Anyone have clue what the BC is for these bullets on sale at SPS? TIA

If you look on the sale page it should say, if I remember correctly. Wrong again but I came up with a photo of the box that says. 0.389.

The .389 BC is listed for their standard 115 Partition, and it doubt it's that high for the shorter-ogive version, which the SPS ad says "are Overruns of an OEM Partition bullet made by Nosler. Designed to provide a shorter COAL in cartridges such as the 257 Roberts, these have a shorter ogive curve and a slightly more rounded profile than the standard Nosler 25 Cal 115gr partition."
:

I intend to ignore the listed BC and drive them as fast as the weatherby will allow, thus cheating physics like all the guys who say their 270 "is still rising" at 400 yards lol

The BC won't matter much with that combo--but also won't matter much in a .257 Roberts at "normal" ranges.

I've loaded some for my Roberts and a 250 Savage. Just need to get to the range and see how they do.

I loaded up a bunch of them just for grins for my Roberts using H4350 for a MV ~@ 3000 fps. They grouped fine - well under an inch, but then every handload groups fine in that rifle.

I just plan on using them for field practice and save the 110 gr. NABs for hunting.

I would use 0.340 for the 0.525" ogive version on the left. The regular on the right is 0.389

Thanks, that looks reasonable. How did you arrive at that number?

Did some comparing to similar bullets, the 115 TSX is .320, the discontinued 117 Sierra flat base is .351 (Applied Ballistics #s). The TSX .527" ogive and the Sierra .506".

So glad to see this thread. I have bought up a bunch of these myself, even before I knew about the "Roberts" statement (it wasn't on the SPS site when they first marketed these) but they looked perfect for the Roberts to me. and maybe good in my .25-06 too. I have always shot the 100 TSX in the Roberts, and the "regular" 115 Partition in the 25-06. Mule Deer inspired me to buy some 100 TTSX for the Roberts, but I have not yet used them, and then I saw these .525 ogives for cheap on SPS and loaded up on them too. I also have not yet loaded any of them.
If anybody has further educated input on the BC (or even better...tested data), as well as any loads for any of the .25's it could be used in, please share them here.
This thread could turn into a really handy reference for all those who have bought these from SPS.

Thanks to the contributors,
Rex

TRex,

How far do you anticipate shooting them at game?

With all the attention placed on BC these days, due to "long-range hunting," many folks don't realize that there's very little difference in trajectory and wind-drift out to 400 yards between two spitzers of pretty widely differeing BCs.

A good example is the .270 and .308 Winchesters. Both are capable of just about exactly the same muzzle velocity with the same-weight bullets--and despite the higher BCs of .270 bullets of the same make/style, the difference in drop and wind-drift at 400 yards is around two inches.

Which is why I suggested earlier that unless somebody is shooting beyond "normal" ranges with the short-ogive 115 .25 Partition a lower BC won't make any practical difference.

Spot on. This whole BC trip has, well, been a trip...

Mule Deer and EdM,
Good points, and understood. It's just the looneyism in me interested in having a good number to play around with.
In order to calculate accurately enough to show the very good comparison points y'all just made above, wouldn't you need valid BC numbers to input to run the trajectory numbers? Or just shoot side by side but my regular shooting range only runs to 200.

And to answer MD's first question - yes, 400 yards would be about the limit I think I'd shoot my 722 to with these bullets and conditions would have to be good. I think its furthest kill since I've owned it has been 415 yards, but that was by my buddy after I loaned it to him when the "goats" were holding way out in a frying pan flat and his rifle choice that day had been an iron-sighted M1886 45-70, but the weather was making him inclined to go ahead and "make some meat." I've had quite a few kills beyond 300 with that old Roberts but none past 400 myself. And all of those were with a 4X Leupold compact. If I'd had one of those fancy dialing Hubble space telescopes I might have done different, but I just never felt the need.

400 yards is also about the limit I have killed anything with the "normal" 115 NPT in my 25-06 - the furthest with it was 416 paces, back before we had laser range finders.

Still hoping to see some others' range results with this bullet. I've not yet taken them out.

Cheers and thanks again to all,
Rex

No, you don't need "valid BC numbers" to kill big game at 400 yards--which was the point of my previous post.

Other "inputs" easily make as much or more difference, including height of the reticle over the bore, altitude and temperature. I know this from shooting quite a bit beyond 100-200 yards with various rifles.

John,

I get that this is your job just like oil was mine. We can both dive deeply into our work. Very deeply...

Ed,

Yep! If you're a professional, that's what you do.

One of my early role-models in my business was Charley Waterman, who published under the by-line Charles F. Waterman. He explained things simply, yet evocatively, about hunting, hunting guns and fishing (which I also wrote about for many years). He once wrote (very entertainingly) about falling asleep at night while reading a professional journal about bluegill biology--or something like that. He said most of his readers wouldn't find it very interesting--but he did, and simplified it for them.

I am pretty damn sure you did a great job of passing along (and adequately compressing) what you know to the people who worked for you. That's what professionals do, because that's what we care about.

I picked up 200 of these bullets. Not that i needed them but, well, why not. No concern over BC, as I sight all my rifles about 1.5" high at 100yds, and they all mange to hit about the center of the pig silhouette at 300 meters with a top of the back hold.

John, I respect you - well - about as much as it is possible to respect a man, having bought most all your books, read every magazine article of yours I've ever found, and learned so much from you over the years. So please just bear with me a bit on this, and don't go crushing the curiosity you have done a lot to inspire:
I know you don't need "valid BC numbers" to kill game at 400 yards (and you know that is not what I wrote above). I have done so, with and without valid BC numbers. But you presented a specific example comparing the flight path of the .270 Win and .308 Win, concluding their wind drift and trajectory are within 2" at 400 yards. There are two ways to draw this conclusion. The first is actual shooting of 400 yard groups, but we are now talking about a difference of only 1/2 MOA between the centroid of two groups, which for many of us is within the "noise level" of our shooting skill, and of course we would need both rifles to be very accurate to even be able to discern the centroid differences. The second way would be to run the numbers in a ballistics program. The former method has the referenced limitations. The latter requires valid ballistics coefficients as an input variable (along with the others you mentioned, but we must assume those variables are held constant in any reasonable comparison).

That's all I said.

It is perfectly OK for me and others to be curious about the BC of this particular bullet, and that curiosity does not warrant beratement, especially not from a man who has been such an incredible mentor and monumentally contributing mind to the body of knowledge that we only half-jokingly refer to as Rifle Looneyism.
Being curious about the BC of this bullet has nothing to do with whether or not I understand that particular parameter's contribution to killing game at reasonable hunting ranges is trivial. Knowing things like that is FUN, and adds to the enjoyment of our passion.
For the record, I understand that the BC difference between the .525 ogive 115 grain .257 Nosler Partition and that of its "parent" bullet is trivial to killing game effectively within 400 yards. But I would much rather know what that BC difference is than to remain ignorant of it. And there's nothing wrong with that.

I am also very interested in how this bullet performs for others here on this thread, and since it's kind of a one-off bullet, thought this would be a nice place to post those results. When I get a chance to run it in my Roberts I'll share what I learn too.

Most Respectfully,
Rex

Rex,

Sorry that I offended you.

You can actually come up with a pretty good idea of functional BC out to 300-400 yards by chronographing a handload both at the muzzle (or 10 feet in front of it, depending on the chronograph) and then again at 100 yards (or 100 yards, plus 10 feet, then comparing the velocity loss to other bullets with different BCs. Probably the best way is to use a ballistic program, adjusting the BC input until the velocities match your results.

This is pretty much how many companies come up with closer-range BCs, because it's close enough for shooting at what many hunters consider "normal" hunting ranges. It's not valid for longer ranges, because BC isn't the written-in-stone number many shooters believe, but certainly would work well enough at the distances you mention.

Just yesterday I shot this bullet from my Ruger Hawkeye 257 Roberts.
The temperature was 74F, with a slight wind from SW. (today its 41F
raining with wet snow predicted to follow tonight and tomorrow.)
I sighted in last week in back of my house at 1 1/2" hi at 100yds. First shot at
a chuck was a little left (misjudged the wind?). I waited about 10-15
minutes and he came about halfway out of the den. Next shot DRT
range 326 yds. Big old male, really destructive round. Think I'll
get another couple hundred of these bullets. SPS says 'blems',
but I can't see anything wrong with them. Load data;W-W case
IMR4350 -45.5 grains three five shot groups 1.1" 1" 1.3" with
6x scope. Gun is capable of more accuracy than this old
shooter.
Old Cuss

Nice shooting! And thanks for the load.
Rex

tag

what a dumschit

Thanks ribka.
What is your estimate of what the actual BC ought to be? And how did you arrive at it?

what a classy comment...

I just shot some out of my Roberts. W760 and R19 gave the best results. I went to order some more but for the life of me can't figure out how to get the military discount applied. Anybody else tried this??

Should be automatically applied once you've logged in. I'm assuming you've been verified. Been a while since I last ordered from SPS but you might not see it until you go all way to the final purchase screen.

As I recall, early on, I had to send them a DD214 to get verified (or some similar process) and then it auto-applies when I log in. Sometimes "sale" items don't get the discount. And for a brief period over a year ago, it was like they dropped my veteran status, but a phone call got it reinstated with no more paperwork.

Hope that helps,
Rex

I just tried. entered my name, active duty date, and discharge date. And it says i'm qualified

I'm verified. Got an e mail from sheerID.com their military verification team. Maybe it takes a day or so.

Glad to hear it worked out Brothers.
Outfits that respect our service are much appreciated. A win-win for us all.

I wouldn't say it's worked out yet. Logged on this am and the discount wasn't available. I'll probably try calling them tomorrow.

I haven’t tried to order lately, but the last time I tried to order a “SALE” item, it prompted me that double discounted pricing was not available. Lowe’s has become the same way. If it’s on sale, no additional vet discount. At least at store near me. Happy Trails

Hammer bullets go by the honor system for vet and first responders. If you say you are than you get the discount. I wonder how long that will go on?

I tried these .525 ogive 115 NPTs out today in my .257 Roberts and I was very pleased!
My rifle is an old Rem 722, with a 6X Leupold M8 scope, and a repurposed short-action Rem 700 ADL beechwood stock I fit to it (floated after the first 2" of barrel shank), since its original stock had been cut back very short at some point in its life.
I checked the fit of the ogive to my rifle's throat and was happy to see that when seated to .025" off the lands (2.81" COAL), the mouth of a case trimmed to the standard 2.223" lands smack in the center of the cannelure. It seems a perfect fit to this cartridge (I did not crimp my test rounds).
Mule Deer made a recommendation for Ramshot Magnum in the Roberts over on the Sisk thread on how much he loves Big Game, and I decided to try out Magnum, since I have 10 pounds of it on hand.
Case full of Magnum!
I did not use anywhere near as much as was referenced above but I still got a lot more velocity than I expected.
I couldn't find any pressure-tested data for the 115 NPT with Magnum, but Ramshot lists a max of 51.1 gr with the 117 Sierra, providing 2900 FPS with only 56.5K PSI. With the slightly lighter bullet, +P cases, and a rifle capable of handling 65K PSI, I felt pretty comfortable going a half grain over that as max for my little first test run. Here's the load:

Older, once-fired Federal +P .257 Roberts cases (from the days of the red primer sealant), old white-box CCI 250s, the .525 Ogive 115 gr .257, and 49, 50, 51, and 52 grains of Ramshot Magnum. COAL was 2.81", putting the bullets .025" off the lands.

3-shot groups are at 100 yards. Temp was 60F. Velocities surprised me:
49 - 2910 FPS, SD 11, 1.16"
50 - 2984 FPS, SD 15, 1.07"
51 - 3019 FPS, SD 6, 0.80"
52 - 3071 FPS, SD 8, 0.90"

I almost didn't fire the last three rounds due to the exceptional velocities, but there were just no other pressure signs whatsoever. I used my little finger to open the bolt from the firing position on all the shots and they all felt the same, but there is no getting around the fact that those are some way higher speeds than I am used to! But, then again, the highest published data for the Roberts I have run into is 58K PSI. I will try the 51 gr load again, and I will use the same cases again as today's 51 and 52 grain loads to be sure I keep tight primer pockets. Mule Deer got around 2950' with Magnum with the 120 Partition so I reckon 3019' with the 115 is not too out of line. I also have some new Fed +P cases and can do a check of CHE as well - not the end-all, but it's one more piece of data to consider.

If somebody here can run Quickload, I can measure the parameters needed for the run - just PM me what is needed. I'd probably need to convert the COAL to what it would be with the "normal" 115 NPT loaded with its base at the same point as the .525's base, since I doubt Quickload has the .525 in its database.

Looking forward to reading what others learn about loads for this bullet.

Cheers,
Rex

[Error post]

Still puzzling over the higher than expected velocity, I checked the diameter of these SPS partitions. It seems fine at .2568". I tried slipping one into a fired case mouth and it took a pretty good bit of force. So I checked the diameter of the Barnes 100 TSXs that I've been using since I first got this rifle 15-20 years ago, and they are .2565" - not really enough to matter I'm thinking, but I could be wrong. From checking case mouth variance, I already knew my case mouth walls run .014-.015", which is a little on the thick side, so I think I will give them a light turning and see if that gives a little smoother slip fit of a bullet into the fired case after the next rip to the range. Perhaps the neck is being pinched a bit in the chamber.
BTW, I deprimed with a Lee universal deprime die, sized the cases using an RCBS FL die with the decapping/expanding rod removed, then expanded the necks with a Sinclair expander mandrel, which put them only .002-.003" under bullet diameter prior to seating the bullet, if that makes any difference.

Happy shooting,
Rex

Rex, that is outstanding information. I’m in the midst of developing loads for this exact bullet in my .257 Rob & 25-06 and value your efforts a lot. I’ll make sure to add my results to this thread next week once this rain stops in VT and I can get out shooting. Somehow (I blame @Dirtfarmer :-)) for encouraging the purchase of what looks like 1600 of these little .525 115gr .257 devils.

Happy that you got velocity & accuracy in one package.

I had 250 qty arrive today from the SPS. Looking forward to trying them in the 2.8” Rob.

Brad, I’m sure you’ve shot 115’s in a .25 before & know what a little devastator it is. Hard to tell the difference between this bullet and a .270/130 & unbelievable the price that SPS has them for. Let us know what you do with them.

So I measured these against the lands in my Kimber 257 Rob with 2.835” magazine. This bullet touched the lands at 2.825”. Fantastic. My guess is they’ll bughole.

Best part about the 115np is that it kills like a big dog. Gack aside its just flat out awesome. Elk, deer and a bear. Done ..

But Brad, you can tell by looking at them, they have the BC of a ping pong ball. Larry will no doubt be around to tell you that they can't hang with those super bullets (e.g. BC .600 or better) They'll probably just bounce off a whitetail at 75 yards...

If they make it to 75 yards....

OMG, something I'd not thought of!

I live in fear of LNR's (Larry's Narcissistic Rants)...

not.

Thought I’d update the thread - 82 in stock at SPS as of 10 mins ago.

Thanks Pints, but I cut myself off at 600. I just couldn't stop - kept adding a bag or two every time I put an order in with them.

I'll have some updates to my trials with them in the .257 Roberts soon. I'm loving them.
Rex

Hello all.
I neck-turned a thousandth off of nine cases and loaded up the same 51/Magnum, CCI 250 load I posted earlier, and it did not improve accuracy nor reduce velocity. It turns out there was nothing wrong with my cases with the thicker neck walls of .014-.015". After the fact, I discovered that as I withdraw the bolt slowly on the Rem 722 Roberts, intending to catch the case before it is fully ejected, the ejector plunger spring has so much force behind it that when the case mouth clears the rear of the barrel, and snaps right until it hits the inside of the receiver, that puts a tiny little barely noticeable dent in the case mouth. This was the source of the "tight" case mouths I found earlier on my untuned brass. I took a loose one of the .525 ogive partitions to the range with me, and indeed, it did slip easily into the turned case mouths (once I pushed that little dent out of the way), but now knowing the dent was there, it fit the once fired mouth of the unturned brass even better, once I smoothed out the tiny dent.
velocity averaged around 3040 with 51/Magnum in the turned cases and groups averaged 1.24".

The next week I went back with the unturned cases with the thicker walls, loaded with 50.2, 50.5, and 50.8 grains of Magnum. Same CCI 250, and same OAL of 2.81" which puts the partition .025" off the lands. Results:
50.2gr - 2990', 0.88" group, SD 29
50.5gr - 3023', 1.04" group, SD 31
50.8gr - 3020', 0.79" group, SD 22

I'm puzzled by the big velocity spreads, and am wondering if I am getting some squirrely readings off the 35P. I'll change the battery before the next range session and see if that makes a difference.
But overall it looks like that 50.8 grain charge may be a sweet spot. I might try a couple different primers and maybe seating a little forward or back, but that is a pretty darn good load there for a rifle that turned 70 years-old this month.

Anybody else had a chance to work with these and have more to share?

Cheers,
Rex

Outstanding, Rex! I’ll keep an eye out for your data.

as i post this i am next to my nice buck antelope mount i shot at 650 + yards, i measured the distance afterwards but kinda knew before i made the one shot in the alfalfa field i have hunted many times in the past on this private property.
i shot this antelope 20 some years ago before B.C. was a big deal with a hot 257 Weatherby mag. handload 100 gr. Nosler Partition laying down with a bi-pod, i just held about a foot high. i kinda know where to hold when i use this cartridge out west or in my home state too = its called Kentucky Windage. " you don`t always have the time to check distance or B.C. `s when hunting " Pete53

Went ahead and ordered a few bags of each weight. I load for two 257 Roberts and two bolt action 250 Savages with the faster twist. Not many bullets available right now, especially at that price. I've never worked with heavier than 100 grain bullets in either cartridge, we'll see what these rifles think of them.

Sounds like fun ahead for you Ole_270. Be sure to post what you learn back here.
I'll be back at the range on Wednesday to follow up with my Roberts.

Cheers,
Rex

I bought 500 of these over the last couple of months and will try them in my 257 Rob after seeing the information on Ramshot Magnum in this thread, a powder I've not found much use for previously. I also have a recent Miroku 1885 Trapper at my local smith being rebarreled to 25-35 Win that I am anxious to try with this bullet on mulies and whitetail. I'm hoping that with AA 2460 and a 24" barrel, I can get to 2500 FPS or better. Haven't settled on the barrel length yet and might even go up to 26". Regardless of the eventual length, I think I should be able to stay well above the 1800 FPS impact velocity Nosler recommends for the Partition using this mild cartridge at the ranges I expect to shoot. I should have plenty of bullets to find the right load once I get the rifle back.

SPS also has or had .257 120 Partitions with a cannelure that I picked up and will try those in the Rob and 25-06. At that price, there was no reason not to get a couple hundred.

I can keep the latest range report short. I decided to try different seating depths than the .025" off the lands that was getting me good consistent 3/4 MOA-ish groups at over 3000 FPS in the .257 Roberts, with 50.8gr/Magnum. I tried .005", .025", and .050" off the lands. Guess what shot best - yep, the same .025" off I have been using since I started messing with these bullets and Magnum in the .257R. This week's group was the best yet.
I think I may be done with this load development effort.

Cheers,
Rex

I'd say you are GTG! We will look forward to positive reports come deer season!

Looks like you're right. The only loose thread I needed to tie up was to shoot this load in some new, unfired Fed cases, in order to take a case head expansion (CHE) measurement, to back up my assessment of no pressure signs. I got some more data on the load in the process.
Recapping, the load I have settled on is:

.525" Ogive 115 Partition
Older stock Federal .257 Roberts +P cases
50.8 grains of Ramshot Magnum
Fed 215M primer
OAL of 2.81", which places the bullet .025" off the lands.

I have shot five 3-shot groups so far at 100 yards with this load. Largest was 0.94", smallest was 0.75" average of 0.81"
A composite of today's 9 rounds have 8 inside 0.93", with one outlier which opened the 9-shot composite up to 1.53". That outlier, BTW was the source of the 0.94" 3-shot group alluded to above. Except for that group today, all 4 other groups with this load were 0.75" to 0.79" - very consistent.
Velocity with the Fed 215M is smack on 3000 FPS. In earlier tests with some 25-30 year-old CCI-250s, I got about 20-25 FPS faster.

I had a box of N.O.S. Federal .257 Roberts +P cases, of the same vintage as the ones I've been working with, and used these today to check CHE. Average CHE of new brass was .00038". This is pretty good. Max loads typically show .0005" or more. This supports my observation that there seem to be no pressure signs with this load.
Ramshot has no data for the 115gr, but lists a max of 51.5gr/Magnum with the 117gr SGK, at 56.5K PSI, which comports well with my feel and measurement.

Hope this helps someone else get a good load with this bullet too.

Cheers,
Rex

I ran the above load again this week for a follow-up CHE check.
I shot two 3-shot groups which measured 0.70" and 0.61". I fired off the rest of my loads over the first two 3-shot groups, 4 more on the first and 2 more on the second. The composite of all 12 rounds was 1.27".
I'd reloaded the now once-fired cases I had used for the previous CHE check to see if there was any additional expansion over the .00038" average I measured after their first firing. Each case measured exactly the same after its second firing as it had after the first - no additional CHE. This is how I like to see CHE track on a good safe long-term load.

Cheers,
Rex

Thanks for the heads up. Been looking for some Partitions for my Whelen and this popped up. Guess the Roberts will get them first. Time to hammer some deer.