something questionable are often predisposed to accepting answers they want prime facie. Ergo, the responsible thing to do, the THR way, is to always acknowledge in discussing such things that they are accompanied by very real risks to the user and bystanders.
Well said @MachIVshooter
Jeremy2171
Member
No..thats not the definition of headsapce at...
Headspace is the distance from the bolt face to a datum point on the shoulder of the chamber. Or to the mouth of the chamber in straight walls or from bolt face to breech face in the case of rimmed cartridges. NOTHING about headspace is about how the case fits "radially"...ONLY the "length".
Right its for case head failures...not sure your point?
I never said shoot a firearm outside of the design parameters.
What I have said is that excess headspace is not as dangerous as you make it out to be. YOUR case failure had nothing to do with headspace....it was OPERATOR ERROR loading a rifle with a cartridges it wasn't chambered for.
So you presented a perfect example of if you aren't sure of what you are loading/shooting...don't do it and have it checked by competent persons.
- Status
