Quarter bore fans; opinions wanted, what would you do?

[VLD Pilot]

Yes, that's what I was trying to convey in #48: Black Jack (Sierra) set the precedence for others to follow.

Agreed! While rifle companies have not fully embraced fast-twist barrels, a few barrel manufacturers are making 1:7" -1:7.5" in .25 cal for all of us to build upon. Below are some examples:

* X-Caliber
* McGowen
* Pac-Nor
* Muller Works
* Lilja
* Osprey Barrel Works
* Douglas Barrel
* Proof Research
* Benchmark Barrels
* Preferred Barrels
* CarbonSix Barrels
* Hart Barrels


Agreed! We need risk-takers and innovators. @Bghunter338 and I experimented with the 145 Black Hole and have transitioned to the 163 Chinchaga and, soon, the 180 Chinchaga, as noted in #37/39. Again, no one is forcing us to go the fast twist barrel or heavy bullet route. It boils down to personal choice/preference and intended purpose.

Quick question since your experimenting with the heaviest of 257s. What twist stabilizes those 257/163 & 180s ?

 

[FEENIX]

Quick question since your experimenting with the heaviest of 257s. What twist stabilizes those 257/163 & 180s ?

1:7" (post #39).

 

[Bghunter338]

Quick question since your experimenting with the heaviest of 257s. What twist stabilizes those 257/163 & 180s ?

Yes exactly what Feenix said 7 twist. At my elevation I'm borer line with the 163s with my 7.5 twist. I'll be testing some 150-155 grain bullets soon.

 

[VLD Pilot]

Yes exactly what Fenix said 7 twist. At my elevation I'm borer line with the 163s with my 7.5 twist. I'll be testing some 150-155 grain bullets soon.

Elevation certainly makes a difference. I'm at under 1000 ft. Being at 5000+ can make an entire full twist of a difference.

 

[Calvin45]

I may end up just going all out, fully impractical and short lived drag racer style just to have tried it once for myself.

Got a killer deal on some 7 RUM brass . At an auction sale, I couldn't beleive I won it as surely someone else would bid higher, but nope, I just obtained 50 pieces of virgin 7 rum brass for 35 bucks!!!!!

The whole point of this project is to be impractically overbore while sticking to a very tight, very cheap budget haha. And 50 pieces should last the whole life of the barrel on a 257 rum methinks

I wonder…

 

[Phil Rizzo]

I'd say you are going to be "built for speed with the tools you need" to paraphrase Waylon Jennings.
I bet somebody here knows the rest of that line…

 

[K.E.C.]

I may end up just going all out, fully impractical and short lived drag racer style just to have tried it once for myself.

Got a killer deal on some 7 RUM brass . At an auction sale, I couldn't beleive I won it as surely someone else would bid higher, but nope, I just obtained 50 pieces of virgin 7 rum brass for 35 bucks!!!!!

The whole point of this project is to be impractically overbore while sticking to a very tight, very cheap budget haha. And 50 pieces should last the whole life of the barrel on a 257 rum methinks

I wonder…

Go for it.
257RUM

My 270RUM is Awesome.
170EOL are pressuring out just shy of 3500fps.
130 Swift Scirocco likes 3500.
Have Fun.
All and I'm using 7RUM brass.

 

[lancetkenyon]

Why not go to the 257 STW? Cheaper brass than others suggested. The 1-10" twist will be the limiting factor. However my 25-06's have handled 117 and 120 grainers just fine. With that long barrel you might be able to use the 130 range of bullets.

Not the 133/134/135s. Or the 121 Monos. Not in a 1:10" twist.

 

[Phil Rizzo]

100-110-115grs is 10tw territory.
But I like 9tw for them personally.

 

[Calvin45]

Not the 133/134/135s. Or the 121 Monos. Not in a 1:10" twist.

Agreed ALTHOUGH I have seen something very interesting in which the YouTube channel "Reloading Weatherby" guy was shooting 133 or 135 Bergers accurately and stabilized out of a 257 wby with a 10 twist. Couldn't believe it. That being said I talked to him and I think he's at around 5000 feet elevation and it was in warm weather. Moreover I understand that even if the bullets aren't yawing and are shooting accurately, the BC isn't going to be realized and they'll probably still lose to fully stabilized 115 vld type bullets on all fronts. But it was interesting nonetheless to see real world data that didn't agree with what the calculator might tell you is and is not possible

 

[Phil Rizzo]

Agreed ALTHOUGH I have seen something very interesting in which the YouTube channel "Reloading Weatherby" guy was shooting 133 or 135 Bergers accurately and stabilized out of a 257 wby with a 10 twist. Couldn't believe it. That being said I talked to him and I think he's at around 5000 feet elevation and it was in warm weather. Moreover I understand that even if the bullets aren't yawing and are shooting accurately, the BC isn't going to be realized and they'll probably still lose to fully stabilized 115 vld type bullets on all fronts. But it was interesting nonetheless to see real world data that didn't agree with what the calculator might tell you is and is not possible

At what distance?
One of his recent "discoveries" demonstrated how similar the long range performance of a 270win and 7PRC are also. With factory loads. Yeah.

 

[hemiford]

Agreed ALTHOUGH I have seen something very interesting in which the YouTube channel "Reloading Weatherby" guy was shooting 133 or 135 Bergers accurately and stabilized out of a 257 wby with a 10 twist. Couldn't believe it. That being said I talked to him and I think he's at around 5000 feet elevation and it was in warm weather. Moreover I understand that even if the bullets aren't yawing and are shooting accurately, the BC isn't going to be realized and they'll probably still lose to fully stabilized 115 vld type bullets on all fronts. But it was interesting nonetheless to see real world data that didn't agree with what the calculator might tell you is and is not possible

I had a discussion with somebody (forget who), about twist and bullet RPM. I thought bullet RPM would be the ultimate deciding factor in
what weight bullet you could use. Bullet RPM = Muzzle Vel x twist / 6. Basically I'm saying if you have less twist you could make up for it with
more muzzle velocity. But this one fellow told me not quite, it doesn't quite work that way............???.......... I still don't quite understand why it
wouldn't work that way.
A 257stw would generate an awful lot of bullet RPM even in a slower 10 twist if you could get 3800 ~ 4000 ft/s muzzle velocity.

 

[Calvin45]

I had a discussion with somebody (forget who), about twist and bullet RPM. I thought bullet RPM would be the ultimate deciding factor in
what weight bullet you could use. Bullet RPM = Muzzle Vel x twist / 6. Basically I'm saying if you have less twist you could make up for it with
more muzzle velocity. But this one fellow told me not quite, it doesn't quite work that way............???.......... I still don't quite understand why it
wouldn't work that way.
A 257stw would generate an awful lot of bullet RPM even in a slower 10 twist if you could get 3800 ~ 4000 ft/s muzzle velocity.

Extra velocity and rpms help with marginally stable bullets by a little bit but not by a lot.

But sometimes this does work. I actually emailed Sierra about their ultra sleek 200 grain smk, the newer one not the old one, cuz it says 1:9 on the packaging but I figured if my 10 twist 300 win can stabilize a 225 eld m no problem…

Anyway they actually told me I'd be fine with a 10 at 1100 feet elevation at 300 win velocity but it wouldn't work well in a 10 twist 308 at sea level. So that was interesting and straight from the horses mouth as it were.

 

[Calvin45]

At what distance?
One of his recent "discoveries" demonstrated how similar the long range performance of a 270win and 7PRC are also. With factory loads. Yeah.

Good to 785 yards for bangin steel.