Hungry review of M14Doctor M14 Op Rod Spring Guide (pics!)

Hungry

Hungry

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I just received these op rod spring guides from M14Doctor's kind folks the other day and wow (factor) :eek: comes to mind. I'm not worthy, I'm not worthy!

So here comes the review, Got a few minutes to type this up before I head to the gym with my wife to yoga class (get ready for Service Rifle and CQB matches) :nest:

First Impressions

:eek: BLACK tacticool finish, matte surface with Nitride treating (not sure about the terminology). I have to say GUIDES because I was sent all THREE versions of them. Have a look at the picture:

DSCN3010.jpg


You will see the 'cylinder' shaft version, '3 Flat' version, and '3 Flute' version in the picture. For lack of descriptors, I'll just call them those nicnames for the purpose of this review.

DSCN3012.jpg


The other end...

DSCN3013.jpg




I am really pleased that there were no sharp edges (can you say Norc 1911) to harm my girlie soft teacher hands. I was totally impressed by the Nitride finish. It's very similar to the Tartan Tactical model (that's not in production anymore). Mind you that stainless NorthEastern Arms guide is very cool also!

Because (never start a sentence with a conjunction or a paragraph :eek: for that matter) M14Doctor has THREE models, I wanted to spend some time weighing them out. That's the next step. So here goes.... :evil:

Some Initial Observations: Weights

Since I am a Science teacher, I was curious what kind of weight savings could be had by shaving off metal in the "3 Flat" model versus the "3 Flute" model. So here goes:

Have a look at the picture:

DSCN3009.jpg


I even weighed my USGI flat stamped op rod spring guide. Wow, that's a cool thing to know. All units are in ounces since my inexpensive trigger scale was too coarse/rough for grams units.

Just for your own records, I weighed my North Eastern Arms op rod spring guide and it came to 2.5 oz. Perfect to know so that I can bulk up my upper body in anticipation for some CQB and Service Rifle matches! I'm a wannabe tuff guy! :ninja:

Installation & testing

All 3 models dropped straight into my 2007 Norc M14 without any hangups. There was no perceived slop inside the op rod spring guide channel. I'm impressed. The retaining pin slid in without any troubles. The designers/engineers of this unit certainly did their homework! :D

I took 3 pictures of EACH of the models installed into the M14, but they are all identical with respect to a perfect drop in fit so I'll just leave ONE picture in place for you to peruse:

DSCN3016.jpg


This happens to be the "3 Flute" model installed in my M14! :D

Along comes the test using 4 different magazines and yes... ALL THREE of the op rod spring guides were hammered with magazines in and out of the magwell on my carpeted basement floor. I was even trying the Mossad Approved "Krav Maga" magazine changes with these op rod spring guides holding each of my 4 testing magazines! :eek:

All of the spring guides worked as they were intended to work. Life is good :ninja: All good to go.

Have a look at the front ends of the guides:

DSCN3011.jpg


Final Conclusions

Like the North Eastern Arms unit that I love (and other op rod spring guides that are no longer made or sold), I recommend this unit heartily if you want to obtain smaller groups. The need for a consistent return to battery pattern in gas guns is well documented dozens of years ago. :cool: Nothing new here.

The great makers of these units on our CGNutz community are reacting well to the burgeoning desire of the M14 Addicts to tweak their M14's and M1A's. :D So with the proliferation of these units comes my advice not to buy ONE at all. Buy TWO of them instead! :dancingbanana:

Here is a final pic with the 3 versions by my 2007 Norc M14. Now I deliberately installed the USGI FLAT M14 op rod spring guide in place just to illustrate the serpentine spring pattern that causes inaccuracy in any rack grade / service grade M14. Now are you a believer that your #### may (you know I could not resist that one...) fall off ?? :nest:


DSCN3017.jpg


I've been advised that there are many, many of the "Cylinder" models available for sale from M14doctor right now. As more of the "3 Flat" and "3 Flute" versions come on line, M14Doctor and his folks will let you know! Right now they do have LOTS and lots of the "Cylinder" model.

Addendum on Mon 05 April from Gothmog...


The guides are all made of 4041 tool steel with a ferritic nitro carburized finish. The only guide currently available is the round profile guide and price is $40 plus tax and shipping. The flat and fluted versions are experimental prototypes made for testing and evaluation purposes at this point. If results are good, I will look at producing them.

Gotta run off to yoga! Support our dealers and manufacturers because they are fueling the M14 love! :runaway:

Cheers all !

Barney
 
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Yoga 'eh... Good thing I know there's a "dark side" to the Hungry we all know! Are you sure you didn't mean "Yoda"? Your off to meet Yoda... That would be much cooler!

Great review by the way, looks like NICE kit!

Cheers
Jay
 
Hungry or one of the other experts, could you explain the pros and cons of the different versions if you would be so kind.

Some of us don't have a clue as to why a fluted rod may or may not be more suitable than a round rod :confused:
 
hillmanr2 said:
Hungry or one of the other experts, could you explain the pros and cons of the different versions if you would be so kind.

Some of us don't have a clue as to why a fluted rod may or may not be more suitable than a round rod :confused:
Click to expand...

Hungry alluded to the mythical alignment of the parts to get consistent return to battery every time. How they work is to generally keep the spring round and concentric along its stroke. Which one has the better juju is probably impossible to diagnose.
 
hillmanr2 said:
Hungry or one of the other experts, could you explain the pros and cons of the different versions if you would be so kind.

Some of us don't have a clue as to why a fluted rod may or may not be more suitable than a round rod :confused:
Click to expand...

Flutes? Weight reduction is the first benefit that comes to mind.... Cooling properties & increased surface area really are not important since this region of the rifle is not subject to a lot of heat buildup like a barrel. :D

High speed low drag? Not certain that flutes would help lot....

One thing is for sure, with all that extra weight; my Douglas Heavy NM barrel and the cylindrical heavier op rod spring guide, the recoil of my 2007 M14 rifle is a mild push! Just ask Maritimer, Plink, and Chaser69 who all had a chance to shoot my rifle yesterday at Base Borden!

DSCN1855.jpg


Here is a picture of the cylindrical guides from Marstar (no longer made) and the Tartan Tactical (no longer available either)

Cheers,
Barney
 
Sorry I am slow on the uptake this morning:redface:

You will see the 'cylinder' shaft version, '3 Flat' version, and '3 Flute' version in the picture. For lack of descriptors, I'll just call them those nicnames for the purpose of this review.
Click to expand...

Of the 3 models you reviewed, why would I pick one model over the other model, or did I miss something? :confused:
 
Ok, here's my take on the various op rod spring guides. The advice is free and not intended to flame any of the producers, so take it for what it's worth.

1) The GI or standard Norinco guide is not designed to improve groups. It was designed so that in a trench, the mud of Flanders, or in the jungles of Vietnam, there would be no possible way for enough grit to get inside the operating rod to jam the rifle up on the spring guide. We do not have those concerns when bench shooting the M14, so we opt for rods that decrease clearance tolerances in the hopes of more consistent operation of the operating mechanism, and hence more consistent groups.

2) I ALWAYS advocate replacing the Norinco operating rod spring with something else. I know others will disagree, but in my experience, I've had them lose elasticity to the point the bolt and operating rod were needlessly impacting hard on the receiver face and heel. Some springs are probably fine, but some clearly lacked in heat treatment quality control. The way I look at it is an M1A spring is under 10 bucks so why skimp out if you are going to buy a $45+ op rod guide to go with it?

3) Speaking of springs... I like to shoot cheap 150gr bulk Hornady bullets a lot of the time. If you like that too, get a standard weight operating spring. I recommend the M1A spring as it is close to USGI spec. If you constantly shoot 168gr SMK's (and can afford to - yikes! - I typically only shoot those at matches and practise with cheaper bulk bullets), then get a Wolf over-powered spring. If you use this spring and shoot 150's, I find with my most accurate powder loadings I sometimes get short-stroking. With a GI weight spring, I get 100% reliability. You decide.

4) ALL the NM type guides on the market will work with a USGI or equivalent (M1A, Wolf, etc.) spring. None of the US-made guides that I know of will work with the Chinese spring as it is smaller in internal diameter then US-made springs. Probably an inch vs metric thing. Most Canadian-made guides will work with the Chinese spring, but ideally I'd like to see them also make them with optional US diameter sizes as the idea is to minimize clearance with the spring inner diameter.

5) Fluted vs. Cylindrical. Oh boy - here is where I'll inadvertently piss a few people off. I do not advocate fluted NM guides unless the flutes are very narrow. More on that later.

Why are fluted guides on the market? Well, for starters, there is "look cool factor" which has been known to sell tacticool kit for years. Next there are theoretical benefits such as: (a) less surface area contacts the spring coils, thus lowering friction and improving cycling time of the action, (b) the flutes provide area to absorb excess grease and/or grit thereby improving reliability if the operating spring gets fouled and (c) the reduction in weight alters the balance of the rifle closer to GI spec which is the way God and John C. Garand intended things.

Now enter the real world... Nobody is going to notice the difference between 0.5 to 1.0 ounces of weight at the rifle's median balance point. If you weigh two in-spec GI stocks, there will be that much difference between them due to normal variability, so unless you are on a crusade to cut weight this benefit is dubious. On a match rifle, the goal is usually to strategically INCREASE weight for a lot of different reasons that Hungry can weigh in about if he so chooses. On an ultra-light hunting rifle using Canadian Tire soft point ammo, you probably don't need a NM guide rod to begin with.

Now the dirt and debris argument. If you are going into this sort of environment, install a GI guide rod. Chances are there will be enough dirt in your rifle that consistent action cycling is a pipe dream anyhow and you'll need reliability.

Lastly, as for surface area contact, BY FAR the largest area of contact is between the inner diameter of the operating rod and the spring. Except for the rearmost portion of bolt stroke, most of the spring never touches the guide rod. When it does, the spring is at full compression and any friction you have is probably helping to lessen bolt impact at the heel and oprod impact at the receiver face - you don't want to be promoting action speed and lowered friction at this point in the bolt cycle IMHO. Also, on a fluted rod, you are only reducing that friction by between 10% and 20%, though the friction is already minute because the guide and spring are both thoroughly greased. If you reduce the area by more than 20%, you are over-widening the flutes and allowing the circularity of the spring to distort with greater unpredictability at full compression, defeating the purpose of a NM guide rod.

This is one reason why I like the NEA guide rod, the flutes are narrow and minimal. It allows a slight weight reduction for those who care while not overly compromising the surface area, and hence continuous support to the interior circularity of the spring coils.

It's hard to see in the pics what the flute width is on the M14 Doctor fluted guide rod and I certainly will not e-review a guide rod without having seen one yet in person, but (and my apologies to the 'doc), I would not personally consider using the model with the flats milled into it. That guide rod is going to lower coil support surface on the order of around 50%+ and will only improve non-deformation performance over the GI guide rod by about 30%. You have to remember the spring at 700 rpm (11.66 rounds per second) is being violently compressed in less than 9/100th of a second and will be subject to about an 11hz impulse wave. This will cause each coil in the spring not only to compress linearly, but to try to deform laterally as well. In my view this rod with flats compromises too much of the 100% circularity support of the full-round version. It would need to be proven on targets in several rifles, but I would expect accuracy to improve less than on the full-round model. Additionally, you have introduced 6 shallow angle ridges the spring is now sliding against which no matter how much you radius those ridges will work to shorten spring life. Not a huge problem with a $10 spring, but for less money you can get the full-round model and not have this issue at all. On the fluted models the angles are steep enough that this problem is likely avoided.

Nitro-carburized or black-oxide finishes are cool looking and will wear smooth over time. I doubt I'd pay extra for it, but it's a nice feature if price isn't aversely affected. The idea with any of these guides is you want them to be slick and smooth. In a way, they need to break in just like a barrel to reach peak benefit. They can also wear out if they get hammered to the point you get spring impressions on the shaft.

Anyhoot, that's my $.02 worth and kudos to the manufacturers working hard to bring us these products :)
 
Here is my little addition 2 this discussion
Satain said:
...I did a similar shoot this weekend I did it from a buddy's lead sled and I got dramatically different results even though I was shooting with iron sights. The ammo I was using was Winchester 147 gr. 7.62 BALL & the temp was a balmy 8 C with wind gust from the left going from a dead calm to about 10 km. I was consitanly getting around 4 inch groups with the stock Norinco guide rod. The other 2 guide rods were getting around the 3 inch or less mark (No less than 2.75 inches) 1 was fluted and the other was not. The last 1 I tried was the Sadlak 1 and this was the most consitant 1 at 2.5 inches. Besides changing out the guide rod the only other mod to this rifle was the replacement of the Norinco spring with a GI 1 so that my test was equal. It was a stock wood Marstar hazmat 2007 rifle.
Click to expand...
Now please note that this was done when using a USGI spring and the M14Doctor's spring guide is for the Chinese spring hence I would expect if you use your original spring you will get the same resualts as the Sadlak. Test to confirm this theroy next weekend. Also here as some more pic's of what each 1 ways and how nice they are in the rifle!
M14Doctor's round spring guide
IMG00189-20110324-1623.jpg

IMG00191-20110324-1626.jpg

M14Doctor's 3 flutes spring guide
IMG00188-20110324-1623.jpg

IMG00192-20110324-1627.jpg

Sadlak oprod guide
IMG00190-20110324-1625.jpg

IMG00194-20110324-1629.jpg


All mesurements was done in pounds and as you can tell eventhe 3 flats or the round 1 were slightly less in wieght than the Sadlak. Witch in my mind means better because anyone who has hunted with this rifle platform knows that any amount of wieght saving is best.
cou:
 
No harassment intended, but any of your guys been to a range in the last two weeks? cou:

I sense some pent up aggressions that would be best worked out on some paper! :eek:

The warden had me working on some "honey-dew" projects but I still got out. You guys gotta fire some lead and try thing out.

That is all I am saying :D
 
Fully agree that in this application, hardened 4140 or similar is probably a better choice than stainless wrt galling, though if well lubed it should not rear its ugly head.

If you make a carbon steel version in the Sadlak diameter, I'd love to have one as I only run GI springs.
 
Addendum on Mon 05 April from Gothmog...


The guides are all made of 4041 tool steel with a ferritic nitro carburized finish. The only guide currently available is the round profile guide and price is $40 plus tax and shipping. The flat and fluted versions are experimental prototypes made for testing and evaluation purposes at this point. If results are good, I will look at producing them.

This is Gothmog's input about the current status of the M14doctor guide rod!

Cheers,
Barney
 
SKScanuck said:
No harassment intended, but any of your guys been to a range in the last two weeks? cou:

I sense some pent up aggressions that would be best worked out on some paper! :eek:

The warden had me working on some "honey-dew" projects but I still got out. You guys gotta fire some lead and try thing out.

That is all I am saying :D
Click to expand...
I try to farm lead at least once or twice a week but some times in the painting buisness month end can get a little to busy to make it up to the range.
 
Hungry said:
Addendum on Mon 05 April from Gothmog...


The guides are all made of 4041 tool steel with a ferritic nitro carburized finish. The only guide currently available is the round profile guide and price is $40 plus tax and shipping. The flat and fluted versions are experimental prototypes made for testing and evaluation purposes at this point. If results are good, I will look at producing them.

This is Gothmog's input about the current status of the M14doctor guide rod!

Cheers,
Barney
Click to expand...

Ooops!

My dyslexia has struck again ... that's 4140 tool steel and not 4041 ... I am told that internal hardness is about 45 Rockwell with an external hardness (due to the finish) of around 60 Rockwell.
 
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