CM vs SS barrel ?

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  • Last Post 28 March 2013
gpb posted this 26 March 2013

I am starting a project putting together a rifle that will primarily be used for cast bullets. The donor action is a Stevens 200 short action. I will be purchasing a barrel geared specifically for this project. The barrel will be 30 caliber.

The first decision point on a barrel is the material of construction. A quick review of common barrel makers show that most offer a choice of Chrome Moly (CM) or Stainless Steel (SS). A few offer only one or the other.

The first question is: Does CM or SS offer any advantage over the other in cast bullet use, or is the selection of the barrel manufacturer more important and the material used is moot?

Thank you for your input.

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onondaga posted this 26 March 2013

The finish of the bore is more important than selecting CM or SS. Cast bullets like a slick fine polished bore a little finer than today's match bores for jacketed bullets. I would choose a less expensive barrel and polish it like this:

 http://www.castbulletassoc.org/viewtopic.php?id=8364&forumid=63

Gary

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pat i. posted this 26 March 2013

You don't have to blue stainless and I agree with Gary about the rest.....up to the surface finish statement. I don't know what cast bullets like or dislike but I have a bore scope and have looked at a few Savage barrels. They looked like they were rifled with a garden trowel but shot great.

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onondaga posted this 26 March 2013

http://www.castbulletassoc.org/view_user.php?id=5498>pat i.:

Everybody is welcome to disagree with my finish statement. It is my opinion that bullets should be big enough to be sized by the barrel when shot and I draw the critical line by how this barrel sizing of bullets is accomplished. The barrel can swage or burnish the cast bullets down with a slick barrel or it can abrade the bullet down with a coarser bore, or somewhere in between.  The slick does it for me and I don't feel any need to compensate for bore finish with bullet lube either,   simple tumble lube on any bullet design I shoot works just fine with the way I polish my barrels and fit my bullet size.

I also am pretty confident that much of the debate on quality and effectiveness of the myriad of bullet lubes available has a root cause that is ignored by many. Bore finish does a great deal to regulate how well a bullet lube can work in my opinion.

Gary

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RicinYakima posted this 26 March 2013

I go with Gary on this one: bore specifications and smoothness are the issues. BUT, I have never built a match rifle from scratch, so what do I know? I shoot military rifles! Ric

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delmarskid1 posted this 27 March 2013

Some people say that CM barrels are easier to manufacture and are easier on tooling. Many shooters like stainless because they supposedly stand up longer. I have a rifle built on a Stevens short 200 and it shoots pretty well. I'm not done with load work but it's real promising. It has a stainless barrel that was cut rifled and lapped when I got it. I ordered CM and they messed up and built it with stainless. CM was cheaper. I'm pretty sure that dimensional conformity and finish are more important than material.

bruxbarrels.com I'm going to plug for these guys because when they made my barrel with the expensive stainless by mistake they charged me for chrome moly. These fellows are Palma shooters and you know how they are about barrels.

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billwnr posted this 27 March 2013

There is such a thing as too smooth and it's not a good thing.

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onondaga posted this 27 March 2013

http://castbulletassoc.org/view_user.php?id=182>billwnr:

There are a couple people that have gone to loggerheads with me on that issue of over polishing a bore. They don't listen and make reference to copper jacket bullet shooting barrels. The method I posted on bore polishing specifies an abrasive product and method that does not  over polish barrels.

The people using abrasives 800-1000 grit and even finer and insisting they are using the right abrasive and ruining their barrels....guess how I feel about that....They got what they deserved by not researching their work and just jumping in thinking fine is good, so finer is better or that is all I had to work with.

An over slick bore will pull copper off of jacketed bullets if you have enough velocity. This site is not about jacketed bullets anyway.

 The 400-500 grit abrasive in Turtle Wax Chrome Polish And Rust Remover I recommended in my post will not over slick a bore for cast or copper jacketed bullets with the method I describe if you follow the post directions.. The highest shine match commercial barrels exhibit a 300-400 grit finish. My polishing method will get you a 400-500 grit hand finish that I believe cast bullets shoot better from and the bore is also easier to maintain with the slick finish.

The rifling called “Button Rifling” actually can be finer than I like personally but there is a lot of variation in button rifling caused by tool condition and method variance so many of that type are excellent also, but some are doodoo and can be fixed with polishing.

Gary

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billwnr posted this 27 March 2013

What I hear you saying is you take issue that they don't agree with you.

Again, there is such a thing as too smooth and it's not a good thing.

Just so you know I've been a member of this site since this site was created in 2006 and have shot in a few CBA matches, both Military and Benchrest.

Once you get your “street cred” of shooting in a number of CBA matches, with posted results, and you have good results, more people will listen to what you may have to say.

Embrace the diversity of different opinions.

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Tom Acheson posted this 27 March 2013

From the FWIW department, the Turtle Wax polishing compound with pumice and kaolin clay.

MOH hardness values of each: kaolin clay 2.5 calcined kaolin clay 4-5 (which kaolin clay is in the TW product?) pumice 6

MOH hardness is considered when evaluating the potential abrasiveness of a material when designing dry bulk material handling equipment (as well as other situations). Materials with a MOH hardness of 8-10 (10 is the hardest) include....aluminum oxide, alundum, chrysoberyl, boron carbide (10), burundum, emery, diamond (10), silicon carbide (10), steel shot, spinel, topaz, tungsten carbide and zirconia.

Tom

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onondaga posted this 27 March 2013

http://www.castbulletassoc.org/view_user.php?id=281>Tom Acheson:

The kaolin  clay 2.5 or 4-5, in either case is part of the carrier for the pumice MOH6 abrasive. The aggregate of these abrasives is much lower than the MOH 10 abrasives you list. Selecting an abrasive paste  with MOH10 abrasives and following the instructions on my post (  http://www.castbulletassoc.org/viewtopic.php?id=8364&forumid=63  ) would be pretty ill advised. The MOH 10 abrasives are much more aggressive and 100 pulls with a BoreSnake and those MOH10 abrasives would cause excessive bore wear damage. Tom, you have  the supporting reason that I selected the Turtle Wax Chrome Polish And Rust Remover, it isn't aggressive with 100 pulls and only polishes while not changing bore dimension.

Thank you, perhaps others will understand bore polishing better with regard to abrasives. However this is repetitious to my original post and comments. My selection of the abrasive recommended was based on using a readily available low cost  abrasive and a readily available low cost delivery system ( the BoreSnake ) with a reasonably easy method of 100 pulls with the snake to arrive at a decent bore polishing. The method and materials are simple, available  and they work easily.

It is possible that you could experiment with modifying the number of pulls with a BoreSnake and an alternate, more aggressive MOH10  abrasive to achieve a similar result. Neither you nor anyone else has made an effort and published such a method and donated it to the shooting community in forums such as this one.

Perhaps one of our members might even market a kit,  and I'd wish him well using my donation. I didn't R&D this project for a profit and have given it freely.

Gary

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Tom Acheson posted this 27 March 2013

Gary,

Wasn't suggesting that higher hardness materials be used. Those other material hardness values were just listed to give readers a sense for how hard the components of the TW were using a well known ranking method. It might be repetitious but it's a non factor because maybe someone reading the current post didn't see the earlier info.

It is incorrect to say no one else has marketed a barrel polishing product. Years back Merrill Martin, a writer in Precision Shooting magazine, put together a set of small jars of varying hardness grits that people could buy. You were to use soft lead bullets, roll them in the abrasive and then fire 10 with the most abrasive, then 10 with second hardest and so on, working your way to the finest (softest?) grit. I have (had?) one of the kits somewhere but I'm not sure I can find it. Would be interesting what the ID of those various abrasives were. I seem to recall others offering similar kits but I might be mistaken. Again, unsure memory but didn't LBT also sell 2 jars of grit (two different gradations) for a similar purpose?

Lastly a friendly writing suggestion....over use and misplacement of the word “you” can cause it to take on the feeling of being accusatory, but maybe you're familiar with that concept?

Tom

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onondaga posted this 27 March 2013

http://www.castbulletassoc.org/view_user.php?id=281>Tom Acheson: I'm well aware of Merrill Martin type fire-polishing methods using  abrasive coated projectiles. I have tried fire polishing and it is a fine method that can produce excellent results.

I developed my method as an alternative for shooters that don't reload and don't have a press to seat the coated bullets in cartridges. The cost of fire polishing kits is also a factor.  A inexpensive simplification of bore polishing methods to date was the goal of my project. The necessity of a reloading setup to use the fire polishing method is to this day a prohibitive factor of the fire polishing method for shooters that don't reload. This has been discussed in posts associated with my original article and the summary of my methods as posted in the Reloaders Nest Forum subsequent to my original posting on this CBA forum.

I had not realized that members of the Reloaders Nest could not access posts on this forum without being a member. So I summarized the method on The Reloaders Nest forum for their use after members at Reloaders Nest made it clear to me they could not open links to posts on the CBA Forum without being a member.

Menbers of the Reloaders Nest Forum can access the summary of my polishing method on their site  at: http://www.reloadersnest.com/topic.asp?TOPIC_ID=18974&SearchTerms=bore,polishing>http://www.reloadersnest.com/topic.asp?TOPICID=18974&SearchTerms=bore,polishing

Gary

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TomG posted this 27 March 2013

Like Pat, I've had some barrels that were quite rough looking inside using my Hawkeye borescope. One, a Marlin barrel had crosswise striations from the reaming operation on top of the lands that looked like railroad cross ties. This shot very well and was consistent. I also had a Savage SS barrel that was pretty rough looking and threw fliers in every group. It had two problems. One was a crooked chamber. This was corrected and it still threw the occasional flier. I then found a defect in the top of a land 3/4 ” inside the muzzle. I cut it back to good rifling and re crowned and it shot varmint bullets in the low 4's. It was still rough but it shot extremely well.

Bottom line: The surface finish has much less to do with the accuracy of a barrel when compared to a uniform bore diameter. Polishing didn't help as long as it allowed the tight spots to remain in the barrel. It might make it clean easier but didn't help accuracy. I once polished a barrel interior to 1000 grit finish. It looked beautiful but accuracy didn't change.

I routinely hand lap my match barrels using Clover silicon carbide compound. I start with 180 or 220 grit to remove tight spots and when it feels uniform from one end to the other, I finish with 320 grit or 400 if my memory is good.

MY theory is that the grit breaks down as it's used and the surface finish ends up slightly better than the size of the grit. I've used this method for the cast bullet barrels with good results. I feel the small valleys in the surface of the barrel provide a place for the lube to reside from shot to shot. Thus the barrel can become seasoned. I've experimented at length as to how much lube is needed. With my #24 lube, I found that .4 grs. weight of lube on a 30 cal. bullets was best and if too much lube was used it would cause lube purging fliers. It wouldn't surprise me to see the lube purging made worse by a very smooth surface barrel. At the time I did the 1000 grit lap job, I only looked at accuracy with light loads in a 308 with cast bullets. At that time I didn't test that gun for the optimum lube on the bullets.

Chrome Moly vs. 416 R stainless? It doesn't make much difference as long as the bore variation is held to one to two tenths TIR from end to end.

I also had a few match grade SS barrels make up with different ratio of lands and grooves. I tested from 75/25, 60/40 and 50/50 ratio. They were all custom made by a well known firm in Rapid City.

One of the barrels had pretty prominent reaming marks remaining on the lands. It was hand lapped and uniform. This barrel was accurate but it would take up to 10 shots for the velocity to stabilize. A smooth barrel of 300 grit finish took only one or two fouling shots. Again, a rough barrel can be very accurate but may take longer to come up to the normal internal friction in the barrel. I was driving 30 cal. bullets over 2500 fps. in a 30 br with Varget and some years shooting 5000 rounds a year in matches and for testing different things. In this case, the company had lost their employee who turned out really good barrels. His replacement made the rough one. I had occasion to visit the plant and meet the QC people They explained that they had lured the old employee with the great skill back and he made me up a new barrel and it shot well. He was a master at running one of the old Pratt and Whitney barrel rifling machines.

If someone has some quantified accuracy data on polishing barrels for accuracy, please let us know. My opinion from some limited experience is that it's not worth the effort and can even be detrimental to performance with cast bullets.

I once questioned a match barrel maker from Montana who had a lot of record breaking and match winning cast bullet barrels out there. I was shooting his barrels in matches and installing a lot of them for my customers at the time. He advised that he felt that a finish lap with 320 grip was best for cast or jacketed bullets. His theory was that if the barrel was too smooth, it would allow too much bullet surface in contact with too much barrel surface and cause undue friction in the barrel. This would lead to bullet metal transfer to the barrel surface.

He felt that the ideal situation for accuracy was having the microscopic peaks in the barrel surface in contact with the bullet surface. This riding on top of the peaks reduced friction and shot better over time. This guy really knows his stuff and had mucho experience. He cautioned against getting the barrel too smooth.

Tom Gray

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rmrix posted this 27 March 2013

I would throw in on the side of SS barrels. I have had many match rifles made. Mostly on Traditional Singleshot action rifles using CM barrels. I have the most experience with CM but like SS too.  I know that sounds like a typo but CM can be great! Just look at all the old data, records, and history from the old dead guys.

This is what I think I know and have been told by others whom I respect. I am writing from the hip and not prepared to back this up so check me on this.

Stainless barrels machine to a better finish with less work I am told by the smiths I have used. SS also dissipates heat (hot barrel) faster, resists erosion from gunfire better and resists some chemicals better but is more easily scratched and warn from cleaning incorrectly. 

I have two (only) lead bullet rifles made of SS and am very happy with them. The very latest rifle I had built received a barrel made for lead bullets is a CPA Stevens in CM for use as a Schuetzen rifle in 32-20 CPA.  I have yet to use it.  I was more then willing to have it made with a SS barrel but CPA likes the Douglas CM barrels for this application and so went with that.

I have had a fellow shooter lap a choke into two CM barrels, Fire lap (very sparingly) a few old rifles with the LBT compound and on yet another rifle followed Ernie Stallman's (former owner of Badger Barrels) instructions to recondition one of my badgers barrels after somehow getting a mess going inside of it......with great success.  Ernie cautions on going too smooth on a lead bullet rifle. All Badgers were lapped and cyro -ed (frozen-however that is spelled).

I think the advice in the above posts is really good. That is, either SS or CM barrel, well made, with a good chamber and crown and then taking care of it is 99%.   Much has been written about rough, smooth, very smooth and too smooth and I do not even want to get into that! :dude:

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Chargar posted this 27 March 2013

There two kinds of barrels, those that shoot well and those that don't. Examples of each can be found in a variety of barrel steels.

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6pt-sika posted this 27 March 2013

Chargar wrote: There two kinds of barrels, those that shoot well and those that don't. Examples of each can be found in a variety of barrel steels.

I will agree with that !

Been there done that dontyaknow !

 

But if I am going to build a bench gun regardless of whether I plan to shoot jacketed or cast I'm getting a stainless barrel . $100-150 dollers more for a GOOD custom stainless barrel over a carbon steel barrel is very little in the whole scheme of things for a match shooter .

 

I'm also more then likely going to use a 700 action of some type if I plan on building a full tilt BR gun . Whether it's a worked over 700 , a worked over 40X or one of the custom 700 clone actions that there seem to be plenty of on the market now .

 

Actions ,barrel steels, trigger etc are as far as I'm concerned a personal thing . I'f I'm paying the bill I don't give a F what someone else thinks (unless I ask their opinion point blank), if they're paying the bill I understand that they feel the same about my opinion .

 

Some folks need to understand that concept .

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6pt-sika posted this 27 March 2013

rmrix wrote: I have two (only) lead bullet rifles made of SS and am very happy with them. The very latest rifle I had built received a barrel made for lead bullets is a CPA Stevens in CM for use as a Schuetzen rifle in 32-20 CPA.  I have yet to use it.  I was more then willing to have it made with a SS barrel but CPA likes the Douglas CM barrels for this application and so went with that.

I am like you and prefer stainless for a full blown competitive rifle !

 

But like you if I were ordering a CPA 44 1/2 I would follow those folks guidelines as I've always had a good deal of RESPECT for the word of Paul Shuttleworth . And as a plus with a schuetzen blued carbon steel looks a heck of alot more classic or traditional in that application .

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6pt-sika posted this 27 March 2013

TomG wrote: If someone has some quantified accuracy data on polishing barrels for accuracy, please let us know. My opinion from some limited experience is that it's not worth the effort and can even be detrimental to performance with cast bullets. 

I spoke with a custom barrel maker a few years back and I asked him about the break in process as well as fire lapping and all that stuff !

He first said to me that he loved it when an actual competititve shooter did that as they were that many shots closer to getting a new barrel .

Then he brought up a rather valid point in my opinion , a person was buying a barrel from him that was  already lapped polished etc hence there really wasn't a need for most of that stuff being done by the buyer .

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RicinYakima posted this 28 March 2013

Thank you, TomG. Words of wisdom and the voice of experience, as always. I was hoping you would weight in on this subject.

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CB posted this 28 March 2013

RicinYakima wrote: Thank you, TomG. Works of wisdom and the voice of experience, as always. I was hoping you would weight in on this subject.

Yup, I've been using Tom's advise on barrel conditioning for my 10 years of competition....makes the most sense to me.

gpb, I still shoot j-bullets for varmints, that's where stainless steel is better to stand up to copper bore cleaners. I use Ed's Red for cb shooting, CM steel barrels are just fine........Dan

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