'Field of Dreams' 270/284

[CheshireC]

I remember the old Bob Newhart show where he's helping one of his patients overcome his fear of children,as the patient is a kid show host), and he is made to go onto the show in case some intervention is needed. Bob is a walk on side-kick for the host and is dressed in a full length Beagle costume, large fake black nose, floppy ears and all. At the end of the show,Bobs' big chance at TV stardom), he gets to say a line. It was something like " Well kids it's time for us to go back over the rainbow bridge back to rainbow land" then he says ...
" Well, it seems kinda silly, but we're gunna do to anyway."
I find these words to be inspirational


the 270x284, 270/284 ... why/why not ???
why ...
--- 270/284 would be better bore adjusted than 6.5,combustion efficiency)
--- the lrbr, Long Range Bench Rest ?) guys say the 6.5 is a barrel burner when loaded up to levels that are needed for 600m and 1k
--- 6.5x284 loading data could be used as a general starting point guide, within reason).
--- would kick less than similar 7mm rounds needed for 600m, 1k
--- similar winning 6.5 high BC bullets could be made for 277 that could buck conditions "as well or better" because of the extra attendant weight ??
--- brass is good for xxx/284

why not ...
--- no 277 bullets,match type) besides the 135z
--- 277 barrels seem to be stuck on 1/10 in twist,need 1/9.5 for needed heavies ???)

Well, what say you ... too silly or does this sound like it has some merits if the negatives can be overcome
By the way, I don't know if some of these suppositions are way off base
Thanks Mark

 

[jb1000br]

For hunting, sure...for comp, definitely not.

JB

 

[6Dasher]

More weight means less speed, so you have to have a bullet of the same weight, with bigger diameter,277) and same or better BC. Why not go with 7mm then?

 

[Wild_Bill]

Your biggest issue is match bullets in .277 there is one 135gr MatchKing that is it and the BC is not to good as apposed to the 175gr 7mm. i use a 284 and 175gr Sierra's that is the way i would go or if you want bigger again a 30-284 with a 30" barrel will push a 190gr MatchKing at 2940fps with ease.

Cheers Bill
Australia

 

[CheshireC]

Thanks you guys for the replies... I'd like to come off as a considerate, inquisitive brnewb,not a know-it-all) to insipre a thought provoking dialog, this is my intent, maybe a joke or two, ohnooo!! )

6Dasher ...,me thinks your sandbagging a little ... not already with the jokes !!!) What a person trying a new combo out ends up doing is chasing BCs and SDs up and down the barrel sizes to get, hopefully, a needed advantage for a particular set of conditions. Gererally. more gas surface at the base of the bullet 'usually' traslates into same weight/higher fps than the next lower bore size in theses cases,243to338/40-100 capacity), although there are exceptions. This would allow a hevier bullet to achive "same speed" in the next bore up with similar pressure. So what I'd hope for is better barrel life that the 6.5 and less recoile than the 7mm. I might also mention the less tangable "sweet spot",more on that if you'd like).

What I'd hope for would be a SD in the .270+ range and a BC near .500 .. wieght would need to be 151-158 ish, I would think, pushed to the magic 3000 fps range +/- 50 . This will take a little digging .. so off to the old balistic charts...
ok for the ~ .280 SD
6.5 @ 1000 yards is ~ -218 all these zeroed @ 400
277....................... -243
7mm.......................~ -220
308.........................-215
This is probably not the best example because the middle two where not competition bullets, I'd have to think that the 270 is distictly less slippery than the otters. It does have some purpose though. I will suppose that a 27 similar SD/BC will have similar 1000 yard drop as the rest. Maybe someone has better numbers on a high BC 27.


The idea of right sizing for a particular bore is a very old concept ...i.e. 277/7mm/30Mag-Smith .. and low and behold, 40 or so years later ) a commercial cartrige is produced, hats off to the engineers .. I don't think that any of this stuff is easy design work, then you have to sell it. Some reading material somewhere states that the " highest practical maximum capacity" for the 30 cal is near 70gr., I can't find aanything like that for the other calibers. But, from what I've been reading there are guys out there shooting big overbore thumpers that would have a distict advantage in gail force winds .. or sudden gusting, with better tragectory numbers. Is this legitimate reasoning ... probably. Many of the other comp cartiges are slightly to significatly overbore and there must be a good reason for it. I just don't know what that could be. I would still contend that a better bore adjusted 27 would do well. What is the error in this logic that I just can't see?
Thanks Mark

 

[Cheechako]

cheshirec

Hey, if you want a 27 caliber rifle go for it.

My real point here is that I'm a Newhart fan too. I have most of the shows on tape, including the ill-fated "BOB" which i thought was as good as the others.

I like to pattern my life after Dr. Hartley's college professor and mentor. His philosophy? "Bob, it's all a crock."

Ray

 

[6Dasher]

Hi,

Didn't mean anything personal by it.. You are correct that with the same weigth, the bigger bore will produce more speed. But the bullet,same weight) will have lower BC, for which speed does not make up. So you would have to shoot a longer/heavier bullet which raises recoil. If you can get good 277 match bullets with BC/speed ratio that is the same or better than the 6.5/142 then you are in luck. But there are no such 277 bullets.

 

[Aussie_bob]

There are a few projectiles you could use the 140-gr HT with a BC of .530 the Nosler Ballistic tip with BC of 456 or 150gr Jensen J26 with BC of .563 and some of the top bullet makers like Randy could probable knock out some good bullets in the weight you want that is if they arn`t over worked try to supply all the other good projectiles they make.

 

[CheshireC]

6Dasher:
Sorry about the confusion.. I thought you were saying something that you weren't. I'll bet you weren't expecting a "Spanish Inquisition ". Anyway, no offense taken, or given for that matter . I was not directing most of that post "on you", mostly just a general rant I guess. The Internet is a hard place to communicate properly and things can seem confusing to me on occasion . Your a good man 6Dasher, and don't let anyone tell you different.
Yea, looks like 6.5 or 7mm or custom bullet.. load development with a "off the shelf" bullet in similar wieght would yeald much diffent results than a custom
Thanks Mark

 

[6Dasher]

No offense taken, still trying to figure out what I said
Anyways...

My point was the lack of available 277 bullets to compete with the current 6.5 and 7mm bullets.