I have not used this weight before, and would like to experiment.
Has anyone had success with the weight? I have read that you need to seat bullets at least a caliber's depth into the case mouth for best acuracy, and with the short 75gr. bullet, that will leave a rather large jump to the rifling.
What sort of loads have worked best for the combination?

I have H4895 and IMR 4064 available, as well as H4350 and H4831 SC. Which of those powders will do the best job?

I have a Ruger MK II, with a long throat. What sort of seating depth seems to work best, even though my rifle will probably be some different?
Thanks.

My Roberts is a dedicated deer rifle. During load developmentI tried some 75grV-max. Of the powders you list IMR4064 is the only one I tried. 4064 and Varget both shot very well.
GOOD LUCK and GOOD SHOOTING!!!

i used 47.5 gr of H380 with a 75 grain in my sons bob when he started shooting 20 some odd years ago. 4064 wouldn't be to far off the burning rate of H380. the load was a pretty good one, light recoil and quite accurate.

I have limited experience loading for the 257 Bob, only 2 rifles but I found that heavier bullet were best with 4350 and lighter were better with 4064. I would start with 4064 and if it didn't like that I'd try something else listed for light bullet loads.
Your rifle may like it different.
Good luck!

44gr.-H4895 has shot very well with the 75 Sierra hp in 3 different barrels for me. Getting about 3400 fps and like you said, a long jump to the lands. I'm not seating more than .150 deep, but still have quite a jump. The 75 V-Max shot just as well, I just use more of the Sierra's for some reason.

When I had my 700 ADL bob, I was shooting 47.8 gr of H380 with the 75 Hornady hp. 5/8" groups.

My Roberts Imp. loves H-380 and 87 grain bullets.

my Bob likes all bullet weights, and does a fine job with 75gr bullets and 4064

I use the 75 gr Sierra Varminteer with 42.0 gr Varget(0VER MAX LOAD) and get .5 inch groups with no sign of pressure.

quote:

I have read that you need to seat bullets at least a caliber's depth into the case mouth for best acuracy

Definitely not always true. The one-caliber seating depth rule insures that the bullet is gripped enough for rough field treatment, not to insure accuracy. But....

The 147-grain bullet used in the 7.62 NATO cartridge has a full-diameter shank below the cannelure of less than .20", yet the bullets have no problem staying in cases in full-auto combat use. The bullets are crimped and in some cases use a sealant....



.

In 80's had 257 Roberts. Used 100gr Hor at 2900fps. Tried 75gr in it,I think Sierra, with H414 (aka Win 760) and was able to do 3500fps with a less than pub. max load and 3/4" @100yds.

What I might suggest is to find out just how far out you can seat the bullet. Take a fired case, resize the case just enough so about 1/32 - 1/16 inch of the neck gets sized. Now just barley start the bullet in the case. Carefully chamber the round. As you chamber the round the bullet will touch the rifling and be pushed into the case. Well maybe, some Bobs are very long throated. If it touches the rifling and gets pushed into the case, carefully remove the round.
Now if you hold up a bullet by the one in the case you can see how much is in the case. If it seats in a fair amount At least 1/2 caliber it might work fine if the rounds are handled carefully. If they are going to be cycled thru the magazine, then seat them deeper or use a crimp. Lee's Factory crimp die can crimp a bullet without a channlure without effecting bullet performance

quote:

Originally posted by TX Nimrod:

quote:

I have read that you need to seat bullets at least a caliber's depth into the case mouth for best acuracy

Definitely not always true. The one-caliber seating depth rule insures that the bullet is gripped enough for rough field treatment, not to insure accuracy.

One should not be unwilling to load less than a full diameter in the case neck!

quote:

Originally posted by vapodog:

quote:

Originally posted by TX Nimrod:

quote:

I have read that you need to seat bullets at least a caliber's depth into the case mouth for best acuracy

Definitely not always true. The one-caliber seating depth rule insures that the bullet is gripped enough for rough field treatment, not to insure accuracy.

One should not be unwilling to load less than a full diameter in the case neck!

One caliber seating depth is a rule of thumb, but not an absolute. They must be seated deep enough to be physically/mechanically secure. The true minimum seating depth is that depth which will hold the bullet securely for every situation the cartridge will encounter. The only way you'll know if you rifle will be accurate with a long jump to the lands is to try it. Some do very well, others don't.