Home Forums Hunting & Shooting Ask The Gunwriters 115 Partitions .525 Ogive

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.