6BR, 6BRA, Dasher for 87-Vmax

[RAG]

I wouldnt say that, lots of guys here shoot way more than I do. I was into it a few years ago more than I am now. A lot of guys like the smaller bores so they can watch impacts. I did a 22 dasher but went back to the 6mm. The smaller bore didnt really kick that much less and I found the 6 much easier to keep in tune and less picky. Plus those 6mm 55-60 grain bullets at 4k will throw a ground squirrel 20 feet.

Well, before I ended up picking up a used BR gun that came with new Dasher barrel, I was planning to have you chamber up a 6BRA for me...for this very reason. Throat life. I'll be monitoring closely. On one hand, I was able to drive the 88 Bergers 3,500 FPS without notable pressure signs (AA2520) with the Dasher, which is nice, but I'll be depressed if it burns out too quick. Now that I'm "pot committed" with a buncha fireformed Dasher brass, it might be a tough call (between 6BRA and Dasher) once this barrel burns out. I wish there was more "data" on the barrel life differential between a short neck and longer neck.

For high volume varminting, my previous 6BR barrels each went about 6,000 rounds. My most recent one went 6,000 and was (is) still "generally" shooting .25" groups at 100...just firecracked pretty bad and I was getting tired of the fouling so I put a new barrel on. IF I were using the same cool burning powder and 55gn bullets, I'd sure hope the Dasher would go 4,000...if not, the trade-off for extra 100 fps simply would not be worth it at all!

 

[RAG]

Had a McGowen 28” 1:8 twist chamber with BRA reamer for fclass: .268 neck with .150” free bore. 87gr V-max with 36.0 of CFE shoot 3350fps. Bipod/sand bag accuracy from 10# rifle and factory savage trigger is repeatable ragged hole .25moa 5shot groups at 200 yards. Love the fast twist barrels for lateral dispersion of body parts. Lol

Exactly my intentions! Just need my bore rider to show up so these fat bodied 87 Vmaxs will chamber reliably! In velocity testing with AA250, I was able to run the velocity with 88 VLDs up into 3,500s (28" barrel) before getting a little bolt pressure and ejector mark, so I hope to find a note in the high 3,400s! I sure hope I can get those 87s to shoot like yours...much cheaper, and much more explosive than the likes of the Berger 88VLD...but darn those 88VLDS are as accurate as the come.

 

[RAG]

I wouldnt say that, lots of guys here shoot way more than I do. I was into it a few years ago more than I am now. A lot of guys like the smaller bores so they can watch impacts. I did a 22 dasher but went back to the 6mm. The smaller bore didnt really kick that much less and I found the 6 much easier to keep in tune and less picky. Plus those 6mm 55-60 grain bullets at 4k will throw a ground squirrel 20 feet.

Oh, one more good topic for me...the 22 vs 6mm. I've been working on components to do a 22BR for quite some time. But as I analyze the numbers between a 6BR and 22BR, I'm starting to think the only real difference is reduced barrel life . Using verified BC data, the 55 6mm pushed 150 fps faster than the 22 equivalent is virtually equal, ballistic-wise. And surely no noticeable difference in recoil. Oh well, I'll probably still go for it and see for myself, or just to have something different. (I'd really like to do a 6BRA Short...short by about .060 to keep the body/shoulder junction in the same place and leave neck as long as possible to help extend throat life...but that'll be a project for another day!

 

[Alex Wheeler]

In the bench guns the throat movement is much less in the BRA. My last dasher barrel moved over .040 by the time I pulled it and I would expect .001-.002 per match weekend. Sometimes a little more. With the BRA you hardly see them move at all. I wouldnt say there is a huge difference in barrel life. They get pulled as soon as you see the accuracy falling off. Maybe you could get 500 more out of a BRA than a dasher but I wouldnt guarantee it.

 

[urbanrifleman]

80 grain Bergers from my new 8 twist Wilson 6bra 50 freebore.

I will be testing 87 vmax, 85 Sierra Hp, and 88 Bergers next.

 

[urbanrifleman]

Exactly my intentions! Just need my bore rider to show up so these fat bodied 87 Vmaxs will chamber reliably! In velocity testing with AA250, I was able to run the velocity with 88 VLDs up into 3,500s (28" barrel) before getting a little bolt pressure and ejector mark, so I hope to find a note in the high 3,400s! I sure hope I can get those 87s to shoot like yours...much cheaper, and much more explosive than the likes of the Berger 88VLD...but darn those 88VLDS are as accurate as the come.

That is really standing on those. I ran my 243 at 3550 with 80s in a 28 inch 10 twist barrel and that wasn't a mild load.

I'm going to test TS 11, AR COMP, and Ts15. 5 in the 6bra using the 88s. I have tons of them.

How do they splodey?

 

[RAG]

That is really standing on those. I ran my 243 at 3550 with 80s in a 28 inch 10 twist barrel and that wasn't a mild load.

I'm going to test TS 11, AR COMP, and Ts15. 5 in the 6bra using the 88s. I have tons of them.

How do they splodey?

Yeah, I suppose so! I suppose I have always stood on all my loads/cartridges, with very few exceptions...but the custom actions and Lapua Brass have always seemed to be up tot he task!

In this case, I think the AA2520 is a bit of magic. I started to notice/feel pressure with the 88s at 3,520 FPS, so I'll typically find a node somewhere between 50 and 100 fps below that.

 

[urbanrifleman]

Yeah, I suppose so! I suppose I have always stood on all my loads/cartridges, with very few exceptions...but the custom actions and Lapua Brass have always seemed to be up tot he task!

In this case, I think the AA2520 is a bit of magic. I started to notice/feel pressure with the 88s at 3,520 FPS, so I'll typically find a node somewhere between 50 and 100 fps below that.

It was 107 yesterday and 3330 out of my 25 inch barrel was comfortable with the 6bra and Berger 80s. After that the bolt got more stiff. I think I could have hit 3450 if I really tried.

It shot effortlessly at 3200.

 

[rayporter]

i have had some trouble with the 88 bergers disappearing before they reach the varmint once the barrel gets a little wear on it.

 

[urbanrifleman]

i have had some trouble with the 88 bergers disappearing before they reach the varmint once the barrel gets a little wear on it.

How did they blow up on the varmint ?

 

[rayporter]

a very good varmint bullet if it gets to the varmint.

 

[foxguy]

i have had some trouble with the 88 bergers disappearing before they reach the varmint once the barrel gets a little wear on it.

What is your barrel twist rate and do you know how fast they were traveling in FPS?

If you don't now the FPS can you share your Powder type and load data?

 

[rayporter]

first barrel was a 10 tw and the rest have been 8 tw.
3400fps when a barrel is new but cut back to 3250 for the second trip doggin on a barrel.

 

[RAG]

How did they blow up on the varmint ?

I loaded up 50 rds of the 88VLD at a very moderate 3300 fps to try on pdogs. I opened them up with drill bit, but just barely. Because I hadn't actually tuned the load and there were p-dogs everywhere, I didn't shoot any past 300 yards. Given that, I found them quite explosive...darn near as good as the 87 V-max. But I bet past 350 yards or so, with lower velocity impacts, these Berger 88 VLDs wouldn't be very frangible.

 

[Forum Boss]

Unless you can benefit from the extra case body length for magazine feeding, I would go with the 6BRA if you really need more velocity than the std 6 BR. Honestly, though for a dedicated Prairie Dog rifle, I'd probably just make a 22 BR, no-turn neck.

 

[JEFFPPC]

Had a McGowen 28” 1:8 twist chamber with BRA reamer for fclass: .268 neck with .150” free bore. 87gr V-max with 36.0 of CFE shoot 3350fps. Bipod/sand bag accuracy from 10# rifle and factory savage trigger is repeatable ragged hole .25moa 5shot groups at 200 yards. Love the fast twist barrels for lateral dispersion of body parts. Lol

Put that picture in the dictionary under "SPLAT".

 

[urbanrifleman]

Unless you can benefit from the extra case body length for magazine feeding, I would go with the 6BRA if you really need more velocity than the std 6 BR. Honestly, though for a dedicated Prairie Dog rifle, I'd probably just make a 22 BR, no-turn neck.

I have been doing some numbers. You probably can't do a whole lot better than 22br or a 22br Ackley and the 75 grain eldm. You could get more speed with the 22 XC or a 22 250 or a 22 creedmoor but there's not much difference in the trajectory or the drift. But you will burn the barrel up a lot faster.

 

[Ackman]

Not sure there's any advantage to shooting 87's. The Hornady Cartridge Reloading book #2 is an amazing compendium of drop tables for every bullet they make. A lot of computer time in this. The numbers are staggering and comparing the 87Vmax with 58Vmax was eye-opening for me. My 6BR 55/58gr load is over 3800, so for 6BRA I'll just say 3800 although it'll be more. And the 6BRA I figure 3400 with a 24/25" barrel and 87Vmax. Hornady data says, with 200yd zero...... at 300yds the 87 drops 5.2", the 58 drops 4.8"....... at 400yds the 87 drops 15.2", the 58 drops 14.9. I wouldn't have thought that. Holdover when varminting is no big deal so these numbers are really no big deal. There are no windage tables. Also at my 6500' elevation the BC becomes considerably higher than what's given by the factory, so trajectories will be noticeably flatter up here. But according to these numbers I'm not sure there's any point in shooting 87's. Through a standard 6BR the 55's and 58's are very effective on chuck size and smaller targets, but I've never used 87's and can't compare them. .

 

[BCPB6mmMAX]

Sitting on a 28" 10-twist Krieger blank and trying to decide what to do with it. Leading towards building something around the 87 vmax, and and leaning 6 Dasher. Prairie Dogs at medium range, or on the windy days, would be the name of the game (22BR with 53s and 6BR with 58s for the high volume shorter stuff).

I was even thinking about 243AI for a little more juice, but I might be happier with the inherent accuracy and barrel life of the 6BR derivatives.

I have Harrels dies, and wouldn't need to fireform with standard 6BR, but I'm thinking the Dasher ought to be able to get me into a higher node with the 87s, and getting a Harrels Dasher die wouldn't cost much. Any feedback much appreciated!

6mm max will be an option in November when dies arrive. 87vmax 3009fps.

 

[RAG]

I have been doing some numbers. You probably can't do a whole lot better than 22br or a 22br Ackley and the 75 grain eldm. You could get more speed with the 22 XC or a 22 250 or a 22 creedmoor but there's not much difference in the trajectory or the drift. But you will burn the barrel up a lot faster.

And that's saying something cause i know 22BR burns em up a lost faster than 6BR!! I have one, but haven't been able to shoot/test it yet.