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Kimber 257 Rob OAL constraints

I knew going in this may be a struggle with mag OAL restrictions ....
Longer than 2.820 and a loaded round won't clear ejection port..

Thinking about shortening the ejector and opening up the port...

Mag mod is the easy part...

Any tips besides rebarrel it to 7-08AI or 6XC?

Dave

Dave, while I know the Rob, like the 308, is long-throated because its SAAMI specs were achieved with a RN bullet, is the rifle not shooting with bullets seated at 2.820+/-?

If it's accurate enough for you, I'd live with constraint and go kill stuff. You aren't losing enough velocity to matter, and it's a sweet little rifle/cartridge combo.

I have not wore it out but so far it shows it wants the bullets closer to the lands.
100 Hornady was 2" with 46grs of H4350
100BT was 1.5" triangles with same load above
80TTSX wax 1.5" with double group (4 shots) using 49grs R17

Is everything else copacetic? Cartridge runout, magazine box binding or not, ...

I personally wouldn't compromise the front receiver. There's very little there to begin with. Cutting out an M70 or 700 is one thing, the 84M an entirely different thing.

What I've found with Kimber Robs is not to get wedded to a particular bullet. Try a variety. It will shoot something sub moa within mag constraints, but not everything.

It's a crying shame the 25-08 was never legitimized.

I'd go 6.5 Creed were I thinking of a rebarrel.

I feel your pain. I have a sweet little Browning A-Bolt Micro hunter in 257Rob that has the same issue. I was lucky to find a 100gr Nosler BT load that shoots under 3/4" but everything else is like yours (1-1/2 to 2").
This load has killed a big buck and a few hogs, but I'mm bummed at the lack of bullet options.
Oh well...not going to mess with mine.
Good luck with yours.

Maybe no help for the OP, but someone contemplating a .25 and wanting the most velocity and some flexibility might want to look at a .25/06 instead. The Kimber comes in at 6lbs 2oz.

Going 6.5CR makes sense if he wants to keep the rifle he's got, but I'd be trying a bunch of other bullets before I gave up, with 100gr NPs at the top of the list. Besides, 2" rifles may not impress your friends, but the deer won't notice.

DaveH
I had the same issue with an older M70 Featherweight in 257 Bob.
It did shoot most anything I feed it well, but I was constrained with the short box. Only thing I did to the gun was to put a shim under the front of the action to insure free floating.
I would have liked to load the bullet out more and to squeeze more powder in, but......

Worked up several loads, but did not kill with it before letting it go. Were I younger and/or had fewer hunting rifles, I would have matte finished it and bedded it, but I passed it on.

I could share loads if interested.
Tim

I had to fix the mag box, float on barrel is ok. Loads have .002-.003 runout but no more.
I will try more powder and bullet combos.
Will heed the advice on mods until later. I don't do 6.5's as I have every other caliber and figure that is enough....

Dave

7mm-08AI is a lovely solution, highly recommended...

David

Another bullet you might try is the Nosler 110gr Accubond.

I've got fair accuracy, 1 to 1.5" 3 shot groups and great results on deer in my Kimbers.

Seated to 2.805" I have two loads shooting to almost the same point and velocity.

46gr RL19 @ 2858fps

43gr IMR 4350 @ 2845fps

YMMV

Kimbers are such sweet little rifles and the 257R such a sweet little cartridge. If you exhaust all possibilities just rebarrel.
But like Pappy said, 2MOA will kill stuff just fine.

Mine liked 110 accubonds really well.

Whether the deer notice or not I just couldn't abide 2 MOA.

Never had much success with the 110AB in anything

I will get the 100BT to shoot but all I have left are pulled ones now....

In desperation I will try the 110's if all else fails...

My model 70 will only allow 2.850 OAL, but 2.825 works
pretty well. Most accurate bullet in mine is 115gr
Nosler Partition with 110 Accubond close behind.
Slower powders were a big help, like RL22,and Norma MRP.
I,m working on loads for RL23, RL26, and Rl17.

You could have the barrel set back and rechambered with a shorter throat.

To the OP:

I have a .257 Roberts in the 84M Montana. Yeah, the throat is long but it shoots several bullets well despite that.

It does real well with 100 grain ballistic tips and respectable with the 110 grain Accubond. It seemed to do ok with the 120 grain partition but I ran out.

It doesn't shoot for [bleep] with the 115 grain partition or ballistic tip nor with the 100 grain partition.

It would be worth trying your gun with 100 grain TTSX and 100 grain E-tips since both of those like some jump to the lands anyway. I have a number of other bullets to try still, just a matter of finding time.

I probably wouldn't use the 110 grain accubond on game again, the deer both died but there was a LOT of meat loss. Both bullets stopped between the ribs and shoulder blade on the off side and shook things real bad. Couple quarts each of purple goo ... 'bout the consistency of snot.

I wouldn't mess with the gun itself. Rebarrel, yes, try to open it up for longer cartridges, no.

Tom