Loading Nosler 100 grain BTSP in .257 Roberts

Reloader2025

Beginner
Jun 24, 2025
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Has anyone loading a .257 Roberts case with the Nosler 100 grain BTSP had problem with the bullet crimping on the olgive (bullet curvature) when set to maximum OAL? When I seat the Nosler 100 grain BTSP bullet to factory maximum OAL, the case rim will have to crimp on the olgive thereby not getting a good, solid crimp into the widest section of the bullet
shaft. I found that in so doing, the slightest bump and the bullet falls back into the case due to insufficient crimp. If I seat into the widest section of the bullet shaft, the finished round exceeds maximum OAL. Suggestions?
 
I loaded the Speer 100 BTSP in my first Roberts ( Mod 500 Classic). I was able to seat them out alot farther. any reason you cannot seat them farther out? A LEE Factory Crimp Die is your friend, but even then, you want that ogive farther out. Good luck to you sir.
 
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Welcome to the forum.
You can seat longer than max COAL but you need to know where the lands are and your maximum magazine length.
I load my M700 Classic 257 Roberts to a COAL of 2.900". My rifle is a long/magnum action which allows for the longer COAL.
What rifle are you loading for?

JD338
 
The rifle used is a Remington Model 700 chambered got .257 Roberts. I tried exceeding the bullet's OAL for my rifle but when I move the bullet out 0.001 beyond stated maximum OAL, it will still fit in the magazine but the cartridge will not chamber in the barrel.
 
I have used the 100 grain ballistic tips. If memory serves me I seated longer that the book length but not by a lot due to the short throat in the Ruger m77. It wouldn't have mattered much since I never crimp rifle rounds except for the AR.
 
Jim - I think the Rem 700's in 257 Roberts were short-action rifles, like my 6mm Remington. It can be difficult to load to the proper length.

OP - I suggest going to a shorter, flat-base bullet. Perhaps the Nosler Partition would work? I don't have one on hand to measure.

Guy
Guy,
I believe you are correct however my 700 Classic 257 Roberts is on the long/magnum action.
I think the OP's issue is due to his rifle being on the short action. Your suggestion on using a PT is a good idea.

JD338
 
Guy,
I believe you are correct however my 700 Classic 257 Roberts is on the long/magnum action.
I think the OP's issue is due to his rifle being on the short action. Your suggestion on using a PT is a good idea.

JD338
I was trying to remember if the Classic 257 was on the long action Remington. Thanks!

Guy
 
I have similar issue with 7x57 on short action. I use flat base bullets, which work great. The Nosler partitions would likely be my first choice for big game. Sierra 87 grain varminter for small game is most accurate in 25 cal i have found. You might investigate the Hornady 117 round nose measurements too if you want a heavy for caliber bullet and a classic vintage look. They shoot very accurately in my 25's.
 
Guy,
I believe you are correct however my 700 Classic 257 Roberts is on the long/magnum action.
I think the OP's issue is due to his rifle being on the short action. Your suggestion on using a PT is a good idea.

JD338
I have two Winchester M70 Featherweights, one a .257 Roberts and the other is a 7x57. Both rifles are using the long action with blocks in the magazine to accommodate the cartridge length.

The magazine for the 7x57 has not been a problem regarding cartridge lenght as load with different weight bullets so far have given quite acceptable accuracy. The .257 though? Not so much. If I seat the bullets out to where they shoot decent groups, then they're too long for the magazine thus reducing the rifle to be used as a single shot.

Another 7x57 I have is based on an FN Mauser that was originally a .270 Win. and it feeds just fine. Why Winchester in their vaunted wisdom decided to use blocked magazines is way beyond my comprehension?

I have a few Remington M700s in 30-06 and they use Remington's long action. You can take a cartridge like the .375 H&H and it will fit with room to spare in my M700 30-06. The 30-06 feeds just fine in that overly long magazine. In act, so did the 7x57 I tried when doing some checking which tells me the ,257 Robt. should feed just fine as well.
Paul B.
 
I seem to recall the M700 Mountain Rifle was chambered in 257 Roberts on the short action .

JD338
 
I have two Winchester M70 Featherweights, one a .257 Roberts and the other is a 7x57. Both rifles are using the long action with blocks in the magazine to accommodate the cartridge length.

The magazine for the 7x57 has not been a problem regarding cartridge lenght as load with different weight bullets so far have given quite acceptable accuracy. The .257 though? Not so much. If I seat the bullets out to where they shoot decent groups, then they're too long for the magazine thus reducing the rifle to be used as a single shot.

Another 7x57 I have is based on an FN Mauser that was originally a .270 Win. and it feeds just fine. Why Winchester in their vaunted wisdom decided to use blocked magazines is way beyond my comprehension?

I have a few Remington M700s in 30-06 and they use Remington's long action. You can take a cartridge like the .375 H&H and it will fit with room to spare in my M700 30-06. The 30-06 feeds just fine in that overly long magazine. In act, so did the 7x57 I tried when doing some checking which tells me the ,257 Robt. should feed just fine as well.
Paul B.
Hey Paul, is it possible to remove the block in the magazine well then use a longer follower so it will accommodate the longer cartridge length?
 
My .257 Roberts was chambered in a Remington model 722, which is a short action. I seated my bullets to a OAL of .010" off the end of the magazine box. This insured that they would feed and they were still well of the lands. I've always been under the belief that published COAL is based on some minimum number, but bullet selection, magazine length, and barrel chambering and throating variations makes the actual COAL more of a rifle specific number.
 
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