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Ruger's PC Carbine Tungsten weight...

3K views 32 replies 9 participants last post by  metroplex 
#1 · (Edited)
I never had any reason to look into Tungsten, but after acquiring my Ruger PC Carbine, it gave me a reason to check into it.

Anyhow, the weight of that little rectangular block of Tungsten in the PC Carbine's bolt assembly is quite the little heffer.
Well, Tungsten is about 2.5 times heavier than steel.
So, if Ruger would have tried achieving their current overall bolt assembly weight by only using steel, the bolt assembly would have obviously needed to be made bigger or longer, (or maybe both).
Their receiver would have also needed to be bigger or longer to accept it.
So, while maybe the whole dead blow weight thing has some validity... I believe their biggest reason for incorporating the Tungsten weight into the bolt's design, was simply to help them in being able to make a smaller bolt assembly and receiver.

I was surprised to read that Tungsten is almost as heavy as Gold, bring right their in that weight range.

And as for lead, it ain't even close... Tungsten's much heavier!
Cool stuff 👍😎👍
 
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#4 ·
Tungsten tends to absorb vibration well too. The weight is part of the pc c magic. I have made things out of tungsten. It is not hard to machine. Close to leaded steel. The pc c imo is a well thought out design. I tried to convey that before. As to the mim bolt face, idk. But mine is fine, but I understand it has failed on some folks and makes others nervous
 
#5 ·
IMO... MIM is being used by Ruger to make the bolt head for one major reason... That reason is simply that it costs them way less than having to machine them from solid steel or from forgings.

Just like I believe that using a chintzy plastic retaining clip for their recoil spring assembly is a poor choice for that component's purpose, so too do I believe that using MIM for the bolt head is a poor choice for that component's purpose.

But, hey, I calls them as I personally see them.
👍😎👍
 
#6 ·
As for machining, cutting, or drilling Tungsten, I have no personal experience with it.
That said, this is some info I found online pertaining to that subject...

"Since crystal grains of tungsten are much harder than that of molybdenum, milling it can rapidly wear the cutting edges of the tool. Even worse, tungsten is brittle and prone to cracking and breaking during machining operations. As mentioned above, tungsten is ultra-hard and is extremely difficult to machine."

That must be describing pure Tungsten, but maybe other less pure alloyed versions are a different story.

All I really know about it... It's heavy!
👍😂👍
 
#7 · (Edited)
As for machining, cutting, or drilling Tungsten, I have no personal experience with it.
That said, this is some info I found online pertaining to that subject...

"Since crystal grains of tungsten are much harder than that of molybdenum, milling it can rapidly wear the cutting edges of the tool. Even worse, tungsten is brittle and prone to cracking and breaking during machining operations. As mentioned above, tungsten is ultra-hard and is extremely difficult to machine."

That must be describing pure Tungsten, but maybe other less pure alloyed versions are a different story.

All I really know about it... It's heavy!
👍😂👍
It's not bad to machine. But then again, as with most things it is all relative. I have cut a lot of tripple 5 titanim and various inconels so in my experience tungsten is freer machining than those. Or even 6alv. But again, it is relative to what you are used to.
 
#8 ·
Here's an article about bolt/buffer weight at a site with a lot of pistol caliber carbine info:


The site concentrates on AR9s, but it is interesting to me to read about the operation of blowback 9mm rifles in general.

In the article he does show the weights of the bolt/buffer of various pccs and Ruger hit the sweet spot with the weight.

He also has an article on how the deadblow action helps prevent out of battery discharges. Ruger got the spacing in that dead low weight in the sweet spot also.

There is a lot of interesting reading on that site.

I know that both 9f my Ruger PC Carbine s just work.
 
#9 · (Edited)
GOOD INFO in that article. Written primarily for AR9's but worth reading for any PCC9 owner.

Buddy brought the buffer from his AR9 over today. Beat to all hell with the end peened flat. I weighed the buffer and it was 5.7 ounces. He just called after weighing his bolt and told me it is 12.5 ounces.

WAY undersprung from the 22 to 24 ounce recommended weight. He just ordered up a Vltor 10 ounce buffer.

Ruger seems to have the PCC9 tuned fairly well.

Bepe
 
#15 · (Edited)
In looking at the picture of the Ruger bolt assembly I would say the holder that the end of the recoil rod is attached to would be considered reciprocating mass also. It slides back and forth with the bolt assembly. The rod and spring would not. Also the bolt head, extractor, pins and bolt charging handle should be factored in.

Add the weight of the holder and other parts to the bolt and tungsten weight and it most likely is right in the recommended 22+ ounce area. This is not new science to Ruger. They had the original PC9 and PC40 designed correctly.

Bepe
 
#16 · (Edited)
I was just reminiscing about a fun Pistol Caliber Rifle I had years ago. It was one of those Auto Ordnance 1927-A1 Thompson .45 acp semi-auto's that resemble the Auto Ordnance Submachine Guns of the past.
It was then a product of Auto Ordnance when they were owned and operated in West Hurley, New York.
Anyhow, it's frame, receiver, and bolt, were all made from milled solid billets of steel... it was HEAVY!
I remember the bolt being a pretty big and heavy chunk of steel. The gun overall must have weighed 11 or 12 pounds, but, I must say, recoil was about as non existent as could possibly be. I guess the Auto Ordnance brand is still around, having been purchased by the Kahr Arms company. Anyhow, I paid under $600 brand new for that gun, right out of their sister company store, (Gun Parts Corporation), which had a shop that was right next door to the Auto Ordnance operation.
I believe that same model now sells in the $1,500 - $1,700 price range. It wasn't practical, but I sure wish I hadn't sold it, because it was truly such a fun gun to shoot. It also actually did some justice in the way it visually mimicked the original submachine guns, except for the required longer barrel. I believe the barrel was 16 + inches long, and with such an elongated receiver as the Tommy Guns have, it made for a rifle length gun, not what one would consider to be a carbine.
Yup, a pure heavy bolt blowback gun. No real practical purpose, except for fun and making for a great conversation piece in one's man cave 👍😁👍

As heavy as the Ruger PC Carbine's are, they are lightweight when compared to those semi auto Thompsons 😂
 
#20 ·
I'll keep you all filled in. Wednesday is range day. I plan on bringing a box of the Power Pistol loads and then some Blazer Brass. I want to see how it functions with different ammo.

I tore it down today and put a drop of light oil on the trigger pins and a swipe of grease on the hammer and hammer sears. The unit was bone dry on assembly. I smoothed the trigger out considerably. Break on trigger isn't bad just has a bit of creep. I'll run it a bit and see how it does. Punched the bore and it is ready to go.

Bepe
 
#25 · (Edited)
Here's a guy that offers in basic terms why milled from solid billet steel, (of course milled from forged steel being similar), is a better method of making some gun components. In this case he speaks of firing pins, but it gets to the point of things, (no pun intended).
He does not bash MIM at all, in fact, he even says he uses some mim. But goes on to express why the milled from steel billet makes for a better component.



We are not talking here about a low abuse part for a gun when we discuss the bolt head in the PC Carbine, it's a major importance component that is a part of where the magic happens. It's responsible for stripping a round off of the magazine and ramming it home into the chamber. None of this happens gently, but rather quite aggressively. The bolt head also gets violently pushed back while temporarily keeping the shell in the chamber while the explosion of it's gun powder takes place. The bolt head then gets violently kicked back, shoving the entire bolt assembly back with it to the rear.
I think if most folks were totally honest and given a choice of having a well made mim bolt head, or having a well made milled from billet steel or well made milled from forged steel bolt head, the vast majority of people would obviously choose the milled over mim.
But, hey, to each their own on their preferences and such... I believe in the freedom for a person to choose whatever they choose to believe in 👍
 
#27 · (Edited)
It's always good to share some info 👍

I will add this link that gives some basic explaining of Forged Steel...

.

The problem with most sources detailing information concerning these methods of manufacturing, is that most are biased. The companies know what's best to promote what they sell, or even what they would rather sell.
One has to do a lot of reading between the lines.
There are also tons of opinions shared on many websites, but they too can be biased and lean heavily one way or the other.
They can be found supporting one method here, but then the opposite over there.

Again, in my opinion, I believe that most folks, if given the choice, would rather have a quality milled from solid billet or quality milled from a forging component, over that of a quality mim.

By the way, notice how I say quality when comparing any of these methods.
The reason is that I have seen so many folks trying to defend their position on the matter by stating something like...
"Well, a quality MIM is going to out perform an inferior Investment Casting, Forging, or Milled from barstock component."

Umm... How can such a comparison be considered to be fair! It's always the most ignorant argument, and yet it gets used a lot.
Their argument is that one would first have to assume that the MIM part was made to a quality level, while the other parts being compared to it were all made to an inferior quality level... Like, huh!? 😂

Of course if one is going to fairly compare them, they each have to be considered to have been made by being subjected to good quality standards during their production 👍
 
#31 ·
Wow, I guess that explains a lot. I had owned one in the .45 ACP caliber, and it wasn't like Marlin skimped out on making the receivers for those guns.
Heck, if the weight on their bolt was in the 14 ounce range, that only makes it about four and a half ounces heavier than just the Ruger PC Carbine's Tungsten weight that is found within the bolt assembly. With the consensus seemingly being that a 20+ ounce bolt weight is required, they definitely fell short of that.
Since Ruger's PC Carbine line has taken off solidly, I don't foresee them ever reintroducing the Marlin Camp Carbines, but, if they ever did, I could see them redesigning the bolt assembly to incorporate a similar tungsten weight as used in the Ruger PC Carbine.
I would seriously consider buying another .45 ACP Camp Carbine from Ruger's Marlin line, with it taking the 1911 magazines like they did before.
If it ever happened, it would be nice to see it in two initial flavors... One with a walnut stock, (instead of birch), and one in a black synthetic. I'd likely wind up with both 😂

But, wow, that weighing the bolt on the vintage one is an eye opener for me now. I always wondered why the Marlin Camp Carbine was having issues with receivers cracking and pounding on their buffers so hard, (although the age of those buffers contributed as the guns got older, brittleness occuring to the plastic).
The bolt being too light would seem to be the biggest culprit on all that battering.
I sold my .45 Camp Carbine off a long time ago, but always thought it was a neat gun 🙂
 
#33 ·
The tungsten weight is also needed for straight blowback systems to allow enough time for the case pressure to subside before extraction as well as slow the cyclic rate down on full auto weapons. My FN PS90 came with a small tungsten weight, but the aftermarket tungsten block is reported to help reduce feeding issues especially when suppressed.
 
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