.257 Bob vs. .270 Win

[Marlin Junky]

I'd like to get some opinions on which of the two cartridges would make the most successful/satisfying PP rifle. I'm looking for either a 721 (for the .270) or 722 (for the .257). This would be mostly a target rifle but coyotes and deer would also be the quarry.

Thanks,
MJ

[StarMetal]

Well, I like the 257 for the smaller case capacity, but the 270 has more diameter and weight for deer hunting. If it weren't for deer hunting I'd go with the 257, not to say it won't do it. Would feel better with a 270 bullet, which you know is very close to being a 7mm, for deer. Now if you're going to use jacketed that changes everything.

Joe

[1874Sharps]

Marlin Junky,

I am not familiar with the 257 Bob. Can you tell me something about this caliber?

[pdawg_shooter]

If you are going to PP both will work fine. With the alloy matched to the velocity you are using they will work fine for deer.

[scrapcan]

1874Sharps,

Look up 257 Roberts, commonly referred to as the 257 Bob. I am pretty sure you ahve heard of the roberts.

[StarMetal]

First let me say you can kill a deer with a 22 short. It's not the most optimum caliber. Now a pp bullet for a 25 caliber rifle is going to be even lighter then a full size cast or jacketed and with that I feel it's not up to the task for humanely taking deer unless you're shooting them in the head. With 270 you're going to be getting a heavier bullet although pp for it won't be full .277.

Joe

[atr]

get the 257 Roberts.....if its for coyotes, deer, etc. its a proven killer and very accurate....
its effective range will be less than that of the 270......
but its easy to reload for...
usually lighter is weight than a 270
its one of my favorite cartridges to reload and shoot

Joe has a point about bullet weights

art

[Marlin Junky]

Basically, I'm looking for something that'll shoot into 1 MOA all the way out to 300 yards or a bit farther on coyotes. Also to get started, I'd want to be able to utilize commercial boolit molds. I suppose wrapped clip-on WW metal will be good for 2500+ fps (I've done 1 MOA at near 2500 with my Whelen); however, would I need to HP the boolits for instant kills? To date, my successes with PP'ing has been limited to the Whelen so I've got a lot to learn about the skinny boolit guns launching little missiles at 150 grains or less. I'm not going to use metal patched boolits in this particular rifle.

MJ

P.S. I think I may have discovered a plus for the .270: WC-860 may work with 150 grain PP... but that's really more recoil than I wanted to deal with.

[280Ackley]

Marlin Junky - Not to change the subject, but why not a 721 in 280 or 280AI. Much better selection of molds. I have both a 257 and a 280AI. Don't have any experience with killing deer with cast, but there is a notable difference in knock down using J bullets. The difference between the 270 and the 280 in terminal performance is not noticeable in the field.

[Digital Dan]

MJ, wassa matter with using the Whelen? Heck of a lot more tractable cartridge for PP work than Bob or the .270. Can't tell you how much it hurts to say that, I'm one of the original 1/4 bore sluts....but it's true. Still, if you're determined to proceed, then by all means do it with Bob.

[35remington]

MJ, you're pretty far gone when you've got a "nichy niche" of a high velocity rifle that is ONLY to be used with paper patched for coyote and deer and nothing else, and never with jacketed! I might say that about a 45/70 or 38/55 but I don't know that I could commit to never shooting an accurate, proven jacketed bullet in two calibers that are at their best with jacketed bullets, especially given their high velocities and range.

You've got a tough row to hoe trying to equal jacketed with cast at 270 and Roberts speeds, especially in bullet weights appropriate to coyotes, and all the way to 300 yards. I'd rather doubt you can find both a streamlined and accurate lead bullet, even patched, that will match the 3300-3500 fps potential of these two calibers.

Some questions to answer.....

How's bullet/patch integrity and case neck tension when running up the feedramp into the chamber?

How's your skill with patching? What's the likelihood you'll exceed jacketed bullet accuracy with a paper patched bullet at varmint bullet speeds?

Given that coyotes are the primary aim, and a .270 seems a little overpowered and wasteful of effort on 'yotes, combined with the fact that the .257 is a fine deer caliber (I own both of these mentioned) and also granting I am ascribing all these characteristics to suitable jacketed bullets, it's with jacketed that I'm recommending the .257 for what you envision.

Getting it to work with paper patched is almost immaterial and doesn't enter into it IMO. If it doesn't work out like you plan, it's probably due to technique more than anything else, so caliber doesn't matter except to say the .270 is certainly overdoing it for a coyote gun. Sure, you can shoot 90 and 100 grain bullets in it, but you can shoot 75's with about 20% less powder needed in the Roberts.

FWIW, though, I can't imagine a Roberts being adequate for deer at 300 yards with a PP'd bullet. I have my reasons for suspecting this, although I haven't tried it.

[montana_charlie]

Marlin Junky,

I am not familiar with the 257 Bob. Can you tell me something about this caliber?

1874Sharps,

Look up 257 Roberts, commonly referred to as the 257 Bob. I am pretty sure you ahve heard of the roberts.

I had no idea that was the common way to say it.
"257 Bob"...why that's just precious!
Oooo! Makes my nose tickle, just saying such a cute thing!

And, it saves all the extra effort that pronouncing a second syllable requires.

Wow, who knew..?

[1874Sharps]

Ah, yes the 257 Roberts! Yes, of that I have heard.

[RMulhern]

Neither!!

[303Guy]

I have an idea that the Roberts is going to be around the top end paper patch cartridge. I'm just on developing my patching skills for a 25 cal and can say I would probably not want to patch for much smaller. Not with my fingers anyway. I suspect it would be better to go with heavy for caliber PP's in the Roberts to get the cartridge's full potential. It keeps pressure high enough and velocity low enough. The boolits I find manageable are 110gr to 120gr. I'm not sure how streamlined a commercial cast boolit might be but there is no way my smooth sided 118grainers are going to be poor!

Obviously, I'm going to be recommending the 257 Roberts. Then find a way to make it work with PP!

Fregzample, I can load my 303-25 with a 118gr PPCBoo with a new full case of AR2209/H4350 to get reasonably mild pressure. Magazine functioning is fine and I can hand press a PPCBoo into a fired case neck and it will stay put on chambering and extraction and still have a slight resistance as the nose section slightly engraves the rifling. I seat this boolit in a less than normally sized neck i.e. not too tight.

[Marlin Junky]

The RCBS SP or SILH molds were those I had in mind to get me started. I'm concerned the 10" twist of the 722 in .257 isn't going to be fast enough to stabilize a 120+ grain boolit out to long range. I'm going to have a look at a 721 in .270 on Friday. Here's the .270 RCBS mold I have in mind: There's also a SAECO 140 but it's a TC and doesn't look as streamlined.

[Marlin Junky]

I just bought an RCBS 308-165-SIL from Midway for 58 bucks (clearance sale) and I'm going to give that one a whirl in my old 4-groove '06 before investing time and money in another rifle. If I can't get this 'un to shoot 1 MOA then then I haven't lost much.

MJ

[pdawg_shooter]

First let me say you can kill a deer with a 22 short. It's not the most optimum caliber. Now a pp bullet for a 25 caliber rifle is going to be even lighter then a full size cast or jacketed and with that I feel it's not up to the task for humanely taking deer unless you're shooting them in the head. With 270 you're going to be getting a heavier bullet although pp for it won't be full .277.

Joe

A paper patched bullet can weigh anything you want it to. My mould throws a 115gr .251 diameter bullet that will stabilize in a 1/10 twist as long as the velocity is above 2500 fps or so.

[StarMetal]

A paper patched bullet can weigh anything you want it to. My mould throws a 115gr .251 diameter bullet that will stabilize in a 1/10 twist as long as the velocity is above 2500 fps or so.

...yet the 25 is never going to shoot as heavy bullet as 270. You've been lucky getting a 25 too shoot. With jacketed no feat at all. With cast or PP quite a feat at HV with accuracy. Already we see a caveat ...as long as the velocity is above 2500 fps.

Like I said before, a 22 short will kill a deer, but in opinion the 25 cast bullet is just on the small side for deer.

Joe

[303Guy]

Well, I was hoping the 257 Roberts would win!

I've never shot a deer with a 25 so I can't say about adequacy but I tend to agree with it being a tad on the small side.

On stabilizing heavy boolits, it would depend a lot on the design of the boolit. A RN smooth sided boolit of 120gr would be no longer than a 100gr flat base spitzer J-word. A lube groove GC design would be quite long at 120gr.

I shall be testing mine in a day or two!

I'd be interested to know why a particular boolit only stabilizes above 2500fps? It's not as simple as just RPM. The required RPM is proportional to the velocity, meaning that in theory a given bullet will be stable at all velocities as long as it stays away from the transonic zone. What could be going on?