7 rem mag-140 partition.

I acquired 300 7mm nosler partitions for free. Initially I planned to run them through a 7 08. I ended up with a 139 interlock load that I am happy with first. Got to thinking, pushed hard in a rem mag they would probably hit a Texas whitetail like a thunderbolt. Up till now this rem mag has been easy to load for with most any 160 as well as a 150 SGK. No such luck with the 140 partition. It has shot a few 1"-1 1/4" fluke groups but nothing repeatable. 2"-2 1/2" is about how they shoot. Before anyone says it, I agree the big 7 is at its best with 160's. It's also hard to complain about "free". Any ideas to try to tighten them up? It may just be my rifle isn't going to get along with them.

Yes, what powders (and load specifics) are you trying with the Partitions? I need more info on what's not working, to help guide you to what might help.

Tried both H and IMR 4350. Nosler brass. Also tried IMR 4831. CCI magnum primers. Loaded .020 from lands. Measured from ogive with Hornady comparators. With all 3 powders I started 7% under nosler advertised max and worked up to advertised max. Best combo was 64.5 gr of IMR 4350.

0.5 gr increments. 26" barrel

Slower powder, and more of it, perhaps.

Thanks fireman. With both IMR powders I got ejector swipes and pulled the last stuff. With the H no signs of pressure and no signs of decent accuracy. I figured with the 140's the faster powders would have worked but they did not.

I found increased accuracy once I approached 69g RL22. Obviously work up.

Don't remember the amount of powder but the guy that taught me to reload used IMR 7828 with 140's in his 7mm rem Mag.

Jgraider, did you give them much jump with the R 22?

On a Partition, they are not seating depth sensitive, so a good jump is fine. Every belted mag cartridge shoots best at max or just over max powder charge with a slower burning powder. The 4831 and 7828 powder burn rates would be an ideal spot to play with a 140 grain. .5 grain increments might be too much of a jump, IMO. Somewhere around the 66-67 grains should be good. 4350 powder will work, but it's a little fast burning for your combo. Plus, the Partitions I have played with shot ok, but never amazingly tight. I'm sure it's possible, but the groups I always saw with them were just ok for a hunting load.

Also, what did the groups look like? As in the pattern of the groups- stringing diagonally, random open groups, 3rd, 4th, 5th shots doing the same thing from each group? If it's a hunting rifle with a thin barrel, you have to read what the groups are telling you when you shoot them. Pay attention to the patterns and if certain shots are fliers. Some hunting rifles are great for 2-3 shots, but shots 4+ are more open. That's often common on a hunting rifle that is unbedded and barrel maybe not free floated.

Thank you for your reply Chad. Groups are big fat and round. No stringing. As for the rifle it is a shooter. Rem 700. Action is bedded and has pillars. Magnum contour barrel floated. 9.25 twist. Timney trigger. Groups have all been shot with hunting accuracy in mind. 5 minutes between shots and not letting the barrel heat up. Giving it every chance. Your experience with the rem mag mirror mine as far as usually liking to be approaching max pressure. That was why with the first two powders I tried, I worked up till I got pressure signs. I tried the 4350 because nosler showed it to be close to the top velocity wise with a 140. I guess just keep going slower with the powder till I hit. I do remember when I first started loading for the Rem Mag, 7828 under a 175 was "the load". Nosler showed VV-N165 to be the most accurate with their 140's. It also showed a little over 2900 fps as max. Not exactly magnum velocity with a 140. I'll shoot them out of the 7-08 before I burn 65 grains of powder for 2900 fps with a 140. My rifle likes H 4831 and have A good supply on hand. I'll give it a try next and see what happens. After that I guess RL 22 or IMR 7828, which I will have to go buy.

I was not getting good groupings with the Accubonds on either 7mm or 300 Magnums until I was at max pressure or a tad over. 7mm Mag with 160 AB at 3100 fps. ( Retumbo ) and 300 Win Mag with 180 AB at 3180 fps. ( RL-22 ) Try to increase your speed, it should tighten up but watch your pressure.

Ok. Are you using all the same head stamp brass (one brand, all the same)? If groups are big, fat and round, then it's not there yet. 4831 should be a good one to go with. I don't use any VV powders, since they are more expensive and harder to get.

In my experience... and I shoot a lot of partitons, they are seating depth sensitive, in that they do like a jump. I have never developed a load for them that shot worth a darn that didnt have a significant jump.

^^ Correct.

Chad, yes. Using 50 pieces of Nosler brass that I have obtained stellar accuracy in same rifle with another load.

Tackdriver and Red Chevy, thank you both for your insight. Useful information on both counts.

I've usually found Partitions to shoot well from 0.025 to 0.030 inch off the lands.

Thank you sir.

I loaded them to mag box length, which still put them app .050 off.

Thanks Jgraider. getting ready to take another stab at em.