Have a Savage model 111 in 257 Roberts. Switching to H4350, and at max load exceeded listed book velocities by 175 FPS, according to 3 different source books. Chrony gave repeat results for 2 other rifles I was double checking, no reason not to believe chrony. I know it usually takes a gross amount of excess pressure to show signs, and none were present. I am some say overly anal, and I know my scale is correct. Got 2954 FPS with Sierra 117 gr HPBT. I am not a speed demon, but kinda like the bonus velocity. Thoughts.....

Outside of a strain gage, velocity is the best indicator of pressure there is.

Are you using roberts or roberts +p load data?

Mmmm, spicy! I wonder what your brass life will be. I don't have the where-with-all at the moment to do a rudimentary calculation, but, as bucktail was alluding to, or attempting to, I'm sure you're far past book pressure. It doesn't sound unsafe, but I wonder if brass life will suffer. The Roberts is not a high-pressure affair, so there is a lot of room between book max and 'dangerous'. A lot of room.

When I deal with a 'problem' like that, my solution is to load 5 pieces of brass, 5 times and keep an eye on the brass and primer pocket for any signs of problems...

if they don't show any and the 6th reloading still gives me a tight primer pocket, I call it good...

a Roberts is like a 6.5 Swede... American load data is pretty anemic....so in a modern rifle meant to take SAAMI spec pressures on other calibers...results will be a lot higher than the average guy may be use to...

I let the rifle and the brass tell me what that action likes, not some book giving out general info...rifle results have varied from books, in both directions... able to take a lot more than load data listed, or had issues with starting loads alone...

.....................No reason for the concern. Your rifle is NOT anyone else's rifle, which include any test rifles used for the reloading manuals. As long as the accuracy meets your standards then fine.

As the 'ol saying goes....."Don't look a gift horse in the mouth."................

I agree with this. There is no "free" velocity, other than with additional barrel length.

If your rifle is generating higher velocity, then either the components or slight dimensional differences are likely responsible, but all else being equal, one rifle doesn't have higher velocity than another. If it's faster, then the pressure is higher, for whatever reason.

Components, like the rifles themselves, have a manufacturing tolerance, and if they "stack" in the right direction, you'll see an increase such as what is stated in the OP.

As noted, the Roberts is somewhat of a low-pressure round and the Savage is a strong action, so the additional velocity may not have you in "dangerous" territory.

Two examples come to mind in regards to exploring the action's strength, in this case the Marlin 336, and that would be the .35 Remington which can be safely loaded to gain 200 fps, and the .45-70, which can be loaded to a completely different level than the original load.

All my manuals have only 257 Data. No +P data.

So I looked up the roberts in a couple of different manuals plus the online one for Hogden. Most of them show at least 100 fps over book max with H4350 and a 117. The Speer had +p, but 120's and no 117, and IMR 4350 but no H4350. Book max was 2800 there. The one exception is the Hornady 5th edition. It had book max at 2900 for a 117 with H4350. I'd take that one with a grain of salt though. Their Roberts improved was slower than their Roberts with the same powder and bullet. If I couldn't find better +p data to support the velocity, I'd back it down. I wouldn't be overly concerned about it, but there's no animal in the world that will know the difference if you don't tell them.

I wonder if a phone call to the guys at Hodgdon might help end the mystery...

Match their velocities, match their pressures. Exceed their velocities, exceed their pressures.

It's that simple.

Not uncommon for a like load to have less velocity in an AI. It has more space.

oldotter,

As Seafire mentioned, most .257 loading data is anemic, and for no good reason other than that's the way Remington loaded the cartridge originally, because that's the level where Ned Roberts got the best accuracy with the bullets of the day. Even +P data isn't quite up to .30-06 SAAMI levels, which don't push any envelopes.

I usually load 115-117 grain bullets to 2900+ fps, and have had no problems others than with one lot of VERY soft Remington brass. With most Remington and all Winchester cases I expect 2900 or a little more.

I have called hodgdon several and they have been very helpful and friendly. But i wish I could talk to them face to face. On pressure matters, with a T3 Lite 6.5x55, they wont give me anything more than what is published. I could tell the guy knew there is more to be had, and would have liked to share, but couldn't. I understand his position and would hate to be in it.Had same problem with reduced loads for 223 using SR-4759. Was trying to extrapolate 222 and 222mag data. They were very cautious but did sort of give me a wink and nod.

This re-enforces what I thought. Knew the 257 Roberts had more potential, without compromising safety. Thanks MD / Seafire