Home Forums Reloading Big Game Rifles Load for 257 Roberts and 100 TTSX

In my 257 Ackley Improved with 23" bbl.

100gn Sierra

51.0gns H4350.........3215fps.
44.5gns H4895........3165fps
43.0gns RL15..........3019fps
50.0gns IMR4350.....3190fps
45.5gns H380..........3030fps

So I was able to get to the range today and check out the new MagnetoSpeed V3 and shoot the 257 Roberts ladder that I loaded up with CCI 200, IMR 4350 and 120 TTSXs. The chrono was a breeze to set up and seems to have worked flawlessly. I really think I'm going to like it.

Below are the results. I was a bit surprised at the low velocities, given the max load, according to Barnes, is 44.5 gr at 3124 out of a 24" barrel. Even assuming 50-100 fps slower out of the Montana's 22"tube, I was only 1.5 gr off max, after all, and just barely seeing 2700. I'm also puzzled by the fact that in 3 instances, an increase in charge resulted in a decrease in velocity. Primers all looked good, bolt lift and extraction were fine and there were no signs of pressure. Maybe I can get a few opinions from y'all as to what you think....Thanks

IMR 4350
41.2 2627 42.2 2653
41.4 2632 42.4 2654
41.6 2608 42.6 2714
41.8 2642 42.8 2688
42.0 2616 43.0 2715

How many rounds did you shoot at each charge level?

One. Isn't that the standard for a ladder?

That's the problem with such a ladder. Using one shot and assigning much significance to each level isn't cutting it statistically. Each charge level doesn't produce "the" velocity for that charge. One shot is only one sample from a velocity distribution at each charge level. This would be OK if the distribution had zero variance, but it doesn't

Thanks, mathman! Ya know, that very thing has been nigling at my brain, since I just got back into reloading, after a 12 year hiatus. But all that I've read, and videos I've watched, have convinced me that this was the the new and improved way to better loads. Previously, without a chronograph way back when, we used to pick a bullet and powder, and loaded 3-5 rounds each in .5 gr increments until we either found accuracy or pressure or max load. It was more time consuming and expensive, but it worked, most of the time. But it was more a hunt, seeky, find kind of proposition.

So, would you, or any other member, care to share your method for achieving a new load... hopefully in an expeditious and economical way. Or, is the old way still the best.? Thanks.

I do really like that MS V3 !

What were you looking to identify with the ladder? Are you looking for a velocity plateau like I've seen discussed?

I'm confused which is not uncommon. I've never used a ladder for velocity as such. My understanding was that it was to identify a node where the barrel was in a "quiet" place in its harmonics to find an accuracy node. Once you identify that node, you can check velocity and see if it is close enough to the velocity you were trying to achieve. If it is, you can experiment with more or less powder to tweak it.
When I have used a ladder, those are the steps that have gotten me to workable hunting loads in the least amount of wasted components.
So for example, Barnes lists 40.5-44.5 IMR4350 with the 100TTSX. I loaded 2 each of 41,41.5,42,42.5,43,43.5,44,44.5 gr and shot them at a target at 200 yards.( I loaded 2 of each in case I pulled a shot.) The loads at 41.5-42.5 clustered so I loaded more in that range and checked velocity which was acceptable and settled on 42.0 because it gave me sub MOA out of my old Mauser. Done.

Yes, a velocity plateau, or node, which is supposedly an indicator of an accurate charge if I'm understanding correctly. From that point, you'd load multiple rounds and shoot groups to check, verify and tweak for accuracy. Once satisfied with a charge weight, then one could play with seating depth to further optimize accuracy.



You think YOU'RE confused...
Again, what I'm taking away from what I'm reading/seeing is that the harmonic "quiet" place that you refer to, is the result of a flat spot (node) in velocity, where an increase of say, .2 - .4 gr results in relatively no or little change in velocity. That bears itself out with your method of shooting at a target and getting vertical clusters.

So, the 2 differences between your method and mine is that: 1) You load 2 rounds for each charge graduation where I only loaded 1. 2) You shoot at paper and look for vertical clusters to indicate a "quiet"/flat spot,where I shot over a chrono and used velocity numbers to indicate same. After that, the shooting for accurate groups and tweaking would be the same process. Does that sound about right to you?

BTW, would you know what the velocities were for those charge weights you listed for your Mauser? You can see what I was getting from my post above. Although its a 22" barel, I still felt that they were rather low. Just curious as to what you are getting at those weights.

mathman and Blacktailer,
Gentlemen, thank you both for you responses. I appreciate the input.

I loaded 2 each but only shot 1 unless I happened to pull the shot. Bullet pullers are a man's best friend.
When shooting a ladder at a target you don't usually get just vertical strings, your barrel is moving in more like a figure eight so a change in charge might give you a 3-4 inch lateral POI change.
Also you need to shoot a ladder at a minimum of 200 yards (300 is better) so the dispersion becomes obvious.
I'll see if I have velocity figures for the other charges but I may not have shot the ladder over the chrono and/or might not have recorded those numbers.

[/quote]
I loaded 2 each but only shot 1 unless I happened to pull the shot. Bullet pullers are a man's best friend.
When shooting a ladder at a target you don't usually get just vertical strings, your barrel is moving in more like a figure eight so a change in charge might give you a 3-4 inch lateral POI change.
Also you need to shoot a ladder at a minimum of 200 yards (300 is better) so the dispersion becomes obvious.
I'll see if I have velocity figures for the other charges but I may not have shot the ladder over the chrono and/or might not have recorded those numbers.[/quote]

Yeah, I understand that a longer range is more desirable when testing on paper. Unfortunately, I very rarely have access to anything over 100 yds here in Fl. That's another reason for the chrono and my searching for nodes via velocity data.

I don't know what the answer is. I guess, in the end, I'm just going to have to experiment until I land on a technique that gets me where I want to be at the most expedient and economic way possible.

I sure would like to get an answer to my original question as to why my velocities were so much lower than book and others' experiences. I've heard guys mention "slow" barrels. Maybe its just that simple....?

As mathman said, 1 shot doesn't give you much data for velocity but your numbers do seem a little low. My data is with an older Oehler recorded at 15' from the muzzle and is at least 5 shots which as mathamn will tell you is NOT statistically significant but is close enough for minute of deer out to 200 yards or so.
The rifle has a 24 inch barrel but even accounting for the 2 inch difference shouldn't equal 200ft/sec MV. BTW mine is an Adams and Bennet which was Midway's private label which were made by Green Mountain so it isn't a premium by any means.
If I were you I would clean the heck out of it, load up some more rounds, maybe verify your chrono is calibrated and see what happens. Could be it will speed up as you shoot it more.
Depending on your application a few hundred ft/sec isn't going to make a lot of diff to the game anyway.
Good luck!

Five shots isn't bad for velocity, it's standard deviation that really needs a lot more than that.

46.0 - 47.0 gr of Hunter and Fed 210 primer is your huckleberry. Ask MD…

44.0 to 48.0 gr

Thank you sir.

Go to the Ramshot data guide online. They have data for MILD Bob loads using Big Game. When I wanted to work up a load using Big Game & 90 Gr GMXs I used max 100 Gr data from that table as a start and worked up until I got the groups I wanted.

Not for the ttsx, but for 92g hammer hunters…
43.5g IMR 4064

I’ll echo what Jeffrey said about H414. I have a Ruger 77 Liberty model in .257 Bob, and my pet load is 47.0 grains of H414 and a 90 grain Barnes XBT. Have also loaded 100 grain X bullets, and before I switched to Barnes, 100 grain Nosler Partitions and Ballistic tips at 44.5 grains of H414. I did load some Bobs using IMR 4064 for a friend a while back. They were 120 grain Partitions with 35.0 grains of 4064. Not sure if this info helps, but thought I’d offer.

Doc_Holidude

IMR4350