re-barreled to 257 swedish mauser

[UMD]

Now here's a good one.  I just received back from the 'smith my little swedish mauser.  Had been a 6.5x55, but had it rebarreled to 257 Roberts so my son and I could shoot the same cailber out in the woods, and, I like the 257 Bob.  In any case, this little mannlicher stocked swede had a very short 6.5 barrel - like 16.5" - and the gunsmith called me to make sure I wanted to rebarrel at the exact same dimension.  Stock had been inletted well - great job - and I said yes, let's do the same length/contour.  He wanted to make sure I knew I'd lose some ballistic performance with my 257R in 16.5" barrel, but the 6.5 shot real well, and I said let's keep it the same length - it's going to be my northern MN/WI woods gun, and I don't really expect to shoot much past 100yds anyway.

Well, I haven't yet fired this new barrel so can't report on effectiveness.  I'm going to site it in at 50yds, like I do all my rifles.  I know it'll be a bit loud, but I'm curious as to just how much performance I'll be losing.  I have never had a lick of trouble killing deer with our 257R BLR/20" barrel - using 100g PP or 117g CL, up to the 120g Nosler partitions(Fed Premium) - and don't expect to with this new little mannlicher swede.  I'm a walker, not a stander, and it is going to be my carry rifle - you know, load up lunch in the backpack, cut a track, and spend the day on it.

Anyone willing to do some figuring to see where I'll be at?  How about a comparison between the 6.5X55 and the 257R out of a 16.5" barrel?

[BBF]

Just a feeling here, nothing to prove,  I think you should have left it a 6.5

[Lone Star]

To each his own, but a difference of 0.007" in bullet diameter is nothing.  No animal would ever notice. 

From various published sources for the 6mm Remington - the same case as the .257 Roberts but higher pressures:

Load......22".....20"....18"
100gr....2981...2896..2795
100gr..3077...3004
80gr....3328...3226...3049
75gr....3313...3308...3228

Based on the loss from 20" to 18", I'd guess you'd be at around a 200 fps loss over the 20" velocity if you load to max pressure.  That said, I used a 15" .250 Savage for years and always killed my deer quickly and well.  100 Nosler BTs worked great at the lower velocity.


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[MGMorden]

Just a feeling here, nothing to prove,  I think you should have left it a 6.5

Eh, speaking as someone who has both, I truly doubt it will make much long term difference.  Both are nice, light recoil rounds, and both are typically seen as "refined" or "classy" rounds to have a rifle in (just watch - take a .300 Win Mag to a gunsmith and you get "grumble grumble back in my day" conversation.  Take a .257 Roberts, or a 6.5x55, to one and their face lights up ). 

[Catfish]

16 1/2 in,  that babby will sure be loud and blow fire. Would be fun to fire at nite. Even with all of that it should handle nice and be sweet in the woods. Just don`t set it on fire.

[WyoStillhunter]

I understand the (intellectual) curiosity about changes in MV between barrel lengths.  But as others have said, the answer is very likely of no consequence.

The way I feel about the rifle I carry is (almost) as important to me as any ballistic data.  There are days that it just feels right to carry my .444 Marlin levergun into the elk woods and other days when the scoped Whelen has more appeal.  And it doesn't have anything to do with ballistics, trajectory, terrain or weather--just a feeling.

It sounds like that 257 Roberts carbine is going to be just right regardless of a few fps here and there.  My Roberts is a new Ruger Hawkeye and it just doesn't have the character I look for in a rifle.  I expect I will end up with a different rifle, maybe something like yours or a rebarreled Model 7.

[UMD]

Thank you, one and all, for the thoughts and figures.  I'll have to let you know how accurate it is when I finally get around to shootin' it.  Onward...