Home Forums Hunting & Shooting Ask The Gunwriters More Partition Questions

OK, silly question time.
I just got my 7mm 150 PT's delivered from SPS and they have the cannelure. The previous box that I bought locally doesn't have this. Is this something that's changed or do they offer different versions?
Does this line up with the partition for reducing pressure?
Last question (for now ) When comparing, say, the 140 & 150 7mm partitions, is the extra weight behind the partition or spread evenly? I asked Nosler and they couldn't tell me.

Sorry for the questions, but I'm a Partition newby.

Thanks!

All other factors equal, a Partition will produce slightly higher pressures and velocities than standard bullets. They are harder to engrave, and that increases the time before the gas can expand into the barrel.

That cannelure is likely there because Nosler was making bullets for someone's loaded factory ammo (like Federal Premium for instance)and they just had an overrun or blemish. I pay no attention to it in my reloading.

No answer for your other questions except that the partition is likely the best hunting bullet made IMO.

The cannelure is simply there because some other company ordered the bullet with it, usually for crimping in factory ammo. It does not aid in pressure reduction.

Sometimes the extra weight is behind the partition, sometimes not. Each Partition bullet is a design unto itself. The only way to know for sure is to section the ones you are comparing to see what is inside.

Remember, these are seconds of whatever production run they were producing at the time. Some will have cannelures, other runs of the same bullet won't.

No, the cannelure is where a crimp will be to produce SAAMI spec ammo. Obviously this run of seconds you bought were intended for loaded ammo. Probably a third of my Partition seconds have cannelures, and I treat them the same as those without.

Generally, the partition will be at a point proportional to the bullet weight. In other words the 150gr partition will be slightly forward of the 140gr, but the proportion of lead in the front and back of the bullet will be the same for both bullets.

Although, there are some Partitions that will have a heavier jacket in front and/or the partition moved further forward, changing the "normal" proportions of the lead core.

I don't know why Nosler is so coy with that kind of info, but they usually are...........

Casey

You are absolutely right, JG. It's still the standard by which all others are judged, which is amazing considering how long it's been around. I don't use them much anymore but have always considered them well-suited for anything I'd want to shoot. They'll open on soft tissue at still penetrate through the heaviest of bone/muscle.

Put me in this camp too.

do yall have good luck getting them to group?

I've shot them out of 4 different rifles, 3 of which were pretty easy to find "accurate" (ie 1.5" groups) using other projectiles (Sierra GK, Nos BT, etc).

....but I've never found a single Partition load that shot really well in any of those rifles. Most were ~2.5" groups or worse.

I've used 140's and 150's in 7mm-08

180's in 300WSM

225's in 358 Win

and 180's in 308

none shot real well.

am I all alone in this experience? do I need to change brands of chewing tobacco to get them to shoot right?

You're doing something wrong:



I guess my skinny barreled rifles shoot 1.5" groups with partitions:


Even my old 100 year old rifle shoots them well enough:


My 300WSM liked the 180gr. partition. Of course these were "blemished" bullets:


375H&H likes them:

That 06 I got from bsa shoots 180 partition pretty damn good!

Yes it does, that 6 digit classic is a thing of beauty. That rifle is not finicky at all though.... Kind of like the 30-06 I sold to EricM. That one would shoot lights out too...

I don't know why I used rl22 in it with the 180's but it shot great so why mess with it😁..

Your not alone. I had only one rifle that liked them. It was a 1975 Garcia/Sako .270 Win. and it would shoot 5 shot one inch groups of 130 w/ 60/H4831 and 150 w/ 58/H4831.

All other rifles I've tried them in since, give results like you describe.
Lately, I don't even bother with them anymore.

I usually don't have any issues getting them to group well enough for a hunting rifle.

My experience shows accuracy with Partitions is more dependant on reducing runout than most other hunting bullets such as TSX/TTSX's, NBT's, Game kings, Interlocks,etc. As long as my ammo's runout is 0.005" or less I usually have no problem getting 1.5" groups or less @100yds. Several of my rifles do better consistently shooting 1" for 5 shots and I have one that I hit the lottery with that will maintain 0.5" for 5 shots @100yds (.30-06 w/165gr and a stiff charge of IMR4350).

I think a bit of clarification is needed with Partitions. I've had few rifles where they were the most accurate bullet. In most situations they aren't. It depends on your purposes. I'll take 1.5" Partition groups over a subMOA 'non-premium' bullet everyday and twice on Sunday. It's more important what happens when the bullet arrives than it getting there fractions of an inch closer to the center of the target. Use 400 yards as an example. A 1.5" Partition will land bullets within 0.75" of aim point at 100, 1.5 at 200, 2.25 at 300, 3 at 400. A 0.5" gun does 0.25, 0.5, 0.75, 1.0 at same distances. Basically you gain 2" closer to your true aim point. Even deer lungs will catch a 1.5" Partition at 400 yards. Caribou, elk, moose make it certain. And that's all predicated on 1.5" Partitions. I can normally get them to 1 MOA without much problem.

Bottom line: I'll take terminal performance inside the animal and not sweat that I could have been an inch or 2 'closer' to the center of the lungs. You put a Partition anywhere close to the middle of the lungs, get the knife out.

A couple tricks. Try a slightly faster powder, try seating them at 0.010, 0.020, 0.040. Most of my loads all Ito one of those groupings.

A lot of guys try to load partitions like mono bullets. Partition usually don't like a lot of jump

When I have had problems(rare), it's been rifle issues, or I failed to watch runout.


But yeah Partitions are tough to get to shoot.....I'm trying to recall a rifle that did not shoot them well so that I was forced to use other bullts, but can't recall one right now.

I've given up on partitions and gone to Accubond and TTSX and have been completely satisfied.

I have always gotten good groups out of them, accubonds better

The main reason that I shoot more AccuBonds than anything else, now.