150 SMKs and the 6.5 x 284 ***UPDATE***

Discussion in 'Big Stuff--7mm, 30 Cal, .338+' started by ShootDots, Jan 31, 2018.

  1. 1shot

    1shot

    Joined:
    Feb 19, 2006
    Messages:
    1,925
    I have my bbl. throated for the 150 SMK for optimal bullet placement in the neck. The bearing surface is so much longer with the ELD-M that it would clearly be into the powder collumn. after the throat has eroded somewhat, I'll give them a whirl.
    I hope this helps,

    Lloyd
     
  2. Longrange57

    Longrange57

    Joined:
    Jun 22, 2018
    Messages:
    137
    Understand!
     
  3. whatwind?

    whatwind?

    Joined:
    Mar 19, 2015
    Messages:
    134
    Reminders
     
    TZaun likes this.
  4. 284winner

    284winner Gold $$ Contributor

    Joined:
    Dec 6, 2015
    Messages:
    3,066
    Old thread I know but speed isn't everything but accuracy is. The 5Rs bring that to the table even if you can't run bullets as fast. Technology is moving faster than the barrel companies are. Relax, they'll catch up. Accuracy is there better than ever before.
     
  5. FrankG

    FrankG

    Joined:
    Jul 27, 2006
    Messages:
    401
    The 5R does help fight bullet failure. I’ve maintained it now for several years and earlier this year both Hornady and Sierra have confirmed it to me.

    What does 284winner mean you cannot run the bullets that fast in a 5R?

    Technology is moving faster than barrel companies? You sure about that?
     
  6. 284winner

    284winner Gold $$ Contributor

    Joined:
    Dec 6, 2015
    Messages:
    3,066
    I don't believe the 5Rs cause bullet failure. I don't believe they are as fast as some others are. Certainly just as accurate. Yes, IMO, I think bullet technology is actually faster than barrel technology. At least in the last few years.
     
  7. ShootDots

    ShootDots Gold $$ Contributor

    Joined:
    Jan 9, 2008
    Messages:
    4,898
    One of the things we need to remember and keep in mind is that from the early days of Benchrest competition, thinner bullet jackets were used for competition. With the evolution of long range competition, heavy for caliber (read that LONG) bullets and very fast twist barrels to stabilize those bullets, heavier jacket had to come into being. How many times have you heard "I would like to use the Berger HUNTING bullets for competition"? The reason is, I believe, is that they are a tad bit more accurate than their heavier jacketed competition counterparts. The problem is, now that we have fast twist barrels, is just how THICK of jackets do we need in order to keep bullet failure from happening? I believe this is still being investigated! You may even see such "warning / disclaimers" in the near future of " minimum 7 twist barrel with 5R rifling".. Both barrels and bullets are developing at break-neck speed, which will demand a higher level of selection, both to the projectile used and the necessary barrel, to minimize or eliminate bullet failure. NOBODY wants to be at "The Nationals" and have bullet failure!
    Another thought: The jury may still be out on "Gain-Twist" barrels. However, it does stand to reason, on fast twist barrels, that a gain twist may also aide in lessening the prospect of bullet failure.. I would bet a substantial sum that that is also in the investigative stages..
     
    Last edited: Jun 14, 2019
    Grimstod, Zero333, FrankG and 2 others like this.
  8. 1shot

    1shot

    Joined:
    Feb 19, 2006
    Messages:
    1,925
    As I have stated before, I've had the 150 SMK's over 3,100 fps. without any bullet failure out of a 7.5 twist 5R barrel from Bartlein. I specced this barrel with the expressed purpose of shooting the 150 class bullets and it does so very well.
    I hope this helps,

    Lloyd
     
    muleystalker, FrankG and Mulligan like this.
  9. FrankG

    FrankG

    Joined:
    Jul 27, 2006
    Messages:
    401
    Fast as some others how? Do you mean 5R style rifled barrels produce less velocity compared to other styles? If that is what you mean that is not accurate.

    Over the last about 5 years we’ve made ammunition test barrels for Federal Cart., Hornady, Sierra, the Gov’t etc....you name the caliber it is has probably been tested, .223, .308, 7mm’s, .300wm, .300 Norma, .338 Lapua, .260 Rem., 6.5CM are just some that come to mind. With the equivalent total surface bore area, a 4 groove or 6 groove barrel in the proper caliber and with the same chamber reamer being used etc..the same loads etc...the other style of rifling in the barrels didn’t produce anymore or any less velocity.
     
  10. Geno C

    Geno C

    Joined:
    Aug 2, 2014
    Messages:
    863
    Every 5r I’ve ever had has been noteably faster than any equivalent 4 or 6 groove. Not to dispute you Frank, you have a lot larger sample than I’ll ever have, but that’s my experience
     
  11. FrankG

    FrankG

    Joined:
    Jul 27, 2006
    Messages:
    401
    Geno C, No sweat!

    What everyone needs to think about is in the examples I’m listing.....the bore and groove sizes are held to the correct tolerances as well as the total surface area of the bore. The only difference is the number and style of the grooves.

    Even the same chamber reamer and ammo lots, reference ammo etc...used where the same.

    When a shooter has a barrel chambered and they start changing the spec’s of the bore or groove size (or in most cases you don’t know the exact bore and groove dimensions) and or a minor difference on a dimension change on the reamer you can easily effect pressure and velocity.

    A good example we we’re involved in was on .300AAC blackout. The reamer cut the throat diameter .0001” undersize and the bullets where at max. Diameter tolerance. The combination drove up pressures 4K-6k psi and drove up pressures almost 100fps.

    Seen some 6.5 test barrels not made properly about two years ago (not ours) and when we we’re asked to check the barrels for opinions etc...the bore and grooves where .0005” undersize and it drove up pressures 8k-10k psi and drove up velocities 150-200fps.

    A minor change/difference can make a big difference.
     
    Geno C likes this.
  12. 1shot

    1shot

    Joined:
    Feb 19, 2006
    Messages:
    1,925
    Since the advent of the 5R barrel configurations, I have found that these barrels pressured out at a higher velocity than other similar four groove barrels. I have 5R barrels in 6MM through 308. It appears to me that the larger the caliber, the more evident the changes are . In 6MM, I see no difference between 5R and standard for groove rifling. However, on 6.5 and above I have seen a documented difference in the amount of powder/pressure that a given barrel will tolerate over a 20 shot for record string.
    As an aside a note, I have found that five groove barrels clean much easier than the four groove counterparts.
    I hope this helps,

    Lloyd
     
    Last edited: Jun 15, 2019
  13. ebb

    ebb

    Joined:
    Oct 31, 2010
    Messages:
    1,866
    Frank have any of the US barrel companies started using the honing machine that was in the bulletin a few years ago?
     
    FrankG likes this.
  14. 284winner

    284winner Gold $$ Contributor

    Joined:
    Dec 6, 2015
    Messages:
    3,066
    Your correct, I'm sorry. I didn't mean to generalize that Bartlein barrels are slower than some other companies barrels. It's my experience from the Bartlein vs Broughton barrels I have had, the Broughton's were all faster. In the beginning, mid-range and end of the barrels lives. Same loads, same barrel lengths. Shouldn't have said "Others". One other barrel makers barrels were faster than my Bartlein's. Maybe your test results showed Bartlein to be faster than all others. My results didn't match those that yours did. I had a choice of buying a Bartlein or Broughton when building a 338 Lapua Imp rifle. I chose the Broughton simply from my results knowing I was striving for the most velocity I could get from the barrel length I have. I knew my Broughton barrels were the fastest of all my barrels so that choice made sense. Wasn't stricktly accuracy because if it was, Bartlein may have been my choice.
     
    Last edited: Jun 16, 2019
    Geno C likes this.
  15. FrankG

    FrankG

    Joined:
    Jul 27, 2006
    Messages:
    401
    No offense taken.

    That’s why I did want to point out...

    With everything being equal in terms of bore size and groove size and same chamber etc...the style or number of grooves for the most part will have no impact on pressures and velocities.

    Unless you know the bore and groove size to the 4th decimal place there are just too many variables to make a accurate comparison.
     
  16. FrankG

    FrankG

    Joined:
    Jul 27, 2006
    Messages:
    401
    We did all the testing on the prototype machine as we we’re approached by Sunnen Hone to do it. We did. Initially it was suppose to be a 6 month test but we ended up running the machine for over a year I believe it was. We liked it so much we bought two!

    To my knowledge Benchmark bought one and just last year I want to say Krieger bought one. Don’t know of anyone else using one off hand.

    Later, Frank
     
  17. ebb

    ebb

    Joined:
    Oct 31, 2010
    Messages:
    1,866
    The Sunnen machines are pretty much the high water mark for auto machinist to bore and line bore crank shaft bearings. I didn't think that they would come out with some thing that was sub par. I asked this question to point out to others the barrel industry is working just as hard as bullet makers to keep making better products. I have a 7mm rum and I bought barrels from you last time it needed attention. I like the speed I can get with the 180 Berger, so I just buy them 2 at a time.
     
    FrankG likes this.
  18. Raythemanroe

    Raythemanroe Bullet Whisperer Silver $$ Contributor

    Joined:
    Oct 28, 2012
    Messages:
    3,852
    38-39g of H4350 146g Eazors

    Ray
     
    Last edited: Jun 17, 2019
  19. 284winner

    284winner Gold $$ Contributor

    Joined:
    Dec 6, 2015
    Messages:
    3,066
    I only know it's a 5C barrel. All of them are that I own and they shoot well. Can't say better than my Bartlein's but well. Bartlein barrels will always wear and action in my safes and be in various hunting rifles I own. My 284 shoots better than any rifle I own with a Bartlein HV barrel. For some reason that I can't explain, my Broughton's just are a bit faster
     
  20. FrankG

    FrankG

    Joined:
    Jul 27, 2006
    Messages:
    401
    Get the bore and groove measured to the 4th decimal place. That can tell you a lot and would be a good start.
     

Share This Page