Chrome-moly vs. Stainless

Discussion in 'Long Range Hunting & Shooting' started by 7mmstwuser, Jan 14, 2008.

  1. 7mmstwuser

    7mmstwuser Active Member

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    I'm trying to make a price list for a custom gun and what I would need and was wondering what are the differences between Chrome-moly and stainless. Weight? Finish? Quality? The only time I've ever heard of Chrome-moly is someone was building a race car and opted to go with it instead of steel and the only reason he told me was is was a little lighter.
    How much lighter? Would I be able to tell the difference and does it make any difference in accuracy? Looking into barrels and actions. Any input is appreciated.
    Thanks:):D
     
  2. diderr

    diderr Well-Known Member

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    stainless steel is stronger, has a longer barrel life, corrosive resistant. It may have a better harmonics too.
     

  3. long ranger

    long ranger Well-Known Member

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    There is not significant difference in the cost between a CM barrel and the same barrel made of stainless, the CM will be slightly less costly, but not enough to make it important in my opinion.
    Stainless has less concern as far as corrosion goes if left unfinished. Most of the rifles I build have stainless barrels as then I do not need to blue, parkerize or coat them to prevent rusting. Stainless is not impervious to corrosion as some would think, just less suseptable.
    The difference in cost can be offset by the need to have a CM barrel finished in some form of rust preventative, like blueing or coating.
    Stainless is very slightly heavier than CM, but not noticeably, so no real difference there.
    There are 2 distinct camps on whether 1 is better than the other for life expectancy and accuracy. I really don't think there is any documentable proof either way. Alot more boils down to the manner of rifling and overall quality of the barrel itself.
    I use stainless mostly because I like the way it tools, it seems to give me better results in the rifles I build. And the fact that I don't have to blue it, which is a process I detest. Other gunmakers may find CM works better for them.
    CM tends to be easier to heat treat reliably, which is why so many manufacturers took so long to jump onto the stainless action wagon.
    I have had less failures with CM actions than stainless due to galling.
    Possibly it has to do with experience of the heat treater, CM is old school for most, SS is a bit newer in the gun market and the stresses of firearms are different than most industrial uses.
     
  4. uncleB

    uncleB Well-Known Member

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    well said.
    UB
     
  5. davewilson

    davewilson Well-Known Member

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    i'm not going to claim to be an expert here, but i'm gonna disagree about strength and say that stainless steel is not as strong as CM.the other quality would be it's a little easier to machine. the lands and grooves are just a bit smoother or they can be made a bit faster. stainless may also be more prone to fail in extremely cold temperatures.
     
  6. James Jones

    James Jones Well-Known Member

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    Chrome-moly is stronger in both yield strength and hardness which is why its a better material to build high pressure action on like the 338 Lapua case on a Rem 700 action. The 400 (416) series SS commonly known as ordnance grade , is what barrels are made from , while its softer and has a little lower yield strength it allows for a better internal finish and is less affected by the high pressure corrosive/errosive effects that take place in the first few inches after the chamber so they are said to last longer before needing to be set back or replaced.
    Now , if you are going to find yourself hunting is say the extreme artic climate where the high temps are well below zero you DON NOT want a stainless steel barrel as the SS will shrink more than the CM will and that will make for a tight bore situation , remember that .001" is a equlivlent to a mile in highend machining such as barrel bores.

    all the 400 series Stainless Steels can be heat treaded to increase its strength and hardness but you have to keep it soft enough to be tough so that it doesen't fracture. Stainless machines very nice because its soft and it doesen't work harden nearly as fast so it you get a tool that rubs a bit you won't end up with a hard spot.

    Idealy if you could make a barrel out of 718 Inconel you would be set as its the best material for high heat high corosion application but the cost is off the chart just a baller blank before amching would cost you $500+ and having sombody machine it for you would likely cost 5x's that due to its poor machinability. a few barrel makers have tinkered with differant materials , Blackstar had their barrel made from 17-4 Stainless which is very strong tough and corosion resistant but its also alot harder to machine and material cost is more , Lothar Walther uses a steel that they have a patten on that is very similer to 17-4. barrel makers have tried to find differant materials differant grades and so on and they keep comming back to 416

    So aside for all the technical BS above look at what the guys that shoot for a living are using , the vast majority are using SS as it last longer. Accuracy wise I'd be willing to bet alot that you can't find a CM barrels that shoot as well as SS barrels , they just won't do it for as long.
     
  7. 7mmstwuser

    7mmstwuser Active Member

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    Thanks

    Thanks everyone for all the helpful feed back. I have always loved my stainless. But I am looking to build a 338 Lupua or 338 Edge. So if I get this right James Jones I would possibly be better off with a chrome moly action and a stainless barrel. Correct me if I read that wrong. I would probably get mine painted as well and use a tactical stock in a McMillian A5 or something comparable.
    Can stainless be painted fairly easy and how will the paint hold up? I usually baby all my guns in the field, but there is times that it still gets bumped and dinged.
    The rifle below is like the one that I have in mind. I can't remember where I got this picture so if someone recognizes it Sorry!! I think it may even be one that Shawn Carlock has made. I just know that I saved with what the name that it had on it and it said Adamsrifle.jpg. Sorry Again!!! But all in all this is what I think I'm looking for. Any suggestions on where to start? How easy it to get a 700 action in stainless and how expensive are they?
    [​IMG]
     
  8. James Jones

    James Jones Well-Known Member

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    In my personal oppinion the RUM case is the fattest I would use ain a SS factory action , if I were gonna use a Lapua case I'l prefer the CM cause we all know that we're gonna push the pressure a bit. Unless I'm mistaken Kirby's preferance for his hotter mags is the CM action but don't quote me on that.

    Another benifit is that their is little chance of the SS barrel getting "galled" in a CM action.

    If its gonna be coated then theirs no reason to need a SS action
     
  9. long ranger

    long ranger Well-Known Member

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    7mm
    If planning to build a 338 Lapua or Edge I would certainly recommend going with a CM action, I have had some high end SS actions where the bolt lugs have been galled and been set back from pressure. CM is a harder and stronger material as J Jones points out. I would still favor a SS barrel for ease of cleaning and longevity.
    Bead blasting the finish on both materials gives an excellent base for coatings to adhere to. On CM actions I parkerize the action 1st to get corrosion protection inside the action then Cerrocoat all the external metal parts to match the barrel I use Cerrocoat and it is very tough, comes in many colors and is easy to use. As long as there is ZERO residual oil in the metal it bonds to the metal very well.
     
  10. J E Custom

    J E Custom Well-Known Member

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    7 MM

    Chrome moly is not lighter than steel but much stronger .

    On race cars they use chrome moly to save weight by using thin
    wall tubing made of chrome moly as apposed to heaver carbon steel
    tubing with the same strength.

    Throats appear to last longer on stainless barrels than chrome moly.

    As to the cold weather issue regarding stainless I will have to investigate
    all of these claims before I'm convinced there is a problem.

    All actions are designed to withstand a required pound per square inch
    and if you increse the bolt face diameter you increse the square inches
    of surface .( The reason I like Weatherby MK 5 actions for bolt faces
    larger than .534) because they are designed for the large case heads.

    The last thing you want to do is exceed the 2 to 1 safety factor (50 % of
    the design).

    Just my 2 cents worth
    J E CUSTOM
     
  11. Chawlston

    Chawlston Guest

    Now, I know whey I like my 17-4 precipitation hardened SS actions. I chose that action because it was made out of the same material we use in Nuclear Reactor coolant pump bearings that are designed to last the life (many years) of the core. And, one of the reasons the Navy chose that material was because of it's resistance to become neutron embrittled. Anyway, large aircraft landing gear is made out of the same material.

    Finally, the benchrest game switched to stainless steel barrels because they were cheaper in the long run when one considers chambering fees and barrel life over say 20,000 of shooting.

    Chawslton
     
  12. G-gear

    G-gear Well-Known Member

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  13. G-gear

    G-gear Well-Known Member

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    Chrome-moly Vs. Stainless

    [​IMG] 09-20-2006, 04:00 PM
    Frank Green [​IMG] vbmenu_register("postmenu_275359", true);
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    The c.m. barrels shoot just as well. We don't see a difference in accuracy. I haven't shot one as a short range bench gun. But have used them on service rifles and an f-class rifles and don't see any difference in accuracy. We lean towards them lasting longer because they seem to be more abrasion resistant than the s.s. the hardness of the material being approx. the same. They do seem to machine a little harder/more finesse needed with the chamber reamer etc... but nothing out of the ordinary. Start with your same speeds and feeds like you would with s.s. The chrome moly might take a little bit longer to break in (throat area of the chamber is about all you really break in) again because they seem to more abrasion resistant.
    The c.m. seems to have more affinity for the copper or it seems like you can see the copper easier. I compare it to like taking white chalk and writing on a black board and taking the same chalk and writing on the side walk. The copper seems to stand out more in a c.m. barrel than a s.s. that's all I'm trying to say here.
    When I started shooting hi-power rifle I heard you have to get a s.s. barrel because they last about a 1000rds. longer than a c.m. barrel. No truth to it. Back when we we're at Krieger we made a couple of dozen service rifle barrels in c.m. (for ar15 service rifles) for Lackland Airforce Base. One of the armorers (don't know if I spelled that right) called me up and asked how long should these barrels last? I asked him if there was a problem? He said no. All of them had just shy of 10,000rds on them and we're all still shooting very well. I told him I would get more barrels in the works and that they wouldn't last to much longer.
    Just talked to a customer last week shooting one of our barrels on a ar15 match rifle. The barrel is in s.s. and has 9400rds. on it and it shoots as good as his Krieger which has 3500rds. on it.
    From what I've learned especially for a service rifle where you have a flashhider and in cases like with a M14/M1A where you have to enter the cleaning rod from the muzzle end the c.m. barrels seem to stand up to cleaning better than the s.s. (damage to the crown end of the barrel). I would lean towards having a c.m. barrel on my service rifle than a s.s.

    I'm not comparing hi-power rifle accuracy to benchrest accuracy here. The requirment that a benchrest shooter wants to see is different from a hipower shooter. I'm just trying to give you feed back on things that I've seen and have learned overtime.
    The major down side to a c.m. barrel for most people is it requires more maintence than a s.s. barrel. Getting it blued or parkerized (some type of finish on it because it will rust easier than s.s.). S.S. can still pit/get corrosion on it/to it so you should still take care of it but it is more resistant than the c.m.

    Frank
     
  14. P KUNDA

    P KUNDA Well-Known Member

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    CM is stronger, harder, weares better, but

    ,,,,,,,,,,

    it's not corrosion resistant, but neither is 416 SS that's commonly used in making barrels. The harmonics has to be delt with in any barrel individually, CM or SS.

    Peter