JGFLHunter

Yes, I am new to reloading and learning a lot and finding out a lot as I go. I decided to take numbers from the 257 Weatherby 100gr Spitzer that Weatherby sells.

Granted these are 100 grain bullets. What I am attempting to perfect are 115 TSX. Anyway, Overall length was 3.144 and whatever powder they used ( Really looked like some type of RL? who knows) it had 72 grains though. the case was trimmed to 2.540''. Even the barnes manual says 3.170 as overall length for 100 grain TSX. Just odd IMO.

It really is hard to find 257 Weatherby data(reliable) besides the reloading manuals. I trim to the minimum which is 2.539''.

Does anyone have any factory specs with the 257 using 1115 grain bullets?

Also, has anyone ever duplicate factory specs with their reloading and get results? Why are reloading manuals and factory specs differ somewhat greatly?

alleyyooper

Most Lyman manuals I have will give a factory dupcluta data.

Al

Wayspr

I don't understand why you would want to duplicate factory ammo. The numbers reported by most ammo manufacturers are bs. The beauty of reloading is finding a component combination that is taylored to your gun. As to why relaoding manuals and factory specs differ? You mention that the factory cases were 2.540 and trim to is 2.539, we're talking about .001"? Isn't 2.540 greater than the min trim to length? I checked 2 manuals, Speer and Lyman, Lyman shows a trim to of 2.540, Speer shows 2.539. For cartridge overall length (COL), factory ammo tends to be shorter so it fits in a variety of guns. I am not concerned with published COL. I take 3 factors into condideration when determining COL: 1) that point at which the ogive contacts the rifling, this may determine max COL unless I want to jam the bullets into the rifling 2) max magazine length, this may determine my max COL if I want to feed from the magazine 3) minimum amount of the bullet I want in the case, most folks talk about having at least 1 bullet diameter in the case (not counting the boattail), this could also determine max COL. The shortest of 1-3 determines my max COL in any particular rifle.

If I was trying to duplicate factory ammo, I'd start with the same primer, case and bullet. I'd then weigh the charge and choose a powder from the manual that appears to give similar speeds with a similar charge and seat to same length. Understand though that you may never achieve the published speeds of the ammo manufacturers as most of their #s are bs in my opinion.

JGFLHunter

I wasn't looking for duplicating the actual numbers. I just wondered if anyone used factory specs like COL and stuff like that for their gun. You did answer my question though as it may be shorter to fit in variety of guns. Thanks Wayspr. By no means am I trying to make reloads as they are from factory. Again just wondered.

Ridge Runner

my guess is you won't reach the rifling with a weatherby, they have a lot of freebore to keep velocities up without excessive pressure.
max case length is normaly .010" over the trim to length. the secret to accuracy is consistency, find a load that has a low es, and use a bullet your rifle likes, and it will fall into place. use a powder that has over 90% fill rate of the case with a max load, (retumbo, H4831 (sc), IMR 4831, ect, then tweak the seating depth. you'll get there.
RR

Bbj270

Dads use 117 he Sierra boattails with 62 gr imr 4831. In his mark v with 26" barrel 257 wby

RobertSubnet

I do not try to duplicate factory specs but I do like to chrono factory ammo against my rounds. I am still new to reloading but already my .223 rounds are more consistent than factory ammo.

It has been mentioned here before about the importance of a chrono and I certainly agree. When you look at chrono data, targets and notes it can be very eye-opening.

handloader1

JHFLHunter:

If you want to duplicate Weatherby,s ballistics use Norma MRP Powder, and Federal 215 primers. I have a old Norma Reloading Guide with the same data Weatherby is suppose to use http://www.tiropratico.com/ricarica/...0Reloading.pdf . Good luck.