Very long barrels for the 6BRX

[TonyR]

Issues related to this topic have been discussed on another thread:

http://www.accurateshooter.com/forum/index.php/topic,3763748.0.html

My 6mmBR has a 31 Kreiger Heavy Palma barrel on it and it has given me outstanding accuracy with loads up to 30.5 grains of N540 shooting 3 F-Class matches per day between cleanings.

I have heard this issue raised more often with some of the hot 7mm Magnums in string fire matches even with straight 1.250 cylinder barrels but some of them are running up to 71 grains of powder. I shot a 30 round test string with a 7mmBooBoo loaded with over 71 grains of powder and a 180 grain bullet going over 3100 fps through a 30 inch Heavy Varmint barrel with no problems. I doubt that the risk of failure is high enough with a 6BRX that chambering a barrel to test the idea would be a waste of money.

 

[rcw3]

Donovan

Well then, I guess the answer is, you do what you do that works for you and I'll do what I do that works for me. My impression is you are taking the position that barrel contour and weight have no effect on whether a barrel can run long strings of higher velocity firing without a break and still stay accurate. We all have a lot of experience and have shot a lot of rounds over many years (that's a non issue), but I don't see you saying that you actually shoot any medium Palma contour barrels and do 22 shot sustained fire group testing with those barrels, so I am not really sure you can apply what you do to that situation.

Robert

 

[308nate]

Robert,
I'm not a dasher shooter, but figured I would join in here as what you are saying doesn't really make sense to me.
Question 1. What is hot rodding? What are the ill effects of it? In my opinion hot rodding wrecks brass and doesn't really have a lot to do with sustained accuracy. If you feel the hot rod round heats up your barrel that much faster, then the 6.5-.284's would definitely be out for high powered shooters in palma contours even at non "hot rod" loads as the heat generated would be significantly more due to more BTU's burned. This is definitely not the case.

As far as barrel contour with hot rodding rounds, in my experience barrel contour has nothing to do with brass life when hot rodding. even some #3 contours have 1.25 breech diameters. What wrecks a case when over pressuring is action stretch and breech stretch (and case base expansion, which has nothing to do with contour as it's not even suported in the chamber.), in other words a straight 1.25 bull would have no more breech or action stretch than a #3 with a 1.25 breech. All this said I build a lot of long range hunting rifles, dealing with big calibers and light contours as well as numerous high power and "F" class rifles. In 09' I won the ND 1,000YD regional "F" class match and still hold the state record for highest aggregate. This was done with my personal 6x47 Lapua, 105 Berger's, 3175FPS, 26" #5 contour Brux barrel(heavy sporter..lighter than a palma contour).


It is easy to draw conclusions to soon.(get a barrel that fouls up to fast.) I have personally had over six, 6x47's and am still learning things about the round.
They have all liked almost the exact same load and the velocity being 3150 -3175FPS. I'm still on my original 200 pieces of brass, that makes well over 20 firings a piece and showing no signs of giving up soon.

So, nothing wrong with the lower accuracy node, I typically like to run the higher accuracy node if there are no ill effects. It just gives a little more wind advantage. I have several buddies that shoot the dasher and like Donovan, do well at the higher accuracy node and don't feel it falls into hot rodding as they claim they are getting good brass life. The claims that hot rodding has accuracy problems in a palma contour just holds no water, anyway just my thoughts on the subject. I'm all for keeping it safe and if it's working for you keep hamming that X ring! but keep your mind open as things may get better. Once we figure "we are there and know it all" there is no room for improvement.....that would be boring!.

All the best,
308nate

Donovan

Well then, I guess the answer is, you do what you do that works for you and I'll do what I do that works for me. My impression is you are taking the position that barrel contour and weight have no effect on whether a barrel can run long strings of higher velocity firing without a break and still stay accurate. We all have a lot of experience and have shot a lot of rounds over many years (that's a non issue), but I don't see you saying that you actually shoot any medium Palma contour barrels and do 22 shot sustained fire group testing with those barrels, so I am not really sure you can apply what you do to that situation.

Robert

 

[in2deep]

I don't know much except that after shortening my sight radius 4 inches after switching to a short-barreled rifle with no bloop tube I am shooting so much better and get a much clearer and quicker sight picture than before and no more eye strain or headache after a long match.
To me the idea of a longer sight radius offering theoretically better geometry or line to the target is questionable and subject to many other variables like ones vision, aperture size and light transmittal plus other stuff and impossible to quantify and subject to individual needs.
It was really hurting my scores for a year till I figured it out by accident and went against what everybody said was optimum but your mileage may vary.

 

[rcw3]

Definition of "hot rodding" - It's a verb and it means (literally and by dictionary definition) to drive fast (i.e. running at a high velocity).

I mean this with no disrespect to people on the forums, and I address this paragraph to no one in particular, but sometimes reading the velocities and results people tout on postings is a little like listening to "fish stories". It always seems there's someone out there who gets super high velocities from the cartridge they shoot and of course their rifle also shoots "lights out" like that "all day long".

 

[308nate]

So then that would mean all high power cartridges would fall under "hot Rodding" as they are all driven fast and at high velocities? Therefore it sounds like your dasher is being hot rodded as well ;D

No offense taken by your remark and I do understand some of your frustrations yet at the same time I find it amusing when somebody claims to know so much about something and they have so much faith in their understanding that they can't learn anything new. when it comes to velocities and cartridges I have decided to be very slow to draw definite conclusions as many times I personally have been wrong on my conclusions as well as seen many other people's "definite conclusions" be quite wrong.

Although I am not a bench-rest shooter I know several fairly well and will say these guys definitely know their stuff. Their reloading techniques as well as when they are in the node.

When you are running the upper end you need to have good reloading techniques, you need to know what you are doing. I would say more so than when running lower velocities as lower pressures are more forgiving for "sloppy" reloading....in my opinion

So keep aiming for perfection!
To you benchresters, 2" at a thousand yards is good, but you can do better than that. I know you will ;D ;D
308nate

Definition of "hot rodding" - It's a verb and it means (literally and by dictionary definition) to drive fast (i.e. running at a high velocity).

I mean this with no disrespect to people on the forums, and I address this paragraph to no one in particular, but sometimes reading the velocities and results people tout on postings is a little like listening to "fish stories". It always seems there's someone out there who gets super high velocities from the cartridge they shoot and of course their rifle also shoots "lights out" like that "all day long".

 

[rcw3]

308nate

I understand you point on the definitional problem with the wording of "hot rodding" as I guess there is a subjective element in there.

I consider "hot rodding" when you run a cartridge at or near its max loading and you are getting close to going "over the top". For a 6mm Dasher running the 105-108 gr. bullets, I consider that point somewhere around or close to 3050 fps. I don't consider that point with a Dasher 2900 - 2950 fps. Now I know that I have just said 3050 fps, someone is probably going to get on this forum and make a posting that they run their Dasher at 3100+ fps and never get any pressure issues and have 25 re-loadings on their brass without having to bump the shoulder or body size - that's how it goes - there's always someone out there that wants to "puff" about their velocities.

The reality is, if you are in a particular shooting discipline or competition, you have to do and stay with what works if you expect to do well. Bench rest shooters seem to suggest they run a good bit higher velocities than what I see winning prone and high power shooters do, but the disciplines are different, the course of fire is different and the equipment is different. A 7 lb + pound barrel typically does not work for a prone or high power shooter but it works fine in many bench rest applications.

I don't know why people seem to be incredulous when I say that based on my of testing 22 shot groups (shot as a continuous course of fire) lighter or medium weight Palma type contour barrels with at or near max loads don't typically stay tight and accurate the whole way, and in order to get there and have the group stay tight you need to back off the load some.

Robert

 

[alf]

Robert,

You're like arguing with a women........

Despite the evidence to the contrary.........

You're still right.........

 

[rcw3]

Robert,

You're like arguing with a women........

Despite the evidence to the contrary.........

You're still right.........

That's funny Alf (actually it's not at all considering the inference you are making about women) but please show me the evidence.

Where are the test results of people taking light and medium Palma contour barrels and doing 22 shot group testing with a sustained course of fire with hot loads vs mild to moderate loads?

I have never seen anyone who did this and published any such results, but I have done such testing repeatedly.

FYI, here's a bit of evidence:

Nate (the starter of this thread and as far as I understand from the postings) shot his 6mm BRX shooting his bullets in the 2900's last month on March 13, 2011 in Bridgeville Delaware at a 600 yard match in a 3 x 600 when he shot a 600/43X (200/15x,200/15x and 200/13x) which is a perfect score with an excellent x count.

A quote from Larry Isenhour speaking of his 2009 IBS 600 yard record shooting the BRX: "I’ve run ‘em as fast as 3050 fps with the BRX but the accuracy is better at 2970"

Sam Hall's June 12, 2010 IBS 600 World Records were shot with his BRX running 32 gr of Norma 203B powder and the 105 Berger VLD's (in my BRX that runs at 2915 fps with an ES of 18 and an SD of 7)

Sherri Gallagher won the Camp Perry Nation High Power Rifle championships last year running her 260 Rem with a 600 Yard load running 142 Sierras around 2750 fps (at least according to Emil Praslick) and she hammered things with that. That's not exactly a hot rod velocity with those bullets and that cartridge.

Gary Eliseo shot the Berger Southwest Long Range Nationals recently and placed very high in the standings using his 6mm BRX running 107 Sierras at "2940 fps".

Watch the YouTube video of Robert Hoppe (the 2009 NBRSA 600 Yard champion) on working up loads for the Dasher, his target accuracy velocity is "2930 - 2990"

Robert

 

[NateG]

Just to clarify... the 600 I shot at Bridgeville was with a 30" barrel, and at 3020fps. My comment about the speed was that I doubted I could get much more than 2950ish with some of the shorter barrels that were mentioned in the thread, at least, not if my gut feeling about how much speed I'd lose with the shorter barrel is any where near right...

But, the load shoots just fine at the end of a string. In the first match, I had a different seating depth (in the lands, usual VLD loading method. The other load was jumped a long way), but it didn't shoot as well. The second match I coulda-woulda ended with 10 Xs on the back 10, but the wind got squirrelly on the last two shots, and I just missed scratch Xs at 9 on both shots. I would describe the load as "on the warm end" in my gun, in that the load would have to shoot *really* well to justify loading much hotter than I was. (Brass holds up fine, but some primer flattening. The load is 32.9 grains of 203b. I shot that same load for several thousand rounds in my previous barrel. I'm on the same batch of about 300 pieces, so I'm looking at 10+ firings at this point. I'll take that.)

 

[rcw3]

Nate

I stand corrected - my understanding from the postings was you were not over the 2900's (your earlier posting is suggestive of that) but nothing like getting it "straight from the horse's mouth". I have not had good results up that high with my BRX or Dasher with a 22 shot string, but in the 2900's I have. By the way - superb shooting!

Robert

 

[rcw3]

Nate

By the way - you run moly or naked bullets?

Robert

 

[rcw3]

Alf, NateG, 308nate & Donovan

In my eyes, my postings on this forum are not meant to be personal attacks at you, your experience, your wisdom or credibility. I have been perplexed for a few years over the phenomenon I brought forward (i.e. barrel contour vs hotter loads) and I have done a lot of testing relating to it that seems to confirm what I put forward in this thread. I am trying to ferret out the forum postings and information I receive without just blindly accepting things. To some extent it may seem I am a bit testy in questioning the information you have brought forward, but that is more because I am trying to sort out if what you do is directly applicable or there's something else in the mix that is in play. If you feel I am over the line, then I apologize to you all. Good luck to you all and please enjoy your shooting!

Robert

 

[TonyR]

Robert.
I believe that your question about moly is relevant as is the question of barrel design. Somewhere on this site there is an interview with John Whidden about his use of the 243 Win for long range. I can't find it or I would post the link, but as I recall, the gist of it is that he runs the 105 thin jacket VLDs at somehere in the 3400 fps region using coated bullets and barrels with shallow grooves and canted rifling, such as a Broughton 5C, which don't engrave the bullet jacket deeply. I don't recall any mention of barrel contour or twist.

 

[NateG]

Nate

By the way - you run moly or naked bullets?

Robert

Naked. I tried moly a while back in a service rifle, where it doesn't really make much of a difference, and I haven't tried it since then.

 

[Heavies]

Robert.
I believe that your question about moly is relevant as is the question of barrel design. Somewhere on this site there is an interview with John Whidden about his use of the 243 Win for long range. I can't find it or I would post the link, but as I recall, the gist of it is that he runs the 105 thin jacket VLDs at somehere in the 3400 fps region using coated bullets and barrels with shallow grooves and canted rifling, such as a Broughton 5C, which don't engrave the bullet jacket deeply. I don't recall any mention of barrel contour or twist.

I really like the interview.
http://www.accurateshooter.com/shooting-skills/john-whidden-shares-championship-secrets/

 

[TonyR]

Robert.
I believe that your question about moly is relevant as is the question of barrel design. Somewhere on this site there is an interview with John Whidden about his use of the 243 Win for long range. I can't find it or I would post the link, but as I recall, the gist of it is that he runs the 105 thin jacket VLDs at somehere in the 3400 fps region using coated bullets and barrels with shallow grooves and canted rifling, such as a Broughton 5C, which don't engrave the bullet jacket deeply. I don't recall any mention of barrel contour or twist.

I really like the interview.
http://www.accurateshooter.com/shooting-skills/john-whidden-shares-championship-secrets/

Heavies.
Thank you very much. So it's 105 molyed VLDs at 3300 fps from a 1:8 32 inch Broughton 5C light Palma contour. More detail than I remembered. Interesting facts.

 

[Heavies]

No prob!
3300 fps, that's smokin!

20 3/4 moa and 6 moa windage 10mph @ 1k

Cool!

Can any ol' body get that kind of results? Don't know for sure, but it works for him. ;D

If I had the dough, I'd try it! I wonder what kind of barrel life goes with that?
No such thing as a free lunch.

 

[MarkS]

Mike Davis, Larry Isenhour, and myself were shooting 6BR at 1000 yds before most anyone at Hawks Ridge NC, around 2002'. We started shoot 6BRX about the same time in 600 yds Brenchrest. We found that our loads and speed were very close to the same 33.0 to 33.5 gr Varget with a 105 gr Berger and running 2975 f/s.I was doing this with a bumped 6BR chamber in a 25" barrel. Mike and I talked on my last barrel barrel, and went with a 26" barrel, and run sub 3000' speeds. Richard Schatz has been running a 26" Dasher for years with the lower speeds. I don't worry about speed.

Mark Schronce

 

[tclaunch]

Mike Davis is the MAN in my book. I went to Piedmont last year 101/2 hr drive to hopefully shake his hand and personally thank him for all he has done to help me get some things straight in my mind. I was lucky and got a 1.250" 8t .237" Krieger from him chambered with the retired BRX reamer. I was working loads for that barrel, and the 3rd day @ 600 shot 2 back to back sub 1 1/2" groups. ;D I later chronographed my load on a very similar day, and the 103 Spencers were running 2979.

I named that barrel "Pressure Cooker", when the World Record holder competitor/gunsmith, chambers you a barrel and uses his multiple world record setting reamer, it surely seemed a good name. His knowledge was unbelievable about certain things I had noticed and ran past other smiths that didn`t seem to have an answer for.

Cannot leave out another few guys who were very helpful and have only met both, Samuel Hall and Rodney Wagner, Al Forbes, Donovan Moran. If you want to see what Rodney can do click on the IBS site for results, click on Piedmonts last match and see how his Lt gun was working!!!. I wish all these gentlemen the best, and hopefully can share the line with them again soon. Tim Claunch