27 RPM reloading dilemma

[K.E.C. Darkside]

Bushing dies are being made f


Bushing dies are being made for the 7mm RPM so you could pick up a set along with tge appropriate .277 bushing.

So does this mean your building a
7mm/284 RPM. WOW
Weatherby needs to pay attention to some of the Threads that have been and are popping up.
25 RPM been done.
26 RPM Factory
27 RPM being considered.
28 RPM being built.
So that leaves 30
33 RPM Factory.

 

[archeratlrg]

So does this mean your building a
7mm/284 RPM. WOW
Weatherby needs to pay attention to some of the Threads that have been and are popping up.
25 RPM been done.
26 RPM Factory
27 RPM being considered.
28 RPM being built.
So that leaves 30
33 RPM Factory.

I have a 35 RPM, A 8mm RPM, building a 30, and I have the 7 and 270 that I'm in the process of stocking.

 

[archeratlrg]

Graf and sons usually carries one bushing die you can go down with a bushing dies, but you can't go up without recutting an existing set.

 

[8x68s]

Barrel twist will be 1:9 as I don't intend to do the long heavy's. I'm of the opinion that anything beyond 150gr and I go to my 7mm's. I did ask for extended throat on the reamer as Manson was suggesting a freebore of .090" which didn't appear nearly enough to accommodate the dummy I made up.
"Why go with a 6.5rpm necked up instead of a 338rpm necked down?" Always easier to neck up than down. I would never even try necking down that far.

Archeratlrg: Where are you seeing 7mmRPM bushing dies? Custom?

 

[TonyRumore]

Dang it… that photo makes me drool for a long barreled 6mm RPM to replace my 6-280AI ….

I have a 6mm RPM. 27" Krieger 1:7, left hand Weatherby Mark V. It's quite a bit faster than my 6-270imp.(Catbird)

Tony

 

[8x68s]

I bet it outruns the 240WBY by a bunch!

 

[fmuguira]

My 6-280 AI easily outruns my 240 WB by 150-200 fps… guessing the RPM case might go an additional 75-100 fps over the 6-280; law of diminishing returns though as getting seriously over bore. The 6-280 AI likes R33, US869 with 110 s so guessing coal is about perfect for the 6 rpm!!

Mind sharing your powder/bullet/velocities with that 27" combo??

 

[8x68s]

Your question is probably for TonyRumore...??

 

[fmuguira]

Yes

 

[FEENIX]

Big difference.
Would you have the case capacity for these two. Thanks.

I do not. If I have the time and remember it, I will do a quick H2O case capacity comparison when I get home.

@K.E.C. Darkside , here you go ...

.270 AI 1X unprepped Win brass

6.5 RPM 80.9g virgin WBY (Norma?) brass unprepped.

 

[fmuguira]

About 11% increase. Using the 1/4 rule then velocity gains would be approximately 3% … thus 100 +/- more fps all else equal….

 

[7mm man]

@K.E.C. Darkside , here you go ...
View attachment 622402
.270 AI 1X unprepped Win brass

View attachment 622403
6.5 RPM 80.9g virgin WBY (Norma?) brass unprepped.

I assume this is the case capacity as measured by filling both with water and taring the case weight on both? If so the RPM capacity is impressive for a standard boltface cartridge. That related rim, got to love it. Thank you 284 winchester....

 

[FEENIX]

I assume this is the case capacity as measured by filling both with water and taring the case weight on both? If so the RPM capacity is impressive for a standard boltface cartridge. That related rim, got to love it. Thank you 284 winchester....

Yes!

 

[K.E.C. Darkside]

@K.E.C. Darkside , here you go ...
View attachment 622402
.270 AI 1X unprepped Win brass

View attachment 622403
6.5 RPM 80.9g virgin WBY (Norma?) brass unprepped.

Thanks
That is impressive..