Skimbleshanks
Well-Known Member
What do you think the 358 would do? Did you neck that up in 1 go? Moderately heavy 35s going kinda fast are really cool to me. Even more so with a round nose bullet!
Cranking up the RPM
- Thread starter Swamplord
- Start date
Help Support Long Range Hunting Forum
the straight necked up 358 RPM should mimic the 358 Norma Magnum, case capacities are withing a grain or two of each other, if you improve the taper you'll gain some more capacity and be right on the heels of the 358 STA
I used the tapered exanders in hornady FL sizing dies and K&M exander mandrels for their neck turner, all cases were sized up in same order to move as little material as possible per sizing until reaching desired caliber neck diameter, that way necks remain even in thickness and there is no thinning/thickening creating out of round necks, as follows
7mm Rem Mag Hornady FL die
300 Win Mag Hornady FL die
8mm K&M expander
338 Rum Hornady die
358 K&M expander
375 Ruger Hornady die
408 K&M expander
416 K&M expander
used Redding Imperial sizing wax for every step to insure even expansion
Last edited:
Hi Andrew.
Should stand a chance of being good Brass then if it is Norma.
Not expecting to see Brass anytime soon this side of Atlantic.
I have a 6.5x284 built on a Tikka 690 action and this cartridge interests me when a rebarrel comes.
Great write up Swamplord! Sure gets a wildcatter thinking.
I remember reading about the 284 when it came out in 1963. There was a "flurry of activity necking it up and down" After it was all over the 25-284 and 6mm-284 were the favorites of the gunwriters. At that time the 6.5-284 was an oh hum cartridge. Funny how things change AND repeat themselves. Enter the 6.5 RPM and we get to do this all over again.
I have a LA Rem chambered for a long throated 284 win. 1 in 7 twist 28". Accuracy load with 180 berger hybrid is 2800 fps. According to the 1/4 capacity rule a 7mm RPM should yield approximately 2925 fps. That puts it close to 7 rem mag performance.
I have the 284 reamer, need to figure out if it will work or requires regrinding. All would be straight forward with minimal cost except the dies.
I heard that there are other RPM caliber offerings in the works. Specifically the 7mm and the 308. Would like to see that happen soon. Then dies and formed brass will be available.
I remember reading about the 284 when it came out in 1963. There was a "flurry of activity necking it up and down" After it was all over the 25-284 and 6mm-284 were the favorites of the gunwriters. At that time the 6.5-284 was an oh hum cartridge. Funny how things change AND repeat themselves. Enter the 6.5 RPM and we get to do this all over again.
I have a LA Rem chambered for a long throated 284 win. 1 in 7 twist 28". Accuracy load with 180 berger hybrid is 2800 fps. According to the 1/4 capacity rule a 7mm RPM should yield approximately 2925 fps. That puts it close to 7 rem mag performance.
I have the 284 reamer, need to figure out if it will work or requires regrinding. All would be straight forward with minimal cost except the dies.
I heard that there are other RPM caliber offerings in the works. Specifically the 7mm and the 308. Would like to see that happen soon. Then dies and formed brass will be available.
Take that puppy up to 458 and see what it would do in a straight wall case lile the 450 bushmaster and those other straight case legal states. Wouldn't be long range. But i bet someone could extract enough energy to double the 4570 in those states
Yep, and it gets most of us in trouble.
I'ts my transmission in high gear, I'm trying to get in neutral but the stick won't budgeYep, and it gets most of us in trouble.
L
L!Thus the whole reason we do things..... if we were good little sheep. We wouldnt. Even be hereYep, and it gets most of us in trouble.
Agreed!
Appears that the two cases are almost identical if not identical in length is this correct ?
Appears that the two cases are almost identical if not identical in length is this correct ?
slikmrc
Well-Known Member
This was a great read, well done Swamplord ! The 416 RPM looks like a little sleeker version of my 416 Taylor.
