Very long barrels for the 6BRX

[NateG]

Has anyone tried a very long (~34") barrel in the 6BRX?

I normally use 32" inch barrels, but with my new INCH, with the action further back compared to the trigger, the breech is closer to me, so the sight radius is a bit shorter than my set up with 32" barrels and Rem-clone actions. So, I got to thinking that a 34" barrel would get me back to my normal sight radius without using a bloop tube--and if the BRX can use the extra barrel length, I could get to 3050ish fps without working the brass as much.

So, is the long barrel crazy? Good idea? Worked before?

 

[rcw3]

I have run 32" 6mm barrels before but not a 34" barrel. No particular reason I can see why you would not be fine with a 34" barrel. If it turns out not to be ideal, it can always be cut down and re-crowned. I doubt with the burn rate of powders appropriate for a BRX you are going to get any extra velocity from the additional 2" of barrel beyond 32". Like you, I dislike using bloop tubes if I can do it with the barrel instead. A blank to finish at 34" will certainly cost more, but so does an extra bloop tube, and I suspect the extra length of barrel would be less than a bloop tube add on.

Robert Whitley

 

[MarkS]

Guys,

I have gone the other way. I don't like paying extra for the barrel, and you gain very little velocity. I had a 28" that I shot 3 IBS 600 yds records. My gunsmith Mike Davis, after he had talked with Richard Schatz has gone to 26" barrels. Richard has shot 26" barrels with a 6 Dasher for a long time ( look up his match results ). I have found out that 2975 f/s is the best speed. Mike is shooting a 26" 6BR and my new 6BRX barrel is 26". It is shooting great.

Mark Schronce

 

[rcw3]

Mark

I think there may be a misunderstanding in your post. Nate is doing the extra length for sight radius (with a front iron sight on the end of the barrel). I assume your shooting does not involve that aspect of things.

Robert

 

[NateG]

I don't think I any of the barrels I've had could have reached 2975 without the 30-32" inches of tube.

And, yes, even if the 34" is no better than 32", I'd be interested in it (sight radius thing), as long as 34" isn't *worse* than 32" in some important way. (e.g., doesn't shoot well, blows up bullets)

Thanks for the replies, though.

 

[alf]

FYI, my Dashers run at 3050-3060 in 28" with 105/107's.

 

[rcw3]

FYI, my Dashers run at 3050-3060 in 28" with 105/107's.

For bench shooting of 5 - 10 shots, you can run "hot rod" like that, but for a prone shooter the group will likely never hold together for 22 shots in a row at that level with no break - back it off or blow your group apart on the back 10 and you can easily lose your match or the day's aggregate. Just my opinion FWIW.

Robert

 

[alf]

For bench shooting of 5 - 10 shots, you can run "hot rod" like that, but for a prone shooter the group will likely never hold together for 22 shots in a row at that level with no break -

Robert

For IBS 1K HG, during ugly conditions, I might run between 10 and 15 sighters, then run my 10 shots ASAP, and I never see a break down in group size.

Or at 600, during the 6 minute sighter period, I've run 10+ rounds, then the 5 shot group, the immediately go into another 2 minute sight period and shoot 5+ sighters, and then another 5 shot group. Again, no break down in groups.

You may consider it "hot rodding", but I can take 1 piece of brass, and shoot, neck size, load, and shoot again for 12+ times before it starts to get snug, calling for a bump.

In my humble experiences.........

 

[Laurie]

Nate,

you won't lose velocity with anything beyond 32", albeit you'll gain very little, probably less than 10 fps per inch at that low an expansion ratio. But as pointed out, MV plain and simple isn't the objective anyway. I don't see why it should affect accuracy adversely for your type of shooting. You may find it's a bit more finicky on loads and a little harder to find a sweet spot at suitable velocities than in a shorter stiffer tube, but it is a 6BRX after all, not a .30-338 WBY Magnum. When all's said and done you can always have the barrel shortened at no great expense if it doesn't work out - but I bet it will. If you go ahead, be sure to revive the thread and let us know how things work out. It's always interesting to see what happens when people try things 'outside the box'.

Laurie,
York, England

 

[rcw3]

For IBS 1K HG, during ugly conditions, I might run between 10 and 15 sighters, then run my 10 shots ASAP, and I never see a break down in group size.

Or at 600, during the 6 minute sighter period, I've run 10+ rounds, then the 5 shot group, the immediately go into another 2 minute sight period and shoot 5+ sighters, and then another 5 shot group. Again, no break down in groups.

You may consider it "hot rodding", but I can take 1 piece of brass, and shoot, neck size, load, and shoot again for 12+ times before it starts to get snug, calling for a bump.

In my humble experiences.........

But then again you are probably not running with a medium Palma contour barrel either, and likely you had a chance to and did clean your barrel before you started shooting the sequence (and a prone shooter would typically not). Any way you cut it 3050-3060 fps with a 105-108 gr. bullets in a 6mm Dasher is very near "red line" (or even over "red line") for that cartridge and that's why I say it's a "hot rod" loading for a Dasher.

Robert

 

[alf]

I shoot moly, the barrels are 1K contours, and I don't clean at all during the day.

 

[rcw3]

I shoot moly, the barrels are 1K contours, and I don't clean at all during the day.

Hmm - moly - a critical additional piece of info. It does make a difference in barrel heating and fouling, especially around and over 3000 fps. It just goes to show, one has to be careful on what info you rely on with postings as you may not be getting some key info that can make a difference in the whole analysis.

 

[alf]

'pears only one of us was jumping to conclusions.......

 

[Moderator]

A few years back, with the help of Jackie Schmidt, we did a cut-down test with a 6mm BR. We started at 33" bbl length and cut it down in 1" increments to 28". The total velocity loss was 40 fps, and it was pretty linear -- about 8 fps per inch.

Conceivably you might get a little more velocity from a Dasher (vs. a 6BR) because it is burning more powder.

When looking to achieve certain velocity goals (e.g. 3000 fps from a Dasher) keep in mind that some barrels really are faster than others. We've seen up to 140 fps spreads between different bbls, of equal length, fired with the exact same 6BR load. Unfortunately, I don't have any good way to predict what barrels are slow and which ones are fast, although a good internal finish (high quality lapping job) seems to help.

 

[lynn]

Listen to Alf.
All of our 6Dashers are running between 3025-3055 fps using 28-30 inch barrels and anywhere from from 33.2-33.5 grains of RE15.
We shoot 3 five shot groups in lightgun with unlimited sighters then 3 ten shot groups in heavygun with unlimited sighters and don't swap guns or clean them.
Lynn

 

[rcw3]

Listen to Alf.
All of our 6Dashers are running between 3025-3055 fps using 28-30 inch barrels and anywhere from from 33.2-33.5 grains of RE15.
We shoot 3 five shot groups in lightgun with unlimited sighters then 3 ten shot groups in heavygun with unlimited sighters and don't swap guns or clean them.
Lynn

Lynn

Good posting - I understand and am certain you know of what you speak here.

I am not saying what Alf says is not true for the bench rest shooting discipline, but I will say it typically does not exactly work for the high power rifle and prone shooting discipline (which is what Nate the original poster is involved with). I can run my Dasher and BRX up over 3000 fps too with the 105-108 gr. bullets, they typically run great like that 12 to 15 shots in a row without break up there, but run them 22 shots in a row with no break and the groups will typically blow apart at the back end unless they are backed off some. I have done 22 shot group testing many times (more than I ever wanted or expected to) on load work ups and they typically just do not hold the whole way with a high power or prone rifle set up. There's a difference in the equipment and disciplines and what the bench rest shooters can get away with, many high power rifle and prone shooters cannot in terms of pushing the top end loads.

What you typically see with the winning shooters in high power and prone shooting, with the BRX and Dasher, are people shooting in the 2900's with those cartridges. They load their ammo all ahead of time and bring it to the match, and the load needs to be forgiving.

I am not saying one discipline is better or worse than the other, but they are different, and to just pitch out velocity numbers with nothing more is not really helpful.

Robert

 

[rcw3]

I have always questioned how much the "meaty" barrel contour can factor into this whole discussion (with Alf, Lynn and Donovan) as many F-Class and bench rest barrels are a good bit heavier throughout their length than the contours of the barrels of most high power or prone shooters. Take a look at a typical Krieger Heavy Varmint #17 Contour vs a Medium Palma contour - huge difference in the stoutness and the amount of mass with the heavy bench and F-Class barrels to soak up heat, stress, etc.
Robert

 

[queen_stick]

You guys that stated that you would prefer NOT to use a bloop tube... why is that? (this subject doesn't apply to me, I'm just curious why).

Walt

 

[rcw3]

Donovan

Yes - but what's the contour of your F-Class barrel? I suspect it is pretty heavy - most are because there is a generous weight limit for F-Class, and a lot of guys run straight pipes 1.250" dia. all the way, or a 30" or so #17 contour but with a 1" dia. muzzle.

Your LV barrel above is still a straight taper and likely also is at least a full pound of steel heavier than a typical Medium Palma barrel (that has a double taper).

The issue in my mind is not how fast one can push bullets (heck anyone can push bullets fast), it's how fast you can push them and keep them tight and accurate for the full course of fire, and for high power or prone that's at least 22 shots in a row with no break. With that course of fire a heavier barrel may provide an advantage to run slightly hotter loads over the full course of fire before the groups come apart.

Robert

 

[NateG]

You guys that stated that you would prefer NOT to use a bloop tube... why is that? (this subject doesn't apply to me, I'm just curious why).

Walt

They're a pain to clean, another thing to buy/install/mess with, and something else that could be screwed up.

But, I don't hate them so much that I won't use them... at this point my space gun and half my tube guns have them. (All are epoxied on, though another one on a 1411 (smallbore gun) is clamped on)