Best Semi-Auto 30-06?

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I beginning to think you are some kind of shill for GG products...

I have supported my claim on pg 4 and pg 6...maybe you should do some more research because LC66 ammo does not reach 2800fps..its barely 2600. It doesn't have 50grn of I4895 in it either.

FYI 50grn of 4895 is more like 2910fps from a garand I should know...I chronyed that load last week....

More ignorant gibberish.

You are a menace to facts and the truth.


First, Read this:

Testing Hardware

The most useful data for this investigation is obtained by measuring the actual gas pressure in the gas cylinder, rather than at the barrel gas port. The gas cylinder pressure is easier to obtain than measuring the barrel port pressure. Measuring the pressure in the gas cylinder also saves us the effort of trying to model the gas transfer into the gas cylinder. I will discuss why the modeling of the gas transfer is challenging later in the article.

The pressure pulse in the gas cylinder is very short, approximately four milliseconds. A high-speed pressure transducer was required for the test along with all the associated amplifiers, computers, and data acquisition systems. The transducer also needed to be able to survive in a high temperature environment. A suitable pressure sensor was chosen and purchased for the test. Two custom gas screws where machined that would house the pressure transducer. The first gas screw would act like a standard GI gas screw; the second emulated the port in the ported gas screw.

The rifle used for the test was a 2.5M range Springfield Armory Garand purchased from the CMP. The rifle had a new criterion barrel installed. All of the gas cylinder and operating rod components where inspected, measured and verified to be in spec. The barrel gas port was inspected and verified to also be in spec. A new USGI spec operating rod spring was installed and the rifle was properly lubricated. Figure 1 shows the sensor installed in the rifle.

Figure1_sm.jpg


The Effect of Port Pressure and Bullet Velocity on Peak Pressures


As mentioned in the introduction, the modeling of gas flowing from the barrel into the gas cylinder is very difficult. This is because the modeling of the flow of gas through the gas port has several variables that are not easily determined. The flow of gas from the barrel to the gas cylinder is choked through the barrel port and is not linear. For this reason, we cannot use barrel pressure alone as an indication of the peak pressure seen in the gas cylinder.

Bullet velocity plays an important role in determining the final peak pressure seen in the gas cylinder. As bullet velocity increases, the time to transfer gas into the gas cylinder decreases. This factor is often overlooked and under appreciated. The time spent in Stage 1 decreases as bullet velocity increases. This effect moderates the possible peak pressures. For example, if two bullets are fired and each reach the gas port with the same barrel pressure but different velocities, the slower bullet will produce higher peak pressures in the gas cylinder.

M2 Ball -- Our Benchmark for Gas Cylinder Pressures

We chose M2 Ball to be our benchmark for what a safe gas cycle should look like. This is reasonable since the M1 Garand in its current configuration is designed to use M2 ball ammunition. The ported gas screw will prevent pressures from exceeding this base line when shooting other types of ammunition.

Our initial pressure testing showed that the pressure curve varied significantly between different years of production and manufacturers. To be safe, we choose the lowest peak pressure measured as the value that the ported gas screw should never exceed when using commercial ammunition. Figure 3 below shows one pressure curve and the peak pressures measured from several different years of M2 ball ammunition. For historic reasons we also tested M1 ball ammunition and included the results in the graph. The Army technical manual [TM 43-0001-27] describes M2 ball ammunition as being loaded with 50gr of IMR4895. For reference, this load is also included in the figure.


Army technical manual [TM 43-0001-27]:

TM-43-0001-27.png

(The Army technical manual [TM 43-0001-27]) states that M2 Ball IS 50gr of IMR4895 to a MV of 2805 fps. (or, 2740 fps, 78 ft. from the muzzle)​



Now, Look at the "Reference Round" in this this graph:
(Along with the other common MilSurp M2 rounds, such as Greek HXP, and a M1 Ball round thrown in as well)

The M1 Garand and Commerical Ammunition

index.php

It contains Actual Peak pressures, as well as Area under the curve pressure - all obtained from the Same testing method and equipment.

Now, go look at the GarandGear Commercial Ammunition and "Ported Gas Screw" overlay curves and determine whether a specific 30-06 load would benefit from it.

Use one during hunting season - because Remington Core-Lokt is not always the ammo available or shot, and my prime load, Remington 168 gr, TSX, isn't in the test matrix.

Then remove it, although it is not really necessary except for matches, for off season shooting.



GR
 
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More ignorant gibberish.

You are a menace to facts and the truth.
The only one being ignorant here is you...I keep pointing out holes in their experiment..you keep ignoring it...THAT is ignorance..

First, Read this:
The Army technical manual [TM 43-0001-27] describes M2 ball ammunition as being loaded with 50gr of IMR4895. For reference, this load is also included in the figure.


Army technical manual [TM 43-0001-27]:

View attachment 949636

(The Army technical manual [TM 43-0001-27]) states that M2 Ball IS 50gr of IMR4895 to a MV of 2805 fps. (or, 2740 fps, 78 ft. from the muzzle)​
I have read that..often...matter of fact I have a hard copy of it right here... and yes the "book" load is 50grn of 4895..it can ALSO be WC852 (H380) which is a ball powder. In reality 50grn of IMR4895 with an M2 bullet gets you an avg of 2918fps at 15ft.. as I confirmed two weeks ago.

When is the last time you tested and inspected late 60's M2 ball? I have 66, 67,68 and 69 in my collection along with LC72. The 60s are all underspec according to your TM you presented and the LC72 DOES meet spec. With much higher port pressure.

Lets don't forget the obvious TYPO in that TM for M72 MATCH where they state it's the same 50grn load of 4895 for the 173gr M72 bullet...while in reality it's closer to 46grn.




Now, Look at the "Reference Round" in this this graph:
(Along with the other common MilSurp M2 rounds, such as Greek HXP, and a M1 Ball round thrown in as well)

I have and what I keep pointing out to you and you keep ignoring is that GG tested weak and underspec late 60s M2 ball as their "control" ammo. While in reality pretty much all other milsurp M2 ball performs with much higher velocity and pressure all moving the bolt/oprod at a much higher velocity...on the likes of nearly 6fps faster...

So again..stop copy and pasting a whole webpage that I've already read and pointed out problems with their methodology.
Notice anything in this video of the same rifle shooting two different types of ammo? I mean the bolt speed is the same for both..that means the operating pressure is also similar. One rifle is shooting S&B M2 Ball "garand safe" ammo the other is Federal 220gr Hydroshok.




Please explain how that is possible...

Come back with a valid discussion...OR...just move along....K thanks...​
 
...Notice anything in this video of the same rifle shooting two different types of ammo? I mean the bolt speed is the same for both..that means the operating pressure is also similar. One rifle is shooting S&B M2 Ball "garand safe" ammo the other is Federal 220gr Hydroshok.


Please explain how that is possible...

As explained "ad nauseam" - Bolt Speed - your obvious sum YouTube education and religion, is driven by Area under the Curve... Not Peak pressure.

Bolt Speed - is irrelevant to Op-rod stress.

...also explained "ad nauseam."


Physics.

Given:
A 24" Bbl'ed M1 Rifle pushing a 150 gr. bullet with 50gr of IMR4895 to a MV of 2800 fps.
(The Army technical manual [TM 43-0001-27] and empirically tested by GarandGear)

Now, push the same bullet, from the same rifle, to the same MV, ...this time with Reloader non-canister powder.


Area under the curve - will be the same.

Slide velocity - will be the same.


But, your ignorance will win you yet another special prize.

... an empirical education in Port pressure.


Your ignorant FUD - is why the internet has the reputation that it does.

A religious menace to Facts and the Truth.




GR
 
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All this back and forth has confused me. Bottom line commercial ammunition in the bullet weight of 150 to 180 Grains should be perfectly alright for M-1 Garand's, correct?
 
All this back and forth has confused me. Bottom line commercial ammunition in the bullet weight of 150 to 180 Grains should be perfectly alright for M-1 Garand's, correct?

Absolutely... Not.

Ignore the religious FUD and consult:


Only ammo that is:

1. M2 Ball.
2. Labeled as "Garand Safe."
or
3. Has Peak pressures at or below M2 Ball. (and is not loaded with non-canister powder)

Regardless of bullet weight.

Are "safe" for the M1 Rifle and OEM Gas Cylinder Lock Screw.


The GarandGear ""Ported Gas Screw" - is an elegant solution to any ammo not suitably indicated.




GR
 
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All this back and forth has confused me. Bottom line commercial ammunition in the bullet weight of 150 to 180 Grains should be perfectly alright for M-1 Garand's, correct?
Terry please ignore the Garand Gear shill...he is unable to understand anything I've explained to him and he continues to ignore evidence to the contrary... CMP themselves state commercial ammo 180grn or less is fine...and that 220gr "may" (not will) cause increased wear. Testing with 220s shows no appreciable increased oprod velocity compared to known good garand ammo.

In CMPs own words...

cmpammo.jpg
 
As explained "ad nauseam" - Bolt Speed - your obvious sum YouTube education and religion, is driven by Area under the Curve... Not Peak pressure.

Bolt Speed - is irrelevant to Op-rod stress.

...also explained "ad nauseam."


Physics.

Given:
A 24" Bbl'ed M1 Rifle pushing a 150 gr. bullet with 50gr of IMR4895 to a MV of 2800 fps.
(The Army technical manual [TM 43-0001-27] and empirically tested by GarandGear)

Now, push the same bullet, from the same rifle, to the same MV, ...this time with Reloader non-canister powder.


Area under the curve - will be the same.

Slide velocity - will be the same.


But, your ignorance will win you yet another special prize.

... an empirical education in Port pressure.


Your ignorant FUD - is why the internet has the reputation that it does.

A religious menace to Facts and the Truth.




GR
As I've already explained to you more than ones...50grn of 4895 gets you over 2900 at 15ft from the muzzle.

You refused to answer any of my questions regarding any actual testing YOU have done..

Then you make some wild claim that if you push the same bullet in the same rifle to the same velocity using a DIFFERENT powder you will still get the same oprod velocity..utter rubbish and you should get a new physics degree because yours failed you...

Testing time and time again shows us that different powder burn rates affect oprod velocity...

Here is some test data for you to persue...showing load and oprod velocity... M1M2handload.jpg


You should stop calling people FUDs when you yourself can only cut and paste from a website that has flawed test data. Besides isn't that a personal attack which goes against the rules?


Please come back WITHOUT COPY AND PASTING from the GG sight...(how much do they pay you?) with some facts and manners...


thanks...
 
As I've already explained to you more than ones...50grn of 4895 gets you over 2900 at 15ft from the muzzle.

You say.

The U.S. Army says different.

And so what?

It is a MilSpec and tests mid-range for Peak pressure among the M2 ammo tested.

Then you make some wild claim that if you push the same bullet in the same rifle to the same velocity using a DIFFERENT powder you will still get the same oprod velocity..utter rubbish and you should get a new physics degree because yours failed you...

More ignorant gibberish.

Look at ANY load table.

And Op-rod speed is a function of Area under the curve pressure... Only.

That this escapes you only validates your blinding religious ignorance.


Testing time and time again shows us that different powder burn rates affect oprod velocity...

More ignorant gibberish.

For a given charge/chamber pressure - not for a given muzzle velocity.


You should stop calling people FUDs when you yourself can only cut and paste from a website that has flawed test data. Besides isn't that a personal attack which goes against the rules?

I should call you more... but That would be against the rules.

You are an ignorant disciple of the "Church of the Speeding Op-rod"; understand Nothing of the Physics/Forces/Stress involved in the M1 Rifle cycle of operation; are in blinding denial of the Science/Engineering that GarandGear has developed/utilized to both identify and resolve the problem; and are toxic to facts and the Truth as you spew your YouTube FUD regarding irrelevant bolt speed as any issue with Op-rod stress.

This is Science - as elegant solutions exist beyond your ignorance.

Good day.



Introduction

The purpose of this article is to discuss the M1 Garand gas cycle and the effects of using commercial ammunition in the rifle. In this article we'll measure and discuss the gas cycle pressure for several different brands of ammunition. It is commonly stated that shooting commercial ammunition in the M1 Garand will cause damage to the operating rod. With the supply of M2 Ball ammunition dwindling, it seemed an appropriate time to investigate this topic and look for solutions.

Several manufacturers sell a venting type of gas screw that addresses the potential of high pressure in the gas cylinder. John Garand patented such a device for the M1 in 1945 (Patent #2369669). The venting gas screw works by bleeding gas out of the gas cylinder. I am going to present a different solution to the potential high-pressure problem, one that I believe is more elegant and simple in design and use.

At GarandGear.com we have designed a new ported gas screw for use in the M1 Garand. Unlike a venting gas screw, our product works by changing the initial conditions in the gas cylinder. The ported gas screw increases the starting volume in the gas cylinder, which results in lower peak pressures. No adjustments are required and no gas will vent from the device. The ported gas screw will produce lower peak pressures in all brands of ammunition that meet the SAAMI specifications for the 30-06 cartridge, regardless of bullet weight.

GasPlug.jpg

To evaluate the design of the ported gas screw, several sets of pressure data was acquired. The first data set measures the gas cycle when using standard M2 ball ammunition. This initial data set will define the accepted "safe" operating range for the M1 Garand gas cycle. The second data set surveys several brands of commercial ammunition. This data set was then compared against the M2 ball pressure set. Finally, the ported gas screw design was tested and its ability to lower peak pressures was verified.

Testing Hardware

The most useful data for this investigation is obtained by measuring the actual gas pressure in the gas cylinder, rather than at the barrel gas port. The gas cylinder pressure is easier to obtain than measuring the barrel port pressure. Measuring the pressure in the gas cylinder also saves us the effort of trying to model the gas transfer into the gas cylinder. I will discuss why the modeling of the gas transfer is challenging later in the article.

The pressure pulse in the gas cylinder is very short, approximately four milliseconds. A high-speed pressure transducer was required for the test along with all the associated amplifiers, computers, and data acquisition systems. The transducer also needed to be able to survive in a high temperature environment. A suitable pressure sensor was chosen and purchased for the test. Two custom gas screws where machined that would house the pressure transducer. The first gas screw would act like a standard GI gas screw; the second emulated the port in the ported gas screw.

The rifle used for the test was a 2.5M range Springfield Armory Garand purchased from the CMP. The rifle had a new criterion barrel installed. All of the gas cylinder and operating rod components where inspected, measured and verified to be in spec. The barrel gas port was inspected and verified to also be in spec. A new USGI spec operating rod spring was installed and the rifle was properly lubricated. Figure 1 shows the sensor installed in the rifle.

Figure1_sm.jpg

(Figure 1)

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.

Figure2_sm.jpg (Figure 2)

The Effect of Port Pressure and Bullet Velocity on Peak Pressures

As mentioned in the introduction, the modeling of gas flowing from the barrel into the gas cylinder is very difficult. This is because the modeling of the flow of gas through the gas port has several variables that are not easily determined. The flow of gas from the barrel to the gas cylinder is choked through the barrel port and is not linear. For this reason, we cannot use barrel pressure alone as an indication of the peak pressure seen in the gas cylinder.

Bullet velocity plays an important role in determining the final peak pressure seen in the gas cylinder. As bullet velocity increases, the time to transfer gas into the gas cylinder decreases. This factor is often overlooked and under appreciated. The time spent in Stage 1 decreases as bullet velocity increases. This effect moderates the possible peak pressures. For example, if two bullets are fired and each reach the gas port with the same barrel pressure but different velocities, the slower bullet will produce higher peak pressures in the gas cylinder.

M2 Ball -- Our Benchmark for Gas Cylinder Pressures

We chose M2 Ball to be our benchmark for what a safe gas cycle should look like. This is reasonable since the M1 Garand in its current configuration is designed to use M2 ball ammunition. The ported gas screw will prevent pressures from exceeding this base line when shooting other types of ammunition.

Our initial pressure testing showed that the pressure curve varied significantly between different years of production and manufacturers. To be safe, we choose the lowest peak pressure measured as the value that the ported gas screw should never exceed when using commercial ammunition. Figure 3 below shows one pressure curve and the peak pressures measured from several different years of M2 ball ammunition. For historic reasons we also tested M1 ball ammunition and included the results in the graph. The Army technical manual [TM 43-0001-27] describes M2 ball ammunition as being loaded with 50gr of IMR4895. For reference, this load is also included in the figure.

Figure3_sm.jpg (Figure 3)

How the Ported Gas Screw Works

When a cartridge is fired, it has a limited amount of gas that can be transferred to the gas cylinder before the pressure decays. If we increase the volume of the gas cylinder – by means of the port, the resulting peak pressure must decrease. Peak pressure is the component that can cause damage to the operating rod. Total impulse is the component that determines if the rifle cycles correctly. In simple terms, total impulse is the area under the pressure curve times a constant.

A venting gas screw drops peak pressure and it drops total impulse. The ported design drops peak pressure and preserves most of the total impulse potential. The result of this design is that the ported gas screw can correctly cycle the rifle at lower peak pressures when compared against a venting style of gas screw.

Reducing the peak pressure lowers the acceleration of the operating rod, and helps reduces the wear and tear on sliding parts and bearing surfaces.

Commercial Ammunition Data

Several of the most common brands of ammunition were purchased for testing. Each of the following graphs will list the brand tested, and show two pressure curves. The first curve is the pressure generated when the ammunition was fired using a standard GI gas cylinder screw. The second graph will show the pressure curve when the GarandGear ported gas screw was installed. Two M2 ball reference lines are included for comparison purposes in each graph. The velocities listed in the graphs are actual velocities measured using a chronograph.

It is important to mention that the commercial ammunition tested is for a specific lot number. The manufacturers can change the load at any time, and without warning. Some of the loads tested do not produce excessive peak pressures. This can change without notice if the manufacture reformulates their ammunition.

Pressure2.jpg
Pressure3.jpg
Pressure12.jpg
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Pressure4.jpg
Pressure14.jpg
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Pressure24.jpg
Pressure20.jpg




GR
 

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Would like to see where the pressure spike is in relation to bullet placement in barrel!
 
Here's where I'm at. I use 180 Grain Remington Soft Point for Deer in my Browning BAR. For Canada excursions (Garand is legal) I bring my M-1 with Winchester 150 Grain Soft Points for possible Black Bear problems, not for hunting. The Winchester ammunition is warranted safe in Garand's. I'm just wondering if the Remington is also. I have M2 Military both Greek and US manufacture, but would prefer taking soft point to Canada. I've fired exactly one round in Canada to scare away a troublesome Male which didn't work. Bear Spray did. IMG_0908.JPG Smokey 3.jpg
 
Would like to see where the pressure spike is in relation to bullet placement in barrel!

For Commercial Ammo - would expect it to be a non-event - bullets being seated well back in the std. SAAMI chamber and throat.
Here's where I'm at. I use 180 Grain Remington Soft Point for Deer in my Browning BAR. For Canada excursions (Garand is legal) I bring my M-1 with Winchester 150 Grain Soft Points for possible Black Bear problems, not for hunting. The Winchester ammunition is warranted safe in Garand's. I'm just wondering if the Remington is also. I have M2 Military both Greek and US manufacture, but would prefer taking soft point to Canada. I've fired exactly one round in Canada to scare away a troublesome Male which didn't work. Bear Spray did.View attachment 949788 View attachment 949789

Well...

According to the provided GarandGear data: Winchester 150 gr. PowerPoint is a little warm.

Just wouldn't make a regular diet of it.

On the other hand - both the 150 and 180 gr. Remington Core-Lokt offerings are right in the M2 range.

Those have been the traditional M1 Rifle factory hunting rounds for quite a while.

No problem.

Like the 168 gr. Remington/Barnes TSX/"Ported Gas Screw" - as it solves any problem up to and including brown bear.

Drops whitetail just fine, too.




GR
 
For Commercial Ammo - would expect it to be a non-event - bullets being seated well back in the std. SAAMI chamber and throat.


Well...

According to the provided GarandGear data: Winchester 150 gr. PowerPoint is a little warm.

Just wouldn't make a regular diet of it.

On the other hand - both the 150 and 180 gr. Remington Core-Lokt offerings are right in the M2 range.

Those have been the traditional M1 Rifle factory hunting rounds for quite a while.

No problem.

Like the 168 gr. Remington/Barnes TSX/"Ported Gas Screw" - as it solves any problem up to and including brown bear.

Drops whitetail just fine, too.




GR
Thank You. It simplifies having one Hunting round and the same Canada round.
 
I was referring to where the bullet is in the barrel after it is fried with respect to the pressure spike
 
You say.




GR
Holy cow you are a garand gear shill you quote the whole page everytime...

Even when you have the discrepancies pointed out to you....

How much do they pay you?


I noticed you never answered the question about the video of the two rifles cycling at the same speed....

But I'm sure you'll just answer with more cut and paste gibberish...

Lol
 
It was a simple question Grandimal ! Actually post #159 came the closest with average bolt speeds! Just thought in your vast knowledge you might have had that information. I have a adjustable gas plug for heavy bullets. The bolt speed chart show 4895 as giving one of the slower bolt speed, which kind goes with what I have heard for years; that the Garand was designed with powders of that burn rate. I guess if one is going to be concerned with bending the op-rod, it would be wise to error on the side of caution.! I will still use powders that are not slower than 4064, unless I readjust the gas cylinder plug!
If one wants to put 220 grain bullets over a max load of Retumbo powder in THEIR Garand without an adjustable gas plug, go for it! I just ain'ta gunna do it in mine!
 
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OP here, I may have missed it, because I haven't read through the debate yet.

I'm gleaning that the debate is whether a Garand can handle various commercial ammo stock without the aftermarket gas plug thing.

Whether it can or can't, as someone who wants a shooter, not a collector, does it actually hurt to have it on there just in case?
 
OP here, I may have missed it, because I haven't read through the debate yet.

I'm gleaning that the debate is whether a Garand can handle various commercial ammo stock without the aftermarket gas plug thing.

Whether it can or can't, as someone who wants a shooter, not a collector, does it actually hurt to have it on there just in case?
It's just an unnecessary expense in my opinion.

99.9% of garand shooters have no need for it.

Grease your rifle properly and keep good oprod springs in it and you have no worries.

If your rifle has wear in the gas system these aftermarket parts could cause cycling issues.

The danger of damaged rifles/oprods is way over blown thanks to internet myths.
 
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