Why do I ask, because I know that 17-4 PH is a very strong wear resistant Stainless Steel alloy with a 110,000 PSI yeild strength. Seems to me that it would make a superior long lasting rifle barrel.
If memory serves, this is the same material that Nesika builds thier actions from.
As a side note, 15-5PH has a yield strength of 145,000 PSI. Also very high strength and wear resisant properties. Jim Borden builds his Alpine actions out of this material which is why I selected his action for my next project.
(17-4PH has a slightly higher chromium content then 15-5PH for improved corrosion resistance)
Hello Victor , I bought a bunch of Blackstar accumax II barrels from Brownells when the disscontinued them , a tech from brownells acctualy called me before I recieved the barrel to infor me that they were difficult to machine and that I should contact Blackstar about that so I did and they gave me the rundown on their barrels and the material and how they reccomend to machine them , it cuts like heat treated CM which is pretty tough stuff , I just made lighter cuts with carbide cutters and a constant supply of Moly Dee (good cutting fluid). If you rockwell differany barrels you will see that CM barrels are harder than SS barrel plain and simple , the accuracy and longitivity comes from differant aspects other than the barrel hardness , the softer SS is easier to machine and I assume its easier to get more accurate rifling in the bore. The 416SS does resist heat and pressure erosion better than the CM so technicaly it would last longer and should be more accurate. Thanks about the best I can come up with on the CM vs SS issue.. On the point of the 17-4 I don't know why more barrel makers don't use it other than the end cost probably woulden't be cost effective to them , it would be harder and take longer to get a good accurate internal finish which adds to the end cost the 17-4 material is about twice the price for the raw blank added to the cost and from what I've seen they last longer wheich would meen you end up selling less barrels making the cost even higher probably to the point that you woulden't seel 1/4 as manny barrels its just a loose loose situation for the barrel maker. I think that Blackstar gets away with selling their barrles for what they do because the barrel end of the deal is a very small portion of the income to that company and all they are doing is getting a finished barrel for LW and using their electro polishing process in it. As for the material that LW uses I "assume" that its 17-4 or another super alloy and they just stuck their own tital on it since they make Blackstars barrels they are probably already setup to make the barrels from such a hard alloy.
If sombody wanted to make a realy long lasting barrel then somthing like Tungston Carbide , or one ofr the ceramic mixtures would work but then you get into a material thats so hard that its not possible to make the internal dimentions as accurate as needed for the BR shooters. its all a ballancing act I guess , you end up trading barrel life for accuracy hence the BR crownd using 416SS barrels.
Some makers have tried hard crome lining their barrels with "ok" results its just to hard to get the internal dimentions accurate so the end result is a barrel thats not as accurate as needed but will last a long time like in the military's auto weapons , they don't require match accuracy but long life and easy cleaning are a huge benifit.
Robar industries has a metal finish called NP3 which is amazing once its applied the surface never has to be oiled again dirt doesn't collect on it , paint won't stick to it and any liquid beads off of it , I don't know its heat resistant properties but if it was as good as hard crome then it would make a better internal finish , IF , it could be applied evenly.
Blackstar's process isn't a coating but a polishing so if the inside of the barrel is very accurate in all dimentions and their process works as its advertised then the end result is a super accurate barrel thats super smooth..
In the end after I win the lottery , I'm going to build a series of guns that are identical from the action to barrel dimentions using every barrel makers barrel , from the Poly twsit barrel to the 3 groove and the 5R concepts and I'm gonna fire the exact same number of rounds through them from the exact same caliber using the exact same powder and bullets , just as an attempt to see what acctualy last the longest and shoot the best!! because untill this is done the world will ned have more than just speculation as to whos barrrels are the fastest , most accurate longest lasting and so on
If you win the lotery and need someone to help in the tesing just give me a holer and I'll help you out. [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img] [img]/ubbthreads/images/graemlins/grin.gif[/img]
I dont know who ever came up with the imaganary word of "Over Gunned"
I don't know exactly what the differances are between the Blackstar barrels and the LW that Borwnells offers. Brownell's carried the Blackstar Accu-max II barrels about 10-12 years ago , I got a flyer that showed they were going to disscontinue them so i bought several. I sold a few boult a couple guns with some and have one left. They work great and all guns built with them shot very well. I know that they still make them and from what I understand they are still a great product , but lately the other great barrel makers like Rock Creek , Lilja , Hart and on and on have been getting good buisness , I realy don't have the need for barrel burner anymore and I've only made a few trips to shoot high volume varmints so wearing out a barrel takes years for me..
If your looking for a barrel with long life I would either use a 3 groove Lilja or a 5R barrel from Rock Creek , both of them have proven to last a little longer than conventional land and groove barrels. Hart makes a fine barrel and they win their share of comps every year you would be well served with a Hart , as you would with a Kreiger , Lilja , Broughton , Lawton , Schnider , Rock and so on. I haven't even looked at the Blackstar web site in years so I'm not sure what they have going now days.
In a head to head compairison with any of the above listed barrels I would have to say that the Blackstar barrel would out last them "IF" the land and groove dementions were the same simply because the material is harder and less affected by the heat and pressure that eats barrels up
Just got a reply from Blackstar barrels regarding their barrel steel:
Thanks for your interest. The barrels are LW50 which has a DIN (European)
designation that closely resembles a 420 SS. The barrels are tougher and
last longer than a traditional 416R barrel, especially in the throat area.
The barrels began as 17-4 PH steel but were too hard to machine and Lothar
switched BlackStar to there traditional SS barrels. You can buy the same
barrel direct from Lothar Walther but it will not be electropolished or
tapered. Hope that helps.
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Too bad, I really would have liked to try the 17-4 PH barrels.
You wouldn't want to sell the remaining barrel would you?
To understand this subject, one must understand high-strength steel. For the record, I am a metallurgist by trade, and heat treat Quality Manager so I know enough about these steels. I do not like AISI 416 SS for gun barrels and I will explain why:
To achieve the high strength the steel must possess to withstand the forces produced during firing, AISI 416 SS and/or AISI 4140/4150/4340 must be austenitized, quenched and tempered. After quenching, the average 416 SS will be about 40 Hardness Rockwell C (HRC) and 4000 grades about 50 HRC (To benefit those who do not know this scale, a file will be about 60 HRC, and a hammer will be about 30 HRC). In the "as quenched" state, the material is brittle and unstable. Tempering is employed to reduce the hardness to a "tough" state and stabilize the newly formed martensitic structure. In the case of 416 SS, and to get the hardness to about HRC 30 so it is able to be machined, one must temper at about 1075°F. This is not desirable as 416 SS shows a marked reduction in impact resistance when tempered between 700°F and 1100°F (temper imbrittlement). It will also show a marked decrease in corrosion resistance. 416 SS does still however exhibit better wear characteristics and corrosion resistance than the 4000 series high-strength grades mostly due to the higher chromium content. It is also readily available, inexpensive, and it looks good so manufacturers use it. The big problem though is that it is not as free-machining as the 4000 series grades so generally sulphur is added to alleviate that problem. What you then have is a microstructure with "sulphide stringers" in it that has been tempered in a bad tempering range so the impact resistance of the steel is very poor. Failures happen, and are not really wide-spread, but I will not buy a 416 SS barrel for that reason. The AISI 4140/4150/4340 grades do not have this temper imbrittlement problem, and show superior impact resistance when tempered to about 30 HRC. They are cheaper to buy in a production rifle. One who takes good care of a firearm will never have any major corrosion and wear issues with the 4000 grade steel barrels anyway. And if you do use it an awful lot and it begins to wear out, well then you got your money's worth from the product, just buy a new barrel. Nothing lasts forever anyway. As a note, AISI 410 SS is a better alternative to 416 SS as is does not generally have the sulphur issue, however the temper imbrittlement issue is still a concern.
Here is my opinion: Unless you are competition shooter, buy the non-stainless grade barrels. If you are a professional match shooter find a good AISI 17-4PH barrel as it is a much better choice if one wants corrosion resistance, wear resistance, and impact resistance.
For my money and safety, it is a 4000-series material.