I've just about made up my mind on a new Barrel/caliber...I tried shooting 1000Yd VBRS Varmint Bench Rest Silhouette...My 243 Win. Second barrel...Is now at it's half life... It won't last this season...My Plan is to order a [fill in the blank brand] 6MM BRX drop in... I can use my 6mmbr dies & fireform some new brass I have on hand..I plan to stick with the 105 Amax bullet I like the 1-9 twist I use now but I can be swayed to the 1-8 twist rate...Should I cheap out & order the chrome moly or go with the stainless Select grade to try this wildcat cat out???...My action is a Savage small shank...Mike in Ct
Chrome Moly Or Stainless Match grade
- Thread starter mikeinct
- Start date
This has always been a no brainer for me. CM is cheaper until you start applying corrosion protection. If keeping it coated with oil in and out, it remains the cheapest. A DIY spray bomb on the exterior is cheap, but you still have to constantly protect the bore. Bluing, and most other durable coatings usually put you beyond the extra cost of them and in many cases the bore remains unprotected.
Competitive shooting / You guys know what I mean...Lots of rounds, short barrel life...I like the hot fast ones but none are immune to hard usage..I never thought of barrel life before...Or how short lived accuracy can be...That is why I asked..Talk to few of these guys about barrel life..some use 2 or 3 barrels a year...Growing up I learned a centerfire rifle that shot well was a treasure to hand down to the next generation...I had one guy told me flat out Second box [1K] of primers order another barrel for my 243..Yikes..!!!
You can greatly extend your barrel life by shooting the cooler powders, N-160, N-165 or H1000.
Since you are looking at a drop-in barrel, painting with a decent paint works well for a Cro/Moly barrel.
I've had great luck with the below baking in my oven 350 deg. So tuff that scotch-brite will not scratch it.
http://www.brownells.com/gunsmith-t...eflon-moly-oven-cure-gun-finish-prod1145.aspx
Since you are looking at a drop-in barrel, painting with a decent paint works well for a Cro/Moly barrel.
I've had great luck with the below baking in my oven 350 deg. So tuff that scotch-brite will not scratch it.
http://www.brownells.com/gunsmith-t...eflon-moly-oven-cure-gun-finish-prod1145.aspx
DHD
Silver $$ Contributor
How much more is a stainless barrel than chrome moly? I have no doubt a CM will shoot and last a long time, but the only CM barrels I have are on old rifles I don't want to mess with or on my BRCR's where getting stainless would have created other issues I didn't want to deal with. You can keep a CM barrel rust free as long as you stay after it, but you can't neglect it for very long or you'll regret it. Kind of like being married to a redhead (and I've had two of those!).
Using the barrel the way you describe, I would buy and use a stainless barrel and not look back.
Oh yeah, and definitely a 1-8".
Using the barrel the way you describe, I would buy and use a stainless barrel and not look back.
Oh yeah, and definitely a 1-8".
Thanks again Guys...I hope I was clear about competitive shooting..Really?? I may burn out two barrels in a year?? If So I don't care if it rusts some on the outside...it's half life is 3 months ?? That is why I said just buy the cheaper CM & shoot it till it dies..,< than 1200 Rds thru that 243 & it is toast...I don't know the life span of the 6MMBRX...My little 6MMBR is 12 years old but it has had a pretty soft life..mike
Definitely consider hexagonal boron nitride, tungsten disulfide, or moly coating if you want to increase accurate barrel life in a hot cartridge. The hex boron nitride is particularly good at dealing with high temperatures as it doesn't oxidize until something like 2000 degrees. I saw that Norma released a study a few years back that compared 2 nearly identical barrels. One was shot with only bare copper bullets. The other was shot with the identical load and moly-coated bullets. The throat of the moly barrel after 10,000 rounds looked better than the bare bullet barrel after something like 4,000 rounds.
Obviously that's an extreme example, otherwise they wouldn't have advertised the results, but the trend is there as well as posted all over every shooting forum around.
So if coating with HBN or Moly or whatever will give you an extra 400 accurate rounds from a 1000 round barrel, I say it's worth it...can't hurt right?
If you want a cool way to coat your bullets in HBN, give me a PM and we can go over the method that's worked best for me.
Obviously that's an extreme example, otherwise they wouldn't have advertised the results, but the trend is there as well as posted all over every shooting forum around.
So if coating with HBN or Moly or whatever will give you an extra 400 accurate rounds from a 1000 round barrel, I say it's worth it...can't hurt right?
If you want a cool way to coat your bullets in HBN, give me a PM and we can go over the method that's worked best for me.
Stainless steel is more resistant to throat erosion than chrome moly. The ss bbl can be lapped to a finer finish = less break in. Your barking up the wrong tree if you think moly coating(s) will extend barrel life. for one thing it usually takes more powder to net the same pressure as naked bullets.
LHSmith - you're quite correct that the pressures and velocities are lower for coated bullets compared to uncoated bullets. That said, the velocity decrease compared to the chamber pressure is not a linear relationship. The reason the chamber pressure is lower with a coated bullet is because the coefficient of friction of a coated bullet allows it to slide down the barrel more easily.
Remember that the total force required to push a bullet down a barrel is directly proportional to the coefficient of friction between the bullet and barrel.
As a result of using coated bullets, a drop of 5% in pressure (fairly accurate estimate) often equates to a velocity loss of only 1-2%.
Usually that amount of velocity loss is still within a harmonic node (though sometimes it's not of course).
The last part of the puzzle involves the relationship between pressure and temperature. Taking me back to college physics...
PV=nRT where P is pressure and T is temperature. So you can see that decreasing pressure by 5% will also decrease temperature by 5%. The decrease in temp. may be enough to drop the flame front below the threshold for the steel to oxidize/erode.
Though the lower temps may not be a dramatic enough difference to altogether prevent throat wear, they're definitely enough to increase barrel life by a measurable amount.
Finally, coated bullets can usually achieve the same velocity as bare bullets with lower chamber pressures. So that's a win-win. Especially when good brass is $1-1.50 each! There's money saved already...
Remember that the total force required to push a bullet down a barrel is directly proportional to the coefficient of friction between the bullet and barrel.
As a result of using coated bullets, a drop of 5% in pressure (fairly accurate estimate) often equates to a velocity loss of only 1-2%.
Usually that amount of velocity loss is still within a harmonic node (though sometimes it's not of course).
The last part of the puzzle involves the relationship between pressure and temperature. Taking me back to college physics...
PV=nRT where P is pressure and T is temperature. So you can see that decreasing pressure by 5% will also decrease temperature by 5%. The decrease in temp. may be enough to drop the flame front below the threshold for the steel to oxidize/erode.
Though the lower temps may not be a dramatic enough difference to altogether prevent throat wear, they're definitely enough to increase barrel life by a measurable amount.
Finally, coated bullets can usually achieve the same velocity as bare bullets with lower chamber pressures. So that's a win-win. Especially when good brass is $1-1.50 each! There's money saved already...
I suggest you talk to Dan Lilja, John Krieger, and Bill Sutton ( Hart barrels). If you have irrefutable evidence that bullet coatings extend barrel life then send it in to this website so that it can be published.
One more negative to consider- if you're shooting at the high end of load density (which is typical of many SR BR chamberings) you may not get that extra 1/2 grain of propellant in the case as you would be able with naked bullets.
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